void ParticleEmitterRate::stepInternal(ParticleData& particles, PxReal dt, const PxVec3& externalAcceleration, PxReal maxParticleVelocity)
{
PX_ASSERT(mNumX > 0 && mNumY > 0);
PxU32 numEmittedParticles = 0;
//figure out how many particle have to be emitted with the given rate.
mParticlesToEmit += mRate*dt;
PxU32 numEmit = (PxU32)(mParticlesToEmit);
if(numEmit == 0)
return;
PxU32 numLayers = (PxU32)(numEmit / (mNumX * mNumY)) + 1;
PxReal layerDistance = dt * mVelocity / numLayers;
PxU32 sparseMax = 0;
//either shuffle or draw without repeat (approximation)
bool denseEmission = (PxU32(PARTICLE_EMITTER_SPARSE_FACTOR*numEmit) > mNumSites);
if(denseEmission)
{
initDenseSites();
}
else
{
sparseMax = PARTICLE_EMITTER_SPARSE_FACTOR*numEmit;
mSites.resize(sparseMax);
}
// generate particles
PxU32 l = 0;
while(numEmit > 0)
{
PxVec3 layerVec = mAxisZ * (layerDistance * (PxReal)l);
l++;
if(denseEmission)
shuffleDenseSites();
else
initSparseSiteHash(numEmit, sparseMax);
for (PxU32 i = 0; i < mNumSites && numEmit > 0; i++)
{
PxU32 emissionSite;
if (denseEmission)
emissionSite = mSites[i];
else
emissionSite = pickSparseEmissionSite(sparseMax);
PxU32 x = emissionSite / mNumY;
PxU32 y = emissionSite % mNumY;
PxReal offset = 0.0f;
if (y%2) offset = mSpacingX * 0.5f;
if (isOutsideShape(x,y,offset))
continue;
//position noise
PxVec3 posNoise;
posNoise.x = randInRange(-mRandomPos.x, mRandomPos.x);
posNoise.y = randInRange(-mRandomPos.y, mRandomPos.y);
posNoise.z = randInRange(-mRandomPos.z, mRandomPos.z);
PxVec3 emissionPoint = mBasePos + layerVec +
mAxisX*(posNoise.x+offset+mSpacingX*x) + mAxisY*(posNoise.y+mSpacingY*y) + mAxisZ*posNoise.z;
PxVec3 particleVelocity;
computeSiteVelocity(particleVelocity, emissionPoint);
bool isSpawned = spawnParticle(particles, numEmittedParticles, particles.maxParticles - particles.numParticles, emissionPoint, particleVelocity);
if(isSpawned)
{
numEmit--;
mParticlesToEmit -= 1.0f;
}
else
return;
}
}
}
void ParticleEmitterPressure::stepInternal(ParticleData& particles, PxReal dt, const PxVec3& externalAcceleration, PxReal maxParticleVelocity)
{
PX_ASSERT(mNumX > 0 && mNumY > 0);
mSimulationAcceleration = externalAcceleration;
mSimulationMaxVelocity = maxParticleVelocity;
PxU32 numEmittedParticles = 0;
PxU32 maxParticlesPerStep = (PxU32)physx::shdfnd::floor(mMaxRate*dt);
PxU32 maxParticles = PxMin(particles.maxParticles - particles.numParticles, maxParticlesPerStep);
PxU32 siteNr = 0;
for(PxU32 y = 0; y != mNumY; y++)
{
PxReal offset = 0.0f;
if (y%2) offset = mSpacingX * 0.5f;
for(PxU32 x = 0; x != mNumX; x++)
{
if (isOutsideShape(x,y,offset))
continue;
SiteData& siteData = mSites[siteNr];
//position noise
PxVec3 posNoise;
posNoise.x = randInRange(-mRandomPos.x, mRandomPos.x);
posNoise.y = randInRange(-mRandomPos.y, mRandomPos.y);
//special code for Z noise
if (!siteData.predecessor)
siteData.noiseZ = randInRange(-mRandomPos.z, mRandomPos.z);
else
{
PxReal noiseZOffset = PxMin(mMaxZNoiseOffset, mRandomPos.z);
siteData.noiseZ += randInRange(-noiseZOffset, noiseZOffset);
siteData.noiseZ = PxClamp(siteData.noiseZ, mRandomPos.z, -mRandomPos.z);
}
posNoise.z = siteData.noiseZ;
//set position
PxVec3 sitePos = mBasePos + mAxisX*(offset+mSpacingX*x) + mAxisY*(mSpacingY*y) + mAxisZ*siteData.noiseZ;
PxVec3 particlePos = sitePos + mAxisX*posNoise.x + mAxisY*posNoise.y;
PxVec3 siteVel;
computeSiteVelocity(siteVel, particlePos);
if (siteData.predecessor)
{
predictPredecessorPos(siteData, dt);
}
else {
bool isSpawned = spawnParticle(particles, numEmittedParticles, maxParticles, particlePos, siteVel);
if(isSpawned)
{
updatePredecessor(siteData, particlePos, siteVel);
}
else
{
siteData.predecessor = false;
return;
}
}
bool allSpawned = stepEmissionSite(siteData, particles, numEmittedParticles, maxParticles, sitePos, siteVel, dt);
if(!allSpawned)
return;
siteNr++;
}
}
}
