bool btPolyhedralConvexShape::initializePolyhedralFeatures()
{
if (m_polyhedron)
btAlignedFree(m_polyhedron);
void* mem = btAlignedAlloc(sizeof(btConvexPolyhedron),16);
m_polyhedron = new (mem) btConvexPolyhedron;
btAlignedObjectArray<btVector3> orgVertices;
for (int i=0;i<getNumVertices();i++)
{
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++)
{
btVector3 plane = planeEquations[p];
plane[3] -= getMargin();
shiftedPlaneEquations.push_back(plane);
}
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;
int numFaces = conv.faces.size();
faceNormals.resize(numFaces);
btConvexHullComputer* convexUtil = &conv;
btAlignedObjectArray<btFace> tmpFaces;
tmpFaces.resize(numFaces);
int numVertices = convexUtil->vertices.size();
m_polyhedron->m_vertices.resize(numVertices);
for (int p=0;p<numVertices;p++)
{
m_polyhedron->m_vertices[p] = convexUtil->vertices[p];
}
for (int i=0;i<numFaces;i++)
{
int face = convexUtil->faces[i];
//printf("face=%d\n",face);
const btConvexHullComputer::Edge* firstEdge = &convexUtil->edges[face];
const btConvexHullComputer::Edge* edge = firstEdge;
btVector3 edges[3];
int numEdges = 0;
//compute face normals
// btScalar maxCross2 = 0.f;
// int chosenEdge = -1;
do
{
int src = edge->getSourceVertex();
tmpFaces[i].m_indices.push_back(src);
int targ = edge->getTargetVertex();
btVector3 wa = convexUtil->vertices[src];
btVector3 wb = convexUtil->vertices[targ];
btVector3 newEdge = wb-wa;
newEdge.normalize();
if (numEdges<2)
edges[numEdges++] = newEdge;
edge = edge->getNextEdgeOfFace();
} while (edge!=firstEdge);
btScalar planeEq = 1e30f;
if (numEdges==2)
{
faceNormals[i] = edges[0].cross(edges[1]);
faceNormals[i].normalize();
tmpFaces[i].m_plane[0] = faceNormals[i].getX();
tmpFaces[i].m_plane[1] = faceNormals[i].getY();
tmpFaces[i].m_plane[2] = faceNormals[i].getZ();
tmpFaces[i].m_plane[3] = planeEq;
}
else
{
btAssert(0);//degenerate?
faceNormals[i].setZero();
}
for (int v=0;v<tmpFaces[i].m_indices.size();v++)
{
btScalar eq = m_polyhedron->m_vertices[tmpFaces[i].m_indices[v]].dot(faceNormals[i]);
if (planeEq>eq)
{
planeEq=eq;
}
}
tmpFaces[i].m_plane[3] = -planeEq;
}
//merge coplanar faces and copy them to m_polyhedron
btScalar faceWeldThreshold= 0.999f;
btAlignedObjectArray<int> todoFaces;
for (int i=0;i<tmpFaces.size();i++)
todoFaces.push_back(i);
while (todoFaces.size())
{
btAlignedObjectArray<int> coplanarFaceGroup;
int refFace = todoFaces[todoFaces.size()-1];
coplanarFaceGroup.push_back(refFace);
btFace& faceA = tmpFaces[refFace];
todoFaces.pop_back();
btVector3 faceNormalA(faceA.m_plane[0],faceA.m_plane[1],faceA.m_plane[2]);
for (int j=todoFaces.size()-1;j>=0;j--)
{
int i = todoFaces[j];
btFace& faceB = tmpFaces[i];
btVector3 faceNormalB(faceB.m_plane[0],faceB.m_plane[1],faceB.m_plane[2]);
if (faceNormalA.dot(faceNormalB)>faceWeldThreshold)
{
coplanarFaceGroup.push_back(i);
todoFaces.remove(i);
}
}
if (coplanarFaceGroup.size()>1)
{
//do the merge: use Graham Scan 2d convex hull
btAlignedObjectArray<GrahamVector2> orgpoints;
for (int i=0;i<coplanarFaceGroup.size();i++)
{
// m_polyhedron->m_faces.push_back(tmpFaces[coplanarFaceGroup[i]]);
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);
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++)
{
if ((rotatedPt-orgpoints[i]).length2()<0.001)
{
found=true;
break;
}
}
if (!found)
orgpoints.push_back(GrahamVector2(rotatedPt,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);
for (int i=0;i<hull.size();i++)
{
combinedFace.m_indices.push_back(hull[i].m_orgIndex);
}
m_polyhedron->m_faces.push_back(combinedFace);
} else
{
for (int i=0;i<coplanarFaceGroup.size();i++)
{
m_polyhedron->m_faces.push_back(tmpFaces[coplanarFaceGroup[i]]);
}
}
}
m_polyhedron->initialize();
return true;
}
bool btConvexUtility::initializePolyhedralFeatures(const btAlignedObjectArray<btVector3>& orgVertices, bool mergeCoplanarTriangles)
{
btConvexHullComputer conv;
conv.compute(&orgVertices[0].getX(), sizeof(btVector3),orgVertices.size(),0.f,0.f);
