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/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_SHAPE_H
#define B2_SHAPE_H
#include "Box2D/Common/b2BlockAllocator.h"
#include "Box2D/Common/b2Math.h"
#include "Box2D/Collision/b2Collision.h"
/// This holds the mass data computed for a shape.
struct b2MassData
{
/// The mass of the shape, usually in kilograms.
float32 mass;
/// The position of the shape's centroid relative to the shape's origin.
b2Vec2 center;
/// The rotational inertia of the shape about the local origin.
float32 I;
};
/// A shape is used for collision detection. You can create a shape however you like.
/// Shapes used for simulation in b2World are created automatically when a b2Fixture
/// is created. Shapes may encapsulate a one or more child shapes.
class b2Shape
{
public:
enum Type
{
e_circle = 0,
e_edge = 1,
e_polygon = 2,
e_chain = 3,
e_typeCount = 4
};
virtual ~b2Shape() {}
/// Clone the concrete shape using the provided allocator.
virtual b2Shape* Clone(b2BlockAllocator* allocator) const = 0;
/// Get the type of this shape. You can use this to down cast to the concrete shape.
/// @return the shape type.
Type GetType() const;
/// Get the number of child primitives.
virtual int32 GetChildCount() const = 0;
/// Test a point for containment in this shape. This only works for convex shapes.
/// @param xf the shape world transform.
/// @param p a point in world coordinates.
virtual bool TestPoint(const b2Transform& xf, const b2Vec2& p) const = 0;
/// Cast a ray against a child shape.
/// @param output the ray-cast results.
/// @param input the ray-cast input parameters.
/// @param transform the transform to be applied to the shape.
/// @param childIndex the child shape index
virtual bool RayCast(b2RayCastOutput* output, const b2RayCastInput& input,
const b2Transform& transform, int32 childIndex) const = 0;
/// Given a transform, compute the associated axis aligned bounding box for a child shape.
/// @param aabb returns the axis aligned box.
/// @param xf the world transform of the shape.
/// @param childIndex the child shape
virtual void ComputeAABB(b2AABB* aabb, const b2Transform& xf, int32 childIndex) const = 0;
/// Compute the mass properties of this shape using its dimensions and density.
/// The inertia tensor is computed about the local origin.
/// @param massData returns the mass data for this shape.
/// @param density the density in kilograms per meter squared.
virtual void ComputeMass(b2MassData* massData, float32 density) const = 0;
Type m_type;
/// Radius of a shape. For polygonal shapes this must be b2_polygonRadius. There is no support for
/// making rounded polygons.
float32 m_radius;
};
inline b2Shape::Type b2Shape::GetType() const
{
return m_type;
}
#endif
/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "Box2D/Collision/b2BroadPhase.h"
b2BroadPhase::b2BroadPhase()
{
m_proxyCount = 0;
m_pairCapacity = 16;
m_pairCount = 0;
m_pairBuffer = (b2Pair*)b2Alloc(m_pairCapacity * sizeof(b2Pair));
m_moveCapacity = 16;
m_moveCount = 0;
m_moveBuffer = (int32*)b2Alloc(m_moveCapacity * sizeof(int32));
}
b2BroadPhase::~b2BroadPhase()
{
b2Free(m_moveBuffer);
b2Free(m_pairBuffer);
}
int32 b2BroadPhase::CreateProxy(const b2AABB& aabb, void* userData)
{
int32 proxyId = m_tree.CreateProxy(aabb, userData);
++m_proxyCount;
BufferMove(proxyId);
return proxyId;
}
void b2BroadPhase::DestroyProxy(int32 proxyId)
{
UnBufferMove(proxyId);
--m_proxyCount;
m_tree.DestroyProxy(proxyId);
}
void b2BroadPhase::MoveProxy(int32 proxyId, const b2AABB& aabb, const b2Vec2& displacement)
{
bool buffer = m_tree.MoveProxy(proxyId, aabb, displacement);
if (buffer)
{
BufferMove(proxyId);
}
}
void b2BroadPhase::TouchProxy(int32 proxyId)
{
BufferMove(proxyId);
}
void b2BroadPhase::BufferMove(int32 proxyId)
{
if (m_moveCount == m_moveCapacity)
{
int32* oldBuffer = m_moveBuffer;
m_moveCapacity *= 2;
m_moveBuffer = (int32*)b2Alloc(m_moveCapacity * sizeof(int32));
memcpy(m_moveBuffer, oldBuffer, m_moveCount * sizeof(int32));
b2Free(oldBuffer);
}
m_moveBuffer[m_moveCount] = proxyId;
++m_moveCount;
}
void b2BroadPhase::UnBufferMove(int32 proxyId)
{
for (int32 i = 0; i < m_moveCount; ++i)
{
if (m_moveBuffer[i] == proxyId)
{
m_moveBuffer[i] = e_nullProxy;
}
}
}
// This is called from b2DynamicTree::Query when we are gathering pairs.
bool b2BroadPhase::QueryCallback(int32 proxyId)
{
// A proxy cannot form a pair with itself.
if (proxyId == m_queryProxyId)
{
return true;
}
// Grow the pair buffer as needed.
if (m_pairCount == m_pairCapacity)
{
b2Pair* oldBuffer = m_pairBuffer;
m_pairCapacity *= 2;
m_pairBuffer = (b2Pair*)b2Alloc(m_pairCapacity * sizeof(b2Pair));
memcpy(m_pairBuffer, oldBuffer, m_pairCount * sizeof(b2Pair));
b2Free(oldBuffer);
}
m_pairBuffer[m_pairCount].proxyIdA = b2Min(proxyId, m_queryProxyId);
m_pairBuffer[m_pairCount].proxyIdB = b2Max(proxyId, m_queryProxyId);
++m_pairCount;
return true;
}
/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_BROAD_PHASE_H
#define B2_BROAD_PHASE_H
#include "Box2D/Common/b2Settings.h"
#include "Box2D/Collision/b2Collision.h"
#include "Box2D/Collision/b2DynamicTree.h"
#include <algorithm>
struct b2Pair
{
int32 proxyIdA;
int32 proxyIdB;
};
/// The broad-phase is used for computing pairs and performing volume queries and ray casts.
/// This broad-phase does not persist pairs. Instead, this reports potentially new pairs.
/// It is up to the client to consume the new pairs and to track subsequent overlap.
class b2BroadPhase
{
public:
enum
{
e_nullProxy = -1
};
b2BroadPhase();
~b2BroadPhase();
/// Create a proxy with an initial AABB. Pairs are not reported until
/// UpdatePairs is called.
int32 CreateProxy(const b2AABB& aabb, void* userData);
/// Destroy a proxy. It is up to the client to remove any pairs.
void DestroyProxy(int32 proxyId);
/// Call MoveProxy as many times as you like, then when you are done
/// call UpdatePairs to finalized the proxy pairs (for your time step).
void MoveProxy(int32 proxyId, const b2AABB& aabb, const b2Vec2& displacement);
/// Call to trigger a re-processing of it's pairs on the next call to UpdatePairs.
void TouchProxy(int32 proxyId);
/// Get the fat AABB for a proxy.
const b2AABB& GetFatAABB(int32 proxyId) const;
/// Get user data from a proxy. Returns nullptr if the id is invalid.
void* GetUserData(int32 proxyId) const;
/// Test overlap of fat AABBs.
bool TestOverlap(int32 proxyIdA, int32 proxyIdB) const;
/// Get the number of proxies.
int32 GetProxyCount() const;
/// Update the pairs. This results in pair callbacks. This can only add pairs.
template <typename T>
void UpdatePairs(T* callback);
/// Query an AABB for overlapping proxies. The callback class
/// is called for each proxy that overlaps the supplied AABB.
template <typename T>
void Query(T* callback, const b2AABB& aabb) const;
/// Ray-cast against the proxies in the tree. This relies on the callback
/// to perform a exact ray-cast in the case were the proxy contains a shape.
/// The callback also performs the any collision filtering. This has performance
/// roughly equal to k * log(n), where k is the number of collisions and n is the
/// number of proxies in the tree.
/// @param input the ray-cast input data. The ray extends from p1 to p1 + maxFraction * (p2 - p1).
/// @param callback a callback class that is called for each proxy that is hit by the ray.
template <typename T>
void RayCast(T* callback, const b2RayCastInput& input) const;
/// Get the height of the embedded tree.
int32 GetTreeHeight() const;
/// Get the balance of the embedded tree.
int32 GetTreeBalance() const;
/// Get the quality metric of the embedded tree.
float32 GetTreeQuality() const;
/// Shift the world origin. Useful for large worlds.
/// The shift formula is: position -= newOrigin
/// @param newOrigin the new origin with respect to the old origin
void ShiftOrigin(const b2Vec2& newOrigin);
private:
friend class b2DynamicTree;
void BufferMove(int32 proxyId);
void UnBufferMove(int32 proxyId);
bool QueryCallback(int32 proxyId);
b2DynamicTree m_tree;
int32 m_proxyCount;
int32* m_moveBuffer;
int32 m_moveCapacity;
int32 m_moveCount;
b2Pair* m_pairBuffer;
int32 m_pairCapacity;
int32 m_pairCount;
int32 m_queryProxyId;
};
/// This is used to sort pairs.
inline bool b2PairLessThan(const b2Pair& pair1, const b2Pair& pair2)
{
if (pair1.proxyIdA < pair2.proxyIdA)
{
return true;
}
if (pair1.proxyIdA == pair2.proxyIdA)
{
return pair1.proxyIdB < pair2.proxyIdB;
}
return false;
}
inline void* b2BroadPhase::GetUserData(int32 proxyId) const
{
return m_tree.GetUserData(proxyId);
}
inline bool b2BroadPhase::TestOverlap(int32 proxyIdA, int32 proxyIdB) const
{
const b2AABB& aabbA = m_tree.GetFatAABB(proxyIdA);
const b2AABB& aabbB = m_tree.GetFatAABB(proxyIdB);
return b2TestOverlap(aabbA, aabbB);
}
inline const b2AABB& b2BroadPhase::GetFatAABB(int32 proxyId) const
{
return m_tree.GetFatAABB(proxyId);
}
inline int32 b2BroadPhase::GetProxyCount() const
{
return m_proxyCount;
}
inline int32 b2BroadPhase::GetTreeHeight() const
{
return m_tree.GetHeight();
}
inline int32 b2BroadPhase::GetTreeBalance() const
{
return m_tree.GetMaxBalance();
}
inline float32 b2BroadPhase::GetTreeQuality() const
{
return m_tree.GetAreaRatio();
}
template <typename T>
void b2BroadPhase::UpdatePairs(T* callback)
{
// Reset pair buffer
m_pairCount = 0;
// Perform tree queries for all moving proxies.
for (int32 i = 0; i < m_moveCount; ++i)
{
m_queryProxyId = m_moveBuffer[i];
if (m_queryProxyId == e_nullProxy)
{
continue;
}
// We have to query the tree with the fat AABB so that
// we don't fail to create a pair that may touch later.
const b2AABB& fatAABB = m_tree.GetFatAABB(m_queryProxyId);
// Query tree, create pairs and add them pair buffer.
m_tree.Query(this, fatAABB);
}
// Reset move buffer
m_moveCount = 0;
// Sort the pair buffer to expose duplicates.
std::sort(m_pairBuffer, m_pairBuffer + m_pairCount, b2PairLessThan);
// Send the pairs back to the client.
int32 i = 0;
while (i < m_pairCount)
{
b2Pair* primaryPair = m_pairBuffer + i;
void* userDataA = m_tree.GetUserData(primaryPair->proxyIdA);
void* userDataB = m_tree.GetUserData(primaryPair->proxyIdB);
callback->AddPair(userDataA, userDataB);
++i;
// Skip any duplicate pairs.
while (i < m_pairCount)
{
b2Pair* pair = m_pairBuffer + i;
if (pair->proxyIdA != primaryPair->proxyIdA || pair->proxyIdB != primaryPair->proxyIdB)
{
break;
}
++i;
}
}
// Try to keep the tree balanced.
//m_tree.Rebalance(4);
}
template <typename T>
inline void b2BroadPhase::Query(T* callback, const b2AABB& aabb) const
{
m_tree.Query(callback, aabb);
}
template <typename T>
inline void b2BroadPhase::RayCast(T* callback, const b2RayCastInput& input) const
{
m_tree.RayCast(callback, input);
}
inline void b2BroadPhase::ShiftOrigin(const b2Vec2& newOrigin)
{
m_tree.ShiftOrigin(newOrigin);
}
#endif
/*
* Copyright (c) 2007-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "Box2D/Collision/b2Collision.h"
#include "Box2D/Collision/Shapes/b2CircleShape.h"
#include "Box2D/Collision/Shapes/b2PolygonShape.h"
void b2CollideCircles(
b2Manifold* manifold,
const b2CircleShape* circleA, const b2Transform& xfA,
const b2CircleShape* circleB, const b2Transform& xfB)
{
manifold->pointCount = 0;
b2Vec2 pA = b2Mul(xfA, circleA->m_p);
b2Vec2 pB = b2Mul(xfB, circleB->m_p);
b2Vec2 d = pB - pA;
float32 distSqr = b2Dot(d, d);
float32 rA = circleA->m_radius, rB = circleB->m_radius;
float32 radius = rA + rB;
if (distSqr > radius * radius)
{
return;
}
manifold->type = b2Manifold::e_circles;
manifold->localPoint = circleA->m_p;
manifold->localNormal.SetZero();
manifold->pointCount = 1;
manifold->points[0].localPoint = circleB->m_p;
manifold->points[0].id.key = 0;
}
void b2CollidePolygonAndCircle(
b2Manifold* manifold,
const b2PolygonShape* polygonA, const b2Transform& xfA,
const b2CircleShape* circleB, const b2Transform& xfB)
{
manifold->pointCount = 0;
// Compute circle position in the frame of the polygon.
b2Vec2 c = b2Mul(xfB, circleB->m_p);
b2Vec2 cLocal = b2MulT(xfA, c);
// Find the min separating edge.
int32 normalIndex = 0;
float32 separation = -b2_maxFloat;
float32 radius = polygonA->m_radius + circleB->m_radius;
int32 vertexCount = polygonA->m_count;
const b2Vec2* vertices = polygonA->m_vertices;
const b2Vec2* normals = polygonA->m_normals;
for (int32 i = 0; i < vertexCount; ++i)
{
float32 s = b2Dot(normals[i], cLocal - vertices[i]);
if (s > radius)
{
// Early out.
return;
}
if (s > separation)
{
separation = s;
normalIndex = i;
}
}
// Vertices that subtend the incident face.
int32 vertIndex1 = normalIndex;
int32 vertIndex2 = vertIndex1 + 1 < vertexCount ? vertIndex1 + 1 : 0;
b2Vec2 v1 = vertices[vertIndex1];
b2Vec2 v2 = vertices[vertIndex2];
// If the center is inside the polygon ...
if (separation < b2_epsilon)
{
manifold->pointCount = 1;
manifold->type = b2Manifold::e_faceA;
manifold->localNormal = normals[normalIndex];
manifold->localPoint = 0.5f * (v1 + v2);
manifold->points[0].localPoint = circleB->m_p;
manifold->points[0].id.key = 0;
return;
}
// Compute barycentric coordinates
float32 u1 = b2Dot(cLocal - v1, v2 - v1);
float32 u2 = b2Dot(cLocal - v2, v1 - v2);
if (u1 <= 0.0f)
{
if (b2DistanceSquared(cLocal, v1) > radius * radius)
{
return;
}
manifold->pointCount = 1;
manifold->type = b2Manifold::e_faceA;
manifold->localNormal = cLocal - v1;
manifold->localNormal.Normalize();
manifold->localPoint = v1;
manifold->points[0].localPoint = circleB->m_p;
manifold->points[0].id.key = 0;
}
else if (u2 <= 0.0f)
{
if (b2DistanceSquared(cLocal, v2) > radius * radius)
{
return;
}
manifold->pointCount = 1;
manifold->type = b2Manifold::e_faceA;
manifold->localNormal = cLocal - v2;
manifold->localNormal.Normalize();
manifold->localPoint = v2;
manifold->points[0].localPoint = circleB->m_p;
manifold->points[0].id.key = 0;
}
else
{
b2Vec2 faceCenter = 0.5f * (v1 + v2);
float32 s = b2Dot(cLocal - faceCenter, normals[vertIndex1]);
if (s > radius)
{
return;
}
manifold->pointCount = 1;
manifold->type = b2Manifold::e_faceA;
manifold->localNormal = normals[vertIndex1];
manifold->localPoint = faceCenter;
manifold->points[0].localPoint = circleB->m_p;
manifold->points[0].id.key = 0;
}
}
/*
* Copyright (c) 2007-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "Box2D/Collision/b2Collision.h"
#include "Box2D/Collision/Shapes/b2CircleShape.h"
#include "Box2D/Collision/Shapes/b2EdgeShape.h"
#include "Box2D/Collision/Shapes/b2PolygonShape.h"
// Compute contact points for edge versus circle.
