void VoronoiFractureDemo::voronoiBBShatter(const btAlignedObjectArray<btVector3>& points, const btVector3& bbmin, const btVector3& bbmax, const btQuaternion& bbq, const btVector3& bbt, btScalar matDensity) {
// points define voronoi cells in world space (avoid duplicates)
// bbmin & bbmax = bounding box min and max in local space
// bbq & bbt = bounding box quaternion rotation and translation
// matDensity = Material density for voronoi shard mass calculation
btVector3 bbvx = quatRotate(bbq, btVector3(1.0, 0.0, 0.0));
btVector3 bbvy = quatRotate(bbq, btVector3(0.0, 1.0, 0.0));
btVector3 bbvz = quatRotate(bbq, btVector3(0.0, 0.0, 1.0));
btQuaternion bbiq = bbq.inverse();
btConvexHullComputer* convexHC = new btConvexHullComputer();
btAlignedObjectArray<btVector3> vertices;
btVector3 rbb, nrbb;
btScalar nlength, maxDistance, distance;
btAlignedObjectArray<btVector3> sortedVoronoiPoints;
sortedVoronoiPoints.copyFromArray(points);
btVector3 normal, plane;
btAlignedObjectArray<btVector3> planes;
std::set<int> planeIndices;
std::set<int>::iterator planeIndicesIter;
int numplaneIndices;
int cellnum = 0;
int i, j, k;
int numpoints = points.size();
for (i=0; i < numpoints ;i++) {
curVoronoiPoint = points[i];
btVector3 icp = quatRotate(bbiq, curVoronoiPoint - bbt);
rbb = icp - bbmax;
nrbb = bbmin - icp;
planes.resize(6);
planes[0] = bbvx; planes[0][3] = rbb.x();
planes[1] = bbvy; planes[1][3] = rbb.y();
planes[2] = bbvz; planes[2][3] = rbb.z();
planes[3] = -bbvx; planes[3][3] = nrbb.x();
planes[4] = -bbvy; planes[4][3] = nrbb.y();
planes[5] = -bbvz; planes[5][3] = nrbb.z();
maxDistance = SIMD_INFINITY;
sortedVoronoiPoints.heapSort(pointCmp());
for (j=1; j < numpoints; j++) {
normal = sortedVoronoiPoints[j] - curVoronoiPoint;
nlength = normal.length();
if (nlength > maxDistance)
break;
plane = normal.normalized();
plane[3] = -nlength / btScalar(2.);
planes.push_back(plane);
getVerticesInsidePlanes(planes, vertices, planeIndices);
if (vertices.size() == 0)
break;
numplaneIndices = planeIndices.size();
if (numplaneIndices != planes.size()) {
planeIndicesIter = planeIndices.begin();
for (k=0; k < numplaneIndices; k++) {
if (k != *planeIndicesIter)
planes[k] = planes[*planeIndicesIter];
planeIndicesIter++;
}
planes.resize(numplaneIndices);
}
maxDistance = vertices[0].length();
for (k=1; k < vertices.size(); k++) {
distance = vertices[k].length();
if (maxDistance < distance)
maxDistance = distance;
}
maxDistance *= btScalar(2.);
}
if (vertices.size() == 0)
continue;
// Clean-up voronoi convex shard vertices and generate edges & faces
convexHC->compute(&vertices[0].getX(), sizeof(btVector3), vertices.size(),CONVEX_MARGIN,0.0);
// At this point we have a complete 3D voronoi shard mesh contained in convexHC
// Calculate volume and center of mass (Stan Melax volume integration)
int numFaces = convexHC->faces.size();
int v0, v1, v2; // Triangle vertices
btScalar volume = btScalar(0.);
btVector3 com(0., 0., 0.);
for (j=0; j < numFaces; j++) {
const btConvexHullComputer::Edge* edge = &convexHC->edges[convexHC->faces[j]];
v0 = edge->getSourceVertex();
v1 = edge->getTargetVertex();
edge = edge->getNextEdgeOfFace();
v2 = edge->getTargetVertex();
while (v2 != v0) {
// Counter-clockwise triangulated voronoi shard mesh faces (v0-v1-v2) and edges here...
btScalar vol = convexHC->vertices[v0].triple(convexHC->vertices[v1], convexHC->vertices[v2]);
volume += vol;
com += vol * (convexHC->vertices[v0] + convexHC->vertices[v1] + convexHC->vertices[v2]);
edge = edge->getNextEdgeOfFace();
v1 = v2;
v2 = edge->getTargetVertex();
}
}
com /= volume * btScalar(4.);
volume /= btScalar(6.);
// Shift all vertices relative to center of mass
int numVerts = convexHC->vertices.size();
for (j=0; j < numVerts; j++)
{
convexHC->vertices[j] -= com;
}
// Note:
// At this point convex hulls contained in convexHC should be accurate (line up flush with other pieces, no cracks),
// ...however Bullet Physics rigid bodies demo visualizations appear to produce some visible cracks.
// Use the mesh in convexHC for visual display or to perform boolean operations with.
