436 lines
12 KiB
C++
436 lines
12 KiB
C++
/*
|
|
Bullet Continuous Collision Detection and Physics Library
|
|
* The b2CollidePolygons routines are Copyright (c) 2006-2007 Erin Catto http://www.gphysics.com
|
|
|
|
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.
|
|
*/
|
|
|
|
///btBox2dBox2dCollisionAlgorithm, with modified b2CollidePolygons routines from the Box2D library.
|
|
///The modifications include: switching from b2Vec to btVector3, redefinition of b2Dot, b2Cross
|
|
|
|
#include "btBox2dBox2dCollisionAlgorithm.h"
|
|
#include "BulletCollision/CollisionDispatch/btCollisionDispatcher.h"
|
|
#include "BulletCollision/CollisionShapes/btBoxShape.h"
|
|
#include "BulletCollision/CollisionDispatch/btCollisionObject.h"
|
|
#include "BulletCollision/CollisionDispatch/btBoxBoxDetector.h"
|
|
#include "BulletCollision/CollisionShapes/btBox2dShape.h"
|
|
|
|
#define USE_PERSISTENT_CONTACTS 1
|
|
|
|
btBox2dBox2dCollisionAlgorithm::btBox2dBox2dCollisionAlgorithm(btPersistentManifold* mf,const btCollisionAlgorithmConstructionInfo& ci,btCollisionObject* obj0,btCollisionObject* obj1)
|
|
: btActivatingCollisionAlgorithm(ci,obj0,obj1),
|
|
m_ownManifold(false),
|
|
m_manifoldPtr(mf)
|
|
{
|
|
if (!m_manifoldPtr && m_dispatcher->needsCollision(obj0,obj1))
|
|
{
|
|
m_manifoldPtr = m_dispatcher->getNewManifold(obj0,obj1);
|
|
m_ownManifold = true;
|
|
}
|
|
}
|
|
|
|
btBox2dBox2dCollisionAlgorithm::~btBox2dBox2dCollisionAlgorithm()
|
|
{
|
|
|
|
if (m_ownManifold)
|
|
{
|
|
if (m_manifoldPtr)
|
|
m_dispatcher->releaseManifold(m_manifoldPtr);
|
|
}
|
|
|
|
}
|
|
|
|
|
|
void b2CollidePolygons(btManifoldResult* manifold, const btBox2dShape* polyA, const btTransform& xfA, const btBox2dShape* polyB, const btTransform& xfB);
|
|
|
|
//#include <stdio.h>
|
|
void btBox2dBox2dCollisionAlgorithm::processCollision (btCollisionObject* body0,btCollisionObject* body1,const btDispatcherInfo& dispatchInfo,btManifoldResult* resultOut)
|
|
{
|
|
if (!m_manifoldPtr)
|
|
return;
|
|
|
|
btCollisionObject* col0 = body0;
|
|
btCollisionObject* col1 = body1;
|
|
btBox2dShape* box0 = (btBox2dShape*)col0->getCollisionShape();
|
|
btBox2dShape* box1 = (btBox2dShape*)col1->getCollisionShape();
|
|
|
|
resultOut->setPersistentManifold(m_manifoldPtr);
|
|
|
|
b2CollidePolygons(resultOut,box0,col0->getWorldTransform(),box1,col1->getWorldTransform());
|
|
|
|
// refreshContactPoints is only necessary when using persistent contact points. otherwise all points are newly added
|
|
if (m_ownManifold)
|
|
{
|
|
resultOut->refreshContactPoints();
|
|
}
|
|
|
|
}
|
|
|
|
btScalar btBox2dBox2dCollisionAlgorithm::calculateTimeOfImpact(btCollisionObject* /*body0*/,btCollisionObject* /*body1*/,const btDispatcherInfo& /*dispatchInfo*/,btManifoldResult* /*resultOut*/)
|
|
{
|
|
//not yet
|
|
return 1.f;
|
|
}
|
|
|
|
|
|
struct ClipVertex
|
|
{
|
|
btVector3 v;
|
|
int id;
|
|
//b2ContactID id;
|
|
//b2ContactID id;
|
|
};
|
|
|
|
#define b2Dot(a,b) (a).dot(b)
|
|
#define b2Mul(a,b) (a)*(b)
|
|
#define b2MulT(a,b) (a).transpose()*(b)
|
|
#define b2Cross(a,b) (a).cross(b)
|
|
#define btCrossS(a,s) btVector3(s * a.getY(), -s * a.getX(),0.f)
|
|
|
|
int b2_maxManifoldPoints =2;
|
|
|
|
static int ClipSegmentToLine(ClipVertex vOut[2], ClipVertex vIn[2],
|
|
const btVector3& normal, btScalar offset)
|
|
{
|
|
// Start with no output points
|
|
int numOut = 0;
|
|
|
|
// Calculate the distance of end points to the line
|
|
btScalar distance0 = b2Dot(normal, vIn[0].v) - offset;
|
|
btScalar 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
|
|
btScalar interp = distance0 / (distance0 - distance1);
|
|
vOut[numOut].v = vIn[0].v + interp * (vIn[1].v - vIn[0].v);
|
|
if (distance0 > 0.0f)
|
|
{
|
|
vOut[numOut].id = vIn[0].id;
|
|
}
|
|
else
|
|
{
|
|
vOut[numOut].id = vIn[1].id;
|
|
}
|
|
++numOut;
|
|
}
|
|
|
|
return numOut;
|
|
}
|
|
|
|
// Find the separation between poly1 and poly2 for a give edge normal on poly1.
