Remove frensel references from material nodes

scene/optimized_scene.go

@@ -117,12 +117,12 @@ type MaterialNode struct {
 	// For leafs it contains a BRDF-specific parameter like roughness e.t.c
 	Nval float32
 
-	// Reserved space; used by the kernels as scratch space while evaluating materials
-	reserved [2]float32
-
 	// Set to 1 if this is a node; 0 if this is a leaf
 	IsNode uint32
 
+	// Alignment padding
+	reserved [2]float32
+
 	// This union like structure has different contents depending on the node
 	// type.
 	//

tracer/opencl/CL/bxdf/ideal_specular.cl

@@ -20,7 +20,7 @@ float3 idealSpecularSample(Surface *surface, MaterialNode *matNode, __global Tex
 	*pdf = 1.0f;
 
 	float3 ks = matGetSample3f(surface->uv, matNode->kval, matNode->kvalTex, texMeta, texData);
-	return cosTheta > 0.0f ? matNode->fresnel * ks / cosTheta : 0.0f;
+	return cosTheta > 0.0f ? ks / cosTheta : 0.0f;
 }
 
 // Get PDF for idealSpecular surface given a pre-calculated bounce ray.

tracer/opencl/CL/bxdf/lambert.cl

@@ -7,7 +7,7 @@ float3 lambertDiffuseEval(Surface *surface, MaterialNode *matNode, __global Text
 
 // Sample ideal diffuse (lambert) surface:
 //
-// BXDF = F * kval  / PI
+// BXDF = kval  / PI
 // PDF = cos(theta) / PI
 float3 lambertDiffuseSample(Surface *surface, MaterialNode *matNode, __global TextureMetadata *texMeta, __global uchar *texData, float2 randSample, float3 *rayOutDir, float *pdf){
 	*rayOutDir = rayGetCosWeightedHemisphereSample(surface->normal, randSample);	
@@ -16,7 +16,7 @@ float3 lambertDiffuseSample(Surface *surface, MaterialNode *matNode, __global Te
 
 	float3 kd = matGetSample3f(surface->uv, matNode->kval, matNode->kvalTex, texMeta, texData);
 
-	return matNode->fresnel * kd * C_1_PI;
+	return kd * C_1_PI;
 }
 
 // Get PDF for lambert surface given a pre-calculated bounce ray.
@@ -28,6 +28,6 @@ float lambertDiffusePdf(Surface *surface, MaterialNode *matNode, float3 rayOutDi
 // Evaluate BXDF for lambert surface given a pre-calculated bounce ray.
 float3 lambertDiffuseEval(Surface *surface, MaterialNode *matNode, __global TextureMetadata *texMeta, __global uchar *texData, float3 rayOutDir){
 	float3 kd = matGetSample3f(surface->uv, matNode->kval, matNode->kvalTex, texMeta, texData);
-	return matNode->fresnel * kd * C_1_PI;
+	return kd * C_1_PI;
 }
 #endif

tracer/opencl/CL/bxdf/refractive.cl

@@ -46,7 +46,7 @@ float3 refractiveSample(Surface *surface, MaterialNode *matNode, __global Textur
 	*rayOutDir = normalize(normalize(surfNormal * cosI - rayInDir) * sinT - surfNormal * cosTransimission);
 
 	float3 ks = eta * eta * matGetSample3f(surface->uv, matNode->kval, matNode->kvalTex, texMeta, texData);
-	return cosTransimission > 0.0f ? matNode->fresnel * ks / cosTransimission: 0.0f;
+	return cosTransimission > 0.0f ? ks / cosTransimission: 0.0f;
 }
 
 // Get PDF for refractive surface given a pre-calculated bounce ray.

tracer/opencl/CL/samplers/material_sampler.cl

@@ -25,7 +25,6 @@ void matSelectNode(Surface *surface, MaterialNode *selectedMaterial, __global Ma
 	}
 
 	*selectedMaterial = *node;
-	selectedMaterial->fresnel = 1.0f;
 }
 
 // Sample texture using the supplied uv coordinates and return a float3 vector. 

tracer/opencl/CL/types.cl

@@ -132,14 +132,10 @@ typedef struct {
 		float nval;
 	};
 
-	// alignment padding
-	float _reserved1;
-
-	// Fresnel value; for layered materials it contains the product of each node
-	// selection probability in the evaluated material node sub-tree.
-	float fresnel;
-
 	uint isNode;
+
+	// alignment padding
+	float _reserved[2];
 
 	union {
 		// For intermediate nodes