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hslt: improve numerical robustness

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johannes hanika 2014-11-03 17:46:29 +01:00 committed by Wenzel Jakob
parent 6fb326038e
commit ef48c84915
8 changed files with 51 additions and 32 deletions
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5
src/bsdfs/microfacet.h
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@ -550,11 +550,12 @@ protected:
/// Compute the interpolated roughness for the Phong model
inline Float interpolatePhongExponent(const Vector &v) const {
Float invSinTheta2 = 1 / Frame::sinTheta2(v);
const Float sinTheta2 = Frame::sinTheta2(v);
if (isIsotropic() || invSinTheta2 <= 0)
if (isIsotropic() || sinTheta2 <= RCPOVERFLOW)
return m_exponentU;
Float invSinTheta2 = 1 / sinTheta2;
Float cosPhi2 = v.x * v.x * invSinTheta2;
Float sinPhi2 = v.y * v.y * invSinTheta2;

8
src/bsdfs/roughconductor.cpp
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@ -257,8 +257,8 @@ public:
Spectrum eval(const BSDFSamplingRecord &bRec, EMeasure measure) const {
/* Stop if this component was not requested */
if (measure != ESolidAngle ||
Frame::cosTheta(bRec.wi) < 0 ||
Frame::cosTheta(bRec.wo) < 0 ||
Frame::cosTheta(bRec.wi) <= 0 ||
Frame::cosTheta(bRec.wo) <= 0 ||
((bRec.component != -1 && bRec.component != 0) ||
!(bRec.typeMask & EGlossyReflection)))
return Spectrum(0.0f);
@ -295,8 +295,8 @@ public:
Float pdf(const BSDFSamplingRecord &bRec, EMeasure measure) const {
if (measure != ESolidAngle ||
Frame::cosTheta(bRec.wi) < 0 ||
Frame::cosTheta(bRec.wo) < 0 ||
Frame::cosTheta(bRec.wi) <= 0 ||
Frame::cosTheta(bRec.wo) <= 0 ||
((bRec.component != -1 && bRec.component != 0) ||
!(bRec.typeMask & EGlossyReflection)))
return 0.0f;

3
src/integrators/mlt/mlt_proc.cpp
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@ -206,7 +206,10 @@ public:
Float a;
if (!m_config.importanceMap) {
if(Qxy > RCPOVERFLOW)
a = std::min((Float) 1, Qyx / Qxy);
else
a = 0.f;
} else {
const Float *luminanceValues = m_config.importanceMap->getFloatData();
const Point2 &curPos = current->getSamplePosition();

2
src/libbidir/mut_bidir.cpp
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@ -260,7 +260,7 @@ Float BidirectionalMutator::Q(const Path &source, const Path &proposal,
Float luminance = weight.getLuminance();
if (luminance <= 0 || !std::isfinite(luminance)) {
if (luminance <= RCPOVERFLOW || !std::isfinite(luminance)) {
Log(EWarn, "Internal error: luminance = %f!", luminance);
continue;
}

6
src/libbidir/mut_caustic.cpp
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@ -212,7 +212,11 @@ Float CausticPerturbation::Q(const Path &source, const Path &proposal,
source.edge(i), edge);
}
return solidAngleDensity / weight.getLuminance();
const Float lumWeight = weight.getLuminance();
if(lumWeight <= RCPOVERFLOW)
return 0.f;
return solidAngleDensity / lumWeight;
}
void CausticPerturbation::accept(const MutationRecord &) {

6
src/libbidir/mut_lens.cpp
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@ -196,7 +196,11 @@ Float LensPerturbation::Q(const Path &source, const Path &proposal,
source.edge(i-1), edge);
}
return 1.0f / weight.getLuminance();
const Float lumWeight = weight.getLuminance();
if(lumWeight <= RCPOVERFLOW)
return 0.f;
return 1.0f / lumWeight;
}
void LensPerturbation::accept(const MutationRecord &) {

