void Emitter::exportFrame()
{
static int frame=0;
++frame;
// this is the data we are going to store, alembic uses Imath
// internally so we convert from ngl
// this is the array of particle positions for the frame
std::vector<Imath::V3f> positions(m_numParticles);
// these are the particle id's which are required so use use index no
std::vector<Alembic::Util::uint64_t> id(m_numParticles);
// set this to push back into the array
Imath::V3f data;
// colour values
std::vector<Imath::V3f> colours(m_numParticles);
std::vector<Imath::V3f> velocities(m_numParticles);
std::vector< Alembic::Util::float32_t > widths;
AbcG::OFloatGeomParam::Sample widthSamp;
widthSamp.setScope(Alembic::AbcGeom::kVertexScope);
widthSamp.setVals(Alembic::Abc::FloatArraySample(widths));
for(size_t i=0; i<m_numParticles; ++i)
{
positions[i]=Imath::V3f(m_particles[i].m_px,m_particles[i].m_py,m_particles[i].m_pz);
id[i]=i;
colours[i]=Imath::V3f(m_particles[i].m_r,m_particles[i].m_g,m_particles[i].m_b);
velocities[i]=Imath::V3f(m_particles[i].m_r,m_particles[i].m_g,m_particles[i].m_b);
}
// create as samples we need to do this else we get a most vexing parse
// https://en.wikipedia.org/wiki/Most_vexing_parse using below
// psamp(V3fArraySample( positions),UInt64ArraySample(id))
AbcG::V3fArraySample pos(positions);
AbcG::UInt64ArraySample ids(id);
AbcG::OPointsSchema::Sample psamp( pos,ids,velocities );
AbcG::OPointsSchema &pSchema = m_partsOut->getSchema();
std::cout<<"Schema "<<pSchema.getNumSamples()<<" "<<pSchema.valid()<<"\n";
pSchema.set( psamp );
AbcG::V3fArraySample colourArray(colours);
m_rgbOut->set(colourArray);
}
void MayaPointPrimitiveWriter::write(double iFrame)
{
MStatus status;
std::vector<float> position;
std::vector<float> velocity;
std::vector< Alembic::Util::uint64_t > particleIds;
std::vector<float> width;
bool runupFromStart = false;
MTime to(iFrame, MTime::kSeconds);
// need to force re-evaluation
MFnParticleSystem particle(mDagPath);
particle.evaluateDynamics(to, runupFromStart);
unsigned int size = particle.count();
Alembic::AbcGeom::OPointsSchema::Sample samp;
if (size == 0)
{
samp.setPositions(Alembic::Abc::V3fArraySample(NULL, 0));
samp.setVelocities(Alembic::Abc::V3fArraySample(NULL, 0));
samp.setIds(Alembic::Abc::UInt64ArraySample(NULL, 0));
mSchema.set(samp);
return;
}
position.reserve(size*3);
velocity.reserve(size*3);
particleIds.reserve(size);
width.reserve(size);
// get particle position
MVectorArray posArray;
particle.position(posArray);
for (unsigned int i = 0; i < size; i++)
{
MVector vec = posArray[i];
position.push_back(static_cast<float>(vec.x));
position.push_back(static_cast<float>(vec.y));
position.push_back(static_cast<float>(vec.z));
}
samp.setPositions(
Alembic::Abc::P3fArraySample((const Imath::V3f *) &position.front(),
position.size() / 3) );
// get particle velocity
MVectorArray vecArray;
particle.velocity(vecArray);
for (unsigned int i = 0; i < size; i++)
{
MVector vec = vecArray[i];
velocity.push_back(static_cast<float>(vec.x));
velocity.push_back(static_cast<float>(vec.y));
velocity.push_back(static_cast<float>(vec.z));
}
if (!velocity.empty())
{
samp.setVelocities(
Alembic::Abc::V3fArraySample((const Imath::V3f *) &velocity.front(),
velocity.size() / 3) );
}
// get particleIds
MIntArray idArray;
particle.particleIds(idArray);
for (unsigned int i = 0; i < size; i++)
{
particleIds.push_back(idArray[i]);
}
samp.setIds(
Alembic::Abc::UInt64ArraySample(&(particleIds.front()),
particleIds.size()) );
// assume radius is width
MDoubleArray radiusArray;
MPlug radius = particle.findPlug("radiusPP", true, &status);
AbcGeom::GeometryScope widthScope = AbcGeom::kUnknownScope;
if ( status == MS::kSuccess)
{
// RadiusPP exists, get all particles value
widthScope = AbcGeom::kVaryingScope;
particle.radius(radiusArray);
for (unsigned int i = 0; i < size; i++)
{
float radius = static_cast<float>(radiusArray[i]);
width.push_back(radius);
}
}
else
{
// Get the value of the radius attribute
widthScope = AbcGeom::kUniformScope;
width.push_back( particle.findPlug("radius").asDouble() );
}
if (!width.empty())
{
Alembic::AbcGeom::OFloatGeomParam::Sample widthSamp;
widthSamp.setVals(width);
widthSamp.setScope(widthScope);
samp.setWidths( widthSamp );
}
mSchema.set(samp);
}