PxClothMeshDesc
PxClothMeshQuadifierImpl::getDescriptor() const
{
// copy points and other data
PxClothMeshDesc desc = mDesc;
// for now use only 32 bit for temporary indices out of quadifier
desc.flags &= ~PxMeshFlag::e16_BIT_INDICES;
desc.triangles.count = mTriangles.size() / 3;
desc.triangles.data = mTriangles.begin();
desc.triangles.stride = 3 * sizeof(PxU32);
desc.quads.count = mQuads.size() / 4;
desc.quads.data = mQuads.begin();
desc.quads.stride = 4 * sizeof(PxU32);
PX_ASSERT(desc.isValid());
return desc;
}
void PhysXCloth::CreateCloth(const PxVec3& a_position,
unsigned int& a_vertexCount, unsigned int& a_indexCount,
const PxVec3* a_vertices,
unsigned int* a_indices)
{
// set up the cloth description
PxClothMeshDesc clothDesc;
clothDesc.setToDefault();
clothDesc.points.count = a_vertexCount;
clothDesc.triangles.count = a_indexCount / 3;
clothDesc.points.stride = sizeof(glm::vec3);
clothDesc.triangles.stride = sizeof(unsigned int) * 3;
clothDesc.points.data = a_vertices;
clothDesc.triangles.data = a_indices;
// cook the geometry into fabric
PxClothFabric* fabric = PxClothFabricCreate(*m_pPhysicsRef, clothDesc, PxVec3(0, 9.87f, 0));
// set up the particles for each vertex
PxClothParticle* particles = new PxClothParticle[a_vertexCount];
for (unsigned int i = 0; i < a_vertexCount; ++i)
{
particles[i].pos = PxVec3(a_vertices[i].x, a_vertices[i].y, a_vertices[i].z);
// set weights (0 means static)
if (a_vertices[i].x == a_position.x)
particles[i].invWeight = 0;
else
particles[i].invWeight = 1.f;
}
// create the cloth then setup the spring properties
m_cloth = m_pPhysicsRef->createCloth(PxTransform(a_position), *fabric, particles, PxClothFlags());
// we need to set some solver configurations
if (m_cloth != nullptr)
{
m_cloth->setSolverFrequency(240.0f);
m_cloth->setStretchConfig(PxClothFabricPhaseType::eVERTICAL, PxClothStretchConfig(1.0f));
m_cloth->setStretchConfig(PxClothFabricPhaseType::eHORIZONTAL, PxClothStretchConfig(0.9f));
m_cloth->setStretchConfig(PxClothFabricPhaseType::eSHEARING, PxClothStretchConfig(0.75f));
m_cloth->setStretchConfig(PxClothFabricPhaseType::eBENDING, PxClothStretchConfig(0.5f));
PxClothStretchConfig stretchConfig;
stretchConfig.stiffness = 0.8f;
stretchConfig.stiffnessMultiplier = 0.5f;
stretchConfig.compressionLimit = 0.6f;
stretchConfig.stretchLimit = 1.2f;
m_cloth->setStretchConfig(PxClothFabricPhaseType::eVERTICAL, stretchConfig);
// Two spheres located on the x-axis
PxClothCollisionSphere spheres[2] =
{
PxClothCollisionSphere(PxVec3(-1.0f, 0.0f, 0.0f), 0.5f),
PxClothCollisionSphere(PxVec3(1.0f, 0.0f, 0.0f), 0.25f)
};
m_cloth->setCollisionSpheres(spheres, 2);
m_cloth->addCollisionCapsule(0, 1);
m_cloth->addCollisionPlane(PxClothCollisionPlane(PxVec3(0.0f, 1.0f, 0.0f), 0.0f));
m_cloth->addCollisionConvex(1 << 0); // Convex references the first plane
}
delete[] particles;
}
bool PxFabricCookerImpl::cook(const PxClothMeshDesc& desc, PxVec3 gravity, bool useGeodesicTether)
{
if(!desc.isValid())
{
shdfnd::getFoundation().error(PxErrorCode::eINVALID_PARAMETER, __FILE__, __LINE__,