15
src/libbidir/mut_manifold.cpp
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@ -663,10 +663,19 @@ Float ManifoldPerturbation::Q(const Path &source, const Path &proposal,
/* Convert to area density at x_b */
prob *= m_manifold->G(proposal, a, b);
if (prob == 0)
if (prob <= RCPOVERFLOW)
return 0.0f;
#if defined(MTS_DEBUG_FP)
disableFPExceptions();
#endif
weight /= prob;
#if defined(MTS_DEBUG_FP)
enableFPExceptions();
#endif
/* Catch very low probabilities which round to +inf in the above division operation */
if (!std::isfinite(weight.average()))
return 0.0f;
@ -677,7 +686,7 @@ Float ManifoldPerturbation::Q(const Path &source, const Path &proposal,
source.vertex(a)->pdf[mode] * m_probFactor * m_probFactor);
Float pdf = source.vertex(a+step)->perturbPositionPdf(proposal.vertex(a+step), stddev);
if (pdf == 0)
if (pdf <= RCPOVERFLOW)
return 0.0f;
weight /= pdf;
@ -743,7 +752,7 @@ Float ManifoldPerturbation::Q(const Path &source, const Path &proposal,
Float lum = weight.getLuminance();
if (lum <= 0 || !std::isfinite(lum)) {
if (lum <= RCPOVERFLOW || !std::isfinite(lum)) {
Log(EWarn, "Internal error in manifold perturbation: luminance = %f!", lum);
return 0.f;
}