|
|
static btScalar EdgeSeparation(const btBox2dShape* poly1, const btTransform& xf1, int edge1,
|
|
const btBox2dShape* poly2, const btTransform& xf2)
|
|
{
|
|
const btVector3* vertices1 = poly1->getVertices();
|
|
const btVector3* normals1 = poly1->getNormals();
|
|
|
|
int count2 = poly2->getVertexCount();
|
|
const btVector3* vertices2 = poly2->getVertices();
|
|
|
|
btAssert(0 <= edge1 && edge1 < poly1->getVertexCount());
|
|
|
|
// Convert normal from poly1's frame into poly2's frame.
|
|
btVector3 normal1World = b2Mul(xf1.getBasis(), normals1[edge1]);
|
|
btVector3 normal1 = b2MulT(xf2.getBasis(), normal1World);
|
|
|
|
// Find support vertex on poly2 for -normal.
|
|
int index = 0;
|
|
btScalar minDot = BT_LARGE_FLOAT;
|
|
|
|
for (int i = 0; i < count2; ++i)
|
|
{
|
|
btScalar dot = b2Dot(vertices2[i], normal1);
|
|
if (dot < minDot)
|
|
{
|
|
minDot = dot;
|
|
index = i;
|
|
}
|
|
}
|
|
|
|
btVector3 v1 = b2Mul(xf1, vertices1[edge1]);
|
|
btVector3 v2 = b2Mul(xf2, vertices2[index]);
|
|
btScalar separation = b2Dot(v2 - v1, normal1World);
|
|
return separation;
|
|
}
|
|
|
|
// Find the max separation between poly1 and poly2 using edge normals from poly1.
|
|
static btScalar FindMaxSeparation(int* edgeIndex,
|
|
const btBox2dShape* poly1, const btTransform& xf1,
|
|
const btBox2dShape* poly2, const btTransform& xf2)
|
|
{
|
|
int count1 = poly1->getVertexCount();
|
|
const btVector3* normals1 = poly1->getNormals();
|
|
|
|
// Vector pointing from the centroid of poly1 to the centroid of poly2.
|
|
btVector3 d = b2Mul(xf2, poly2->getCentroid()) - b2Mul(xf1, poly1->getCentroid());
|
|
btVector3 dLocal1 = b2MulT(xf1.getBasis(), d);
|
|
|
|
// Find edge normal on poly1 that has the largest projection onto d.
|
|
int edge = 0;
|
|
btScalar maxDot = -BT_LARGE_FLOAT;
|
|
for (int i = 0; i < count1; ++i)
|
|
{
|
|
btScalar dot = b2Dot(normals1[i], dLocal1);
|
|
if (dot > maxDot)
|
|
{
|
|
maxDot = dot;
|
|
edge = i;
|
|
}
|
|
}
|
|
|
|
// Get the separation for the edge normal.
|
|
btScalar s = EdgeSeparation(poly1, xf1, edge, poly2, xf2);
|
|
if (s > 0.0f)
|
|
{
|
|
return s;
|
|
}
|
|
|
|
// Check the separation for the previous edge normal.
|
|
int prevEdge = edge - 1 >= 0 ? edge - 1 : count1 - 1;
|
|
btScalar sPrev = EdgeSeparation(poly1, xf1, prevEdge, poly2, xf2);
|
|
if (sPrev > 0.0f)
|
|
{
|
|
return sPrev;
|
|
}
|
|
|
|
// Check the separation for the next edge normal.
