Remove "sigma" parameter from diffuse materials

Switch to DiffuseBxDF in DiffuseMaterial
Remove "sigma" parameters with --upgrade

src/pbrt/cpu/integrators_test.cpp

@@ -77,9 +77,8 @@ std::vector<TestScene> GetScenes() {
 
         static ConstantSpectrum cs(0.5);
         SpectrumTexture Kd = alloc.new_object<SpectrumConstantTexture>(&cs);
-        FloatTexture sigma = alloc.new_object<FloatConstantTexture>(0.);
         // FIXME: here and below, Materials leak...
-        Material material = new DiffuseMaterial(Kd, sigma, nullptr, nullptr);
+        Material material = new DiffuseMaterial(Kd, nullptr, nullptr);
 
         MediumInterface mediumInterface;
         std::vector<Primitive> prims;
@@ -106,8 +105,7 @@ std::vector<TestScene> GetScenes() {
 
         static ConstantSpectrum cs(0.5);
         SpectrumTexture Kd = alloc.new_object<SpectrumConstantTexture>(&cs);
-        FloatTexture sigma = alloc.new_object<FloatConstantTexture>(0.);
-        const Material material = new DiffuseMaterial(Kd, sigma, nullptr, nullptr);
+        const Material material = new DiffuseMaterial(Kd, nullptr, nullptr);
 
         MediumInterface mediumInterface;
         std::vector<Primitive> prims;
@@ -140,8 +138,7 @@ std::vector<TestScene> GetScenes() {
 
         static ConstantSpectrum cs(0.5);
         SpectrumTexture Kd = alloc.new_object<SpectrumConstantTexture>(&cs);
-        FloatTexture sigma = alloc.new_object<FloatConstantTexture>(0.);
-        const Material material = new DiffuseMaterial(Kd, sigma, nullptr, nullptr);
+        const Material material = new DiffuseMaterial(Kd, nullptr, nullptr);
 
         // We have to do this little dance here to make sure the spectrum is
         // properly normalized (this is usually all handled inside *Light::Create())

src/pbrt/materials.cpp

@@ -180,7 +180,7 @@ HairMaterial *HairMaterial::Create(const TextureParameterDictionary &parameters,
 // DiffuseMaterial Method Definitions
 std::string DiffuseMaterial::ToString() const {
     return StringPrintf("[ DiffuseMaterial displacement: %s reflectance: %s sigma: %s ]",
-                        displacement, reflectance, sigma);
+                        displacement, reflectance);
 }
 
 DiffuseMaterial *DiffuseMaterial::Create(const TextureParameterDictionary &parameters,
@@ -191,10 +191,9 @@ DiffuseMaterial *DiffuseMaterial::Create(const TextureParameterDictionary &param
     if (!reflectance)
         reflectance = alloc.new_object<SpectrumConstantTexture>(
             alloc.new_object<ConstantSpectrum>(0.5f));
-    FloatTexture sigma = parameters.GetFloatTexture("sigma", 0.f, alloc);
     FloatTexture displacement = parameters.GetFloatTextureOrNull("displacement", alloc);
 
-    return alloc.new_object<DiffuseMaterial>(reflectance, sigma, displacement, normalMap);
+    return alloc.new_object<DiffuseMaterial>(reflectance, displacement, normalMap);
 }
 
 // ConductorMaterial Method Definitions
@@ -566,8 +565,8 @@ SubsurfaceMaterial *SubsurfaceMaterial::Create(
 // DiffuseTransmissionMaterial Method Definitions
 std::string DiffuseTransmissionMaterial::ToString() const {
     return StringPrintf("[ DiffuseTransmissionMaterial displacement: %s reflectance: %s "
-                        "transmittance: %s sigma: %s ]",
-                        displacement, reflectance, transmittance, sigma);
+                        "transmittance: %s ]",
+                        displacement, reflectance, transmittance);
 }
 
 DiffuseTransmissionMaterial *DiffuseTransmissionMaterial::Create(
@@ -587,11 +586,10 @@ DiffuseTransmissionMaterial *DiffuseTransmissionMaterial::Create(
 
     FloatTexture displacement = parameters.GetFloatTextureOrNull("displacement", alloc);
     bool remapRoughness = parameters.GetOneBool("remaproughness", true);
-    FloatTexture sigma = parameters.GetFloatTexture("sigma", 0.f, alloc);
     Float scale = parameters.GetOneFloat("scale", 1.f);
 
-    return alloc.new_object<DiffuseTransmissionMaterial>(
-        reflectance, transmittance, sigma, displacement, normalMap, scale);
+    return alloc.new_object<DiffuseTransmissionMaterial>(reflectance, transmittance,
+                                                         displacement, normalMap, scale);
 }
 