"PxFabricCookerImpl::cook: desc.isValid() failed!");
return false;
}
gravity = gravity.getNormalized();
mNumParticles = desc.points.count;
// assemble points
shdfnd::Array<PxVec4> particles;
particles.reserve(mNumParticles);
PxStrideIterator<const PxVec3> pIt((const PxVec3*)desc.points.data, desc.points.stride);
PxStrideIterator<const PxReal> wIt((const PxReal*)desc.invMasses.data, desc.invMasses.stride);
for(PxU32 i=0; i<mNumParticles; ++i)
particles.pushBack(PxVec4(*pIt++, wIt.ptr() ? *wIt++ : 1.0f));
// build adjacent vertex list
shdfnd::Array<PxU32> valency(mNumParticles+1, 0);
shdfnd::Array<PxU32> adjacencies;
if(desc.flags & PxMeshFlag::e16_BIT_INDICES)
gatherAdjacencies<PxU16>(valency, adjacencies, desc.triangles, desc.quads);
else
gatherAdjacencies<PxU32>(valency, adjacencies, desc.triangles, desc.quads);
// build unique neighbors from adjacencies
shdfnd::Array<PxU32> mark(valency.size(), 0);
shdfnd::Array<PxU32> neighbors; neighbors.reserve(adjacencies.size());
for(PxU32 i=1, j=0; i<valency.size(); ++i)
{
for(; j<valency[i]; ++j)
{
PxU32 k = adjacencies[j];
if(mark[k] != i)
{
mark[k] = i;
neighbors.pushBack(k);
}
}
valency[i] = neighbors.size();
}
// build map of unique edges and classify
shdfnd::HashMap<Pair, Edge> edges;
for(PxU32 i=0; i<mNumParticles; ++i)
{
PxReal wi = particles[i].w;
// iterate all neighbors
PxU32 jlast = valency[i+1];
for(PxU32 j=valency[i]; j<jlast; ++j)
{
// add 1-ring edge
PxU32 m = neighbors[j];
if(wi + particles[m].w > 0.0f)
edges[Pair(PxMin(i, m), PxMax(i, m))].classify();
// iterate all neighbors of neighbor
PxU32 klast = valency[m+1];
for(PxU32 k=valency[m]; k<klast; ++k)
{
PxU32 n = neighbors[k];
if(n != i && wi + particles[n].w > 0.0f)
{
// add 2-ring edge
edges[Pair(PxMin(i, n), PxMax(i, n))].classify(
particles[i], particles[m], particles[n]);
}
}
}
}
// copy classified edges to constraints array
// build histogram of constraints per vertex
shdfnd::Array<Entry> constraints;
constraints.reserve(edges.size());
valency.resize(0); valency.resize(mNumParticles+1, 0);
const PxReal sqrtHalf = PxSqrt(0.4f);
for(shdfnd::HashMap<Pair, Edge>::Iterator eIt = edges.getIterator(); !eIt.done(); ++eIt)
{
const Edge& edge = eIt->second;
const Pair& pair = eIt->first;
if((edge.mStretching + edge.mBending + edge.mShearing) > 0.0f)
{
PxClothFabricPhaseType::Enum type = PxClothFabricPhaseType::eINVALID;
if(edge.mBending > PxMax(edge.mStretching, edge.mShearing))
type = PxClothFabricPhaseType::eBENDING;
else if(edge.mShearing > PxMax(edge.mStretching, edge.mBending))
type = PxClothFabricPhaseType::eSHEARING;
else
{
PxVec4 diff = particles[pair.first]-particles[pair.second];
PxReal dot = gravity.dot(reinterpret_cast<const PxVec3&>(diff).getNormalized());
type = fabsf(dot) < sqrtHalf ? PxClothFabricPhaseType::eHORIZONTAL : PxClothFabricPhaseType::eVERTICAL;
}
++valency[pair.first];
++valency[pair.second];
constraints.pushBack(Entry(pair, type));
}
}
prefixSum(valency.begin(), valency.end(), valency.begin());
PxU32 numConstraints = constraints.size();
