slight tweaks to the BSDF API, components now specify whether they are front or back-facing

include/mitsuba/render/bsdf.h

@@ -99,13 +99,24 @@ public:
 	 */
 	enum EBSDFType {
 		EUnknown              = 0x0000,
-		EDiffuseReflection    = 0x0001, /* Perfect diffuse reflection */
+		/// Perfect diffuse reflection 
-		EDiffuseTransmission  = 0x0002, /* Perfect diffuse transmission */
+		EDiffuseReflection    = 0x0001, 
-		EDeltaReflection      = 0x0004, /* Reflection using a delta function */
+		/// Perfect diffuse transmission
-		EDeltaTransmission    = 0x0008, /* Transmission using a delta function */
+		EDiffuseTransmission  = 0x0002,
-		EGlossyReflection     = 0x0010, /* Glossy reflection */
+		/// Reflection using a delta function
-		EGlossyTransmission   = 0x0020, /* Glossy transmission */
+		EDeltaReflection      = 0x0004,
-		EAnisotropicMaterial  = 0x1000  /* Reflection is not invariant to rotation */
+		/// Transmission using a delta function
+		EDeltaTransmission    = 0x0008,
+		/// Glossy reflection
+		EGlossyReflection     = 0x0010,
+		/// Glossy transmission
+		EGlossyTransmission   = 0x0020,
+		/// Reflection is not invariant to rotation
+		EAnisotropic          = 0x1000,
+		/// Supports interactions on the front-facing side
+		EFrontSide            = 0x2000,
+		/// Supports interactions on the back-facing side
+		EBackSide             = 0x4000  
 	};
 
 	/// Type combinations

src/bsdfs/composite.cpp

@@ -112,8 +112,8 @@ public:
 			for (int j=0; j<bsdf->getComponentCount(); ++j) {
 				int componentType = bsdf->getType(j);
 				m_type[offset+j] = componentType;
-				m_combinedType |= componentType;
 			}
+			m_combinedType |= bsdf->getType();
 			offset += bsdf->getComponentCount();
 			m_usesRayDifferentials |= bsdf->usesRayDifferentials();
 			m_pdf[i] = m_bsdfWeight[i];

src/bsdfs/dielectric.cpp

@@ -45,8 +45,8 @@ public:
 
 		m_componentCount = 2;
 		m_type = new unsigned int[m_componentCount];
-		m_type[0] = EDeltaReflection;
+		m_type[0] = EDeltaReflection | EFrontSide;
-		m_type[1] = EDeltaTransmission;
+		m_type[1] = EDeltaTransmission | EFrontSide | EBackSide;
 		m_combinedType = m_type[0] | m_type[1];
 		m_usesRayDifferentials = false;
 	}
@@ -60,8 +60,8 @@ public:
 
 		m_componentCount = 2;
 		m_type = new unsigned int[m_componentCount];
-		m_type[0] = EDeltaReflection;
+		m_type[0] = EDeltaReflection | EFrontSide;
-		m_type[1] = EDeltaTransmission;
+		m_type[1] = EDeltaTransmission | EFrontSide | EBackSide;
 		m_combinedType = m_type[0] | m_type[1];
 		m_usesRayDifferentials = false;
 	}
@@ -246,8 +246,10 @@ public:
 	std::string toString() const {
 		std::ostringstream oss;
 		oss << "Dielectric[" << endl
-			<< "  intIOR=" << m_intIOR << "," << endl 
+			<< "  intIOR = " << m_intIOR << "," << endl 
-			<< "  extIOR=" << m_extIOR << endl
+			<< "  extIOR = " << m_extIOR << "," << endl
+			<< "  reflectance = " << m_reflectance.toString() << "," << endl
+			<< "  transmittance = " << m_transmittance.toString() << endl
 			<< "]";
 		return oss.str();
 	}

src/bsdfs/difftrans.cpp

@@ -34,7 +34,7 @@ public:
 			props.getSpectrum("transmittance", Spectrum(.5f)));
 		m_componentCount = 1;
 		m_type = new unsigned int[m_componentCount];
-		m_combinedType = m_type[0] = EDiffuseTransmission;
+		m_combinedType = m_type[0] = EDiffuseTransmission | EFrontSide | EBackSide;
 		m_usesRayDifferentials = false;
 	}
 
@@ -43,7 +43,7 @@ public:
 		m_transmittance = static_cast<Texture *>(manager->getInstance(stream));
 		m_componentCount = 1;
 		m_type = new unsigned int[m_componentCount];
-		m_combinedType = m_type[0] = EDiffuseTransmission;
+		m_combinedType = m_type[0] = EDiffuseTransmission | EFrontSide | EBackSide;
 		m_usesRayDifferentials = m_transmittance->usesRayDifferentials();
 	}
 
