public PSSMLTSampler()
{
rnd =
new FastRandom();
//new HaltonSequence();
TotalSamples = 0L;
state = MCMCSamplerState.Initialized;
}
public Sample GetSample(Sample prevSample)
{
Sample newSample = null;
switch (state)
{
case MCMCSamplerState.Initialized:
if (currentSample == null)
{
currentSample = GetNewSample(true);
}
newSample = GetNewSample(false);
newSample.sampleData = currentSample.sampleData;
initializedSamples++;
if (initializedSamples > screenWidth*screenHeight*4)
{
state = MCMCSamplerState.LargeStep;
}
return newSample;
case MCMCSamplerState.LargeStep:
currentSample = GetNewSample(true);
currentMutation = 0;
state = MCMCSamplerState.SmallStep;
break;
case MCMCSamplerState.SmallStep:
currentSample = Mutate(prevSample??currentSample, currentMutation++, MaxMutations);
if (currentMutation >= MaxMutations)
{
state = MCMCSamplerState.LargeStep;
currentSample = GetNewSample(true);
currentMutation = 0;
}
break;
}
if (GetLazyValue(currentSample) < LargeStepProbability)
{
state = MCMCSamplerState.LargeStep;
}
return currentSample;
}
public override void Splat(SampleBuffer sampleBuffer)
{
//Check tentative prob
//Add contribution
//Change state
// Change sample state in init by ChangedState
var yImportance = sampler.EvalImportance(ref Throughput, pathWeight);
float sampleWeight = yImportance;
if (yImportance<=0f)
goto @init;
var yContribution = Radiance / yImportance;
bool accept;
float a = 0f;
if (!sampler.ImportanceReady)
{
sampler.Add_B(ref yContribution);
sampleBuffer.SplatSample(this.Sample.imageX, this.Sample.imageY, ref Radiance);
this.InitPath(this.pathIntegrator);
return;
}
if (yImportance > 0f)
{
if ((SamplerState != MCMCSamplerState.SmallStep || xImportance <= 0f || mutate))
{
SwitchToSmallStep(yImportance, pathWeight, ref yContribution);
goto init;
//Print(string.Format("{0} changed state to {1}", this.SamplerID, this.SamplerState));
}
else if (SamplerState == MCMCSamplerState.SmallStep)
{
a = Math.Min(1f, (yImportance/xImportance));
//contrib = (contrib / sampler.Importance) / sampler.MaxMutations;
sampleWeight = a;
this.mutationsCount++;
if (sampler.NextFloat() < a)
{
xImportance = yImportance;
this.xContribution = yContribution;
//this.TentativeSample = new Sample(this.Sample);
Push();
accept = true;
//this.pathWeight = a;
}
else
{
if (!this.Pop())
{
//Print("Chain restart - stack empty - mutations " + mutationsCount);
//sampleBuffer.SplatSample(this.Sample.imageX, this.Sample.imageY, ref contrib, 1f-a);
this.Sample = new Sample(this.TentativeSample);
rejectCount++;
this.pathWeight = this.TentativeWeight;
}
//Splat = false;
//return;
}
/*
* */
//var newSample = sampler.GetNextSample(this.Sample, I, oldI, 1.0f, ref contrib, out outC, out newW, false);
}
}
else if (xImportance >= 0f && this.SamplerState == MCMCSamplerState.SmallStep)
{
if (!this.Pop())
{
if (this.TentativeSample != null)
{
//Print("Chain restart - stack empty - mutations " + mutationsCount);
//sampleBuffer.SplatSample(this.Sample.imageX, this.Sample.imageY, ref contrib, 1f-a);
this.Sample = new Sample(this.TentativeSample);
rejectCount++;
this.pathWeight = this.TentativeWeight;
}
else
{
this.SamplerState = MCMCSamplerState.LargeStep;
}
}
}
if (!xContribution.IsBlack())
{
//sampleWeight *= 1f/pathWeight;
//contrib *= (1f/sampler.MaxMutations);
//contrib *= new RgbSpectrum((float)this.sampler.B[0],(float)this.sampler.B[1],(float)this.sampler.B[2]);
var contribution = xContribution;
/*
if (accept)
{
contribution *= sampleWeight*sampler.Importance;
}
else
{
contribution *= (1f - sampleWeight) * sampler.Importance;
}
*/
sampleBuffer.SplatSample(this.Sample.imageX, this.Sample.imageY, ref contribution);
}
if ((mutationsCount >= sampler.MaxMutations) & (sampler.NextFloat() > (1f - sampler.LargeStepProb)))//time > mutationsCount ||
{
this.SamplerState = MCMCSamplerState.LargeStep;
this.time = 0;
//Print(string.Format("{0} changed state to {1}", this.SamplerID, this.SamplerState));
//Print("Chain restart - max mutations");
}
@init:
this.InitPath(this.pathIntegrator);
}
private void SwitchToSmallStep(float imp, float pathW, ref RgbSpectrum contribution)