|
|
int nextEdge = edge + 1 < count1 ? edge + 1 : 0;
|
|
btScalar sNext = EdgeSeparation(poly1, xf1, nextEdge, poly2, xf2);
|
|
if (sNext > 0.0f)
|
|
{
|
|
return sNext;
|
|
}
|
|
|
|
// Find the best edge and the search direction.
|
|
int bestEdge;
|
|
btScalar bestSeparation;
|
|
int increment;
|
|
if (sPrev > s && sPrev > sNext)
|
|
{
|
|
increment = -1;
|
|
bestEdge = prevEdge;
|
|
bestSeparation = sPrev;
|
|
}
|
|
else if (sNext > s)
|
|
{
|
|
increment = 1;
|
|
bestEdge = nextEdge;
|
|
bestSeparation = sNext;
|
|
}
|
|
else
|
|
{
|
|
*edgeIndex = edge;
|
|
return s;
|
|
}
|
|
|
|
// Perform a local search for the best edge normal.
|
|
for ( ; ; )
|
|
{
|
|
if (increment == -1)
|
|
edge = bestEdge - 1 >= 0 ? bestEdge - 1 : count1 - 1;
|
|
else
|
|
edge = bestEdge + 1 < count1 ? bestEdge + 1 : 0;
|
|
|
|
s = EdgeSeparation(poly1, xf1, edge, poly2, xf2);
|
|
if (s > 0.0f)
|
|
{
|
|
return s;
|
|
}
|
|
|
|
if (s > bestSeparation)
|
|
{
|
|
bestEdge = edge;
|
|
bestSeparation = s;
|
|
}
|
|
else
|
|
{
|
|
break;
|
|
}
|
|
}
|
|
|
|
*edgeIndex = bestEdge;
|
|
return bestSeparation;
|
|
}
|
|
|
|
static void FindIncidentEdge(ClipVertex c[2],
|
|
const btBox2dShape* poly1, const btTransform& xf1, int edge1,
|
|
const btBox2dShape* poly2, const btTransform& xf2)
|
|
{
|
|
const btVector3* normals1 = poly1->getNormals();
|
|
|
|
int count2 = poly2->getVertexCount();
|
|
const btVector3* vertices2 = poly2->getVertices();
|
|
const btVector3* normals2 = poly2->getNormals();
|
|
|
|
btAssert(0 <= edge1 && edge1 < poly1->getVertexCount());
|
|
|
|
// Get the normal of the reference edge in poly2's frame.
|
|
btVector3 normal1 = b2MulT(xf2.getBasis(), b2Mul(xf1.getBasis(), normals1[edge1]));
|
|
|
|
// Find the incident edge on poly2.
|
|
int index = 0;
|
|
btScalar minDot = BT_LARGE_FLOAT;
|
|
for (int i = 0; i < count2; ++i)
|
|
{
|
|
btScalar dot = b2Dot(normal1, normals2[i]);
|
|
if (dot < minDot)
|
|
{
|
|
minDot = dot;
|
|
index = i;
|
|
}
|
|
}
|
|
|
|
// Build the clip vertices for the incident edge.
|
|
int i1 = index;
|
|
int i2 = i1 + 1 < count2 ? i1 + 1 : 0;
|
|
|
|
c[0].v = b2Mul(xf2, vertices2[i1]);
|
|
// c[0].id.features.referenceEdge = (unsigned char)edge1;
|
|
// c[0].id.features.incidentEdge = (unsigned char)i1;
|
|
// c[0].id.features.incidentVertex = 0;
|
|
|
|
c[1].v = b2Mul(xf2, vertices2[i2]);
|
|
// c[1].id.features.referenceEdge = (unsigned char)edge1;
|
|
// c[1].id.features.incidentEdge = (unsigned char)i2;
|
|
// c[1].id.features.incidentVertex = 1;
|
|
}
|
|
|
|
// 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(btManifoldResult* manifold,
|
|
const btBox2dShape* polyA, const btTransform& xfA,
|
|
const btBox2dShape* polyB, const btTransform& xfB)
|
|
{
|
|
|
|
int edgeA = 0;
|
|
btScalar separationA = FindMaxSeparation(&edgeA, polyA, xfA, polyB, xfB);
|
|
if (separationA > 0.0f)
|
|
return;
|
|
|
|
int edgeB = 0;
|
|
btScalar separationB = FindMaxSeparation(&edgeB, polyB, xfB, polyA, xfA);
|
|
if (separationB > 0.0f)
|
|
return;
|
|
|
|
const btBox2dShape* poly1; // reference poly
|
|
const btBox2dShape* poly2; // incident poly
|
|
btTransform xf1, xf2;
|
|
int edge1; // reference edge
|
|
unsigned char flip;
|
|
const btScalar k_relativeTol = 0.98f;
|
|
const btScalar k_absoluteTol = 0.001f;
|
|
|
|
// TODO_ERIN use "radius" of poly for absolute tolerance.