// This accounts for edge connectivity.
void b2CollideEdgeAndCircle(b2Manifold* manifold,
const b2EdgeShape* edgeA, const b2Transform& xfA,
const b2CircleShape* circleB, const b2Transform& xfB)
{
manifold->pointCount = 0;
// Compute circle in frame of edge
b2Vec2 Q = b2MulT(xfA, b2Mul(xfB, circleB->m_p));
b2Vec2 A = edgeA->m_vertex1, B = edgeA->m_vertex2;
b2Vec2 e = B - A;
// Barycentric coordinates
float32 u = b2Dot(e, B - Q);
float32 v = b2Dot(e, Q - A);
float32 radius = edgeA->m_radius + circleB->m_radius;
b2ContactFeature cf;
cf.indexB = 0;
cf.typeB = b2ContactFeature::e_vertex;
// Region A
if (v <= 0.0f)
{
b2Vec2 P = A;
b2Vec2 d = Q - P;
float32 dd = b2Dot(d, d);
if (dd > radius * radius)
{
return;
}
// Is there an edge connected to A?
if (edgeA->m_hasVertex0)
{
b2Vec2 A1 = edgeA->m_vertex0;
b2Vec2 B1 = A;
b2Vec2 e1 = B1 - A1;
float32 u1 = b2Dot(e1, B1 - Q);
// Is the circle in Region AB of the previous edge?
if (u1 > 0.0f)
{
return;
}
}
cf.indexA = 0;
cf.typeA = b2ContactFeature::e_vertex;
manifold->pointCount = 1;
manifold->type = b2Manifold::e_circles;
manifold->localNormal.SetZero();
manifold->localPoint = P;
manifold->points[0].id.key = 0;
manifold->points[0].id.cf = cf;
manifold->points[0].localPoint = circleB->m_p;
return;
}
// Region B
if (u <= 0.0f)
{
b2Vec2 P = B;
b2Vec2 d = Q - P;
float32 dd = b2Dot(d, d);
if (dd > radius * radius)
{
return;
}
// Is there an edge connected to B?
if (edgeA->m_hasVertex3)
{
b2Vec2 B2 = edgeA->m_vertex3;
b2Vec2 A2 = B;
b2Vec2 e2 = B2 - A2;
float32 v2 = b2Dot(e2, Q - A2);
// Is the circle in Region AB of the next edge?
if (v2 > 0.0f)
{
return;
}
}
cf.indexA = 1;
cf.typeA = b2ContactFeature::e_vertex;
manifold->pointCount = 1;
manifold->type = b2Manifold::e_circles;
manifold->localNormal.SetZero();
manifold->localPoint = P;
manifold->points[0].id.key = 0;
manifold->points[0].id.cf = cf;
manifold->points[0].localPoint = circleB->m_p;
return;
}
// Region AB
float32 den = b2Dot(e, e);
b2Assert(den > 0.0f);
b2Vec2 P = (1.0f / den) * (u * A + v * B);
b2Vec2 d = Q - P;
float32 dd = b2Dot(d, d);
if (dd > radius * radius)
{
return;
}
b2Vec2 n(-e.y, e.x);
if (b2Dot(n, Q - A) < 0.0f)
{
n.Set(-n.x, -n.y);
}
n.Normalize();
cf.indexA = 0;
cf.typeA = b2ContactFeature::e_face;
manifold->pointCount = 1;
manifold->type = b2Manifold::e_faceA;
manifold->localNormal = n;
manifold->localPoint = A;
manifold->points[0].id.key = 0;
manifold->points[0].id.cf = cf;
manifold->points[0].localPoint = circleB->m_p;
}
// This structure is used to keep track of the best separating axis.
struct b2EPAxis
{
enum Type
{
e_unknown,
e_edgeA,
e_edgeB
};
Type type;
int32 index;
float32 separation;
};
// This holds polygon B expressed in frame A.
struct b2TempPolygon
{
b2Vec2 vertices[b2_maxPolygonVertices];
b2Vec2 normals[b2_maxPolygonVertices];
int32 count;
};
// Reference face used for clipping
struct b2ReferenceFace
{
int32 i1, i2;
b2Vec2 v1, v2;
b2Vec2 normal;
b2Vec2 sideNormal1;
float32 sideOffset1;
b2Vec2 sideNormal2;
float32 sideOffset2;
};
// This class collides and edge and a polygon, taking into account edge adjacency.
struct b2EPCollider
{
void Collide(b2Manifold* manifold, const b2EdgeShape* edgeA, const b2Transform& xfA,
const b2PolygonShape* polygonB, const b2Transform& xfB);
b2EPAxis ComputeEdgeSeparation();
b2EPAxis ComputePolygonSeparation();
enum VertexType
{
e_isolated,
e_concave,
e_convex
};
b2TempPolygon m_polygonB;
b2Transform m_xf;
b2Vec2 m_centroidB;
b2Vec2 m_v0, m_v1, m_v2, m_v3;
b2Vec2 m_normal0, m_normal1, m_normal2;
b2Vec2 m_normal;
VertexType m_type1, m_type2;
b2Vec2 m_lowerLimit, m_upperLimit;
float32 m_radius;
bool m_front;
};
// Algorithm:
// 1. Classify v1 and v2
// 2. Classify polygon centroid as front or back
// 3. Flip normal if necessary
// 4. Initialize normal range to [-pi, pi] about face normal
// 5. Adjust normal range according to adjacent edges
// 6. Visit each separating axes, only accept axes within the range
// 7. Return if _any_ axis indicates separation
// 8. Clip
void b2EPCollider::Collide(b2Manifold* manifold, const b2EdgeShape* edgeA, const b2Transform& xfA,
const b2PolygonShape* polygonB, const b2Transform& xfB)
{
m_xf = b2MulT(xfA, xfB);
m_centroidB = b2Mul(m_xf, polygonB->m_centroid);
m_v0 = edgeA->m_vertex0;
m_v1 = edgeA->m_vertex1;
m_v2 = edgeA->m_vertex2;
m_v3 = edgeA->m_vertex3;
bool hasVertex0 = edgeA->m_hasVertex0;
bool hasVertex3 = edgeA->m_hasVertex3;
b2Vec2 edge1 = m_v2 - m_v1;
edge1.Normalize();
m_normal1.Set(edge1.y, -edge1.x);
float32 offset1 = b2Dot(m_normal1, m_centroidB - m_v1);
float32 offset0 = 0.0f, offset2 = 0.0f;
bool convex1 = false, convex2 = false;
// Is there a preceding edge?
if (hasVertex0)
{
b2Vec2 edge0 = m_v1 - m_v0;
edge0.Normalize();
m_normal0.Set(edge0.y, -edge0.x);
convex1 = b2Cross(edge0, edge1) >= 0.0f;
offset0 = b2Dot(m_normal0, m_centroidB - m_v0);
}
// Is there a following edge?
if (hasVertex3)
{
b2Vec2 edge2 = m_v3 - m_v2;
edge2.Normalize();
m_normal2.Set(edge2.y, -edge2.x);
convex2 = b2Cross(edge1, edge2) > 0.0f;
offset2 = b2Dot(m_normal2, m_centroidB - m_v2);
}
// Determine front or back collision. Determine collision normal limits.
if (hasVertex0 && hasVertex3)
{
if (convex1 && convex2)
{
m_front = offset0 >= 0.0f || offset1 >= 0.0f || offset2 >= 0.0f;
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = m_normal0;
m_upperLimit = m_normal2;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = -m_normal1;
m_upperLimit = -m_normal1;
}
}
else if (convex1)
{
m_front = offset0 >= 0.0f || (offset1 >= 0.0f && offset2 >= 0.0f);
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = m_normal0;
m_upperLimit = m_normal1;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = -m_normal2;
m_upperLimit = -m_normal1;
}
}
else if (convex2)
{
m_front = offset2 >= 0.0f || (offset0 >= 0.0f && offset1 >= 0.0f);
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = m_normal1;
m_upperLimit = m_normal2;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = -m_normal1;
m_upperLimit = -m_normal0;
}
}
else
{
m_front = offset0 >= 0.0f && offset1 >= 0.0f && offset2 >= 0.0f;
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = m_normal1;
m_upperLimit = m_normal1;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = -m_normal2;
m_upperLimit = -m_normal0;
}
}
}
else if (hasVertex0)
{
if (convex1)
{
m_front = offset0 >= 0.0f || offset1 >= 0.0f;
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = m_normal0;
m_upperLimit = -m_normal1;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = m_normal1;
m_upperLimit = -m_normal1;
}
}
else
{
m_front = offset0 >= 0.0f && offset1 >= 0.0f;
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = m_normal1;
m_upperLimit = -m_normal1;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = m_normal1;
m_upperLimit = -m_normal0;
}
}
}
else if (hasVertex3)
{
if (convex2)
{
m_front = offset1 >= 0.0f || offset2 >= 0.0f;
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = -m_normal1;
m_upperLimit = m_normal2;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = -m_normal1;
m_upperLimit = m_normal1;
}
}
else
{
m_front = offset1 >= 0.0f && offset2 >= 0.0f;
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = -m_normal1;
m_upperLimit = m_normal1;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = -m_normal2;
m_upperLimit = m_normal1;
}
}
}
else
{
m_front = offset1 >= 0.0f;
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = -m_normal1;
m_upperLimit = -m_normal1;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = m_normal1;
m_upperLimit = m_normal1;
}
}
// Get polygonB in frameA
m_polygonB.count = polygonB->m_count;
for (int32 i = 0; i < polygonB->m_count; ++i)
{
m_polygonB.vertices[i] = b2Mul(m_xf, polygonB->m_vertices[i]);
m_polygonB.normals[i] = b2Mul(m_xf.q, polygonB->m_normals[i]);
}
m_radius = polygonB->m_radius + edgeA->m_radius;
manifold->pointCount = 0;
b2EPAxis edgeAxis = ComputeEdgeSeparation();
// If no valid normal can be found than this edge should not collide.
if (edgeAxis.type == b2EPAxis::e_unknown)
{
return;
}
if (edgeAxis.separation > m_radius)
{
return;
}
b2EPAxis polygonAxis = ComputePolygonSeparation();
if (polygonAxis.type != b2EPAxis::e_unknown && polygonAxis.separation > m_radius)
{
return;
}
// Use hysteresis for jitter reduction.
const float32 k_relativeTol = 0.98f;
const float32 k_absoluteTol = 0.001f;
b2EPAxis primaryAxis;
if (polygonAxis.type == b2EPAxis::e_unknown)
{
primaryAxis = edgeAxis;
}
else if (polygonAxis.separation > k_relativeTol * edgeAxis.separation + k_absoluteTol)
{
primaryAxis = polygonAxis;
}
else
{
primaryAxis = edgeAxis;
}
b2ClipVertex ie[2];
b2ReferenceFace rf;
if (primaryAxis.type == b2EPAxis::e_edgeA)
{
manifold->type = b2Manifold::e_faceA;
// Search for the polygon normal that is most anti-parallel to the edge normal.
int32 bestIndex = 0;
float32 bestValue = b2Dot(m_normal, m_polygonB.normals[0]);
for (int32 i = 1; i < m_polygonB.count; ++i)
{
float32 value = b2Dot(m_normal, m_polygonB.normals[i]);
if (value < bestValue)
{
bestValue = value;
bestIndex = i;
}
}
int32 i1 = bestIndex;
int32 i2 = i1 + 1 < m_polygonB.count ? i1 + 1 : 0;
ie[0].v = m_polygonB.vertices[i1];
ie[0].id.cf.indexA = 0;
ie[0].id.cf.indexB = static_cast<uint8>(i1);
ie[0].id.cf.typeA = b2ContactFeature::e_face;
ie[0].id.cf.typeB = b2ContactFeature::e_vertex;
ie[1].v = m_polygonB.vertices[i2];
ie[1].id.cf.indexA = 0;
ie[1].id.cf.indexB = static_cast<uint8>(i2);
ie[1].id.cf.typeA = b2ContactFeature::e_face;
ie[1].id.cf.typeB = b2ContactFeature::e_vertex;
if (m_front)
{
rf.i1 = 0;
rf.i2 = 1;
rf.v1 = m_v1;
rf.v2 = m_v2;
rf.normal = m_normal1;
}
else
{
rf.i1 = 1;
rf.i2 = 0;
rf.v1 = m_v2;
rf.v2 = m_v1;
rf.normal = -m_normal1;
}
}
else
{
manifold->type = b2Manifold::e_faceB;
ie[0].v = m_v1;
ie[0].id.cf.indexA = 0;
ie[0].id.cf.indexB = static_cast<uint8>(primaryAxis.index);
ie[0].id.cf.typeA = b2ContactFeature::e_vertex;
ie[0].id.cf.typeB = b2ContactFeature::e_face;
ie[1].v = m_v2;
ie[1].id.cf.indexA = 0;
ie[1].id.cf.indexB = static_cast<uint8>(primaryAxis.index);
ie[1].id.cf.typeA = b2ContactFeature::e_vertex;
ie[1].id.cf.typeB = b2ContactFeature::e_face;
rf.i1 = primaryAxis.index;
rf.i2 = rf.i1 + 1 < m_polygonB.count ? rf.i1 + 1 : 0;
rf.v1 = m_polygonB.vertices[rf.i1];
rf.v2 = m_polygonB.vertices[rf.i2];
rf.normal = m_polygonB.normals[rf.i1];
}
rf.sideNormal1.Set(rf.normal.y, -rf.normal.x);
rf.sideNormal2 = -rf.sideNormal1;
rf.sideOffset1 = b2Dot(rf.sideNormal1, rf.v1);
rf.sideOffset2 = b2Dot(rf.sideNormal2, rf.v2);
// Clip incident edge against extruded edge1 side edges.
b2ClipVertex clipPoints1[2];
b2ClipVertex clipPoints2[2];
int32 np;
// Clip to box side 1
np = b2ClipSegmentToLine(clipPoints1, ie, rf.sideNormal1, rf.sideOffset1, rf.i1);
if (np < b2_maxManifoldPoints)
{
return;
}
// Clip to negative box side 1
np = b2ClipSegmentToLine(clipPoints2, clipPoints1, rf.sideNormal2, rf.sideOffset2, rf.i2);
if (np < b2_maxManifoldPoints)
{
return;
}
// Now clipPoints2 contains the clipped points.