// build adjacent constraint list
adjacencies.resize(0); adjacencies.resize(valency.back(), 0);
for(PxU32 i=0; i<numConstraints; ++i)
{
adjacencies[--valency[constraints[i].first.first]] = i;
adjacencies[--valency[constraints[i].first.second]] = i;
}
shdfnd::Array<PxU32>::ConstIterator aFirst = adjacencies.begin();
shdfnd::Array<PxU32> colors(numConstraints, numConstraints); // constraint -> color, initialily not colored
mark.resize(0); mark.resize(numConstraints+1, PX_MAX_U32); // color -> constraint index
shdfnd::Array<PxU32> adjColorCount(numConstraints, 0); // # of neighbors that are already colored
shdfnd::Array<ConstraintGraphColorCount> constraintHeap;
constraintHeap.reserve(numConstraints); // set of constraints to color (added in edge distance order)
// Do graph coloring based on edge distance.
// For each constraint, we add its uncolored neighbors to the heap
// ,and we pick the constraint with most colored neighbors from the heap.
while (1)
{
PxU32 constraint = 0;
while ( (constraint < numConstraints) && (colors[constraint] != numConstraints))
constraint++; // start with the first uncolored constraint
if (constraint >= numConstraints)
break;
constraintHeap.clear();
pushHeap(constraintHeap, ConstraintGraphColorCount((int)constraint, (int)adjColorCount[constraint]));
PxClothFabricPhaseType::Enum type = constraints[constraint].second;
while (!constraintHeap.empty())
{
ConstraintGraphColorCount heapItem = popHeap(constraintHeap);
constraint = heapItem.constraint;
if (colors[constraint] != numConstraints)
continue; // skip if already colored
const Pair& pair = constraints[constraint].first;
for(PxU32 j=0; j<2; ++j)
{
PxU32 index = j ? pair.first : pair.second;
if(particles[index].w == 0.0f)
continue; // don't mark adjacent particles if attached
for(shdfnd::Array<PxU32>::ConstIterator aIt = aFirst + valency[index], aEnd = aFirst + valency[index+1]; aIt != aEnd; ++aIt)
{
PxU32 adjacentConstraint = *aIt;
if ((constraints[adjacentConstraint].second != type) || (adjacentConstraint == constraint))
continue;
mark[colors[adjacentConstraint]] = constraint;
++adjColorCount[adjacentConstraint];
pushHeap(constraintHeap, ConstraintGraphColorCount((int)adjacentConstraint, (int)adjColorCount[adjacentConstraint]));
}
}
// find smallest color with matching type
PxU32 color = 0;
while((color < mPhases.size() && mPhases[color].phaseType != type) || mark[color] == constraint)
++color;
// create a new color set
if(color == mPhases.size())
{
PxClothFabricPhase phase(type, mPhases.size());
mPhases.pushBack(phase);
mSets.pushBack(0);
}
colors[constraint] = color;
++mSets[color];
}
}
#if 0 // PX_DEBUG
printf("set[%u] = ", mSets.size());
for(PxU32 i=0; i<mSets.size(); ++i)
printf("%u ", mSets[i]);
#endif
prefixSum(mSets.begin(), mSets.end(), mSets.begin());
#if 0 // PX_DEBUG
printf(" = %u\n", mSets.back());
#endif
// write indices and rest lengths
// convert mSets to exclusive sum
PxU32 back = mSets.back();
mSets.pushBack(back);
mIndices.resize(numConstraints*2);
mRestvalues.resize(numConstraints);