38
src/libbidir/vertex.cpp
View File

@ -192,7 +192,7 @@ bool PathVertex::sampleNext(const Scene *scene, Sampler *sampler,
/* Compute the reverse quantities */
bRec.reverse();
pdf[1-mode] = bsdf->pdf(bRec, (EMeasure) measure);
if (pdf[1-mode] == 0) {
if (pdf[1-mode] <= RCPOVERFLOW) {
/* This can happen rarely due to roundoff errors -- be strict */
return false;
}
@ -508,7 +508,7 @@ bool PathVertex::perturbDirection(const Scene *scene, const PathVertex *pred,
Spectrum value = emitter->evalDirection(dRec, pRec);
Float prob = emitter->pdfDirection(dRec, pRec);
if (value.isZero() || prob == 0)
if (value.isZero() || prob <= RCPOVERFLOW)
return false;
weight[EImportance] = value/prob;
@ -531,7 +531,7 @@ bool PathVertex::perturbDirection(const Scene *scene, const PathVertex *pred,
Spectrum value = sensor->evalDirection(dRec, pRec);
Float prob = sensor->pdfDirection(dRec, pRec);
if (value.isZero() || prob == 0)
if (value.isZero() || prob <= RCPOVERFLOW)
return false;
weight[EImportance] = value * (
@ -556,7 +556,7 @@ bool PathVertex::perturbDirection(const Scene *scene, const PathVertex *pred,
Spectrum value = bsdf->eval(bRec);
Float prob = bsdf->pdf(bRec);
if (value.isZero() || prob == 0)
if (value.isZero() || prob <= RCPOVERFLOW)
return false;
weight[mode] = value/prob;
@ -592,7 +592,7 @@ bool PathVertex::perturbDirection(const Scene *scene, const PathVertex *pred,
/* Compute the reverse quantities */
bRec.reverse();
pdf[1-mode] = bsdf->pdf(bRec, ESolidAngle);
if (pdf[1-mode] == 0) {
if (pdf[1-mode] <= RCPOVERFLOW) {
/* This can happen rarely due to roundoff errors -- be strict */
return false;
}
@ -628,7 +628,7 @@ bool PathVertex::perturbDirection(const Scene *scene, const PathVertex *pred,
Float value = phase->eval(pRec);
Float prob = phase->pdf(pRec);
if (value == 0 || prob == 0)
if (value == 0 || prob <= RCPOVERFLOW)
return false;
pdf[mode] = prob;
@ -710,7 +710,7 @@ bool PathVertex::propagatePerturbation(const Scene *scene, const PathVertex *pre
bRec.typeMask = BSDF::EAll;
Float prob = bsdf->pdf(bRec, EDiscrete);
if (prob == 0) {
if (prob <= RCPOVERFLOW) {
SLog(EWarn, "Unable to recreate specular vertex in perturbation (bsdf=%s)",
bsdf->toString().c_str());
return false;
@ -721,7 +721,7 @@ bool PathVertex::propagatePerturbation(const Scene *scene, const PathVertex *pre
measure = EDiscrete;
componentType = componentType_;
if (weight[mode].isZero() || prob == 0)
if (weight[mode].isZero() || prob <= RCPOVERFLOW)
return false;
/* Account for medium changes if applicable */
@ -747,7 +747,7 @@ bool PathVertex::propagatePerturbation(const Scene *scene, const PathVertex *pre
/* Compute the reverse quantities */
bRec.reverse();
pdf[1-mode] = bsdf->pdf(bRec, EDiscrete);
if (pdf[1-mode] == 0) {
if (pdf[1-mode] <= RCPOVERFLOW) {
/* This can happen rarely due to roundoff errors -- be strict */
return false;
}
@ -1128,6 +1128,7 @@ bool PathVertex::cast(const Scene *scene, EVertexType desired) {
pRec.object = emitter;
pRec.pdf = 0.0f;
getPositionSamplingRecord() = pRec;
measure = pRec.measure;
degenerate = emitter->getType() & Emitter::EDeltaDirection;
return true;
@ -1149,6 +1150,7 @@ bool PathVertex::cast(const Scene *scene, EVertexType desired) {
Vector2i size = sensor->getFilm()->getSize();
pRec.uv.x *= size.x; pRec.uv.y *= size.y;
getPositionSamplingRecord() = pRec;
measure = pRec.measure;
degenerate = sensor->getType() & Sensor::EDeltaDirection;
return true;
@ -1167,11 +1169,11 @@ bool PathVertex::update(const Scene *scene, const PathVertex *pred,
weight[mode] = eval(scene, pred, succ, mode, measure);
weight[1-mode] = eval(scene, succ, pred, (ETransportMode) (1-mode), measure);
if (weight[mode].isZero() || pdf[mode] == 0)
if (weight[mode].isZero() || pdf[mode] <= RCPOVERFLOW)
return false;
Float weightFwd = pdf[mode] == 0 ? 0.0f : 1.0f / pdf[mode],
weightBkw = pdf[1-mode] == 0 ? 0.0f : 1.0f / pdf[1-mode];
Float weightFwd = pdf[mode] <= RCPOVERFLOW ? 0 : 1 / pdf[mode],
weightBkw = pdf[1-mode] <= RCPOVERFLOW ? 0 : 1 / pdf[1-mode];
this->measure = measure;
@ -1331,12 +1333,10 @@ bool PathVertex::connect(const Scene *scene,
if (vs->isDegenerate() || vt->isDegenerate())
return false;
vs->update(scene, pred, vt, EImportance);
if (vs->weight[EImportance].isZero())
if (!vs->update(scene, pred, vt, EImportance))
return false;
vt->update(scene, succ, vs, ERadiance);
if (vt->weight[ERadiance].isZero())
if (!vt->update(scene, succ, vs, ERadiance))
return false;
return edge->connect(scene, predEdge, vs, vt, succEdge);
@ -1357,12 +1357,10 @@ bool PathVertex::connect(const Scene *scene,
return false;
}
vs->update(scene, pred, vt, EImportance, vsMeasure);
if (vs->weight[EImportance].isZero() || vs->pdf[EImportance] == 0.f)
if (!vs->update(scene, pred, vt, EImportance, vsMeasure))
return false;
vt->update(scene, succ, vs, ERadiance, vtMeasure);
if (vt->weight[ERadiance].isZero() || vt->pdf[ERadiance] == 0.f)
if (!vt->update(scene, succ, vs, ERadiance, vtMeasure))
return false;
return edge->connect(scene, predEdge, vs, vt, succEdge);