hslt: new mutator interface with last succeeded mutation record.

include/mitsuba/bidir/mut_bidir.h

@@ -64,7 +64,7 @@ public:
 
 	EMutationType getType() const;
 	Float suitability(const Path &path) const;
-	bool sampleMutation(Path &source, Path &proposal, MutationRecord &muRec);
+	bool sampleMutation(Path &source, Path &proposal, MutationRecord &muRec, const MutationRecord& sourceMuRec);
 	Float Q(const Path &source, const Path &proposal,
 			const MutationRecord &muRec) const;
 	void accept(const MutationRecord &muRec);

include/mitsuba/bidir/mut_caustic.h

@@ -63,7 +63,7 @@ public:
 	EMutationType getType() const;
 	Float suitability(const Path &path) const;
 	bool sampleMutation(Path &source, Path &proposal,
-			MutationRecord &muRec);
+			MutationRecord &muRec, const MutationRecord& sourceMuRec);
 	Float Q(const Path &source, const Path &proposal,
 			const MutationRecord &muRec) const;
 	void accept(const MutationRecord &muRec);

include/mitsuba/bidir/mut_lens.h

@@ -63,7 +63,7 @@ public:
 	EMutationType getType() const;
 	Float suitability(const Path &path) const;
 	bool sampleMutation(Path &source, Path &proposal,
-			MutationRecord &muRec);
+			MutationRecord &muRec, const MutationRecord& sourceMuRec);
 	Float Q(const Path &source, const Path &proposal,
 			const MutationRecord &muRec) const;
 	void accept(const MutationRecord &muRec);

include/mitsuba/bidir/mut_manifold.h

@@ -61,7 +61,7 @@ public:
 	EMutationType getType() const;
 	Float suitability(const Path &path) const;
 	bool sampleMutation(Path &source, Path &proposal,
-			MutationRecord &muRec);
+			MutationRecord &muRec, const MutationRecord& sourceMuRec);
 	Float Q(const Path &source, const Path &proposal,
 			const MutationRecord &muRec) const;
 	void accept(const MutationRecord &muRec);

include/mitsuba/bidir/mut_mchain.h

@@ -63,7 +63,7 @@ public:
 	EMutationType getType() const;
 	Float suitability(const Path &path) const;
 	bool sampleMutation(Path &source, Path &proposal,
-			MutationRecord &muRec);
+			MutationRecord &muRec, const MutationRecord& sourceMuRec);
 	Float Q(const Path &source, const Path &proposal,
 			const MutationRecord &muRec) const;
 	void accept(const MutationRecord &muRec);

include/mitsuba/bidir/mutator.h

@@ -64,13 +64,17 @@ public:
 	 * \param muRec
 	 *     Data record that describes the sampled mutation strategy
 	 *
+	 * \param sourceMuRec
+	 *     Data record that describes the last successful mutation strategy
+	 *	   (for the source path)
+	 *
 	 * \return \a true upon success. When the sampling step is
 	 *     unsuccessful (this could happen due to various
 	 *     reasons), the function returns <tt>false</tt>.
 
-     */
+	 */
 	virtual bool sampleMutation(Path &source, Path &proposal,
-			MutationRecord &muRec) = 0;
+			MutationRecord &muRec, const MutationRecord& sourceMuRec) = 0;
 
 	/**
 	 * \brief For a pair of paths, this function computes the inverse

src/integrators/erpt/erpt_proc.cpp

@@ -174,7 +174,7 @@ public:
 		std::ostringstream oss;
 		Spectrum relWeight(0.0f);
 		Float accumulatedWeight = 0;
-		MutationRecord muRec;
+		MutationRecord muRec, currentMuRec(Mutator::EMutationTypeCount, 0, 0, 0, Spectrum(0.f));
 		Path *current = new Path(),
 			 *proposed = new Path();
 		size_t mutations = 0;
@@ -211,7 +211,7 @@ public:
 				mutator = m_mutators[mutatorIdx].get();
 