for(PxU32 i=0; i<numConstraints; ++i)
{
PxU32 first = constraints[i].first.first;
PxU32 second = constraints[i].first.second;
PxU32 index = --mSets[colors[i]];
mIndices[2*index ] = first;
mIndices[2*index+1] = second;
PxVec4 diff = particles[second] - particles[first];
mRestvalues[index] = reinterpret_cast<
const PxVec3&>(diff).magnitude();
}
// reorder constraints and rest values for more efficient cache access (linear)
shdfnd::Array<PxU32> newIndices(mIndices.size());
shdfnd::Array<PxF32> newRestValues(mRestvalues.size());
// sort each constraint set in vertex order
for (PxU32 i=0; i < mSets.size()-1; ++i)
{
// create a re-ordering list
shdfnd::Array<PxU32> reorder(mSets[i+1]-mSets[i]);
for (PxU32 r=0; r < reorder.size(); ++r)
reorder[r] = r;
const PxU32 indicesOffset = mSets[i]*2;
const PxU32 restOffset = mSets[i];
ConstraintSorter predicate(&mIndices[indicesOffset]);
shdfnd::sort(&reorder[0], reorder.size(), predicate);
for (PxU32 r=0; r < reorder.size(); ++r)
{
newIndices[indicesOffset + r*2] = mIndices[indicesOffset + reorder[r]*2];
newIndices[indicesOffset + r*2+1] = mIndices[indicesOffset + reorder[r]*2+1];
newRestValues[restOffset + r] = mRestvalues[restOffset + reorder[r]];
}
}
mIndices = newIndices;
mRestvalues = newRestValues;
PX_ASSERT(mIndices.size() == mRestvalues.size()*2);
PX_ASSERT(mRestvalues.size() == mSets.back());
#if 0 // PX_DEBUG
for (PxU32 i = 1; i < mSets.size(); i++)
{
PxClothFabricPhase phase = mPhases[i-1];
printf("%d : type %d, size %d\n",
i-1, phase.phaseType, mSets[i] - mSets[i-1]);
}
#endif
if (useGeodesicTether)
{
PxClothGeodesicTetherCooker tetherCooker(desc);
if (tetherCooker.getCookerStatus() == 0)
{
PxU32 numTethersPerParticle = tetherCooker.getNbTethersPerParticle();
PxU32 tetherSize = mNumParticles * numTethersPerParticle;
mTetherAnchors.resize(tetherSize);
mTetherLengths.resize(tetherSize);
tetherCooker.getTetherData(mTetherAnchors.begin(), mTetherLengths.begin());
}
else
useGeodesicTether = false;
}
if (!useGeodesicTether)
{
PxClothSimpleTetherCooker tetherCooker(desc);
mTetherAnchors.resize(mNumParticles);
mTetherLengths.resize(mNumParticles);
tetherCooker.getTetherData(mTetherAnchors.begin(), mTetherLengths.begin());
}
return true;
}
void
SampleCharacterCloth::createCape()
{
// compute root transform and positions of all the bones
PxTransform rootPose;
SampleArray<PxVec3> positions;
SampleArray<PxU32> indexPairs;
mCharacter.getFramePose(rootPose, positions, indexPairs);
// convert bones to collision capsules
SampleArray<PxClothCollisionSphere> spheres;
spheres.resize(positions.size());
for (PxU32 i = 0; i < positions.size(); i++)
{
spheres[i].pos = positions[i];
spheres[i].radius = gCharacterScale * gSphereRadius[i];
}
PxClothCollisionData collisionData;
collisionData.numSpheres = static_cast<PxU32>(positions.size());
collisionData.spheres = spheres.begin();
collisionData.numPairs = static_cast<PxU32>(indexPairs.size()) / 2; // number of capsules
collisionData.pairIndexBuffer = indexPairs.begin();
// create the cloth cape mesh from file
PxClothMeshDesc meshDesc;
