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perform GrahamScanConvexHull2D around an arbitrary oriented 2D plane in 3D, to fix some convex hull face merging problems

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add compound shape support to BulletXmlWorldImporter and fix some compile issue under Debian (hopefully)
object picking change in the demos: create a ball-socket picking constraint when holding shift while mouse dragging, otherwise a fixed (6dof) constraint
add assert in constraint solver, when both objects have their inertia tensor rows set to zero
btPolyhedralContactClipping: add edge-edge contact point in  findSeparatingAxis (similar to the default GJK case)
This commit is contained in:
erwin.coumans
2012-09-28 07:14:48 +00:00
parent 837e5cb5e0
commit 60bf599246
24 changed files with 385 additions and 153 deletions
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31
src/BulletCollision/CollisionShapes/btConvexHullShape.cpp
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@@ -201,13 +201,11 @@ const char* btConvexHullShape::serialize(void* dataBuffer, btSerializer* seriali
return "btConvexHullShapeData";
}
void btConvexHullShape::project(const btTransform& trans, const btVector3& dir, btScalar& min, btScalar& max) const
void btConvexHullShape::project(const btTransform& trans, const btVector3& dir, btScalar& minProj, btScalar& maxProj, btVector3& witnesPtMin,btVector3& witnesPtMax) const
{
#if 1
min = FLT_MAX;
max = -FLT_MAX;
btVector3 witnesPtMin;
btVector3 witnesPtMax;
minProj = FLT_MAX;
maxProj = -FLT_MAX;
int numVerts = m_unscaledPoints.size();
for(int i=0;i<numVerts;i++)
@@ -215,31 +213,30 @@ void btConvexHullShape::project(const btTransform& trans, const btVector3& dir,
btVector3 vtx = m_unscaledPoints[i] * m_localScaling;
btVector3 pt = trans * vtx;
btScalar dp = pt.dot(dir);
if(dp < min)
if(dp < minProj)
{
min = dp;
minProj = dp;
witnesPtMin = pt;
}
if(dp > max)
if(dp > maxProj)
{
max = dp;
maxProj = dp;
witnesPtMax=pt;
}
}
#else
btVector3 localAxis = dir*trans.getBasis();
btVector3 vtx1 = trans(localGetSupportingVertex(localAxis));
btVector3 vtx2 = trans(localGetSupportingVertex(-localAxis));
witnesPtMin = trans(localGetSupportingVertex(localAxis));
witnesPtMax = trans(localGetSupportingVertex(-localAxis));
min = vtx1.dot(dir);
max = vtx2.dot(dir);
minProj = witnesPtMin.dot(dir);
maxProj = witnesPtMax.dot(dir);
#endif
if(min>max)
if(minProj>maxProj)
{
btScalar tmp = min;
min = max;
max = tmp;
btSwap(minProj,maxProj);
btSwap(witnesPtMin,witnesPtMax);
}

2
src/BulletCollision/CollisionShapes/btConvexHullShape.h
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@@ -73,7 +73,7 @@ public:
virtual void batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3* vectors,btVector3* supportVerticesOut,int numVectors) const;
virtual void project(const btTransform& trans, const btVector3& dir, btScalar& min, btScalar& max) const;
virtual void project(const btTransform& trans, const btVector3& dir, btScalar& minProj, btScalar& maxProj, btVector3& witnesPtMin,btVector3& witnesPtMax) const;
//debugging