if (primaryAxis.type == b2EPAxis::e_edgeA)
{
manifold->localNormal = rf.normal;
manifold->localPoint = rf.v1;
}
else
{
manifold->localNormal = polygonB->m_normals[rf.i1];
manifold->localPoint = polygonB->m_vertices[rf.i1];
}
int32 pointCount = 0;
for (int32 i = 0; i < b2_maxManifoldPoints; ++i)
{
float32 separation;
separation = b2Dot(rf.normal, clipPoints2[i].v - rf.v1);
if (separation <= m_radius)
{
b2ManifoldPoint* cp = manifold->points + pointCount;
if (primaryAxis.type == b2EPAxis::e_edgeA)
{
cp->localPoint = b2MulT(m_xf, clipPoints2[i].v);
cp->id = clipPoints2[i].id;
}
else
{
cp->localPoint = clipPoints2[i].v;
cp->id.cf.typeA = clipPoints2[i].id.cf.typeB;
cp->id.cf.typeB = clipPoints2[i].id.cf.typeA;
cp->id.cf.indexA = clipPoints2[i].id.cf.indexB;
cp->id.cf.indexB = clipPoints2[i].id.cf.indexA;
}
++pointCount;
}
}
manifold->pointCount = pointCount;
}
b2EPAxis b2EPCollider::ComputeEdgeSeparation()
{
b2EPAxis axis;
axis.type = b2EPAxis::e_edgeA;
axis.index = m_front ? 0 : 1;
axis.separation = FLT_MAX;
for (int32 i = 0; i < m_polygonB.count; ++i)
{
float32 s = b2Dot(m_normal, m_polygonB.vertices[i] - m_v1);
if (s < axis.separation)
{
axis.separation = s;
}
}
return axis;
}
b2EPAxis b2EPCollider::ComputePolygonSeparation()
{
b2EPAxis axis;
axis.type = b2EPAxis::e_unknown;
axis.index = -1;
axis.separation = -FLT_MAX;
b2Vec2 perp(-m_normal.y, m_normal.x);
for (int32 i = 0; i < m_polygonB.count; ++i)
{
b2Vec2 n = -m_polygonB.normals[i];
float32 s1 = b2Dot(n, m_polygonB.vertices[i] - m_v1);
float32 s2 = b2Dot(n, m_polygonB.vertices[i] - m_v2);
float32 s = b2Min(s1, s2);
if (s > m_radius)
{
// No collision
axis.type = b2EPAxis::e_edgeB;
axis.index = i;
axis.separation = s;
return axis;
}
// Adjacency
if (b2Dot(n, perp) >= 0.0f)
{
if (b2Dot(n - m_upperLimit, m_normal) < -b2_angularSlop)
{
continue;
}
}
else
{
if (b2Dot(n - m_lowerLimit, m_normal) < -b2_angularSlop)
{
continue;
}
}
if (s > axis.separation)
{
axis.type = b2EPAxis::e_edgeB;
axis.index = i;
axis.separation = s;
}
}
return axis;
}
void b2CollideEdgeAndPolygon( b2Manifold* manifold,
const b2EdgeShape* edgeA, const b2Transform& xfA,
const b2PolygonShape* polygonB, const b2Transform& xfB)
{
b2EPCollider collider;
collider.Collide(manifold, edgeA, xfA, polygonB, xfB);
}
/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "Box2D/Collision/b2Collision.h"
#include "Box2D/Collision/Shapes/b2PolygonShape.h"
// Find the max separation between poly1 and poly2 using edge normals from poly1.
static float32 b2FindMaxSeparation(int32* edgeIndex,
const b2PolygonShape* poly1, const b2Transform& xf1,
const b2PolygonShape* poly2, const b2Transform& xf2)
{
int32 count1 = poly1->m_count;
int32 count2 = poly2->m_count;
const b2Vec2* n1s = poly1->m_normals;
const b2Vec2* v1s = poly1->m_vertices;
const b2Vec2* v2s = poly2->m_vertices;
b2Transform xf = b2MulT(xf2, xf1);
int32 bestIndex = 0;
float32 maxSeparation = -b2_maxFloat;
for (int32 i = 0; i < count1; ++i)
{
// Get poly1 normal in frame2.
b2Vec2 n = b2Mul(xf.q, n1s[i]);
b2Vec2 v1 = b2Mul(xf, v1s[i]);
// Find deepest point for normal i.
float32 si = b2_maxFloat;
for (int32 j = 0; j < count2; ++j)
{
float32 sij = b2Dot(n, v2s[j] - v1);
if (sij < si)
{
si = sij;
}
}
if (si > maxSeparation)
{
maxSeparation = si;
bestIndex = i;
}
}
*edgeIndex = bestIndex;
return maxSeparation;
}
static void b2FindIncidentEdge(b2ClipVertex c[2],
const b2PolygonShape* poly1, const b2Transform& xf1, int32 edge1,
const b2PolygonShape* poly2, const b2Transform& xf2)
{
const b2Vec2* normals1 = poly1->m_normals;
int32 count2 = poly2->m_count;
const b2Vec2* vertices2 = poly2->m_vertices;
const b2Vec2* normals2 = poly2->m_normals;
b2Assert(0 <= edge1 && edge1 < poly1->m_count);
// Get the normal of the reference edge in poly2's frame.
b2Vec2 normal1 = b2MulT(xf2.q, b2Mul(xf1.q, normals1[edge1]));
// Find the incident edge on poly2.
int32 index = 0;
float32 minDot = b2_maxFloat;
for (int32 i = 0; i < count2; ++i)
{
float32 dot = b2Dot(normal1, normals2[i]);
if (dot < minDot)
{
minDot = dot;
index = i;
}
}
// Build the clip vertices for the incident edge.
int32 i1 = index;
int32 i2 = i1 + 1 < count2 ? i1 + 1 : 0;
c[0].v = b2Mul(xf2, vertices2[i1]);
c[0].id.cf.indexA = (uint8)edge1;
c[0].id.cf.indexB = (uint8)i1;
c[0].id.cf.typeA = b2ContactFeature::e_face;
c[0].id.cf.typeB = b2ContactFeature::e_vertex;
c[1].v = b2Mul(xf2, vertices2[i2]);
c[1].id.cf.indexA = (uint8)edge1;
c[1].id.cf.indexB = (uint8)i2;
c[1].id.cf.typeA = b2ContactFeature::e_face;
c[1].id.cf.typeB = b2ContactFeature::e_vertex;
}
// Find edge normal of max separation on A - return if separating axis is found
// Find edge normal of max separation on B - return if separation axis is found
// Choose reference edge as min(minA, minB)
// Find incident edge
// Clip
// The normal points from 1 to 2
void b2CollidePolygons(b2Manifold* manifold,
const b2PolygonShape* polyA, const b2Transform& xfA,
const b2PolygonShape* polyB, const b2Transform& xfB)
{
manifold->pointCount = 0;
float32 totalRadius = polyA->m_radius + polyB->m_radius;
int32 edgeA = 0;
float32 separationA = b2FindMaxSeparation(&edgeA, polyA, xfA, polyB, xfB);
if (separationA > totalRadius)
return;
int32 edgeB = 0;
float32 separationB = b2FindMaxSeparation(&edgeB, polyB, xfB, polyA, xfA);
if (separationB > totalRadius)
return;
const b2PolygonShape* poly1; // reference polygon
const b2PolygonShape* poly2; // incident polygon
b2Transform xf1, xf2;
int32 edge1; // reference edge
uint8 flip;
const float32 k_tol = 0.1f * b2_linearSlop;
if (separationB > separationA + k_tol)
{
poly1 = polyB;
poly2 = polyA;
xf1 = xfB;
xf2 = xfA;
edge1 = edgeB;
manifold->type = b2Manifold::e_faceB;
flip = 1;
}
else
{
poly1 = polyA;
poly2 = polyB;
xf1 = xfA;
xf2 = xfB;
edge1 = edgeA;
manifold->type = b2Manifold::e_faceA;
flip = 0;
}
b2ClipVertex incidentEdge[2];
b2FindIncidentEdge(incidentEdge, poly1, xf1, edge1, poly2, xf2);
int32 count1 = poly1->m_count;
const b2Vec2* vertices1 = poly1->m_vertices;
int32 iv1 = edge1;
int32 iv2 = edge1 + 1 < count1 ? edge1 + 1 : 0;
b2Vec2 v11 = vertices1[iv1];
b2Vec2 v12 = vertices1[iv2];
b2Vec2 localTangent = v12 - v11;
localTangent.Normalize();
b2Vec2 localNormal = b2Cross(localTangent, 1.0f);
b2Vec2 planePoint = 0.5f * (v11 + v12);
b2Vec2 tangent = b2Mul(xf1.q, localTangent);
b2Vec2 normal = b2Cross(tangent, 1.0f);
v11 = b2Mul(xf1, v11);
v12 = b2Mul(xf1, v12);
// Face offset.
float32 frontOffset = b2Dot(normal, v11);
// Side offsets, extended by polytope skin thickness.
float32 sideOffset1 = -b2Dot(tangent, v11) + totalRadius;
float32 sideOffset2 = b2Dot(tangent, v12) + totalRadius;
// Clip incident edge against extruded edge1 side edges.
b2ClipVertex clipPoints1[2];
b2ClipVertex clipPoints2[2];
int np;
// Clip to box side 1
np = b2ClipSegmentToLine(clipPoints1, incidentEdge, -tangent, sideOffset1, iv1);
if (np < 2)
return;
// Clip to negative box side 1
np = b2ClipSegmentToLine(clipPoints2, clipPoints1, tangent, sideOffset2, iv2);
if (np < 2)
{
return;
}
// Now clipPoints2 contains the clipped points.
manifold->localNormal = localNormal;
manifold->localPoint = planePoint;
int32 pointCount = 0;
for (int32 i = 0; i < b2_maxManifoldPoints; ++i)
{
float32 separation = b2Dot(normal, clipPoints2[i].v) - frontOffset;
if (separation <= totalRadius)
{
b2ManifoldPoint* cp = manifold->points + pointCount;
cp->localPoint = b2MulT(xf2, clipPoints2[i].v);
cp->id = clipPoints2[i].id;
if (flip)
{
// Swap features
b2ContactFeature cf = cp->id.cf;
cp->id.cf.indexA = cf.indexB;
cp->id.cf.indexB = cf.indexA;
cp->id.cf.typeA = cf.typeB;
cp->id.cf.typeB = cf.typeA;
}
++pointCount;
}
}
manifold->pointCount = pointCount;
}
/*
* Copyright (c) 2007-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "Box2D/Collision/b2Collision.h"
#include "Box2D/Collision/b2Distance.h"
void b2WorldManifold::Initialize(const b2Manifold* manifold,
const b2Transform& xfA, float32 radiusA,
const b2Transform& xfB, float32 radiusB)
{
if (manifold->pointCount == 0)
{
return;
}
switch (manifold->type)
{
case b2Manifold::e_circles:
{
normal.Set(1.0f, 0.0f);
b2Vec2 pointA = b2Mul(xfA, manifold->localPoint);
b2Vec2 pointB = b2Mul(xfB, manifold->points[0].localPoint);
if (b2DistanceSquared(pointA, pointB) > b2_epsilon * b2_epsilon)
{
normal = pointB - pointA;
normal.Normalize();
}
b2Vec2 cA = pointA + radiusA * normal;
b2Vec2 cB = pointB - radiusB * normal;
points[0] = 0.5f * (cA + cB);
separations[0] = b2Dot(cB - cA, normal);
}
break;
case b2Manifold::e_faceA:
{
normal = b2Mul(xfA.q, manifold->localNormal);
b2Vec2 planePoint = b2Mul(xfA, manifold->localPoint);
for (int32 i = 0; i < manifold->pointCount; ++i)
{
b2Vec2 clipPoint = b2Mul(xfB, manifold->points[i].localPoint);
b2Vec2 cA = clipPoint + (radiusA - b2Dot(clipPoint - planePoint, normal)) * normal;
b2Vec2 cB = clipPoint - radiusB * normal;
points[i] = 0.5f * (cA + cB);
separations[i] = b2Dot(cB - cA, normal);
}
}
break;
case b2Manifold::e_faceB:
{
normal = b2Mul(xfB.q, manifold->localNormal);
b2Vec2 planePoint = b2Mul(xfB, manifold->localPoint);
for (int32 i = 0; i < manifold->pointCount; ++i)
{
b2Vec2 clipPoint = b2Mul(xfA, manifold->points[i].localPoint);
b2Vec2 cB = clipPoint + (radiusB - b2Dot(clipPoint - planePoint, normal)) * normal;
b2Vec2 cA = clipPoint - radiusA * normal;
points[i] = 0.5f * (cA + cB);
separations[i] = b2Dot(cA - cB, normal);
}
// Ensure normal points from A to B.
normal = -normal;
}
break;
}
}
void b2GetPointStates(b2PointState state1[b2_maxManifoldPoints], b2PointState state2[b2_maxManifoldPoints],
const b2Manifold* manifold1, const b2Manifold* manifold2)
{
for (int32 i = 0; i < b2_maxManifoldPoints; ++i)
{
state1[i] = b2_nullState;
state2[i] = b2_nullState;
}
// Detect persists and removes.
for (int32 i = 0; i < manifold1->pointCount; ++i)
{
b2ContactID id = manifold1->points[i].id;
state1[i] = b2_removeState;
for (int32 j = 0; j < manifold2->pointCount; ++j)
{
if (manifold2->points[j].id.key == id.key)
{
state1[i] = b2_persistState;
break;
}
}
}
// Detect persists and adds.
for (int32 i = 0; i < manifold2->pointCount; ++i)
{
b2ContactID id = manifold2->points[i].id;
state2[i] = b2_addState;
for (int32 j = 0; j < manifold1->pointCount; ++j)
{
if (manifold1->points[j].id.key == id.key)
{
state2[i] = b2_persistState;
break;
}
}
}
}
// From Real-time Collision Detection, p179.
bool b2AABB::RayCast(b2RayCastOutput* output, const b2RayCastInput& input) const
{
float32 tmin = -b2_maxFloat;
float32 tmax = b2_maxFloat;
b2Vec2 p = input.p1;
b2Vec2 d = input.p2 - input.p1;
b2Vec2 absD = b2Abs(d);
b2Vec2 normal;
for (int32 i = 0; i < 2; ++i)
{
if (absD(i) < b2_epsilon)
{
// Parallel.
if (p(i) < lowerBound(i) || upperBound(i) < p(i))
{
return false;
}
}
else
{
float32 inv_d = 1.0f / d(i);
float32 t1 = (lowerBound(i) - p(i)) * inv_d;
float32 t2 = (upperBound(i) - p(i)) * inv_d;
// Sign of the normal vector.
float32 s = -1.0f;
if (t1 > t2)
{
b2Swap(t1, t2);
s = 1.0f;
}
// Push the min up
if (t1 > tmin)
{
normal.SetZero();
normal(i) = s;
tmin = t1;
}
// Pull the max down
tmax = b2Min(tmax, t2);
if (tmin > tmax)
{
return false;
}
}
}
// Does the ray start inside the box?
// Does the ray intersect beyond the max fraction?
if (tmin < 0.0f || input.maxFraction < tmin)
{
return false;
}
// Intersection.
output->fraction = tmin;
output->normal = normal;
return true;
}
// Sutherland-Hodgman clipping.
int32 b2ClipSegmentToLine(b2ClipVertex vOut[2], const b2ClipVertex vIn[2],
const b2Vec2& normal, float32 offset, int32 vertexIndexA)
{
// Start with no output points
int32 numOut = 0;
// Calculate the distance of end points to the line
float32 distance0 = b2Dot(normal, vIn[0].v) - offset;
float32 distance1 = b2Dot(normal, vIn[1].v) - offset;
// If the points are behind the plane
if (distance0 <= 0.0f) vOut[numOut++] = vIn[0];
if (distance1 <= 0.0f) vOut[numOut++] = vIn[1];
// If the points are on different sides of the plane
if (distance0 * distance1 < 0.0f)
{
// Find intersection point of edge and plane
float32 interp = distance0 / (distance0 - distance1);
vOut[numOut].v = vIn[0].v + interp * (vIn[1].v - vIn[0].v);
// VertexA is hitting edgeB.
vOut[numOut].id.cf.indexA = static_cast<uint8>(vertexIndexA);
vOut[numOut].id.cf.indexB = vIn[0].id.cf.indexB;
vOut[numOut].id.cf.typeA = b2ContactFeature::e_vertex;
vOut[numOut].id.cf.typeB = b2ContactFeature::e_face;
++numOut;
}
return numOut;
}
bool b2TestOverlap( const b2Shape* shapeA, int32 indexA,
const b2Shape* shapeB, int32 indexB,
const b2Transform& xfA, const b2Transform& xfB)
{
b2DistanceInput input;
input.proxyA.Set(shapeA, indexA);
input.proxyB.Set(shapeB, indexB);
input.transformA = xfA;
input.transformB = xfB;
input.useRadii = true;
b2SimplexCache cache;
cache.count = 0;
b2DistanceOutput output;
b2Distance(&output, &cache, &input);
return output.distance < 10.0f * b2_epsilon;
}
/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_COLLISION_H
#define B2_COLLISION_H
#include "Box2D/Common/b2Math.h"
#include <limits.h>
/// @file
/// Structures and functions used for computing contact points, distance
/// queries, and TOI queries.
class b2Shape;
class b2CircleShape;
class b2EdgeShape;
class b2PolygonShape;
const uint8 b2_nullFeature = UCHAR_MAX;
/// The features that intersect to form the contact point
/// This must be 4 bytes or less.
struct b2ContactFeature
{
enum Type
{
e_vertex = 0,
e_face = 1
};
uint8 indexA; ///< Feature index on shapeA
uint8 indexB; ///< Feature index on shapeB
uint8 typeA; ///< The feature type on shapeA
uint8 typeB; ///< The feature type on shapeB
};
/// Contact ids to facilitate warm starting.
union b2ContactID
{
b2ContactFeature cf;
uint32 key; ///< Used to quickly compare contact ids.