 				/* Sample a mutated path */
-				success = mutator->sampleMutation(*current, *proposed, muRec);
+				success = mutator->sampleMutation(*current, *proposed, muRec, currentMuRec);
 
 				statsAccepted.incrementBase(1);
 				if (success) {
@@ -258,6 +258,7 @@ public:
 						std::swap(current, proposed);
 						relWeight = current->getRelativeWeight();
 						mutator->accept(muRec);
+						currentMuRec = muRec;
 						accumulatedWeight = a;
 						++statsAccepted;
 						++mutations;

src/integrators/mlt/mlt_proc.cpp

@@ -127,7 +127,7 @@ public:
 		BDAssert(!relWeight.isZero());
 
 		DiscreteDistribution suitabilities(m_mutators.size());
-		MutationRecord muRec;
+		MutationRecord muRec, currentMuRec(Mutator::EMutationTypeCount,0,0,0,Spectrum(0.f));
 		ref<Timer> timer = new Timer();
 
 		size_t consecRejections = 0;
@@ -171,7 +171,7 @@ public:
 			mutator = m_mutators[mutatorIdx].get();
 
 			/* Sample a mutated path */
-			success = mutator->sampleMutation(*current, *proposed, muRec);
+			success = mutator->sampleMutation(*current, *proposed, muRec, currentMuRec);
 
 			#if defined(MTS_BD_DEBUG_HEAVY)
 				if (backup != *current)
@@ -263,11 +263,12 @@ public:
 					std::swap(current, proposed);
 					relWeight = current->getRelativeWeight();
 					mutator->accept(muRec);
+					currentMuRec = muRec;
 					accumulatedWeight = a;
 					consecRejections = 0;
 					++statsAccepted;
 				} else {
-	 				/* The mutation was rejected */
+					/* The mutation was rejected */
 					proposed->release(muRec.l, muRec.l + muRec.ka + 1, *m_pool);
 					consecRejections++;
 					if (a > 0) {

src/libbidir/mut_bidir.cpp

@@ -44,7 +44,7 @@ Float BidirectionalMutator::suitability(const Path &path) const {
 }
 
 bool BidirectionalMutator::sampleMutation(
-		Path &source, Path &proposal, MutationRecord &muRec) {
+		Path &source, Path &proposal, MutationRecord &muRec, const MutationRecord& sourceMuRec) {
 	TwoTailedGeoDistr desiredLength(2), deletionLength(2);
 	int k = source.length();
 

src/libbidir/mut_caustic.cpp

@@ -73,7 +73,7 @@ Float CausticPerturbation::suitability(const Path &path) const {
 }
 
 bool CausticPerturbation::sampleMutation(
-		Path &source, Path &proposal, MutationRecord &muRec) {
+		Path &source, Path &proposal, MutationRecord &muRec, const MutationRecord& sourceMuRec) {
 	int k = source.length(), m = k - 1, l = m - 1;
 
 	if (k < 4 || !source.vertex(l)->isConnectable())

src/libbidir/mut_lens.cpp

@@ -70,7 +70,7 @@ Float LensPerturbation::suitability(const Path &path) const {
 }
 
 bool LensPerturbation::sampleMutation(
-		Path &source, Path &proposal, MutationRecord &muRec) {
+		Path &source, Path &proposal, MutationRecord &muRec, const MutationRecord& sourceMuRec) {
 	int k = source.length(), m = k-1, l = m-1;
 	while (!source.vertex(l)->isConnectable() && l >= 0)
 		--l;

src/libbidir/mut_manifold.cpp

@@ -230,7 +230,7 @@ bool ManifoldPerturbation::sampleMutationRecord(
 }
 
 bool ManifoldPerturbation::sampleMutation(
-		Path &source, Path &proposal, MutationRecord &muRec) {
+		Path &source, Path &proposal, MutationRecord &muRec, const MutationRecord& sourceMuRec) {
 	int k = source.length();
 
 	int a, b, c, step, tries = 0;

src/libbidir/mut_mchain.cpp

@@ -66,7 +66,7 @@ Float MultiChainPerturbation::suitability(const Path &path) const {
 }
 
 bool MultiChainPerturbation::sampleMutation(
-		Path &source, Path &proposal, MutationRecord &muRec) {
+		Path &source, Path &proposal, MutationRecord &muRec, const MutationRecord& sourceMuRec) {
 	int k = source.length(), m = k - 1, l = m-1, nChains = 1;
 
 	while (l-1 >= 0 && (!source.vertex(l)->isConnectable()