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fixed the mixture phase function

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Wenzel Jakob 2011-08-07 17:51:02 -04:00
parent c2364efad9
commit 2de99d873e
1 changed files with 13 additions and 49 deletions
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62
src/phase/mixturephase.cpp
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@ -16,7 +16,7 @@
along with this program. If not, see <http://www.gnu.org/licenses/>. along with this program. If not, see <http://www.gnu.org/licenses/>.
*/ */
#include <mitsuba/render/phase.h> #include <mitsuba/render/scene.h>
MTS_NAMESPACE_BEGIN MTS_NAMESPACE_BEGIN
@ -86,9 +86,6 @@ public:
} }
void configure() { void configure() {
m_usesRayDifferentials = false;
size_t componentCount = 0;
if (m_phaseFunctions.size() != m_weights.size()) if (m_phaseFunctions.size() != m_weights.size())
Log(EError, "Phase function count mismatch: " SIZE_T_FMT " phase functions, but specified " SIZE_T_FMT " weights", Log(EError, "Phase function count mismatch: " SIZE_T_FMT " phase functions, but specified " SIZE_T_FMT " weights",
m_phaseFunctions.size(), m_phaseFunctions.size()); m_phaseFunctions.size(), m_phaseFunctions.size());
@ -100,52 +97,27 @@ public:
if (totalWeight <= 0) if (totalWeight <= 0)
Log(EError, "The weights must sum to a value greater than zero!"); Log(EError, "The weights must sum to a value greater than zero!");
if (m_ensureEnergyConservation && totalWeight > 1) { if (totalWeight > 1) {
std::ostringstream oss; std::ostringstream oss;
Float scale = 1.0f / totalWeight; Float scale = 1.0f / totalWeight;
oss << "The phase function " << endl << toString() << endl oss << "The phase function " << endl << toString() << endl
<< "potentially violates energy conservation, since the weights " << "potentially violates energy conservation, since the weights "
<< "sum to " << totalWeight << ", which is greater than one! " << "sum to " << totalWeight << ", which is greater than one! "
<< "They will be re-scaled to avoid potential issues. Specify " << "They will be re-scaled to avoid potential issues.";
<< "the parameter ensureEnergyConservation=false to prevent "
<< "this from happening.";
Log(EWarn, "%s", oss.str().c_str()); Log(EWarn, "%s", oss.str().c_str());
for (size_t i=0; i<m_weights.size(); ++i) for (size_t i=0; i<m_weights.size(); ++i)
m_weights[i] *= scale; m_weights[i] *= scale;
} }
for (size_t i=0; i<m_phaseFunctions.size(); ++i)
componentCount += m_phaseFunctions[i]->getComponentCount();
m_pdf = DiscretePDF(m_phaseFunctions.size()); m_pdf = DiscretePDF(m_phaseFunctions.size());
m_components.reserve(componentCount); for (size_t i=0; i<m_phaseFunctions.size(); ++i)
m_components.clear();
m_indices.reserve(componentCount);
m_indices.clear();
m_offsets.reserve(m_phaseFunctions.size());
m_offsets.clear();
int offset = 0;
for (size_t i=0; i<m_phaseFunctions.size(); ++i) {
const PhaseFunction *phase = m_phaseFunctions[i];
m_offsets.push_back(offset);
for (int j=0; j<phase->getComponentCount(); ++j) {
int componentType = phase->getType(j);
m_components.push_back(componentType);
m_indices.push_back(std::make_pair((int) i, j));
}
offset += phase->getComponentCount();
m_usesRayDifferentials |= phase->usesRayDifferentials();
m_pdf[i] = m_weights[i]; m_pdf[i] = m_weights[i];
}
m_pdf.build(); m_pdf.build();
PhaseFunction::configure(); PhaseFunction::configure();
} }
Float eval(const PhaseFunctionQueryRecord &pRec) const { Float eval(const PhaseFunctionQueryRecord &pRec) const {
Spectrum result(0.0f); Float result = 0.0f;
for (size_t i=0; i<m_phaseFunctions.size(); ++i) for (size_t i=0; i<m_phaseFunctions.size(); ++i)
result += m_phaseFunctions[i]->eval(pRec) * m_weights[i]; result += m_phaseFunctions[i]->eval(pRec) * m_weights[i];
@ -162,14 +134,13 @@ public:
return result; return result;
} }
Spectrum sample(PhaseFunctionQueryRecord &pRec, const Point2 &_sample) const { Float sample(PhaseFunctionQueryRecord &pRec, Sampler *sampler) const {
Point2 sample(_sample);
/* Choose a component based on the normalized weights */ /* Choose a component based on the normalized weights */
size_t entry = m_pdf.sampleReuse(sample.x); size_t entry = m_pdf.sample(sampler->next1D());
Float pdf; Float pdf;
Spectrum result = m_phaseFunctions[entry]->sample(pRec, pdf, sample); Float result = m_phaseFunctions[entry]->sample(pRec, pdf, sampler);
if (result.isZero()) // sampling failed if (result == 0) // sampling failed
return result; return result;
result *= m_weights[entry] * pdf; result *= m_weights[entry] * pdf;
@ -182,17 +153,15 @@ public:
result += m_phaseFunctions[i]->eval(pRec) * m_weights[i]; result += m_phaseFunctions[i]->eval(pRec) * m_weights[i];
} }
pRec.sampledComponent += m_offsets[entry];
return result / pdf; return result / pdf;
} }
Spectrum sample(PhaseFunctionQueryRecord &pRec, Float &pdf, const Point2 &_sample) const { Float sample(PhaseFunctionQueryRecord &pRec, Float &pdf, Sampler *sampler) const {
Point2 sample(_sample);
/* Choose a component based on the normalized weights */ /* Choose a component based on the normalized weights */
size_t entry = m_pdf.sampleReuse(sample.x); size_t entry = m_pdf.sample(sampler->next1D());
Spectrum result = m_phaseFunctions[entry]->sample(pRec, pdf, sample); Float result = m_phaseFunctions[entry]->sample(pRec, pdf, sampler);
if (result.isZero()) // sampling failed if (result == 0) // sampling failed
return result; return result;
result *= m_weights[entry] * pdf; result *= m_weights[entry] * pdf;
@ -205,7 +174,6 @@ public:
result += m_phaseFunctions[i]->eval(pRec) * m_weights[i]; result += m_phaseFunctions[i]->eval(pRec) * m_weights[i];
} }
pRec.sampledComponent += m_offsets[entry];
return result/pdf; return result/pdf;
} }
@ -237,13 +205,9 @@ public:
return oss.str(); return oss.str();
} }
Shader *createShader(Renderer *renderer) const;
MTS_DECLARE_CLASS() MTS_DECLARE_CLASS()
private: private:
std::vector<Float> m_weights; std::vector<Float> m_weights;
std::vector<std::pair<int, int> > m_indices;
std::vector<int> m_offsets;
std::vector<PhaseFunction *> m_phaseFunctions; std::vector<PhaseFunction *> m_phaseFunctions;
DiscretePDF m_pdf; DiscretePDF m_pdf;
}; };