};
/// A manifold point is a contact point belonging to a contact
/// manifold. It holds details related to the geometry and dynamics
/// of the contact points.
/// The local point usage depends on the manifold type:
/// -e_circles: the local center of circleB
/// -e_faceA: the local center of cirlceB or the clip point of polygonB
/// -e_faceB: the clip point of polygonA
/// This structure is stored across time steps, so we keep it small.
/// Note: the impulses are used for internal caching and may not
/// provide reliable contact forces, especially for high speed collisions.
struct b2ManifoldPoint
{
b2Vec2 localPoint; ///< usage depends on manifold type
float32 normalImpulse; ///< the non-penetration impulse
float32 tangentImpulse; ///< the friction impulse
b2ContactID id; ///< uniquely identifies a contact point between two shapes
};
/// A manifold for two touching convex shapes.
/// Box2D supports multiple types of contact:
/// - clip point versus plane with radius
/// - point versus point with radius (circles)
/// The local point usage depends on the manifold type:
/// -e_circles: the local center of circleA
/// -e_faceA: the center of faceA
/// -e_faceB: the center of faceB
/// Similarly the local normal usage:
/// -e_circles: not used
/// -e_faceA: the normal on polygonA
/// -e_faceB: the normal on polygonB
/// We store contacts in this way so that position correction can
/// account for movement, which is critical for continuous physics.
/// All contact scenarios must be expressed in one of these types.
/// This structure is stored across time steps, so we keep it small.
struct b2Manifold
{
enum Type
{
e_circles,
e_faceA,
e_faceB
};
b2ManifoldPoint points[b2_maxManifoldPoints]; ///< the points of contact
b2Vec2 localNormal; ///< not use for Type::e_points
b2Vec2 localPoint; ///< usage depends on manifold type
Type type;
int32 pointCount; ///< the number of manifold points
};
/// This is used to compute the current state of a contact manifold.
struct b2WorldManifold
{
/// Evaluate the manifold with supplied transforms. This assumes
/// modest motion from the original state. This does not change the
/// point count, impulses, etc. The radii must come from the shapes
/// that generated the manifold.
void Initialize(const b2Manifold* manifold,
const b2Transform& xfA, float32 radiusA,
const b2Transform& xfB, float32 radiusB);
b2Vec2 normal; ///< world vector pointing from A to B
b2Vec2 points[b2_maxManifoldPoints]; ///< world contact point (point of intersection)
float32 separations[b2_maxManifoldPoints]; ///< a negative value indicates overlap, in meters
};
/// This is used for determining the state of contact points.
enum b2PointState
{
b2_nullState, ///< point does not exist
b2_addState, ///< point was added in the update
b2_persistState, ///< point persisted across the update
b2_removeState ///< point was removed in the update
};
/// Compute the point states given two manifolds. The states pertain to the transition from manifold1
/// to manifold2. So state1 is either persist or remove while state2 is either add or persist.
void b2GetPointStates(b2PointState state1[b2_maxManifoldPoints], b2PointState state2[b2_maxManifoldPoints],
const b2Manifold* manifold1, const b2Manifold* manifold2);
/// Used for computing contact manifolds.
struct b2ClipVertex
{
b2Vec2 v;
b2ContactID id;
};
/// Ray-cast input data. The ray extends from p1 to p1 + maxFraction * (p2 - p1).
struct b2RayCastInput
{
b2Vec2 p1, p2;
float32 maxFraction;
};
/// Ray-cast output data. The ray hits at p1 + fraction * (p2 - p1), where p1 and p2
/// come from b2RayCastInput.
struct b2RayCastOutput
{
b2Vec2 normal;
float32 fraction;
};
/// An axis aligned bounding box.
struct b2AABB
{
/// Verify that the bounds are sorted.
bool IsValid() const;
/// Get the center of the AABB.
b2Vec2 GetCenter() const
{
return 0.5f * (lowerBound + upperBound);
}
/// Get the extents of the AABB (half-widths).
b2Vec2 GetExtents() const
{
return 0.5f * (upperBound - lowerBound);
}
/// Get the perimeter length
float32 GetPerimeter() const
{
float32 wx = upperBound.x - lowerBound.x;
float32 wy = upperBound.y - lowerBound.y;
return 2.0f * (wx + wy);
}
/// Combine an AABB into this one.
void Combine(const b2AABB& aabb)
{
lowerBound = b2Min(lowerBound, aabb.lowerBound);
upperBound = b2Max(upperBound, aabb.upperBound);
}
/// Combine two AABBs into this one.
void Combine(const b2AABB& aabb1, const b2AABB& aabb2)
{
lowerBound = b2Min(aabb1.lowerBound, aabb2.lowerBound);
upperBound = b2Max(aabb1.upperBound, aabb2.upperBound);
}
/// Does this aabb contain the provided AABB.
bool Contains(const b2AABB& aabb) const
{
bool result = true;
result = result && lowerBound.x <= aabb.lowerBound.x;
result = result && lowerBound.y <= aabb.lowerBound.y;
result = result && aabb.upperBound.x <= upperBound.x;
result = result && aabb.upperBound.y <= upperBound.y;
return result;
}
bool RayCast(b2RayCastOutput* output, const b2RayCastInput& input) const;
b2Vec2 lowerBound; ///< the lower vertex
b2Vec2 upperBound; ///< the upper vertex
};
/// Compute the collision manifold between two circles.
void b2CollideCircles(b2Manifold* manifold,
const b2CircleShape* circleA, const b2Transform& xfA,
const b2CircleShape* circleB, const b2Transform& xfB);
/// Compute the collision manifold between a polygon and a circle.
void b2CollidePolygonAndCircle(b2Manifold* manifold,
const b2PolygonShape* polygonA, const b2Transform& xfA,
const b2CircleShape* circleB, const b2Transform& xfB);
/// Compute the collision manifold between two polygons.
void b2CollidePolygons(b2Manifold* manifold,
const b2PolygonShape* polygonA, const b2Transform& xfA,
const b2PolygonShape* polygonB, const b2Transform& xfB);
/// Compute the collision manifold between an edge and a circle.
void b2CollideEdgeAndCircle(b2Manifold* manifold,
const b2EdgeShape* polygonA, const b2Transform& xfA,
const b2CircleShape* circleB, const b2Transform& xfB);
/// Compute the collision manifold between an edge and a circle.
void b2CollideEdgeAndPolygon(b2Manifold* manifold,
const b2EdgeShape* edgeA, const b2Transform& xfA,
const b2PolygonShape* circleB, const b2Transform& xfB);
/// Clipping for contact manifolds.
int32 b2ClipSegmentToLine(b2ClipVertex vOut[2], const b2ClipVertex vIn[2],
const b2Vec2& normal, float32 offset, int32 vertexIndexA);
/// Determine if two generic shapes overlap.
bool b2TestOverlap( const b2Shape* shapeA, int32 indexA,
const b2Shape* shapeB, int32 indexB,
const b2Transform& xfA, const b2Transform& xfB);
// ---------------- Inline Functions ------------------------------------------
inline bool b2AABB::IsValid() const
{
b2Vec2 d = upperBound - lowerBound;
bool valid = d.x >= 0.0f && d.y >= 0.0f;
valid = valid && lowerBound.IsValid() && upperBound.IsValid();
return valid;
}
inline bool b2TestOverlap(const b2AABB& a, const b2AABB& b)
{
b2Vec2 d1, d2;
d1 = b.lowerBound - a.upperBound;
d2 = a.lowerBound - b.upperBound;
if (d1.x > 0.0f || d1.y > 0.0f)
return false;
if (d2.x > 0.0f || d2.y > 0.0f)
return false;
return true;
}
#endif
/*
* Copyright (c) 2007-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "Box2D/Collision/b2Distance.h"
#include "Box2D/Collision/Shapes/b2CircleShape.h"
#include "Box2D/Collision/Shapes/b2EdgeShape.h"
#include "Box2D/Collision/Shapes/b2ChainShape.h"
#include "Box2D/Collision/Shapes/b2PolygonShape.h"
// GJK using Voronoi regions (Christer Ericson) and Barycentric coordinates.
int32 b2_gjkCalls, b2_gjkIters, b2_gjkMaxIters;
void b2DistanceProxy::Set(const b2Shape* shape, int32 index)
{
switch (shape->GetType())
{
case b2Shape::e_circle:
{
const b2CircleShape* circle = static_cast<const b2CircleShape*>(shape);
m_vertices = &circle->m_p;
m_count = 1;
m_radius = circle->m_radius;
}
break;
case b2Shape::e_polygon:
{
const b2PolygonShape* polygon = static_cast<const b2PolygonShape*>(shape);
m_vertices = polygon->m_vertices;
m_count = polygon->m_count;
m_radius = polygon->m_radius;
}
break;
case b2Shape::e_chain:
{
const b2ChainShape* chain = static_cast<const b2ChainShape*>(shape);
b2Assert(0 <= index && index < chain->m_count);
m_buffer[0] = chain->m_vertices[index];
if (index + 1 < chain->m_count)
{
m_buffer[1] = chain->m_vertices[index + 1];
}
else
{
m_buffer[1] = chain->m_vertices[0];
}
m_vertices = m_buffer;
m_count = 2;
m_radius = chain->m_radius;
}
break;
case b2Shape::e_edge:
{
const b2EdgeShape* edge = static_cast<const b2EdgeShape*>(shape);
m_vertices = &edge->m_vertex1;
m_count = 2;
m_radius = edge->m_radius;
}
break;
default:
b2Assert(false);
}
}
struct b2SimplexVertex
{
b2Vec2 wA; // support point in proxyA
b2Vec2 wB; // support point in proxyB
b2Vec2 w; // wB - wA
float32 a; // barycentric coordinate for closest point
int32 indexA; // wA index
int32 indexB; // wB index
};
struct b2Simplex
{
void ReadCache( const b2SimplexCache* cache,
const b2DistanceProxy* proxyA, const b2Transform& transformA,
const b2DistanceProxy* proxyB, const b2Transform& transformB)
{
b2Assert(cache->count <= 3);
// Copy data from cache.
m_count = cache->count;
b2SimplexVertex* vertices = &m_v1;
for (int32 i = 0; i < m_count; ++i)
{
b2SimplexVertex* v = vertices + i;
v->indexA = cache->indexA[i];
v->indexB = cache->indexB[i];
b2Vec2 wALocal = proxyA->GetVertex(v->indexA);
b2Vec2 wBLocal = proxyB->GetVertex(v->indexB);
v->wA = b2Mul(transformA, wALocal);
v->wB = b2Mul(transformB, wBLocal);
v->w = v->wB - v->wA;
v->a = 0.0f;
}
// Compute the new simplex metric, if it is substantially different than
// old metric then flush the simplex.
if (m_count > 1)
{
float32 metric1 = cache->metric;
float32 metric2 = GetMetric();
if (metric2 < 0.5f * metric1 || 2.0f * metric1 < metric2 || metric2 < b2_epsilon)
{
// Reset the simplex.
m_count = 0;
}
}
// If the cache is empty or invalid ...
if (m_count == 0)
{
b2SimplexVertex* v = vertices + 0;
v->indexA = 0;
v->indexB = 0;
b2Vec2 wALocal = proxyA->GetVertex(0);
b2Vec2 wBLocal = proxyB->GetVertex(0);
v->wA = b2Mul(transformA, wALocal);
v->wB = b2Mul(transformB, wBLocal);
v->w = v->wB - v->wA;
v->a = 1.0f;
m_count = 1;
}
}
void WriteCache(b2SimplexCache* cache) const
{
cache->metric = GetMetric();
cache->count = uint16(m_count);
const b2SimplexVertex* vertices = &m_v1;
for (int32 i = 0; i < m_count; ++i)
{
cache->indexA[i] = uint8(vertices[i].indexA);
cache->indexB[i] = uint8(vertices[i].indexB);
}
}
b2Vec2 GetSearchDirection() const
{
switch (m_count)
{
case 1:
return -m_v1.w;
case 2:
{
b2Vec2 e12 = m_v2.w - m_v1.w;
float32 sgn = b2Cross(e12, -m_v1.w);
if (sgn > 0.0f)
{
// Origin is left of e12.
return b2Cross(1.0f, e12);
}
else
{
// Origin is right of e12.
return b2Cross(e12, 1.0f);
}
}
default:
b2Assert(false);
return b2Vec2_zero;
}
}
b2Vec2 GetClosestPoint() const
{
switch (m_count)
{
case 0:
b2Assert(false);
return b2Vec2_zero;
case 1:
return m_v1.w;
case 2:
return m_v1.a * m_v1.w + m_v2.a * m_v2.w;
case 3:
return b2Vec2_zero;
default:
b2Assert(false);
return b2Vec2_zero;
}
}
void GetWitnessPoints(b2Vec2* pA, b2Vec2* pB) const
{
switch (m_count)
{
case 0:
b2Assert(false);
break;
case 1:
*pA = m_v1.wA;
*pB = m_v1.wB;
break;
case 2:
*pA = m_v1.a * m_v1.wA + m_v2.a * m_v2.wA;
*pB = m_v1.a * m_v1.wB + m_v2.a * m_v2.wB;
break;
case 3:
*pA = m_v1.a * m_v1.wA + m_v2.a * m_v2.wA + m_v3.a * m_v3.wA;
*pB = *pA;
break;
default:
b2Assert(false);
break;
}
}
float32 GetMetric() const
{
switch (m_count)
{
case 0:
b2Assert(false);
return 0.0f;
case 1:
return 0.0f;
case 2:
return b2Distance(m_v1.w, m_v2.w);
case 3:
return b2Cross(m_v2.w - m_v1.w, m_v3.w - m_v1.w);
default:
b2Assert(false);
return 0.0f;
}
}
void Solve2();
void Solve3();
b2SimplexVertex m_v1, m_v2, m_v3;
int32 m_count;
};
// Solve a line segment using barycentric coordinates.
//
// p = a1 * w1 + a2 * w2
// a1 + a2 = 1
//
// The vector from the origin to the closest point on the line is
// perpendicular to the line.