26
src/BulletCollision/CollisionShapes/btConvexPolyhedron.cpp
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@@ -274,23 +274,29 @@ void btConvexPolyhedron::initialize()
#endif
}
void btConvexPolyhedron::project(const btTransform& trans, const btVector3& dir, btScalar& min, btScalar& max) const
void btConvexPolyhedron::project(const btTransform& trans, const btVector3& dir, btScalar& minProj, btScalar& maxProj, btVector3& witnesPtMin,btVector3& witnesPtMax) const
{
min = FLT_MAX;
max = -FLT_MAX;
minProj = FLT_MAX;
maxProj = -FLT_MAX;
int numVerts = m_vertices.size();
for(int i=0;i<numVerts;i++)
{
btVector3 pt = trans * m_vertices[i];
btScalar dp = pt.dot(dir);
if(dp < min) min = dp;
if(dp > max) max = dp;
if(dp < minProj)
{
minProj = dp;
witnesPtMin = pt;
}
if(dp > maxProj)
{
maxProj = dp;
witnesPtMax = pt;
}
}
if(min>max)
if(minProj>maxProj)
{
btScalar tmp = min;
min = max;
max = tmp;
btSwap(minProj,maxProj);
btSwap(witnesPtMin,witnesPtMax);
}
}

2
src/BulletCollision/CollisionShapes/btConvexPolyhedron.h
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@@ -56,7 +56,7 @@ ATTRIBUTE_ALIGNED16(class) btConvexPolyhedron
void initialize();
bool testContainment() const;
void project(const btTransform& trans, const btVector3& dir, btScalar& min, btScalar& max) const;
void project(const btTransform& trans, const btVector3& dir, btScalar& minProj, btScalar& maxProj, btVector3& witnesPtMin,btVector3& witnesPtMax) const;
};