// Create Bullet Physics rigid body shards
btCollisionShape* shardShape = new btConvexHullShape(&(convexHC->vertices[0].getX()), convexHC->vertices.size());
shardShape->setMargin(CONVEX_MARGIN); // for this demo; note convexHC has optional margin parameter for this
m_collisionShapes.push_back(shardShape);
btTransform shardTransform;
shardTransform.setIdentity();
shardTransform.setOrigin(curVoronoiPoint + com); // Shard's adjusted location
btDefaultMotionState* shardMotionState = new btDefaultMotionState(shardTransform);
btScalar shardMass(volume * matDensity);
btVector3 shardInertia(0.,0.,0.);
shardShape->calculateLocalInertia(shardMass, shardInertia);
btRigidBody::btRigidBodyConstructionInfo shardRBInfo(shardMass, shardMotionState, shardShape, shardInertia);
btRigidBody* shardBody = new btRigidBody(shardRBInfo);
m_dynamicsWorld->addRigidBody(shardBody);
cellnum ++;
}
printf("Generated %d voronoi btRigidBody shards\n", cellnum);
}
void Voronoi::voronoiBBShatter(const vector<btVector3>& points, const btVector3& bbmin, const btVector3& bbmax, const btQuaternion& bbq, const btVector3& bbt) {
// points define voronoi cells in world space (avoid duplicates)
// bbmin & bbmax = bounding box min and max in local space
// bbq & bbt = bounding box quaternion rotation and translation
// matDensity = Material density for voronoi shard mass calculation
btVector3 bbvx = quatRotate(bbq, btVector3(1.0, 0.0, 0.0));
btVector3 bbvy = quatRotate(bbq, btVector3(0.0, 1.0, 0.0));
btVector3 bbvz = quatRotate(bbq, btVector3(0.0, 0.0, 1.0));
btQuaternion bbiq = bbq.inverse();
btConvexHullComputer* convexHC = new btConvexHullComputer();
vector<btVector3> vertices;
btVector3 rbb, nrbb;
btScalar nlength, maxDistance, distance;
vector<btVector3> sortedVoronoiPoints;
for(unsigned int i = 0; i < points.size(); i++)
sortedVoronoiPoints.push_back(points[i]);
btVector3 normal, plane;
vector<btVector3> planes;
std::set<int> planeIndices;
std::set<int>::iterator planeIndicesIter;
int numplaneIndices;
int cellnum = 0;
int i, j, k;
int numpoints = points.size();
for (i=0; i < numpoints ;i++) {
curVoronoiPoint = points[i];
btVector3 icp = quatRotate(bbiq, curVoronoiPoint - bbt);
rbb = icp - bbmax;
nrbb = bbmin - icp;
planes.resize(6);
planes[0] = bbvx; planes[0][3] = rbb.x();
planes[1] = bbvy; planes[1][3] = rbb.y();
planes[2] = bbvz; planes[2][3] = rbb.z();
planes[3] = -bbvx; planes[3][3] = nrbb.x();
planes[4] = -bbvy; planes[4][3] = nrbb.y();
planes[5] = -bbvz; planes[5][3] = nrbb.z();
maxDistance = SIMD_INFINITY;
sort(sortedVoronoiPoints.begin(), sortedVoronoiPoints.end(), pointCompare);
//sortedVoronoiPoints(pointCmp());
for (j=1; j < numpoints; j++) {
normal = sortedVoronoiPoints[j] - curVoronoiPoint;
nlength = normal.length();
if (nlength > maxDistance)
break;
plane = normal.normalized();
plane[3] = -nlength / btScalar(2.);
planes.push_back(plane);
getVerticesInsidePlanes(planes, vertices, planeIndices);
if (vertices.size() == 0)
break;
numplaneIndices = planeIndices.size();
if (numplaneIndices != planes.size()) {
planeIndicesIter = planeIndices.begin();
for (k=0; k < numplaneIndices; k++) {
if (k != *planeIndicesIter)
planes[k] = planes[*planeIndicesIter];
planeIndicesIter++;
}
planes.resize(numplaneIndices);
}
maxDistance = vertices[0].length();
for (k=1; k < vertices.size(); k++) {
distance = vertices[k].length();
if (maxDistance < distance)
maxDistance = distance;
}
maxDistance *= btScalar(2.);
}
if (vertices.size() == 0)
continue;
// Clean-up voronoi convex shard vertices and generate edges & faces
convexHC->compute(&vertices[0].getX(), sizeof(btVector3), vertices.size(), CONVEX_MARGIN,0.0);
// At this point we have a complete 3D voronoi shard mesh contained in convexHC
// Calculate volume and center of mass (Stan Melax volume integration)
int numFaces = convexHC->faces.size();
int v0, v1, v2; // Triangle vertices
btScalar volume = btScalar(0.);
btVector3 com(0., 0., 0.);
for (j=0; j < numFaces; j++) {
const btConvexHullComputer::Edge* edge = &convexHC->edges[convexHC->faces[j]];
v0 = edge->getSourceVertex();
v1 = edge->getTargetVertex();
edge = edge->getNextEdgeOfFace();
v2 = edge->getTargetVertex();
while (v2 != v0) {
// Counter-clockwise triangulated voronoi shard mesh faces (v0-v1-v2) and edges here...
btScalar vol = convexHC->vertices[v0].triple(convexHC->vertices[v1], convexHC->vertices[v2]);
volume += vol;
com += vol * (convexHC->vertices[v0] + convexHC->vertices[v1] + convexHC->vertices[v2]);
edge = edge->getNextEdgeOfFace();
v1 = v2;
v2 = edge->getTargetVertex();
}
}
com /= volume * btScalar(4.);
volume /= btScalar(6.);
// Shift all vertices relative to center of mass
int numVerts = convexHC->vertices.size();
for (j=0; j < numVerts; j++)
{
convexHC->vertices[j] -= com;
}
cellnum ++;
}
}
void QuaternionDiff(const btQuaternion &p, const btQuaternion &q, btQuaternion &qt) {
btQuaternion q2 = q.inverse();
qt = q2 * p;
qt.normalize();
}