// e12 = w2 - w1
// dot(p, e) = 0
// a1 * dot(w1, e) + a2 * dot(w2, e) = 0
//
// 2-by-2 linear system
// [1 1 ][a1] = [1]
// [w1.e12 w2.e12][a2] = [0]
//
// Define
// d12_1 = dot(w2, e12)
// d12_2 = -dot(w1, e12)
// d12 = d12_1 + d12_2
//
// Solution
// a1 = d12_1 / d12
// a2 = d12_2 / d12
void b2Simplex::Solve2()
{
b2Vec2 w1 = m_v1.w;
b2Vec2 w2 = m_v2.w;
b2Vec2 e12 = w2 - w1;
// w1 region
float32 d12_2 = -b2Dot(w1, e12);
if (d12_2 <= 0.0f)
{
// a2 <= 0, so we clamp it to 0
m_v1.a = 1.0f;
m_count = 1;
return;
}
// w2 region
float32 d12_1 = b2Dot(w2, e12);
if (d12_1 <= 0.0f)
{
// a1 <= 0, so we clamp it to 0
m_v2.a = 1.0f;
m_count = 1;
m_v1 = m_v2;
return;
}
// Must be in e12 region.
float32 inv_d12 = 1.0f / (d12_1 + d12_2);
m_v1.a = d12_1 * inv_d12;
m_v2.a = d12_2 * inv_d12;
m_count = 2;
}
// Possible regions:
// - points[2]
// - edge points[0]-points[2]
// - edge points[1]-points[2]
// - inside the triangle
void b2Simplex::Solve3()
{
b2Vec2 w1 = m_v1.w;
b2Vec2 w2 = m_v2.w;
b2Vec2 w3 = m_v3.w;
// Edge12
// [1 1 ][a1] = [1]
// [w1.e12 w2.e12][a2] = [0]
// a3 = 0
b2Vec2 e12 = w2 - w1;
float32 w1e12 = b2Dot(w1, e12);
float32 w2e12 = b2Dot(w2, e12);
float32 d12_1 = w2e12;
float32 d12_2 = -w1e12;
// Edge13
// [1 1 ][a1] = [1]
// [w1.e13 w3.e13][a3] = [0]
// a2 = 0
b2Vec2 e13 = w3 - w1;
float32 w1e13 = b2Dot(w1, e13);
float32 w3e13 = b2Dot(w3, e13);
float32 d13_1 = w3e13;
float32 d13_2 = -w1e13;
// Edge23
// [1 1 ][a2] = [1]
// [w2.e23 w3.e23][a3] = [0]
// a1 = 0
b2Vec2 e23 = w3 - w2;
float32 w2e23 = b2Dot(w2, e23);
float32 w3e23 = b2Dot(w3, e23);
float32 d23_1 = w3e23;
float32 d23_2 = -w2e23;
// Triangle123
float32 n123 = b2Cross(e12, e13);
float32 d123_1 = n123 * b2Cross(w2, w3);
float32 d123_2 = n123 * b2Cross(w3, w1);
float32 d123_3 = n123 * b2Cross(w1, w2);
// w1 region
if (d12_2 <= 0.0f && d13_2 <= 0.0f)
{
m_v1.a = 1.0f;
m_count = 1;
return;
}
// e12
if (d12_1 > 0.0f && d12_2 > 0.0f && d123_3 <= 0.0f)
{
float32 inv_d12 = 1.0f / (d12_1 + d12_2);
m_v1.a = d12_1 * inv_d12;
m_v2.a = d12_2 * inv_d12;
m_count = 2;
return;
}
// e13
if (d13_1 > 0.0f && d13_2 > 0.0f && d123_2 <= 0.0f)
{
float32 inv_d13 = 1.0f / (d13_1 + d13_2);
m_v1.a = d13_1 * inv_d13;
m_v3.a = d13_2 * inv_d13;
m_count = 2;
m_v2 = m_v3;
return;
}
// w2 region
if (d12_1 <= 0.0f && d23_2 <= 0.0f)
{
m_v2.a = 1.0f;
m_count = 1;
m_v1 = m_v2;
return;
}
// w3 region
if (d13_1 <= 0.0f && d23_1 <= 0.0f)
{
m_v3.a = 1.0f;
m_count = 1;
m_v1 = m_v3;
return;
}
// e23
if (d23_1 > 0.0f && d23_2 > 0.0f && d123_1 <= 0.0f)
{
float32 inv_d23 = 1.0f / (d23_1 + d23_2);
m_v2.a = d23_1 * inv_d23;
m_v3.a = d23_2 * inv_d23;
m_count = 2;
m_v1 = m_v3;
return;
}
// Must be in triangle123
float32 inv_d123 = 1.0f / (d123_1 + d123_2 + d123_3);
m_v1.a = d123_1 * inv_d123;
m_v2.a = d123_2 * inv_d123;
m_v3.a = d123_3 * inv_d123;
m_count = 3;
}
void b2Distance(b2DistanceOutput* output,
b2SimplexCache* cache,
const b2DistanceInput* input)
{
++b2_gjkCalls;
const b2DistanceProxy* proxyA = &input->proxyA;
const b2DistanceProxy* proxyB = &input->proxyB;
b2Transform transformA = input->transformA;
b2Transform transformB = input->transformB;
// Initialize the simplex.
b2Simplex simplex;
simplex.ReadCache(cache, proxyA, transformA, proxyB, transformB);
// Get simplex vertices as an array.
b2SimplexVertex* vertices = &simplex.m_v1;
const int32 k_maxIters = 20;
// These store the vertices of the last simplex so that we
// can check for duplicates and prevent cycling.
int32 saveA[3], saveB[3];
int32 saveCount = 0;
// Main iteration loop.
int32 iter = 0;
while (iter < k_maxIters)
{
// Copy simplex so we can identify duplicates.
saveCount = simplex.m_count;
for (int32 i = 0; i < saveCount; ++i)
{
saveA[i] = vertices[i].indexA;
saveB[i] = vertices[i].indexB;
}
switch (simplex.m_count)
{
case 1:
break;
case 2:
simplex.Solve2();
break;
case 3:
simplex.Solve3();
break;
default:
b2Assert(false);
}
// If we have 3 points, then the origin is in the corresponding triangle.
if (simplex.m_count == 3)
{
break;
}
// Get search direction.
b2Vec2 d = simplex.GetSearchDirection();
// Ensure the search direction is numerically fit.
if (d.LengthSquared() < b2_epsilon * b2_epsilon)
{
// The origin is probably contained by a line segment
// or triangle. Thus the shapes are overlapped.
// We can't return zero here even though there may be overlap.
// In case the simplex is a point, segment, or triangle it is difficult
// to determine if the origin is contained in the CSO or very close to it.
break;
}
// Compute a tentative new simplex vertex using support points.
b2SimplexVertex* vertex = vertices + simplex.m_count;
vertex->indexA = proxyA->GetSupport(b2MulT(transformA.q, -d));
vertex->wA = b2Mul(transformA, proxyA->GetVertex(vertex->indexA));
b2Vec2 wBLocal;
vertex->indexB = proxyB->GetSupport(b2MulT(transformB.q, d));
vertex->wB = b2Mul(transformB, proxyB->GetVertex(vertex->indexB));
vertex->w = vertex->wB - vertex->wA;
// Iteration count is equated to the number of support point calls.
++iter;
++b2_gjkIters;
// Check for duplicate support points. This is the main termination criteria.
bool duplicate = false;
for (int32 i = 0; i < saveCount; ++i)
{
if (vertex->indexA == saveA[i] && vertex->indexB == saveB[i])
{
duplicate = true;
break;
}
}
// If we found a duplicate support point we must exit to avoid cycling.
if (duplicate)
{
break;
}
// New vertex is ok and needed.
++simplex.m_count;
}
b2_gjkMaxIters = b2Max(b2_gjkMaxIters, iter);
// Prepare output.
simplex.GetWitnessPoints(&output->pointA, &output->pointB);
output->distance = b2Distance(output->pointA, output->pointB);
output->iterations = iter;
// Cache the simplex.
simplex.WriteCache(cache);
// Apply radii if requested.
if (input->useRadii)
{
float32 rA = proxyA->m_radius;
float32 rB = proxyB->m_radius;
if (output->distance > rA + rB && output->distance > b2_epsilon)
{
// Shapes are still no overlapped.
// Move the witness points to the outer surface.
output->distance -= rA + rB;
b2Vec2 normal = output->pointB - output->pointA;
normal.Normalize();
output->pointA += rA * normal;
output->pointB -= rB * normal;
}
else
{
// Shapes are overlapped when radii are considered.
// Move the witness points to the middle.
b2Vec2 p = 0.5f * (output->pointA + output->pointB);
output->pointA = p;
output->pointB = p;
output->distance = 0.0f;
}
}
}
/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_DISTANCE_H
#define B2_DISTANCE_H
#include "Box2D/Common/b2Math.h"
class b2Shape;
/// A distance proxy is used by the GJK algorithm.
/// It encapsulates any shape.
struct b2DistanceProxy
{
b2DistanceProxy() : m_vertices(nullptr), m_count(0), m_radius(0.0f) {}
/// Initialize the proxy using the given shape. The shape
/// must remain in scope while the proxy is in use.
void Set(const b2Shape* shape, int32 index);
/// Get the supporting vertex index in the given direction.
int32 GetSupport(const b2Vec2& d) const;
/// Get the supporting vertex in the given direction.
const b2Vec2& GetSupportVertex(const b2Vec2& d) const;
/// Get the vertex count.
int32 GetVertexCount() const;
/// Get a vertex by index. Used by b2Distance.
const b2Vec2& GetVertex(int32 index) const;
b2Vec2 m_buffer[2];
const b2Vec2* m_vertices;
int32 m_count;
float32 m_radius;
};
/// Used to warm start b2Distance.
/// Set count to zero on first call.
struct b2SimplexCache
{
float32 metric; ///< length or area
uint16 count;
uint8 indexA[3]; ///< vertices on shape A
uint8 indexB[3]; ///< vertices on shape B
};
/// Input for b2Distance.
/// You have to option to use the shape radii
/// in the computation. Even
struct b2DistanceInput
{
b2DistanceProxy proxyA;
b2DistanceProxy proxyB;
b2Transform transformA;
b2Transform transformB;
bool useRadii;
};
/// Output for b2Distance.
struct b2DistanceOutput
{
b2Vec2 pointA; ///< closest point on shapeA
b2Vec2 pointB; ///< closest point on shapeB
float32 distance;
int32 iterations; ///< number of GJK iterations used
};
/// Compute the closest points between two shapes. Supports any combination of:
/// b2CircleShape, b2PolygonShape, b2EdgeShape. The simplex cache is input/output.
/// On the first call set b2SimplexCache.count to zero.
void b2Distance(b2DistanceOutput* output,
b2SimplexCache* cache,
const b2DistanceInput* input);
//////////////////////////////////////////////////////////////////////////
inline int32 b2DistanceProxy::GetVertexCount() const
{
return m_count;
}
inline const b2Vec2& b2DistanceProxy::GetVertex(int32 index) const
{
b2Assert(0 <= index && index < m_count);
return m_vertices[index];
}
inline int32 b2DistanceProxy::GetSupport(const b2Vec2& d) const
{
int32 bestIndex = 0;
float32 bestValue = b2Dot(m_vertices[0], d);
for (int32 i = 1; i < m_count; ++i)
{
float32 value = b2Dot(m_vertices[i], d);
if (value > bestValue)
{
bestIndex = i;
bestValue = value;
}
}
return bestIndex;
}
inline const b2Vec2& b2DistanceProxy::GetSupportVertex(const b2Vec2& d) const
{
int32 bestIndex = 0;
float32 bestValue = b2Dot(m_vertices[0], d);
for (int32 i = 1; i < m_count; ++i)
{
float32 value = b2Dot(m_vertices[i], d);
if (value > bestValue)
{
bestIndex = i;
bestValue = value;
}
}
return m_vertices[bestIndex];
}
#endif
/*
* Copyright (c) 2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "Box2D/Collision/b2DynamicTree.h"
#include <string.h>
b2DynamicTree::b2DynamicTree()
{
m_root = b2_nullNode;
m_nodeCapacity = 16;
m_nodeCount = 0;
m_nodes = (b2TreeNode*)b2Alloc(m_nodeCapacity * sizeof(b2TreeNode));
memset(m_nodes, 0, m_nodeCapacity * sizeof(b2TreeNode));
// Build a linked list for the free list.
for (int32 i = 0; i < m_nodeCapacity - 1; ++i)
{
m_nodes[i].next = i + 1;
m_nodes[i].height = -1;
}
m_nodes[m_nodeCapacity-1].next = b2_nullNode;
m_nodes[m_nodeCapacity-1].height = -1;
m_freeList = 0;
m_path = 0;
m_insertionCount = 0;
}
b2DynamicTree::~b2DynamicTree()
{
// This frees the entire tree in one shot.
b2Free(m_nodes);
}
// Allocate a node from the pool. Grow the pool if necessary.
int32 b2DynamicTree::AllocateNode()
{
// Expand the node pool as needed.
if (m_freeList == b2_nullNode)
{
b2Assert(m_nodeCount == m_nodeCapacity);
// The free list is empty. Rebuild a bigger pool.
b2TreeNode* oldNodes = m_nodes;
m_nodeCapacity *= 2;
m_nodes = (b2TreeNode*)b2Alloc(m_nodeCapacity * sizeof(b2TreeNode));
memcpy(m_nodes, oldNodes, m_nodeCount * sizeof(b2TreeNode));
b2Free(oldNodes);
// Build a linked list for the free list. The parent
// pointer becomes the "next" pointer.
for (int32 i = m_nodeCount; i < m_nodeCapacity - 1; ++i)
{
m_nodes[i].next = i + 1;
m_nodes[i].height = -1;
}
m_nodes[m_nodeCapacity-1].next = b2_nullNode;
m_nodes[m_nodeCapacity-1].height = -1;
m_freeList = m_nodeCount;
}
// Peel a node off the free list.
int32 nodeId = m_freeList;
m_freeList = m_nodes[nodeId].next;
m_nodes[nodeId].parent = b2_nullNode;
m_nodes[nodeId].child1 = b2_nullNode;
m_nodes[nodeId].child2 = b2_nullNode;
m_nodes[nodeId].height = 0;
m_nodes[nodeId].userData = nullptr;
++m_nodeCount;
return nodeId;
}
// Return a node to the pool.
void b2DynamicTree::FreeNode(int32 nodeId)
{
b2Assert(0 <= nodeId && nodeId < m_nodeCapacity);
b2Assert(0 < m_nodeCount);
m_nodes[nodeId].next = m_freeList;
m_nodes[nodeId].height = -1;
m_freeList = nodeId;
--m_nodeCount;
}
// Create a proxy in the tree as a leaf node. We return the index
// of the node instead of a pointer so that we can grow
// the node pool.
int32 b2DynamicTree::CreateProxy(const b2AABB& aabb, void* userData)
{
int32 proxyId = AllocateNode();
// Fatten the aabb.
b2Vec2 r(b2_aabbExtension, b2_aabbExtension);
m_nodes[proxyId].aabb.lowerBound = aabb.lowerBound - r;
m_nodes[proxyId].aabb.upperBound = aabb.upperBound + r;
m_nodes[proxyId].userData = userData;
m_nodes[proxyId].height = 0;
InsertLeaf(proxyId);
return proxyId;
}
void b2DynamicTree::DestroyProxy(int32 proxyId)
{
b2Assert(0 <= proxyId && proxyId < m_nodeCapacity);
b2Assert(m_nodes[proxyId].IsLeaf());
RemoveLeaf(proxyId);
FreeNode(proxyId);
}
bool b2DynamicTree::MoveProxy(int32 proxyId, const b2AABB& aabb, const b2Vec2& displacement)
{
b2Assert(0 <= proxyId && proxyId < m_nodeCapacity);
b2Assert(m_nodes[proxyId].IsLeaf());
if (m_nodes[proxyId].aabb.Contains(aabb))
{
return false;
}
RemoveLeaf(proxyId);
// Extend AABB.
b2AABB b = aabb;
b2Vec2 r(b2_aabbExtension, b2_aabbExtension);
b.lowerBound = b.lowerBound - r;
b.upperBound = b.upperBound + r;
// Predict AABB displacement.
b2Vec2 d = b2_aabbMultiplier * displacement;
if (d.x < 0.0f)
{
b.lowerBound.x += d.x;
}
else
{
b.upperBound.x += d.x;
}
if (d.y < 0.0f)
{
b.lowerBound.y += d.y;
}
else
{
b.upperBound.y += d.y;
}
m_nodes[proxyId].aabb = b;
InsertLeaf(proxyId);
return true;
}
void b2DynamicTree::InsertLeaf(int32 leaf)
{
++m_insertionCount;
if (m_root == b2_nullNode)
{
m_root = leaf;
m_nodes[m_root].parent = b2_nullNode;
return;
}
// Find the best sibling for this node
b2AABB leafAABB = m_nodes[leaf].aabb;
int32 index = m_root;
while (m_nodes[index].IsLeaf() == false)
{
int32 child1 = m_nodes[index].child1;
int32 child2 = m_nodes[index].child2;
float32 area = m_nodes[index].aabb.GetPerimeter();
b2AABB combinedAABB;
combinedAABB.Combine(m_nodes[index].aabb, leafAABB);
float32 combinedArea = combinedAABB.GetPerimeter();
// Cost of creating a new parent for this node and the new leaf
float32 cost = 2.0f * combinedArea;
// Minimum cost of pushing the leaf further down the tree
float32 inheritanceCost = 2.0f * (combinedArea - area);
// Cost of descending into child1
float32 cost1;
if (m_nodes[child1].IsLeaf())
{
b2AABB aabb;
aabb.Combine(leafAABB, m_nodes[child1].aabb);
cost1 = aabb.GetPerimeter() + inheritanceCost;
}
else
{
b2AABB aabb;
aabb.Combine(leafAABB, m_nodes[child1].aabb);
float32 oldArea = m_nodes[child1].aabb.GetPerimeter();
float32 newArea = aabb.GetPerimeter();
cost1 = (newArea - oldArea) + inheritanceCost;
}
// Cost of descending into child2
float32 cost2;
if (m_nodes[child2].IsLeaf())
{
b2AABB aabb;
aabb.Combine(leafAABB, m_nodes[child2].aabb);
cost2 = aabb.GetPerimeter() + inheritanceCost;
}
else
{
b2AABB aabb;
aabb.Combine(leafAABB, m_nodes[child2].aabb);
float32 oldArea = m_nodes[child2].aabb.GetPerimeter();
float32 newArea = aabb.GetPerimeter();
cost2 = newArea - oldArea + inheritanceCost;
}
// Descend according to the minimum cost.