SampleArray<PxVec3> vertices;
SampleArray<PxU32> primitives;
SampleArray<PxReal> uvs;
const char* capeFileName = getSampleMediaFilename("ctdm_cape_m.obj");
PxReal clothScale = gCharacterScale * 0.3f;
PxVec3 offset = PxVec3(0,-1.5,0);
PxQuat rot = PxQuat(0, PxVec3(0,1,0));
Test::ClothHelpers::createMeshFromObj(capeFileName, clothScale, &rot, &offset,
vertices, primitives, &uvs, meshDesc);
if (!meshDesc.isValid()) fatalError("Could not load ctdm_cape_m.obj\n");
// create the cloth
PxCloth& cloth = *createClothFromMeshDesc(
meshDesc, rootPose, &collisionData, PxVec3(0,-1,0),
uvs.begin(), "dummy_cape_d.bmp", PxVec3(0.5f, 0.5f, 0.5f), 0.8f);
mCape = &cloth;
// attach top verts
PxClothReadData* readData = cloth.lockClothReadData();
PX_ASSERT(readData);
PxU32 numParticles = cloth.getNbParticles();
SampleArray<PxClothParticle> particles(numParticles);
SampleArray<PxVec3> particlePositions(numParticles);
for(PxU32 i = 0; i < numParticles; i++)
{
particles[i].pos = readData->particles[i].pos;
particles[i].invWeight = (uvs[i*2+1] > 0.85f) ? 0.0f : readData->particles[i].invWeight;
particlePositions[i] = readData->particles[i].pos;
}
readData->unlock();
cloth.setParticles(particles.begin(), particles.begin());
// compute initial skin binding to the character
mSkin.bindToCharacter(mCharacter, particlePositions);
// set solver settings
cloth.setSolverFrequency(240);
// damp global particle velocity to 90% every 0.1 seconds
cloth.setDampingCoefficient(0.1f); // damp local particle velocity
cloth.setDragCoefficient(0.1f); // transfer frame velocity
// reduce effect of local frame acceleration
cloth.setInertiaScale(0.3f);
const bool useVirtualParticles = true;
const bool useSweptContact = true;
const bool useCustomConfig = true;
// virtual particles
if (useVirtualParticles)
Test::ClothHelpers::createVirtualParticles(cloth, meshDesc, 4);
// ccd
cloth.setClothFlag(PxClothFlag::eSWEPT_CONTACT, useSweptContact);
// use GPU or not
#if PX_SUPPORT_GPU_PHYSX
cloth.setClothFlag(PxClothFlag::eGPU, mUseGPU);
#endif
// custom fiber configuration
if (useCustomConfig)
{
PxClothPhaseSolverConfig config;
config = cloth.getPhaseSolverConfig(PxClothFabricPhaseType::eSTRETCHING);
config.solverType = PxClothPhaseSolverConfig::eSTIFF;
config.stiffness = 1.0f;
cloth.setPhaseSolverConfig(PxClothFabricPhaseType::eSTRETCHING, config);
config = cloth.getPhaseSolverConfig(PxClothFabricPhaseType::eSTRETCHING_HORIZONTAL);
config.solverType = PxClothPhaseSolverConfig::eFAST;
config.stiffness = 1.0f;
cloth.setPhaseSolverConfig(PxClothFabricPhaseType::eSTRETCHING_HORIZONTAL, config);
config = cloth.getPhaseSolverConfig(PxClothFabricPhaseType::eSHEARING);
config.solverType = PxClothPhaseSolverConfig::eFAST;
config.stiffness = 0.75f;
cloth.setPhaseSolverConfig(PxClothFabricPhaseType::eSHEARING, config);
config = cloth.getPhaseSolverConfig(PxClothFabricPhaseType::eBENDING_ANGLE);
config.solverType = PxClothPhaseSolverConfig::eBENDING;
config.stiffness = 0.5f;
cloth.setPhaseSolverConfig(PxClothFabricPhaseType::eBENDING_ANGLE, config);
}
}