@@ -113,7 +113,9 @@ public:
 
 	std::string toString() const {
 		std::ostringstream oss;
-		oss << "DiffuseTransmitter[transmittance=" << m_transmittance->toString() << "]";
+		oss << "DiffuseTransmitter[" << endl
+			<< "  transmittance = " << indent(m_transmittance->toString()) << endl
+			<< "]";
 		return oss.str();
 	}
 

src/bsdfs/irawan.cpp

@@ -50,7 +50,7 @@ public:
 		: BSDF(props) {
 		m_componentCount = 1;
 		m_type = new unsigned int[m_componentCount];
-		m_combinedType = m_type[0] = EGlossyReflection;
+		m_type[0] = m_combinedType = EGlossyReflection | EFrontSide | EAnisotropic;
 		m_usesRayDifferentials = true;
 
 		FileResolver *fResolver = Thread::getThread()->getFileResolver();
@@ -94,7 +94,7 @@ public:
 		m_ksMultiplier = stream->readFloat();
 		m_componentCount = 1;
 		m_type = new unsigned int[m_componentCount];
-		m_combinedType = m_type[0] = EGlossyReflection | EAnisotropicMaterial;
+		m_type[0] = m_combinedType = EGlossyReflection | EFrontSide | EAnisotropic;
 		m_usesRayDifferentials = true;
 	}
 

src/bsdfs/lambertian.cpp

@@ -45,7 +45,7 @@ public:
 			props.getSpectrum("reflectance", Spectrum(.5f)));
 		m_componentCount = 1;
 		m_type = new unsigned int[m_componentCount];
-		m_combinedType = m_type[0] = EDiffuseReflection;
+		m_combinedType = m_type[0] = EDiffuseReflection | EFrontSide;
 		m_usesRayDifferentials = false;
 	}
 
@@ -54,7 +54,7 @@ public:
 		m_reflectance = static_cast<Texture *>(manager->getInstance(stream));
 		m_componentCount = 1;
 		m_type = new unsigned int[m_componentCount];
-		m_combinedType = m_type[0] = EDiffuseReflection;
+		m_combinedType = m_type[0] = EDiffuseReflection | EFrontSide;
 		m_usesRayDifferentials = m_reflectance->usesRayDifferentials();
 	}
 

src/bsdfs/mask.cpp

@@ -55,13 +55,15 @@ public:
 		BSDF::configure();
 		if (!m_nestedBSDF)
 			Log(EError, "A child BSDF is required");
-		m_combinedType = m_nestedBSDF->getType() | EDeltaTransmission;
 		m_usesRayDifferentials = m_nestedBSDF->usesRayDifferentials();
 		m_componentCount = m_nestedBSDF->getComponentCount() + 1;
+		if (m_type)
+			delete[] m_type;
 		m_type = new unsigned int[m_componentCount];
 		for (int i=0; i<m_nestedBSDF->getComponentCount(); ++i)
 			m_type[i] = m_nestedBSDF->getType(i);
-		m_type[m_nestedBSDF->getComponentCount()] = EDeltaTransmission;
+		m_type[m_nestedBSDF->getComponentCount()] = EDeltaTransmission | EFrontSide | EBackSide;
+		m_combinedType = m_nestedBSDF->getType() | m_type[m_nestedBSDF->getComponentCount()];
 	}
 
 	Spectrum getDiffuseReflectance(const Intersection &its) const {
@@ -170,6 +172,14 @@ public:
 
 	Shader *createShader(Renderer *renderer) const;
 
+	std::string toString() const {
+		std::ostringstream oss;
+		oss << "Mask[" << endl
+			<< "  opacity = " << indent(m_opacity->toString()) << "," << endl
+			<< "  nestedBSDF = " << indent(m_nestedBSDF.toString()) << endl
+			<< "]";
+		return oss.str();
+	}
 	MTS_DECLARE_CLASS()
 protected:
 	ref<Texture> m_opacity;

src/bsdfs/microfacet.cpp

@@ -52,8 +52,8 @@ public:
 
 		m_componentCount = 2;
 		m_type = new unsigned int[m_componentCount];
-		m_type[0] = EDiffuseReflection;
+		m_type[0] = EDiffuseReflection | EFrontSide;
-		m_type[1] = EGlossyReflection;
+		m_type[1] = EGlossyReflection | EFrontSide;
 		m_combinedType = m_type[0] | m_type[1];
 		m_usesRayDifferentials = 
 			m_diffuseReflectance->usesRayDifferentials() ||
@@ -72,8 +72,8 @@ public:
 