if (cost < cost1 && cost < cost2)
{
break;
}
// Descend
if (cost1 < cost2)
{
index = child1;
}
else
{
index = child2;
}
}
int32 sibling = index;
// Create a new parent.
int32 oldParent = m_nodes[sibling].parent;
int32 newParent = AllocateNode();
m_nodes[newParent].parent = oldParent;
m_nodes[newParent].userData = nullptr;
m_nodes[newParent].aabb.Combine(leafAABB, m_nodes[sibling].aabb);
m_nodes[newParent].height = m_nodes[sibling].height + 1;
if (oldParent != b2_nullNode)
{
// The sibling was not the root.
if (m_nodes[oldParent].child1 == sibling)
{
m_nodes[oldParent].child1 = newParent;
}
else
{
m_nodes[oldParent].child2 = newParent;
}
m_nodes[newParent].child1 = sibling;
m_nodes[newParent].child2 = leaf;
m_nodes[sibling].parent = newParent;
m_nodes[leaf].parent = newParent;
}
else
{
// The sibling was the root.
m_nodes[newParent].child1 = sibling;
m_nodes[newParent].child2 = leaf;
m_nodes[sibling].parent = newParent;
m_nodes[leaf].parent = newParent;
m_root = newParent;
}
// Walk back up the tree fixing heights and AABBs
index = m_nodes[leaf].parent;
while (index != b2_nullNode)
{
index = Balance(index);
int32 child1 = m_nodes[index].child1;
int32 child2 = m_nodes[index].child2;
b2Assert(child1 != b2_nullNode);
b2Assert(child2 != b2_nullNode);
m_nodes[index].height = 1 + b2Max(m_nodes[child1].height, m_nodes[child2].height);
m_nodes[index].aabb.Combine(m_nodes[child1].aabb, m_nodes[child2].aabb);
index = m_nodes[index].parent;
}
//Validate();
}
void b2DynamicTree::RemoveLeaf(int32 leaf)
{
if (leaf == m_root)
{
m_root = b2_nullNode;
return;
}
int32 parent = m_nodes[leaf].parent;
int32 grandParent = m_nodes[parent].parent;
int32 sibling;
if (m_nodes[parent].child1 == leaf)
{
sibling = m_nodes[parent].child2;
}
else
{
sibling = m_nodes[parent].child1;
}
if (grandParent != b2_nullNode)
{
// Destroy parent and connect sibling to grandParent.
if (m_nodes[grandParent].child1 == parent)
{
m_nodes[grandParent].child1 = sibling;
}
else
{
m_nodes[grandParent].child2 = sibling;
}
m_nodes[sibling].parent = grandParent;
FreeNode(parent);
// Adjust ancestor bounds.
int32 index = grandParent;
while (index != b2_nullNode)
{
index = Balance(index);
int32 child1 = m_nodes[index].child1;
int32 child2 = m_nodes[index].child2;
m_nodes[index].aabb.Combine(m_nodes[child1].aabb, m_nodes[child2].aabb);
m_nodes[index].height = 1 + b2Max(m_nodes[child1].height, m_nodes[child2].height);
index = m_nodes[index].parent;
}
}
else
{
m_root = sibling;
m_nodes[sibling].parent = b2_nullNode;
FreeNode(parent);
}
//Validate();
}
// Perform a left or right rotation if node A is imbalanced.
// Returns the new root index.
int32 b2DynamicTree::Balance(int32 iA)
{
b2Assert(iA != b2_nullNode);
b2TreeNode* A = m_nodes + iA;
if (A->IsLeaf() || A->height < 2)
{
return iA;
}
int32 iB = A->child1;
int32 iC = A->child2;
b2Assert(0 <= iB && iB < m_nodeCapacity);
b2Assert(0 <= iC && iC < m_nodeCapacity);
b2TreeNode* B = m_nodes + iB;
b2TreeNode* C = m_nodes + iC;
int32 balance = C->height - B->height;
// Rotate C up
if (balance > 1)
{
int32 iF = C->child1;
int32 iG = C->child2;
b2TreeNode* F = m_nodes + iF;
b2TreeNode* G = m_nodes + iG;
b2Assert(0 <= iF && iF < m_nodeCapacity);
b2Assert(0 <= iG && iG < m_nodeCapacity);
// Swap A and C
C->child1 = iA;
C->parent = A->parent;
A->parent = iC;
// A's old parent should point to C
if (C->parent != b2_nullNode)
{
if (m_nodes[C->parent].child1 == iA)
{
m_nodes[C->parent].child1 = iC;
}
else
{
b2Assert(m_nodes[C->parent].child2 == iA);
m_nodes[C->parent].child2 = iC;
}
}
else
{
m_root = iC;
}
// Rotate
if (F->height > G->height)
{
C->child2 = iF;
A->child2 = iG;
G->parent = iA;
A->aabb.Combine(B->aabb, G->aabb);
C->aabb.Combine(A->aabb, F->aabb);
A->height = 1 + b2Max(B->height, G->height);
C->height = 1 + b2Max(A->height, F->height);
}
else
{
C->child2 = iG;
A->child2 = iF;
F->parent = iA;
A->aabb.Combine(B->aabb, F->aabb);
C->aabb.Combine(A->aabb, G->aabb);
A->height = 1 + b2Max(B->height, F->height);
C->height = 1 + b2Max(A->height, G->height);
}
return iC;
}
// Rotate B up
if (balance < -1)
{
int32 iD = B->child1;
int32 iE = B->child2;
b2TreeNode* D = m_nodes + iD;
b2TreeNode* E = m_nodes + iE;
b2Assert(0 <= iD && iD < m_nodeCapacity);
b2Assert(0 <= iE && iE < m_nodeCapacity);
// Swap A and B
B->child1 = iA;
B->parent = A->parent;
A->parent = iB;
// A's old parent should point to B
if (B->parent != b2_nullNode)
{
if (m_nodes[B->parent].child1 == iA)
{
m_nodes[B->parent].child1 = iB;
}
else
{
b2Assert(m_nodes[B->parent].child2 == iA);
m_nodes[B->parent].child2 = iB;
}
}
else
{
m_root = iB;
}
// Rotate
if (D->height > E->height)
{
B->child2 = iD;
A->child1 = iE;
E->parent = iA;
A->aabb.Combine(C->aabb, E->aabb);
B->aabb.Combine(A->aabb, D->aabb);
A->height = 1 + b2Max(C->height, E->height);
B->height = 1 + b2Max(A->height, D->height);
}
else
{
B->child2 = iE;
A->child1 = iD;
D->parent = iA;
A->aabb.Combine(C->aabb, D->aabb);
B->aabb.Combine(A->aabb, E->aabb);
A->height = 1 + b2Max(C->height, D->height);
B->height = 1 + b2Max(A->height, E->height);
}
return iB;
}
return iA;
}
int32 b2DynamicTree::GetHeight() const
{
if (m_root == b2_nullNode)
{
return 0;
}
return m_nodes[m_root].height;
}
//
float32 b2DynamicTree::GetAreaRatio() const
{
if (m_root == b2_nullNode)
{
return 0.0f;
}
const b2TreeNode* root = m_nodes + m_root;
float32 rootArea = root->aabb.GetPerimeter();
float32 totalArea = 0.0f;
for (int32 i = 0; i < m_nodeCapacity; ++i)
{
const b2TreeNode* node = m_nodes + i;
if (node->height < 0)
{
// Free node in pool
continue;
}
totalArea += node->aabb.GetPerimeter();
}
return totalArea / rootArea;
}
// Compute the height of a sub-tree.
int32 b2DynamicTree::ComputeHeight(int32 nodeId) const
{
b2Assert(0 <= nodeId && nodeId < m_nodeCapacity);
b2TreeNode* node = m_nodes + nodeId;
if (node->IsLeaf())
{
return 0;
}
int32 height1 = ComputeHeight(node->child1);
int32 height2 = ComputeHeight(node->child2);
return 1 + b2Max(height1, height2);
}
int32 b2DynamicTree::ComputeHeight() const
{
int32 height = ComputeHeight(m_root);
return height;
}
void b2DynamicTree::ValidateStructure(int32 index) const
{
if (index == b2_nullNode)
{
return;
}
if (index == m_root)
{
b2Assert(m_nodes[index].parent == b2_nullNode);
}
const b2TreeNode* node = m_nodes + index;
int32 child1 = node->child1;
int32 child2 = node->child2;
if (node->IsLeaf())
{
b2Assert(child1 == b2_nullNode);
b2Assert(child2 == b2_nullNode);
b2Assert(node->height == 0);
return;
}
b2Assert(0 <= child1 && child1 < m_nodeCapacity);
b2Assert(0 <= child2 && child2 < m_nodeCapacity);
b2Assert(m_nodes[child1].parent == index);
b2Assert(m_nodes[child2].parent == index);
ValidateStructure(child1);
ValidateStructure(child2);
}
void b2DynamicTree::ValidateMetrics(int32 index) const
{
if (index == b2_nullNode)
{
return;
}
const b2TreeNode* node = m_nodes + index;
int32 child1 = node->child1;
int32 child2 = node->child2;
if (node->IsLeaf())
{
b2Assert(child1 == b2_nullNode);
b2Assert(child2 == b2_nullNode);
b2Assert(node->height == 0);
return;
}
b2Assert(0 <= child1 && child1 < m_nodeCapacity);
b2Assert(0 <= child2 && child2 < m_nodeCapacity);
int32 height1 = m_nodes[child1].height;
int32 height2 = m_nodes[child2].height;
int32 height;
height = 1 + b2Max(height1, height2);
b2Assert(node->height == height);
b2AABB aabb;
aabb.Combine(m_nodes[child1].aabb, m_nodes[child2].aabb);
b2Assert(aabb.lowerBound == node->aabb.lowerBound);
b2Assert(aabb.upperBound == node->aabb.upperBound);
ValidateMetrics(child1);
ValidateMetrics(child2);
}
void b2DynamicTree::Validate() const
{
#if defined(b2DEBUG)
ValidateStructure(m_root);
ValidateMetrics(m_root);
int32 freeCount = 0;
int32 freeIndex = m_freeList;
while (freeIndex != b2_nullNode)
{
b2Assert(0 <= freeIndex && freeIndex < m_nodeCapacity);
freeIndex = m_nodes[freeIndex].next;
++freeCount;
}
b2Assert(GetHeight() == ComputeHeight());
b2Assert(m_nodeCount + freeCount == m_nodeCapacity);
#endif
}
int32 b2DynamicTree::GetMaxBalance() const
{
int32 maxBalance = 0;
for (int32 i = 0; i < m_nodeCapacity; ++i)
{
const b2TreeNode* node = m_nodes + i;
if (node->height <= 1)
{
continue;
}
b2Assert(node->IsLeaf() == false);
int32 child1 = node->child1;
int32 child2 = node->child2;
int32 balance = b2Abs(m_nodes[child2].height - m_nodes[child1].height);
maxBalance = b2Max(maxBalance, balance);
}
return maxBalance;
}
void b2DynamicTree::RebuildBottomUp()
{
int32* nodes = (int32*)b2Alloc(m_nodeCount * sizeof(int32));
int32 count = 0;
// Build array of leaves. Free the rest.
for (int32 i = 0; i < m_nodeCapacity; ++i)
{
if (m_nodes[i].height < 0)
{
// free node in pool
continue;
}
if (m_nodes[i].IsLeaf())
{
m_nodes[i].parent = b2_nullNode;
nodes[count] = i;
++count;
}
else
{
FreeNode(i);
}
}
while (count > 1)
{
float32 minCost = b2_maxFloat;
int32 iMin = -1, jMin = -1;
for (int32 i = 0; i < count; ++i)
{
b2AABB aabbi = m_nodes[nodes[i]].aabb;
for (int32 j = i + 1; j < count; ++j)
{
b2AABB aabbj = m_nodes[nodes[j]].aabb;
b2AABB b;
b.Combine(aabbi, aabbj);
float32 cost = b.GetPerimeter();
if (cost < minCost)
{
iMin = i;
jMin = j;
minCost = cost;
}
}
}
int32 index1 = nodes[iMin];
int32 index2 = nodes[jMin];
b2TreeNode* child1 = m_nodes + index1;
b2TreeNode* child2 = m_nodes + index2;
int32 parentIndex = AllocateNode();
b2TreeNode* parent = m_nodes + parentIndex;
parent->child1 = index1;
parent->child2 = index2;
parent->height = 1 + b2Max(child1->height, child2->height);
parent->aabb.Combine(child1->aabb, child2->aabb);
parent->parent = b2_nullNode;
child1->parent = parentIndex;
child2->parent = parentIndex;
nodes[jMin] = nodes[count-1];
nodes[iMin] = parentIndex;
--count;
}
m_root = nodes[0];
b2Free(nodes);
Validate();
}
void b2DynamicTree::ShiftOrigin(const b2Vec2& newOrigin)
{
// Build array of leaves. Free the rest.
for (int32 i = 0; i < m_nodeCapacity; ++i)
{
m_nodes[i].aabb.lowerBound -= newOrigin;
m_nodes[i].aabb.upperBound -= newOrigin;
}
}
/*
* Copyright (c) 2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_DYNAMIC_TREE_H
#define B2_DYNAMIC_TREE_H
#include "Box2D/Collision/b2Collision.h"
#include "Box2D/Common/b2GrowableStack.h"
#define b2_nullNode (-1)
/// A node in the dynamic tree. The client does not interact with this directly.
struct b2TreeNode
{
bool IsLeaf() const
{
return child1 == b2_nullNode;
}
/// Enlarged AABB
b2AABB aabb;
void* userData;
union
{
int32 parent;
int32 next;
};
int32 child1;
int32 child2;
// leaf = 0, free node = -1
int32 height;
};
/// A dynamic AABB tree broad-phase, inspired by Nathanael Presson's btDbvt.
/// A dynamic tree arranges data in a binary tree to accelerate
/// queries such as volume queries and ray casts. Leafs are proxies
/// with an AABB. In the tree we expand the proxy AABB by b2_fatAABBFactor
/// so that the proxy AABB is bigger than the client object. This allows the client
/// object to move by small amounts without triggering a tree update.
///
/// Nodes are pooled and relocatable, so we use node indices rather than pointers.
class b2DynamicTree
{
public:
/// Constructing the tree initializes the node pool.
b2DynamicTree();
/// Destroy the tree, freeing the node pool.
~b2DynamicTree();
/// Create a proxy. Provide a tight fitting AABB and a userData pointer.
int32 CreateProxy(const b2AABB& aabb, void* userData);
/// Destroy a proxy. This asserts if the id is invalid.
void DestroyProxy(int32 proxyId);
/// Move a proxy with a swepted AABB. If the proxy has moved outside of its fattened AABB,
/// then the proxy is removed from the tree and re-inserted. Otherwise
/// the function returns immediately.
/// @return true if the proxy was re-inserted.
bool MoveProxy(int32 proxyId, const b2AABB& aabb1, const b2Vec2& displacement);
/// Get proxy user data.
/// @return the proxy user data or 0 if the id is invalid.
void* GetUserData(int32 proxyId) const;
/// Get the fat AABB for a proxy.
const b2AABB& GetFatAABB(int32 proxyId) const;
/// Query an AABB for overlapping proxies. The callback class
/// is called for each proxy that overlaps the supplied AABB.
template <typename T>
void Query(T* callback, const b2AABB& aabb) const;
/// Ray-cast against the proxies in the tree. This relies on the callback
/// to perform a exact ray-cast in the case were the proxy contains a shape.