 MeasuredMaterial::MeasuredMaterial(const std::string &filename, FloatTexture displacement,

src/pbrt/materials.h

@@ -428,7 +428,7 @@ class HairMaterial {
 class DiffuseMaterial {
   public:
     // DiffuseMaterial Type Definitions
-    using BxDF = RoughDiffuseBxDF;
+    using BxDF = DiffuseBxDF;
     using BSSRDF = void;
 
     // DiffuseMaterial Public Methods
@@ -450,24 +450,20 @@ class DiffuseMaterial {
 
     std::string ToString() const;
 
-    DiffuseMaterial(SpectrumTexture reflectance, FloatTexture sigma,
-                    FloatTexture displacement, Image *normalMap)
-        : displacement(displacement),
-          normalMap(normalMap),
-          reflectance(reflectance),
-          sigma(sigma) {}
+    DiffuseMaterial(SpectrumTexture reflectance, FloatTexture displacement,
+                    Image *normalMap)
+        : displacement(displacement), normalMap(normalMap), reflectance(reflectance) {}
 
     template <typename TextureEvaluator>
     PBRT_CPU_GPU bool CanEvaluateTextures(TextureEvaluator texEval) const {
-        return texEval.CanEvaluate({sigma}, {reflectance});
+        return texEval.CanEvaluate({}, {reflectance});
     }
 
     template <typename TextureEvaluator>
     PBRT_CPU_GPU BSDF GetBSDF(TextureEvaluator texEval, MaterialEvalContext ctx,
-                              SampledWavelengths &lambda, RoughDiffuseBxDF *bxdf) const {
+                              SampledWavelengths &lambda, DiffuseBxDF *bxdf) const {
         SampledSpectrum r = Clamp(texEval(reflectance, ctx, lambda), 0, 1);
-        Float sig = Clamp(texEval(sigma, ctx), 0, 90);
-        *bxdf = RoughDiffuseBxDF(r, SampledSpectrum(0), sig);
+        *bxdf = DiffuseBxDF(r);
         return BSDF(ctx.ns, ctx.dpdus, bxdf);
     }
 
@@ -476,7 +472,6 @@ class DiffuseMaterial {
     FloatTexture displacement;
     Image *normalMap;
     SpectrumTexture reflectance;
-    FloatTexture sigma;
 };
 
 // ConductorMaterial Definition
@@ -799,20 +794,19 @@ class DiffuseTransmissionMaterial {
     using BSSRDF = void;
     // DiffuseTransmissionMaterial Public Methods
     DiffuseTransmissionMaterial(SpectrumTexture reflectance,
-                                SpectrumTexture transmittance, FloatTexture sigma,
-                                FloatTexture displacement, Image *normalMap, Float scale)
+                                SpectrumTexture transmittance, FloatTexture displacement,
+                                Image *normalMap, Float scale)
         : displacement(displacement),
           normalMap(normalMap),
           reflectance(reflectance),
           transmittance(transmittance),
-          sigma(sigma),
           scale(scale) {}
 
     static const char *Name() { return "DiffuseTransmissionMaterial"; }
 
     template <typename TextureEvaluator>
     PBRT_CPU_GPU bool CanEvaluateTextures(TextureEvaluator texEval) const {
-        return texEval.CanEvaluate({sigma}, {reflectance, transmittance});
+        return texEval.CanEvaluate({}, {reflectance, transmittance});
     }
 
     template <typename TextureEvaluator>
@@ -820,8 +814,7 @@ class DiffuseTransmissionMaterial {
                               SampledWavelengths &lambda, RoughDiffuseBxDF *bxdf) const {
         SampledSpectrum r = Clamp(scale * texEval(reflectance, ctx, lambda), 0, 1);
         SampledSpectrum t = Clamp(scale * texEval(transmittance, ctx, lambda), 0, 1);
-        Float s = texEval(sigma, ctx);
-        *bxdf = RoughDiffuseBxDF(r, t, s);
+        *bxdf = RoughDiffuseBxDF(r, t, 0);
         return BSDF(ctx.ns, ctx.dpdus, bxdf);
     }
 
@@ -847,7 +840,6 @@ class DiffuseTransmissionMaterial {
     FloatTexture displacement;
     Image *normalMap;
     SpectrumTexture reflectance, transmittance;
-    FloatTexture sigma;
     Float scale;
 };
 

src/pbrt/parser.cpp

@@ -1556,6 +1556,8 @@ std::string FormattingParserTarget::upgradeMaterial(std::string *name, Parameter
     } else if (*name == "matte") {
         *name = "diffuse";
         dict->RenameParameter("Kd", "reflectance");
+        dict->RemoveFloat("sigma");
+        dict->RemoveTexture("sigma");
     } else if (*name == "metal") {
         *name = "conductor";
         removeParamSilentIfConstant("Kr", 1);