 		m_componentCount = 2;
 		m_type = new unsigned int[m_componentCount];
-		m_type[0] = EDiffuseReflection;
+		m_type[0] = EDiffuseReflection | EFrontSide;
-		m_type[1] = EGlossyReflection;
+		m_type[1] = EGlossyReflection | EFrontSide;
 		m_combinedType = m_type[0] | m_type[1];
 		m_usesRayDifferentials = 
 			m_diffuseReflectance->usesRayDifferentials() ||

src/bsdfs/mirror.cpp

@@ -30,8 +30,7 @@ public:
 		m_reflectance = props.getSpectrum("specularReflectance", Spectrum(0.8f));
 		m_componentCount = 1;
 		m_type = new unsigned int[m_componentCount];
-		m_type[0] = EDeltaReflection;
+		m_type[0] = m_combinedType = EDeltaReflection | EFrontSide;
-		m_combinedType = m_type[0];
 		m_usesRayDifferentials = false;
 	}
 
@@ -40,8 +39,8 @@ public:
 		m_reflectance = Spectrum(stream);
 		m_componentCount = 1;
 		m_type = new unsigned int[m_componentCount];
-		m_type[0] = EDeltaReflection;
+		m_type[0] = m_combinedType = EDeltaReflection | EFrontSide;
-		m_combinedType = m_type[0];
+		m_combinedType = m_type[0] | EFrontSide;
 		m_usesRayDifferentials = false;
 	}
 
@@ -94,6 +93,13 @@ public:
 		return m_reflectance;
 	}
 
+	std::string toString() const {
+		std::ostringstream oss;
+		oss << "Mirror[" << endl
+			<< "  reflectance = " << m_reflectance.toString() << endl
+			<< "]";
+		return oss.str();
+	}
 
 	MTS_DECLARE_CLASS()
 protected:

src/bsdfs/phong.cpp

@@ -46,8 +46,8 @@ public:
 
 		m_componentCount = 2;
 		m_type = new unsigned int[m_componentCount];
-		m_type[0] = EDiffuseReflection;
+		m_type[0] = EDeltaReflection | EFrontSide;
-		m_type[1] = EGlossyReflection;
+		m_type[1] = EDeltaTransmission | EFrontSide;
 		m_combinedType = m_type[0] | m_type[1];
 		m_usesRayDifferentials = false;
 	}
@@ -64,8 +64,8 @@ public:
 
 		m_componentCount = 2;
 		m_type = new unsigned int[m_componentCount];
-		m_type[0] = EDiffuseReflection;
+		m_type[0] = EDeltaReflection | EFrontSide;
-		m_type[1] = EGlossyReflection;
+		m_type[1] = EDeltaTransmission | EFrontSide;
 		m_combinedType = m_type[0] | m_type[1];
 		m_usesRayDifferentials = 
 			m_diffuseReflectance->usesRayDifferentials() ||

src/bsdfs/roughglass.cpp

@@ -40,8 +40,8 @@ public:
 
 		m_componentCount = 2;
 		m_type = new unsigned int[m_componentCount];
-		m_type[0] = EGlossyReflection;
+		m_type[0] = EDeltaReflection | EFrontSide | EBackSide;
-		m_type[1] = EGlossyTransmission;
+		m_type[1] = EDeltaTransmission | EFrontSide | EBackSide;
 		m_combinedType = m_type[0] | m_type[1];
 		m_usesRayDifferentials = false;
 	}
@@ -56,8 +56,8 @@ public:
 
 		m_componentCount = 2;
 		m_type = new unsigned int[m_componentCount];
-		m_type[0] = EGlossyReflection;
+		m_type[0] = EDeltaReflection | EFrontSide | EBackSide;
-		m_type[1] = EGlossyTransmission;
+		m_type[1] = EDeltaTransmission | EFrontSide | EBackSide;
 		m_combinedType = m_type[0] | m_type[1];
 		m_usesRayDifferentials = false;
 	}
@@ -398,11 +398,11 @@ public:
 	std::string toString() const {
 		std::ostringstream oss;
 		oss << "RoughGlass[" << std::endl
-			<< "  specularReflectance=" << m_specularReflectance.toString() << "," << std::endl
+			<< "  specularReflectance = " << m_specularReflectance.toString() << "," << std::endl
-			<< "  specularTransmittance=" << m_specularTransmittance.toString() << "," << std::endl
+			<< "  specularTransmittance = " << m_specularTransmittance.toString() << "," << std::endl
-			<< "  intIOR=" << m_intIOR << "," << std::endl
+			<< "  intIOR = " << m_intIOR << "," << std::endl
-			<< "  extIOR=" << m_extIOR << "," << std::endl
+			<< "  extIOR = " << m_extIOR << "," << std::endl
-			<< "  alphaB=" << m_alphaB << std::endl
+			<< "  alphaB = " << m_alphaB << std::endl
 			<< "]";
 		return oss.str();
 	}