/// The callback also performs the any collision filtering. This has performance
/// roughly equal to k * log(n), where k is the number of collisions and n is the
/// number of proxies in the tree.
/// @param input the ray-cast input data. The ray extends from p1 to p1 + maxFraction * (p2 - p1).
/// @param callback a callback class that is called for each proxy that is hit by the ray.
template <typename T>
void RayCast(T* callback, const b2RayCastInput& input) const;
/// Validate this tree. For testing.
void Validate() const;
/// Compute the height of the binary tree in O(N) time. Should not be
/// called often.
int32 GetHeight() const;
/// Get the maximum balance of an node in the tree. The balance is the difference
/// in height of the two children of a node.
int32 GetMaxBalance() const;
/// Get the ratio of the sum of the node areas to the root area.
float32 GetAreaRatio() const;
/// Build an optimal tree. Very expensive. For testing.
void RebuildBottomUp();
/// Shift the world origin. Useful for large worlds.
/// The shift formula is: position -= newOrigin
/// @param newOrigin the new origin with respect to the old origin
void ShiftOrigin(const b2Vec2& newOrigin);
private:
int32 AllocateNode();
void FreeNode(int32 node);
void InsertLeaf(int32 node);
void RemoveLeaf(int32 node);
int32 Balance(int32 index);
int32 ComputeHeight() const;
int32 ComputeHeight(int32 nodeId) const;
void ValidateStructure(int32 index) const;
void ValidateMetrics(int32 index) const;
int32 m_root;
b2TreeNode* m_nodes;
int32 m_nodeCount;
int32 m_nodeCapacity;
int32 m_freeList;
/// This is used to incrementally traverse the tree for re-balancing.
uint32 m_path;
int32 m_insertionCount;
};
inline void* b2DynamicTree::GetUserData(int32 proxyId) const
{
b2Assert(0 <= proxyId && proxyId < m_nodeCapacity);
return m_nodes[proxyId].userData;
}
inline const b2AABB& b2DynamicTree::GetFatAABB(int32 proxyId) const
{
b2Assert(0 <= proxyId && proxyId < m_nodeCapacity);
return m_nodes[proxyId].aabb;
}
template <typename T>
inline void b2DynamicTree::Query(T* callback, const b2AABB& aabb) const
{
b2GrowableStack<int32, 256> stack;
stack.Push(m_root);
while (stack.GetCount() > 0)
{
int32 nodeId = stack.Pop();
if (nodeId == b2_nullNode)
{
continue;
}
const b2TreeNode* node = m_nodes + nodeId;
if (b2TestOverlap(node->aabb, aabb))
{
if (node->IsLeaf())
{
bool proceed = callback->QueryCallback(nodeId);
if (proceed == false)
{
return;
}
}
else
{
stack.Push(node->child1);
stack.Push(node->child2);
}
}
}
}
template <typename T>
inline void b2DynamicTree::RayCast(T* callback, const b2RayCastInput& input) const
{
b2Vec2 p1 = input.p1;
b2Vec2 p2 = input.p2;
b2Vec2 r = p2 - p1;
b2Assert(r.LengthSquared() > 0.0f);
r.Normalize();
// v is perpendicular to the segment.
b2Vec2 v = b2Cross(1.0f, r);
b2Vec2 abs_v = b2Abs(v);
// Separating axis for segment (Gino, p80).
// |dot(v, p1 - c)| > dot(|v|, h)
float32 maxFraction = input.maxFraction;
// Build a bounding box for the segment.
b2AABB segmentAABB;
{
b2Vec2 t = p1 + maxFraction * (p2 - p1);
segmentAABB.lowerBound = b2Min(p1, t);
segmentAABB.upperBound = b2Max(p1, t);
}
b2GrowableStack<int32, 256> stack;
stack.Push(m_root);
while (stack.GetCount() > 0)
{
int32 nodeId = stack.Pop();
if (nodeId == b2_nullNode)
{
continue;
}
const b2TreeNode* node = m_nodes + nodeId;
if (b2TestOverlap(node->aabb, segmentAABB) == false)
{
continue;
}
// Separating axis for segment (Gino, p80).
// |dot(v, p1 - c)| > dot(|v|, h)
b2Vec2 c = node->aabb.GetCenter();
b2Vec2 h = node->aabb.GetExtents();
float32 separation = b2Abs(b2Dot(v, p1 - c)) - b2Dot(abs_v, h);
if (separation > 0.0f)
{
continue;
}
if (node->IsLeaf())
{
b2RayCastInput subInput;
subInput.p1 = input.p1;
subInput.p2 = input.p2;
subInput.maxFraction = maxFraction;
float32 value = callback->RayCastCallback(subInput, nodeId);
if (value == 0.0f)
{
// The client has terminated the ray cast.
return;
}
if (value > 0.0f)
{
// Update segment bounding box.
maxFraction = value;
b2Vec2 t = p1 + maxFraction * (p2 - p1);
segmentAABB.lowerBound = b2Min(p1, t);
segmentAABB.upperBound = b2Max(p1, t);
}
}
else
{
stack.Push(node->child1);
stack.Push(node->child2);
}
}
}
#endif
/*
* Copyright (c) 2007-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "Box2D/Collision/b2Collision.h"
#include "Box2D/Collision/b2Distance.h"
#include "Box2D/Collision/b2TimeOfImpact.h"
#include "Box2D/Collision/Shapes/b2CircleShape.h"
#include "Box2D/Collision/Shapes/b2PolygonShape.h"
#include "Box2D/Common/b2Timer.h"
#include <stdio.h>
float32 b2_toiTime, b2_toiMaxTime;
int32 b2_toiCalls, b2_toiIters, b2_toiMaxIters;
int32 b2_toiRootIters, b2_toiMaxRootIters;
//
struct b2SeparationFunction
{
enum Type
{
e_points,
e_faceA,
e_faceB
};
// TODO_ERIN might not need to return the separation
float32 Initialize(const b2SimplexCache* cache,
const b2DistanceProxy* proxyA, const b2Sweep& sweepA,
const b2DistanceProxy* proxyB, const b2Sweep& sweepB,
float32 t1)
{
m_proxyA = proxyA;
m_proxyB = proxyB;
int32 count = cache->count;
b2Assert(0 < count && count < 3);
m_sweepA = sweepA;
m_sweepB = sweepB;
b2Transform xfA, xfB;
m_sweepA.GetTransform(&xfA, t1);
m_sweepB.GetTransform(&xfB, t1);
if (count == 1)
{
m_type = e_points;
b2Vec2 localPointA = m_proxyA->GetVertex(cache->indexA[0]);
b2Vec2 localPointB = m_proxyB->GetVertex(cache->indexB[0]);
b2Vec2 pointA = b2Mul(xfA, localPointA);
b2Vec2 pointB = b2Mul(xfB, localPointB);
m_axis = pointB - pointA;
float32 s = m_axis.Normalize();
return s;
}
else if (cache->indexA[0] == cache->indexA[1])
{
// Two points on B and one on A.
m_type = e_faceB;
b2Vec2 localPointB1 = proxyB->GetVertex(cache->indexB[0]);
b2Vec2 localPointB2 = proxyB->GetVertex(cache->indexB[1]);
m_axis = b2Cross(localPointB2 - localPointB1, 1.0f);
m_axis.Normalize();
b2Vec2 normal = b2Mul(xfB.q, m_axis);
m_localPoint = 0.5f * (localPointB1 + localPointB2);
b2Vec2 pointB = b2Mul(xfB, m_localPoint);
b2Vec2 localPointA = proxyA->GetVertex(cache->indexA[0]);
b2Vec2 pointA = b2Mul(xfA, localPointA);
float32 s = b2Dot(pointA - pointB, normal);
if (s < 0.0f)
{
m_axis = -m_axis;
s = -s;
}
return s;
}
else
{
// Two points on A and one or two points on B.
m_type = e_faceA;
b2Vec2 localPointA1 = m_proxyA->GetVertex(cache->indexA[0]);
b2Vec2 localPointA2 = m_proxyA->GetVertex(cache->indexA[1]);
m_axis = b2Cross(localPointA2 - localPointA1, 1.0f);
m_axis.Normalize();
b2Vec2 normal = b2Mul(xfA.q, m_axis);
m_localPoint = 0.5f * (localPointA1 + localPointA2);
b2Vec2 pointA = b2Mul(xfA, m_localPoint);
b2Vec2 localPointB = m_proxyB->GetVertex(cache->indexB[0]);
b2Vec2 pointB = b2Mul(xfB, localPointB);
float32 s = b2Dot(pointB - pointA, normal);
if (s < 0.0f)
{
m_axis = -m_axis;
s = -s;
}
return s;
}
}
//
float32 FindMinSeparation(int32* indexA, int32* indexB, float32 t) const
{
b2Transform xfA, xfB;
m_sweepA.GetTransform(&xfA, t);
m_sweepB.GetTransform(&xfB, t);
switch (m_type)
{
case e_points:
{
b2Vec2 axisA = b2MulT(xfA.q, m_axis);
b2Vec2 axisB = b2MulT(xfB.q, -m_axis);
*indexA = m_proxyA->GetSupport(axisA);
*indexB = m_proxyB->GetSupport(axisB);
b2Vec2 localPointA = m_proxyA->GetVertex(*indexA);
b2Vec2 localPointB = m_proxyB->GetVertex(*indexB);
b2Vec2 pointA = b2Mul(xfA, localPointA);
b2Vec2 pointB = b2Mul(xfB, localPointB);
float32 separation = b2Dot(pointB - pointA, m_axis);
return separation;
}
case e_faceA:
{
b2Vec2 normal = b2Mul(xfA.q, m_axis);
b2Vec2 pointA = b2Mul(xfA, m_localPoint);
b2Vec2 axisB = b2MulT(xfB.q, -normal);
*indexA = -1;
*indexB = m_proxyB->GetSupport(axisB);
b2Vec2 localPointB = m_proxyB->GetVertex(*indexB);
b2Vec2 pointB = b2Mul(xfB, localPointB);
float32 separation = b2Dot(pointB - pointA, normal);
return separation;
}
case e_faceB:
{
b2Vec2 normal = b2Mul(xfB.q, m_axis);
b2Vec2 pointB = b2Mul(xfB, m_localPoint);
b2Vec2 axisA = b2MulT(xfA.q, -normal);
*indexB = -1;
*indexA = m_proxyA->GetSupport(axisA);
b2Vec2 localPointA = m_proxyA->GetVertex(*indexA);
b2Vec2 pointA = b2Mul(xfA, localPointA);
float32 separation = b2Dot(pointA - pointB, normal);
return separation;
}
default:
b2Assert(false);
*indexA = -1;
*indexB = -1;
return 0.0f;
}
}
//
float32 Evaluate(int32 indexA, int32 indexB, float32 t) const
{
b2Transform xfA, xfB;
m_sweepA.GetTransform(&xfA, t);
m_sweepB.GetTransform(&xfB, t);
switch (m_type)
{
case e_points:
{
b2Vec2 localPointA = m_proxyA->GetVertex(indexA);
b2Vec2 localPointB = m_proxyB->GetVertex(indexB);
b2Vec2 pointA = b2Mul(xfA, localPointA);
b2Vec2 pointB = b2Mul(xfB, localPointB);
float32 separation = b2Dot(pointB - pointA, m_axis);
return separation;
}
case e_faceA:
{
b2Vec2 normal = b2Mul(xfA.q, m_axis);
b2Vec2 pointA = b2Mul(xfA, m_localPoint);
b2Vec2 localPointB = m_proxyB->GetVertex(indexB);
b2Vec2 pointB = b2Mul(xfB, localPointB);
float32 separation = b2Dot(pointB - pointA, normal);
return separation;
}
case e_faceB:
{
b2Vec2 normal = b2Mul(xfB.q, m_axis);
b2Vec2 pointB = b2Mul(xfB, m_localPoint);
b2Vec2 localPointA = m_proxyA->GetVertex(indexA);
b2Vec2 pointA = b2Mul(xfA, localPointA);
float32 separation = b2Dot(pointA - pointB, normal);
return separation;
}
default:
b2Assert(false);
return 0.0f;
}
}
const b2DistanceProxy* m_proxyA;
const b2DistanceProxy* m_proxyB;
b2Sweep m_sweepA, m_sweepB;
Type m_type;
b2Vec2 m_localPoint;
b2Vec2 m_axis;
};
// CCD via the local separating axis method. This seeks progression
// by computing the largest time at which separation is maintained.
void b2TimeOfImpact(b2TOIOutput* output, const b2TOIInput* input)
{
b2Timer timer;
++b2_toiCalls;
output->state = b2TOIOutput::e_unknown;
output->t = input->tMax;
const b2DistanceProxy* proxyA = &input->proxyA;
const b2DistanceProxy* proxyB = &input->proxyB;
b2Sweep sweepA = input->sweepA;
b2Sweep sweepB = input->sweepB;
// Large rotations can make the root finder fail, so we normalize the
// sweep angles.
sweepA.Normalize();
sweepB.Normalize();
float32 tMax = input->tMax;
float32 totalRadius = proxyA->m_radius + proxyB->m_radius;
float32 target = b2Max(b2_linearSlop, totalRadius - 3.0f * b2_linearSlop);
float32 tolerance = 0.25f * b2_linearSlop;
b2Assert(target > tolerance);
float32 t1 = 0.0f;
const int32 k_maxIterations = 20; // TODO_ERIN b2Settings
int32 iter = 0;
// Prepare input for distance query.
b2SimplexCache cache;
cache.count = 0;
b2DistanceInput distanceInput;
distanceInput.proxyA = input->proxyA;
distanceInput.proxyB = input->proxyB;
distanceInput.useRadii = false;
// The outer loop progressively attempts to compute new separating axes.
// This loop terminates when an axis is repeated (no progress is made).
for(;;)
{
b2Transform xfA, xfB;
sweepA.GetTransform(&xfA, t1);
sweepB.GetTransform(&xfB, t1);
// Get the distance between shapes. We can also use the results
// to get a separating axis.
distanceInput.transformA = xfA;
distanceInput.transformB = xfB;
b2DistanceOutput distanceOutput;
b2Distance(&distanceOutput, &cache, &distanceInput);
// If the shapes are overlapped, we give up on continuous collision.
if (distanceOutput.distance <= 0.0f)
{
// Failure!
output->state = b2TOIOutput::e_overlapped;
output->t = 0.0f;
break;
}
if (distanceOutput.distance < target + tolerance)
{
// Victory!
output->state = b2TOIOutput::e_touching;
output->t = t1;
break;
}
// Initialize the separating axis.
b2SeparationFunction fcn;
fcn.Initialize(&cache, proxyA, sweepA, proxyB, sweepB, t1);
#if 0
// Dump the curve seen by the root finder
{
const int32 N = 100;
float32 dx = 1.0f / N;
float32 xs[N+1];
float32 fs[N+1];
float32 x = 0.0f;
for (int32 i = 0; i <= N; ++i)
{
sweepA.GetTransform(&xfA, x);
sweepB.GetTransform(&xfB, x);
float32 f = fcn.Evaluate(xfA, xfB) - target;
printf("%g %g\n", x, f);
xs[i] = x;
fs[i] = f;
x += dx;
}
}
#endif
// Compute the TOI on the separating axis. We do this by successively
// resolving the deepest point. This loop is bounded by the number of vertices.
bool done = false;
float32 t2 = tMax;
int32 pushBackIter = 0;
for (;;)
{
// Find the deepest point at t2. Store the witness point indices.
int32 indexA, indexB;
float32 s2 = fcn.FindMinSeparation(&indexA, &indexB, t2);
// Is the final configuration separated?
if (s2 > target + tolerance)
{
// Victory!
output->state = b2TOIOutput::e_separated;
output->t = tMax;
done = true;
break;
}
// Has the separation reached tolerance?
if (s2 > target - tolerance)
{
// Advance the sweeps
t1 = t2;
break;
}
// Compute the initial separation of the witness points.
float32 s1 = fcn.Evaluate(indexA, indexB, t1);
// Check for initial overlap. This might happen if the root finder
// runs out of iterations.