{
this.xImportance = imp;
this.xContribution = contribution;
this.TentativeSample = new Sample(this.Sample);
this.TentativeWeight = pathW;
Push();
this.SamplerState = MCMCSamplerState.SmallStep;
}
public override void Splat(SampleBuffer sampleBuffer)
{
//Check tentative prob
//Add contribution
//Change state
// Change sample state in init by ChangedState
if (!sampler.ImportanceReady)
{
sampler.Add_B(ref Radiance);
sampleBuffer.SplatSample(this.Sample.imageX, this.Sample.imageY, ref Radiance);
this.InitPath(this.pathIntegrator);
return;
}
var yImportance = sampler.EvalImportance(ref Radiance, pathWeight);
if (yImportance <= 0f || Radiance.IsBlack())
{
if (SamplerState == MCMCSamplerState.SmallStep)
{
mutationsCount++;
}
goto @init;
}
float sampleWeight = 1f;
float a;
var yContribution = Radiance / Radiance.y();
var contrib = yContribution;
switch (SamplerState)
{
case MCMCSamplerState.Initialized:
case MCMCSamplerState.LargeStep:
if (xImportance <= 0f || mutate)
{
SwitchToSmallStep(yImportance, pathWeight, ref yContribution);
goto init;
//Print(string.Format("{0} changed state to {1}", this.SamplerID, this.SamplerState));
}
break;
}
if (yImportance > 0f)
{
if (SamplerState == MCMCSamplerState.SmallStep)
{
a = Math.Min(1f, (yImportance / xImportance));
//contrib = (contrib / sampler.Importance) / sampler.MaxMutations;
sampleWeight = a;
this.mutationsCount++;
if (sampler.NextFloat() < a)
{
xImportance = yImportance;
this.xContribution = yContribution;
contrib = yContribution*a;
//this.TentativeSample = new Sample(this.Sample);
Push();
//this.pathWeight = a;
}
else
{
contrib = yContribution*(1f - a);
if (!this.Pop())
{
//Print("Chain restart - stack empty - mutations " + mutationsCount);
//sampleBuffer.SplatSample(this.Sample.imageX, this.Sample.imageY, ref contrib, 1f-a);
this.Sample = new Sample(this.TentativeSample);
rejectCount++;
this.pathWeight = this.TentativeWeight;
}
//Splat = false;
//return;
}
//var newSample = sampler.GetNextSample(this.Sample, I, oldI, 1.0f, ref contrib, out outC, out newW, false);
}
RgbSpectrum c = contrib * (sampler.Importance/ sampler.MaxMutations) * sampler.LargeStepProb;
//var c = Radiance*sampleWeight*sampler.Br;
sampleBuffer.SplatSample(this.Sample.imageX, this.Sample.imageY, ref c);
}
@init:
if (rejectCount >= sampler.MaxMutations)
{
this.SamplerState = MCMCSamplerState.LargeStep;
}
if ((mutationsCount >= sampler.MaxMutations) || (sampler.NextFloat() > (1f - sampler.LargeStepProb)))//time > mutationsCount ||
{
this.SamplerState = MCMCSamplerState.LargeStep;
this.time = 0;
//Print(string.Format("{0} changed state to {1}", this.SamplerID, this.SamplerState));
//Print("Chain restart - max mutations");
}
this.InitPath(this.pathIntegrator);
}
public Sample EvalNextSample(Sample oldSample, float importance)
{
if (oldSample == null)
return GetSample(null);
switch (SamplerState)
{
case MCMCSamplerState.LargeStep:
case MCMCSamplerState.Initialized:
if (importance > 0f)
{
this.SamplerState = MCMCSamplerState.SmallStep;
this.mutationsCount = 0;
this.TentativeSample = new Sample(oldSample);
this.ChainStart = new Sample(oldSample);
this.TentativeWeight = importance;
this.TotalSamples++;
return this.TentativeSample;
}
else
{
return this.GetSample(null);
}
case MCMCSamplerState.SmallStep:
if (importance > 0f)
{
mutationsCount++;
PushSample();
this.SmallStep();
}
else
{
if (!PopSample())
{
this.TentativeSample = new Sample(ChainStart);
}
}
if (mutationsCount > MaxMutations || (rnd.NextFloat() < LargeStepProb))
{
this.SamplerState = MCMCSamplerState.LargeStep;
this.mutationsCount = 0;
return GetSample(null);
}
this.TotalSamples++;
return this.TentativeSample;
default:
return GetSample(null);
}
}
public void Init(int width, int height)
{
rnd.Reinitialise((int)DateTime.Now.Ticks);
if (screenWidth == 0 && screenHeight == 0)
{
Width = screenWidth = width;
Height = screenHeight = height;
screenWidth = width - 1;
screenHeight = height - 1;
}
currentSampleScreenX = 0;
currentSampleScreenY = screenStartLine;
currentSubSampleIndex = 0;
pass = 0;
this.SamplerState = MCMCSamplerState.Initialized;
}