src/bsdfs/roughmetal.cpp

@@ -42,7 +42,7 @@ public:
 
 		m_componentCount = 1;
 		m_type = new unsigned int[m_componentCount];
-		m_combinedType = m_type[0] = EGlossyReflection;
+		m_combinedType = m_type[0] = EGlossyReflection | EFrontSide;
 		m_usesRayDifferentials = false;
 	}
 
@@ -55,7 +55,7 @@ public:
 
 		m_componentCount = 1;
 		m_type = new unsigned int[m_componentCount];
-		m_combinedType = m_type[0] = EGlossyReflection;
+		m_combinedType = m_type[0] = EGlossyReflection | EFrontSide;
 		m_usesRayDifferentials = 
 			m_specularReflectance->usesRayDifferentials();
 	}
@@ -187,7 +187,7 @@ public:
 	std::string toString() const {
 		std::ostringstream oss;
 		oss << "RoughMetal[" << endl
-			<< "  specularReflectance=" << m_specularReflectance.toString() << "," << std::endl
+			<< "  specularReflectance = " << indent(m_specularReflectance->toString()) << "," << std::endl
 			<< "  ior = " << m_ior.toString() << "," << std::endl
 			<< "  k = " << m_k.toString() << "," << std::endl
 			<< "  alphaB = " << m_alphaB << std::endl

src/bsdfs/transparent.cpp

@@ -30,8 +30,7 @@ public:
 		m_transmission = props.getSpectrum("transmission", Spectrum(0.8f));
 		m_componentCount = 1;
 		m_type = new unsigned int[m_componentCount];
-		m_type[0] = EDeltaTransmission;
+		m_combinedType = m_type[0] = EDeltaTransmission | EFrontSide | EBackSide;
-		m_combinedType = m_type[0];
 		m_usesRayDifferentials = false;
 	}
 
@@ -41,7 +40,7 @@ public:
 		m_componentCount = 1;
 		m_type = new unsigned int[m_componentCount];
 		m_type[0] = EDeltaTransmission;
-		m_combinedType = m_type[0];
+		m_combinedType = m_type[0] = EDeltaTransmission | EFrontSide | EBackSide;
 		m_usesRayDifferentials = false;
 	}
 
@@ -99,6 +98,14 @@ public:
 		return m_transmission;
 	}
 
+	std::string toString() const {
+		std::ostringstream oss;
+		oss << "Transparent[" << endl
+			<< "  transmission = " << m_transmission.toString() << endl
+			<< "]";
+		return oss.str();
+	}
+
 	MTS_DECLARE_CLASS()
 protected:
 	Spectrum m_transmission;

src/bsdfs/twosided.cpp

@@ -47,15 +47,19 @@ public:
 	void configure() {
 		if (!m_nestedBRDF)
 			Log(EError, "TwoSidedBRDF: A child BRDF instance is required");
-		m_combinedType = m_nestedBRDF->getType();
 		if (m_combinedType & BSDF::ETransmission)
 			Log(EError, "TwoSidedBRDF: only BRDF child instances (without "
 				"transmission) are supported");
 		m_usesRayDifferentials = m_nestedBRDF->usesRayDifferentials();
 		m_componentCount = m_nestedBRDF->getComponentCount();
+		if (m_type)
+			delete[] m_type;
 		m_type = new unsigned int[m_componentCount];
-		for (int i=0; i<m_nestedBRDF->getComponentCount(); ++i)
+		m_combinedType = 0;
-			m_type[i] = m_nestedBRDF->getType(i);
+		for (int i=0; i<m_nestedBRDF->getComponentCount(); ++i) {
+			m_type[i] = m_nestedBRDF->getType(i) | EFrontSide | EBackSide;
+			m_combinedType |= m_type[i];
+		}
 	}
 