|
|
if (separationB > k_relativeTol * separationA + k_absoluteTol)
|
|
{
|
|
poly1 = polyB;
|
|
poly2 = polyA;
|
|
xf1 = xfB;
|
|
xf2 = xfA;
|
|
edge1 = edgeB;
|
|
flip = 1;
|
|
}
|
|
else
|
|
{
|
|
poly1 = polyA;
|
|
poly2 = polyB;
|
|
xf1 = xfA;
|
|
xf2 = xfB;
|
|
edge1 = edgeA;
|
|
flip = 0;
|
|
}
|
|
|
|
ClipVertex incidentEdge[2];
|
|
FindIncidentEdge(incidentEdge, poly1, xf1, edge1, poly2, xf2);
|
|
|
|
int count1 = poly1->getVertexCount();
|
|
const btVector3* vertices1 = poly1->getVertices();
|
|
|
|
btVector3 v11 = vertices1[edge1];
|
|
btVector3 v12 = edge1 + 1 < count1 ? vertices1[edge1+1] : vertices1[0];
|
|
|
|
btVector3 dv = v12 - v11;
|
|
btVector3 sideNormal = b2Mul(xf1.getBasis(), v12 - v11);
|
|
sideNormal.normalize();
|
|
btVector3 frontNormal = btCrossS(sideNormal, 1.0f);
|
|
|
|
|
|
v11 = b2Mul(xf1, v11);
|
|
v12 = b2Mul(xf1, v12);
|
|
|
|
btScalar frontOffset = b2Dot(frontNormal, v11);
|
|
btScalar sideOffset1 = -b2Dot(sideNormal, v11);
|
|
btScalar sideOffset2 = b2Dot(sideNormal, v12);
|
|
|
|
// Clip incident edge against extruded edge1 side edges.
|
|
ClipVertex clipPoints1[2];
|
|
clipPoints1[0].v.setValue(0,0,0);
|
|
clipPoints1[1].v.setValue(0,0,0);
|
|
|
|
ClipVertex clipPoints2[2];
|
|
clipPoints2[0].v.setValue(0,0,0);
|
|
clipPoints2[1].v.setValue(0,0,0);
|
|
|
|
|
|
int np;
|
|
|
|
// Clip to box side 1
|
|
np = ClipSegmentToLine(clipPoints1, incidentEdge, -sideNormal, sideOffset1);
|
|
|
|
if (np < 2)
|
|
return;
|
|
|
|
// Clip to negative box side 1
|
|
np = ClipSegmentToLine(clipPoints2, clipPoints1, sideNormal, sideOffset2);
|
|
|
|
if (np < 2)
|
|
{
|
|
return;
|
|
}
|
|
|
|
// Now clipPoints2 contains the clipped points.
|
|
btVector3 manifoldNormal = flip ? -frontNormal : frontNormal;
|
|
|
|
int pointCount = 0;
|
|
for (int i = 0; i < b2_maxManifoldPoints; ++i)
|
|
{
|
|
btScalar separation = b2Dot(frontNormal, clipPoints2[i].v) - frontOffset;
|
|
|
|
if (separation <= 0.0f)
|
|
{
|
|
|
|
//b2ManifoldPoint* cp = manifold->points + pointCount;
|
|
//btScalar separation = separation;
|
|
//cp->localPoint1 = b2MulT(xfA, clipPoints2[i].v);
|
|
//cp->localPoint2 = b2MulT(xfB, clipPoints2[i].v);
|
|
|
|
manifold->addContactPoint(-manifoldNormal,clipPoints2[i].v,separation);
|
|
|
|
// cp->id = clipPoints2[i].id;
|
|
// cp->id.features.flip = flip;
|
|
++pointCount;
|
|
}
|
|
}
|
|
|
|
// manifold->pointCount = pointCount;}
|
|
}
|