94
src/BulletCollision/CollisionShapes/btPolyhedralConvexShape.cpp
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@@ -37,7 +37,7 @@ btPolyhedralConvexShape::~btPolyhedralConvexShape()
}
bool btPolyhedralConvexShape::initializePolyhedralFeatures()
bool btPolyhedralConvexShape::initializePolyhedralFeatures(int shiftVerticesByMargin)
{
if (m_polyhedron)
@@ -56,31 +56,34 @@ bool btPolyhedralConvexShape::initializePolyhedralFeatures()
btVector3& newVertex = orgVertices.expand();
getVertex(i,newVertex);
}
#if 0
btAlignedObjectArray<btVector3> planeEquations;
btGeometryUtil::getPlaneEquationsFromVertices(orgVertices,planeEquations);
btAlignedObjectArray<btVector3> shiftedPlaneEquations;
for (int p=0;p<planeEquations.size();p++)
btConvexHullComputer conv;
if (shiftVerticesByMargin)
{
btVector3 plane = planeEquations[p];
plane[3] -= getMargin();
shiftedPlaneEquations.push_back(plane);
btAlignedObjectArray<btVector3> planeEquations;
btGeometryUtil::getPlaneEquationsFromVertices(orgVertices,planeEquations);
btAlignedObjectArray<btVector3> shiftedPlaneEquations;
for (int p=0;p<planeEquations.size();p++)
{
btVector3 plane = planeEquations[p];
btScalar margin = getMargin();
plane[3] -= getMargin();
shiftedPlaneEquations.push_back(plane);
}
btAlignedObjectArray<btVector3> tmpVertices;
btGeometryUtil::getVerticesFromPlaneEquations(shiftedPlaneEquations,tmpVertices);
conv.compute(&tmpVertices[0].getX(), sizeof(btVector3),tmpVertices.size(),0.f,0.f);
} else
{
conv.compute(&orgVertices[0].getX(), sizeof(btVector3),orgVertices.size(),0.f,0.f);
}
btAlignedObjectArray<btVector3> tmpVertices;
btGeometryUtil::getVerticesFromPlaneEquations(shiftedPlaneEquations,tmpVertices);
btConvexHullComputer conv;
conv.compute(&tmpVertices[0].getX(), sizeof(btVector3),tmpVertices.size(),0.f,0.f);
#else
btConvexHullComputer conv;
conv.compute(&orgVertices[0].getX(), sizeof(btVector3),orgVertices.size(),0.f,0.f);
#endif
btAlignedObjectArray<btVector3> faceNormals;
@@ -193,7 +196,8 @@ bool btPolyhedralConvexShape::initializePolyhedralFeatures()
{
//do the merge: use Graham Scan 2d convex hull
btAlignedObjectArray<GrahamVector2> orgpoints;
btAlignedObjectArray<GrahamVector3> orgpoints;
btVector3 averageFaceNormal(0,0,0);
for (int i=0;i<coplanarFaceGroup.size();i++)
{
@@ -201,16 +205,12 @@ bool btPolyhedralConvexShape::initializePolyhedralFeatures()
btFace& face = tmpFaces[coplanarFaceGroup[i]];
btVector3 faceNormal(face.m_plane[0],face.m_plane[1],face.m_plane[2]);
btVector3 xyPlaneNormal(0,0,1);
btQuaternion rotationArc = shortestArcQuat(faceNormal,xyPlaneNormal);
averageFaceNormal+=faceNormal;
for (int f=0;f<face.m_indices.size();f++)
{
int orgIndex = face.m_indices[f];
btVector3 pt = m_polyhedron->m_vertices[orgIndex];
btVector3 rotatedPt = quatRotate(rotationArc,pt);
rotatedPt.setZ(0);
bool found = false;
for (int i=0;i<orgpoints.size();i++)
@@ -223,34 +223,45 @@ bool btPolyhedralConvexShape::initializePolyhedralFeatures()
}
}
if (!found)
orgpoints.push_back(GrahamVector2(rotatedPt,orgIndex));
orgpoints.push_back(GrahamVector3(pt,orgIndex));
}
}
btFace combinedFace;
for (int i=0;i<4;i++)
combinedFace.m_plane[i] = tmpFaces[coplanarFaceGroup[0]].m_plane[i];
btAlignedObjectArray<GrahamVector2> hull;
GrahamScanConvexHull2D(orgpoints,hull);
btAlignedObjectArray<GrahamVector3> hull;
averageFaceNormal.normalize();
GrahamScanConvexHull2D(orgpoints,hull,averageFaceNormal);
for (int i=0;i<hull.size();i++)
{
combinedFace.m_indices.push_back(hull[i].m_orgIndex);
for(int k = 0; k < orgpoints.size(); k++) {
if(orgpoints[k].m_orgIndex == hull[i].m_orgIndex) {
for(int k = 0; k < orgpoints.size(); k++)
{
if(orgpoints[k].m_orgIndex == hull[i].m_orgIndex)
{
orgpoints[k].m_orgIndex = -1; // invalidate...
break;
}
}
}
}
// are there rejected vertices?
bool reject_merge = false;
for(int i = 0; i < orgpoints.size(); i++) {
if(orgpoints[i].m_orgIndex == -1)
continue; // this is in the hull...
// this vertex is rejected -- is anybody else using this vertex?
for(int j = 0; j < tmpFaces.size(); j++) {
btFace& face = tmpFaces[j];
// is this a face of the current coplanar group?
bool is_in_current_group = false;
@@ -276,20 +287,23 @@ bool btPolyhedralConvexShape::initializePolyhedralFeatures()
if(reject_merge)
break;
}
if(!reject_merge) {
if (!reject_merge)
{
// do this merge!
did_merge = true;
m_polyhedron->m_faces.push_back(combinedFace);
m_polyhedron->m_faces.push_back(combinedFace);
}
}
if(!did_merge)
{
for (int i=0;i<coplanarFaceGroup.size();i++)
{
m_polyhedron->m_faces.push_back(tmpFaces[coplanarFaceGroup[i]]);
btFace face = tmpFaces[coplanarFaceGroup[i]];
m_polyhedron->m_faces.push_back(face);
}
}
}

3
src/BulletCollision/CollisionShapes/btPolyhedralConvexShape.h
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@@ -40,7 +40,8 @@ public:
virtual ~btPolyhedralConvexShape();
///optional method mainly used to generate multiple contact points by clipping polyhedral features (faces/edges)
virtual bool initializePolyhedralFeatures();
///experimental/work-in-progress
virtual bool initializePolyhedralFeatures(int shiftVerticesByMargin=0);
const btConvexPolyhedron* getConvexPolyhedron() const
{