 	Spectrum getDiffuseReflectance(const Intersection &its) const {

src/bsdfs/ward.cpp

@@ -49,12 +49,10 @@ public:
 		m_alphaY = props.getFloat("alphaY", .1f);
 		m_componentCount = 2;
 		m_type = new unsigned int[m_componentCount];
-		m_type[0] = EDiffuseReflection;
+		m_type[0] = EDiffuseReflection | EFrontSide;
-		m_type[1] = EGlossyReflection;
+		m_type[1] = EGlossyReflection | EFrontSide;
-		if (m_alphaX != m_alphaY) {
+		if (m_alphaX != m_alphaY) 
-			m_type[0] |= EAnisotropicMaterial;
+			m_type[1] |= EAnisotropic;
-			m_type[1] |= EAnisotropicMaterial;
-		}
 		m_combinedType = m_type[0] | m_type[1];
 		m_usesRayDifferentials = false;
 	}
@@ -72,8 +70,10 @@ public:
 
 		m_componentCount = 2;
 		m_type = new unsigned int[m_componentCount];
-		m_type[0] = EDiffuseReflection;
+		m_type[0] = EDiffuseReflection | EFrontSide;
-		m_type[1] = EGlossyReflection;
+		m_type[1] = EGlossyReflection | EFrontSide;
+		if (m_alphaX != m_alphaY) 
+			m_type[1] |= EAnisotropic;
 		m_combinedType = m_type[0] | m_type[1];
 		m_usesRayDifferentials = 
 			m_diffuseReflectance->usesRayDifferentials() ||

src/libhw/vpl.cpp

@@ -361,7 +361,7 @@ void VPLShaderManager::configure(const VPL &vpl, const BSDF *bsdf,
 		return;
 	}
 
-	bool anisotropic = bsdf->getType() & BSDF::EAnisotropicMaterial;
+	bool anisotropic = bsdf->getType() & BSDF::EAnisotropic;
 
 	m_targetConfig = VPLProgramConfiguration(vplShader, bsdfShader, 
 			lumShader, faceNormals);

src/librender/preview.cpp

@@ -383,7 +383,7 @@ void PreviewWorker::processCoherent(const WorkUnit *workUnit, WorkResult *workRe
 					its.p.x = secRay4.o[0].f[idx];
 					its.p.y = secRay4.o[1].f[idx];
 					its.p.z = secRay4.o[2].f[idx];
-					if (EXPECT_NOT_TAKEN(bsdf->getType() & BSDF::EAnisotropicMaterial)) {
+					if (EXPECT_NOT_TAKEN(bsdf->getType() & BSDF::EAnisotropic)) {
 						its.shFrame.s = normalize(its.dpdu - its.shFrame.n
 							* dot(its.shFrame.n, its.dpdu));
 						its.shFrame.t = cross(its.shFrame.n, its.shFrame.s);

src/librender/trimesh.cpp

@@ -285,7 +285,7 @@ void TriMesh::configure() {
 		computeNormals();
 	}
 
-	if (hasBSDF() && ((m_bsdf->getType() & BSDF::EAnisotropicMaterial)
+	if (hasBSDF() && ((m_bsdf->getType() & BSDF::EAnisotropic)
 		|| m_bsdf->usesRayDifferentials()) && !m_tangents) 
 		computeTangentSpaceBasis();
 }
@@ -547,7 +547,7 @@ void TriMesh::computeNormals() {
 bool TriMesh::computeTangentSpaceBasis() {
 	int zeroArea = 0, zeroNormals = 0;
 	if (!m_texcoords) {
-		bool anisotropic = hasBSDF() && m_bsdf->getType() & BSDF::EAnisotropicMaterial;
+		bool anisotropic = hasBSDF() && m_bsdf->getType() & BSDF::EAnisotropic;
 		if (anisotropic)
 			Log(EError, "\"%s\": computeTangentSpace(): texture coordinates "
 				"are required to generate tangent vectors. If you want to render with an anisotropic "

src/tests/test_chisquare.cpp

@@ -122,7 +122,7 @@ public:
 			for (size_t j=0; j<wiSamples; ++j) {
 				Vector wi;
 	
-				if (bsdf->getType() & (BSDF::EDiffuseTransmission | BSDF::EGlossyTransmission))
+				if (bsdf->getType() & BSDF::EBackSide)
 					wi = squareToSphere(Point2(random->nextFloat(), random->nextFloat()));
 				else
 					wi = squareToHemispherePSA(Point2(random->nextFloat(), random->nextFloat()));
@@ -159,7 +159,7 @@ public:
 					for (size_t j=0; j<wiSamples; ++j) {
 						Vector wi;
 			
-						if (bsdf->getType(comp) & (BSDF::EDiffuseTransmission | BSDF::EGlossyTransmission))
+						if (bsdf->getType(comp) & BSDF::EBackSide)
 							wi = squareToSphere(Point2(random->nextFloat(), random->nextFloat()));
 						else
 							wi = squareToHemispherePSA(Point2(random->nextFloat(), random->nextFloat()));