if (s1 < target - tolerance)
{
output->state = b2TOIOutput::e_failed;
output->t = t1;
done = true;
break;
}
// Check for touching
if (s1 <= target + tolerance)
{
// Victory! t1 should hold the TOI (could be 0.0).
output->state = b2TOIOutput::e_touching;
output->t = t1;
done = true;
break;
}
// Compute 1D root of: f(x) - target = 0
int32 rootIterCount = 0;
float32 a1 = t1, a2 = t2;
for (;;)
{
// Use a mix of the secant rule and bisection.
float32 t;
if (rootIterCount & 1)
{
// Secant rule to improve convergence.
t = a1 + (target - s1) * (a2 - a1) / (s2 - s1);
}
else
{
// Bisection to guarantee progress.
t = 0.5f * (a1 + a2);
}
++rootIterCount;
++b2_toiRootIters;
float32 s = fcn.Evaluate(indexA, indexB, t);
if (b2Abs(s - target) < tolerance)
{
// t2 holds a tentative value for t1
t2 = t;
break;
}
// Ensure we continue to bracket the root.
if (s > target)
{
a1 = t;
s1 = s;
}
else
{
a2 = t;
s2 = s;
}
if (rootIterCount == 50)
{
break;
}
}
b2_toiMaxRootIters = b2Max(b2_toiMaxRootIters, rootIterCount);
++pushBackIter;
if (pushBackIter == b2_maxPolygonVertices)
{
break;
}
}
++iter;
++b2_toiIters;
if (done)
{
break;
}
if (iter == k_maxIterations)
{
// Root finder got stuck. Semi-victory.
output->state = b2TOIOutput::e_failed;
output->t = t1;
break;
}
}
b2_toiMaxIters = b2Max(b2_toiMaxIters, iter);
float32 time = timer.GetMilliseconds();
b2_toiMaxTime = b2Max(b2_toiMaxTime, time);
b2_toiTime += time;
}
/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_TIME_OF_IMPACT_H
#define B2_TIME_OF_IMPACT_H
#include "Box2D/Common/b2Math.h"
#include "Box2D/Collision/b2Distance.h"
/// Input parameters for b2TimeOfImpact
struct b2TOIInput
{
b2DistanceProxy proxyA;
b2DistanceProxy proxyB;
b2Sweep sweepA;
b2Sweep sweepB;
float32 tMax; // defines sweep interval [0, tMax]
};
// Output parameters for b2TimeOfImpact.
struct b2TOIOutput
{
enum State
{
e_unknown,
e_failed,
e_overlapped,
e_touching,
e_separated
};
State state;
float32 t;
};
/// Compute the upper bound on time before two shapes penetrate. Time is represented as
/// a fraction between [0,tMax]. This uses a swept separating axis and may miss some intermediate,
/// non-tunneling collision. If you change the time interval, you should call this function
/// again.
/// Note: use b2Distance to compute the contact point and normal at the time of impact.
void b2TimeOfImpact(b2TOIOutput* output, const b2TOIInput* input);
#endif
/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "Box2D/Common/b2BlockAllocator.h"
#include <limits.h>
#include <string.h>
#include <stddef.h>
int32 b2BlockAllocator::s_blockSizes[b2_blockSizes] =
{
16, // 0
32, // 1
64, // 2
96, // 3
128, // 4
160, // 5
192, // 6
224, // 7
256, // 8
320, // 9
384, // 10
448, // 11
512, // 12
640, // 13
};
uint8 b2BlockAllocator::s_blockSizeLookup[b2_maxBlockSize + 1];
bool b2BlockAllocator::s_blockSizeLookupInitialized;
struct b2Chunk
{
int32 blockSize;
b2Block* blocks;
};
struct b2Block
{
b2Block* next;
};
b2BlockAllocator::b2BlockAllocator()
{
b2Assert(b2_blockSizes < UCHAR_MAX);
m_chunkSpace = b2_chunkArrayIncrement;
m_chunkCount = 0;
m_chunks = (b2Chunk*)b2Alloc(m_chunkSpace * sizeof(b2Chunk));
memset(m_chunks, 0, m_chunkSpace * sizeof(b2Chunk));
memset(m_freeLists, 0, sizeof(m_freeLists));
if (s_blockSizeLookupInitialized == false)
{
int32 j = 0;
for (int32 i = 1; i <= b2_maxBlockSize; ++i)
{
b2Assert(j < b2_blockSizes);
if (i <= s_blockSizes[j])
{
s_blockSizeLookup[i] = (uint8)j;
}
else
{
++j;
s_blockSizeLookup[i] = (uint8)j;
}
}
s_blockSizeLookupInitialized = true;
}
}
b2BlockAllocator::~b2BlockAllocator()
{
for (int32 i = 0; i < m_chunkCount; ++i)
{
b2Free(m_chunks[i].blocks);
}
b2Free(m_chunks);
}
void* b2BlockAllocator::Allocate(int32 size)
{
if (size == 0)
return nullptr;
b2Assert(0 < size);
if (size > b2_maxBlockSize)
{
return b2Alloc(size);
}
int32 index = s_blockSizeLookup[size];
b2Assert(0 <= index && index < b2_blockSizes);
if (m_freeLists[index])
{
b2Block* block = m_freeLists[index];
m_freeLists[index] = block->next;
return block;
}
else
{
if (m_chunkCount == m_chunkSpace)
{
b2Chunk* oldChunks = m_chunks;
m_chunkSpace += b2_chunkArrayIncrement;
m_chunks = (b2Chunk*)b2Alloc(m_chunkSpace * sizeof(b2Chunk));
memcpy(m_chunks, oldChunks, m_chunkCount * sizeof(b2Chunk));
memset(m_chunks + m_chunkCount, 0, b2_chunkArrayIncrement * sizeof(b2Chunk));
b2Free(oldChunks);
}
b2Chunk* chunk = m_chunks + m_chunkCount;
chunk->blocks = (b2Block*)b2Alloc(b2_chunkSize);
#if defined(_DEBUG)
memset(chunk->blocks, 0xcd, b2_chunkSize);
#endif
int32 blockSize = s_blockSizes[index];
chunk->blockSize = blockSize;
int32 blockCount = b2_chunkSize / blockSize;
b2Assert(blockCount * blockSize <= b2_chunkSize);
for (int32 i = 0; i < blockCount - 1; ++i)
{
b2Block* block = (b2Block*)((int8*)chunk->blocks + blockSize * i);
b2Block* next = (b2Block*)((int8*)chunk->blocks + blockSize * (i + 1));
block->next = next;
}
b2Block* last = (b2Block*)((int8*)chunk->blocks + blockSize * (blockCount - 1));
last->next = nullptr;
m_freeLists[index] = chunk->blocks->next;
++m_chunkCount;
return chunk->blocks;
}
}
void b2BlockAllocator::Free(void* p, int32 size)
{
if (size == 0)
{
return;
}
b2Assert(0 < size);
if (size > b2_maxBlockSize)
{
b2Free(p);
return;
}
int32 index = s_blockSizeLookup[size];
b2Assert(0 <= index && index < b2_blockSizes);
#ifdef _DEBUG
// Verify the memory address and size is valid.
int32 blockSize = s_blockSizes[index];
bool found = false;
for (int32 i = 0; i < m_chunkCount; ++i)
{
b2Chunk* chunk = m_chunks + i;
if (chunk->blockSize != blockSize)
{
b2Assert( (int8*)p + blockSize <= (int8*)chunk->blocks ||
(int8*)chunk->blocks + b2_chunkSize <= (int8*)p);
}
else
{
if ((int8*)chunk->blocks <= (int8*)p && (int8*)p + blockSize <= (int8*)chunk->blocks + b2_chunkSize)
{
found = true;
}
}
}
b2Assert(found);
memset(p, 0xfd, blockSize);
#endif
b2Block* block = (b2Block*)p;
block->next = m_freeLists[index];
m_freeLists[index] = block;
}
void b2BlockAllocator::Clear()
{
for (int32 i = 0; i < m_chunkCount; ++i)
{
b2Free(m_chunks[i].blocks);
}
m_chunkCount = 0;
memset(m_chunks, 0, m_chunkSpace * sizeof(b2Chunk));
memset(m_freeLists, 0, sizeof(m_freeLists));
}
/*
* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_BLOCK_ALLOCATOR_H
#define B2_BLOCK_ALLOCATOR_H
#include "Box2D/Common/b2Settings.h"
const int32 b2_chunkSize = 16 * 1024;
const int32 b2_maxBlockSize = 640;
const int32 b2_blockSizes = 14;
const int32 b2_chunkArrayIncrement = 128;
struct b2Block;
struct b2Chunk;
/// This is a small object allocator used for allocating small
/// objects that persist for more than one time step.
/// See: http://www.codeproject.com/useritems/Small_Block_Allocator.asp
class b2BlockAllocator
{
public:
b2BlockAllocator();
~b2BlockAllocator();
/// Allocate memory. This will use b2Alloc if the size is larger than b2_maxBlockSize.
void* Allocate(int32 size);
/// Free memory. This will use b2Free if the size is larger than b2_maxBlockSize.
void Free(void* p, int32 size);
void Clear();
private:
b2Chunk* m_chunks;
int32 m_chunkCount;
int32 m_chunkSpace;
b2Block* m_freeLists[b2_blockSizes];
static int32 s_blockSizes[b2_blockSizes];
static uint8 s_blockSizeLookup[b2_maxBlockSize + 1];
static bool s_blockSizeLookupInitialized;
};
#endif
/*
* Copyright (c) 2011 Erin Catto http://box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "Box2D/Common/b2Draw.h"
b2Draw::b2Draw()
{
m_drawFlags = 0;
}
void b2Draw::SetFlags(uint32 flags)
{
m_drawFlags = flags;
}
uint32 b2Draw::GetFlags() const
{
return m_drawFlags;
}
void b2Draw::AppendFlags(uint32 flags)
{
m_drawFlags |= flags;
}
void b2Draw::ClearFlags(uint32 flags)
{
m_drawFlags &= ~flags;
}
/*
* Copyright (c) 2011 Erin Catto http://box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_DRAW_H
#define B2_DRAW_H
#include "Box2D/Common/b2Math.h"
/// Color for debug drawing. Each value has the range [0,1].
struct b2Color
{
b2Color() {}
b2Color(float32 rIn, float32 gIn, float32 bIn, float32 aIn = 1.0f)
{
r = rIn; g = gIn; b = bIn; a = aIn;
}
void Set(float32 rIn, float32 gIn, float32 bIn, float32 aIn = 1.0f)
{
r = rIn; g = gIn; b = bIn; a = aIn;
}
float32 r, g, b, a;
};
/// Implement and register this class with a b2World to provide debug drawing of physics
/// entities in your game.
class b2Draw
{
public:
b2Draw();
virtual ~b2Draw() {}
enum
{
e_shapeBit = 0x0001, ///< draw shapes
e_jointBit = 0x0002, ///< draw joint connections
e_aabbBit = 0x0004, ///< draw axis aligned bounding boxes
e_pairBit = 0x0008, ///< draw broad-phase pairs
e_centerOfMassBit = 0x0010 ///< draw center of mass frame
};
/// Set the drawing flags.
void SetFlags(uint32 flags);
/// Get the drawing flags.
uint32 GetFlags() const;
/// Append flags to the current flags.
void AppendFlags(uint32 flags);
/// Clear flags from the current flags.
void ClearFlags(uint32 flags);
/// Draw a closed polygon provided in CCW order.
virtual void DrawPolygon(const b2Vec2* vertices, int32 vertexCount, const b2Color& color) = 0;
/// Draw a solid closed polygon provided in CCW order.
virtual void DrawSolidPolygon(const b2Vec2* vertices, int32 vertexCount, const b2Color& color) = 0;
/// Draw a circle.
virtual void DrawCircle(const b2Vec2& center, float32 radius, const b2Color& color) = 0;
/// Draw a solid circle.
virtual void DrawSolidCircle(const b2Vec2& center, float32 radius, const b2Vec2& axis, const b2Color& color) = 0;
/// Draw a line segment.
virtual void DrawSegment(const b2Vec2& p1, const b2Vec2& p2, const b2Color& color) = 0;
/// Draw a transform. Choose your own length scale.
/// @param xf a transform.
virtual void DrawTransform(const b2Transform& xf) = 0;
/// Draw a point.
virtual void DrawPoint(const b2Vec2& p, float32 size, const b2Color& color) = 0;
protected:
uint32 m_drawFlags;
};
#endif
/*
* Copyright (c) 2010 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_GROWABLE_STACK_H
#define B2_GROWABLE_STACK_H
#include "Box2D/Common/b2Settings.h"
#include <string.h>
/// This is a growable LIFO stack with an initial capacity of N.
/// If the stack size exceeds the initial capacity, the heap is used
/// to increase the size of the stack.
template <typename T, int32 N>
class b2GrowableStack
{
public:
b2GrowableStack()
{
m_stack = m_array;
m_count = 0;
m_capacity = N;
}
~b2GrowableStack()
{
if (m_stack != m_array)
{
b2Free(m_stack);
m_stack = nullptr;
}
}
void Push(const T& element)
{
if (m_count == m_capacity)
{
T* old = m_stack;
m_capacity *= 2;
m_stack = (T*)b2Alloc(m_capacity * sizeof(T));
memcpy(m_stack, old, m_count * sizeof(T));
if (old != m_array)
{
b2Free(old);
}
}
m_stack[m_count] = element;
++m_count;
}
T Pop()
{
b2Assert(m_count > 0);
--m_count;
return m_stack[m_count];
}
int32 GetCount()
{
return m_count;
}
private:
T* m_stack;
T m_array[N];
int32 m_count;
int32 m_capacity;
};
#endif
/*
* Copyright (c) 2007-2009 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#include "Box2D/Common/b2Math.h"
const b2Vec2 b2Vec2_zero(0.0f, 0.0f);
/// Solve A * x = b, where b is a column vector. This is more efficient
/// than computing the inverse in one-shot cases.
b2Vec3 b2Mat33::Solve33(const b2Vec3& b) const
{
float32 det = b2Dot(ex, b2Cross(ey, ez));
if (det != 0.0f)
{
det = 1.0f / det;
}
b2Vec3 x;
x.x = det * b2Dot(b, b2Cross(ey, ez));
x.y = det * b2Dot(ex, b2Cross(b, ez));
x.z = det * b2Dot(ex, b2Cross(ey, b));
return x;
}
/// Solve A * x = b, where b is a column vector. This is more efficient
/// than computing the inverse in one-shot cases.
b2Vec2 b2Mat33::Solve22(const b2Vec2& b) const
{
float32 a11 = ex.x, a12 = ey.x, a21 = ex.y, a22 = ey.y;
float32 det = a11 * a22 - a12 * a21;
if (det != 0.0f)
{
det = 1.0f / det;
}
b2Vec2 x;
x.x = det * (a22 * b.x - a12 * b.y);
x.y = det * (a11 * b.y - a21 * b.x);
return x;
}
///
void b2Mat33::GetInverse22(b2Mat33* M) const
{
float32 a = ex.x, b = ey.x, c = ex.y, d = ey.y;
float32 det = a * d - b * c;
if (det != 0.0f)
{
det = 1.0f / det;
}
M->ex.x = det * d; M->ey.x = -det * b; M->ex.z = 0.0f;
M->ex.y = -det * c; M->ey.y = det * a; M->ey.z = 0.0f;
M->ez.x = 0.0f; M->ez.y = 0.0f; M->ez.z = 0.0f;
}
/// Returns the zero matrix if singular.
void b2Mat33::GetSymInverse33(b2Mat33* M) const
{
float32 det = b2Dot(ex, b2Cross(ey, ez));
if (det != 0.0f)
{
det = 1.0f / det;
}
float32 a11 = ex.x, a12 = ey.x, a13 = ez.x;
float32 a22 = ey.y, a23 = ez.y;
float32 a33 = ez.z;
M->ex.x = det * (a22 * a33 - a23 * a23);
M->ex.y = det * (a13 * a23 - a12 * a33);
M->ex.z = det * (a12 * a23 - a13 * a22);
M->ey.x = M->ex.y;
M->ey.y = det * (a11 * a33 - a13 * a13);
M->ey.z = det * (a13 * a12 - a11 * a23);
M->ez.x = M->ex.z;
M->ez.y = M->ey.z;
M->ez.z = det * (a11 * a22 - a12 * a12);
}