btAlignedObjectArray<btVector3> faceNormals;
int numFaces = conv.faces.size();
faceNormals.resize(numFaces);
btConvexHullComputer* convexUtil = &conv;
btAlignedObjectArray<btFace> tmpFaces;
tmpFaces.resize(numFaces);
int numVertices = convexUtil->vertices.size();
m_vertices.resize(numVertices);
for (int p=0;p<numVertices;p++)
{
m_vertices[p] = convexUtil->vertices[p];
}
for (int i=0;i<numFaces;i++)
{
int face = convexUtil->faces[i];
//printf("face=%d\n",face);
const btConvexHullComputer::Edge* firstEdge = &convexUtil->edges[face];
const btConvexHullComputer::Edge* edge = firstEdge;
btVector3 edges[3];
int numEdges = 0;
//compute face normals
btScalar maxCross2 = 0.f;
int chosenEdge = -1;
do
{
int src = edge->getSourceVertex();
tmpFaces[i].m_indices.push_back(src);
int targ = edge->getTargetVertex();
btVector3 wa = convexUtil->vertices[src];
btVector3 wb = convexUtil->vertices[targ];
btVector3 newEdge = wb-wa;
newEdge.normalize();
if (numEdges<2)
edges[numEdges++] = newEdge;
edge = edge->getNextEdgeOfFace();
} while (edge!=firstEdge);
btScalar planeEq = 1e30f;
if (numEdges==2)
{
faceNormals[i] = edges[0].cross(edges[1]);
faceNormals[i].normalize();
tmpFaces[i].m_plane[0] = faceNormals[i].getX();
tmpFaces[i].m_plane[1] = faceNormals[i].getY();
tmpFaces[i].m_plane[2] = faceNormals[i].getZ();
tmpFaces[i].m_plane[3] = planeEq;
}
else
{
btAssert(0);//degenerate?
faceNormals[i].setZero();
}
for (int v=0;v<tmpFaces[i].m_indices.size();v++)
{
btScalar eq = m_vertices[tmpFaces[i].m_indices[v]].dot(faceNormals[i]);
if (planeEq>eq)
{
planeEq=eq;
}
}
tmpFaces[i].m_plane[3] = -planeEq;
}
//merge coplanar faces
btScalar faceWeldThreshold= 0.999f;
btAlignedObjectArray<int> todoFaces;
for (int i=0;i<tmpFaces.size();i++)
todoFaces.push_back(i);
while (todoFaces.size())
{
btAlignedObjectArray<int> coplanarFaceGroup;
int refFace = todoFaces[todoFaces.size()-1];
coplanarFaceGroup.push_back(refFace);
btFace& faceA = tmpFaces[refFace];
todoFaces.pop_back();
btVector3 faceNormalA(faceA.m_plane[0],faceA.m_plane[1],faceA.m_plane[2]);
for (int j=todoFaces.size()-1;j>=0;j--)
{
int i = todoFaces[j];
btFace& faceB = tmpFaces[i];
btVector3 faceNormalB(faceB.m_plane[0],faceB.m_plane[1],faceB.m_plane[2]);
if (faceNormalA.dot(faceNormalB)>faceWeldThreshold)
{
coplanarFaceGroup.push_back(i);
todoFaces.remove(i);
}
}
bool did_merge = false;
if (mergeCoplanarTriangles && coplanarFaceGroup.size()>1)
{
//do the merge: use Graham Scan 2d convex hull
btAlignedObjectArray<GrahamVector2> orgpoints;
for (int i=0;i<coplanarFaceGroup.size();i++)
{
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);
for (int f=0;f<face.m_indices.size();f++)
{
int orgIndex = face.m_indices[f];
btVector3 pt = m_vertices[orgIndex];
btVector3 rotatedPt = quatRotate(rotationArc,pt);
rotatedPt.setZ(0);
bool found = false;
for (int i=0;i<orgpoints.size();i++)
{
//if ((orgpoints[i].m_orgIndex == orgIndex) || ((rotatedPt-orgpoints[i]).length2()<0.0001))
if (orgpoints[i].m_orgIndex == orgIndex)
{
found=true;
break;
}
}
if (!found)
orgpoints.push_back(GrahamVector2(rotatedPt,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);
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) {
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;
for(int k = 0; k < coplanarFaceGroup.size(); k++) {
if(coplanarFaceGroup[k] == j) {
is_in_current_group = true;
break;
}
}
if(is_in_current_group) // ignore this face...
continue;
// does this face use this rejected vertex?
for(int v = 0; v < face.m_indices.size(); v++) {
if(face.m_indices[v] == orgpoints[i].m_orgIndex) {
// this rejected vertex is used in another face -- reject merge
reject_merge = true;
break;
}
}
if(reject_merge)
break;
}
if(reject_merge)
break;
}
if(!reject_merge) {
// do this merge!
did_merge = true;
m_faces.push_back(combinedFace);
}
}
if(!did_merge)
{
for (int i=0;i<coplanarFaceGroup.size();i++)
{
m_faces.push_back(tmpFaces[coplanarFaceGroup[i]]);
}
}
}
return true;
}
