set up for new MIS random variable usage

Author: devshgraphicsprogramming

examples_tests/42.FragmentShaderPathTracer/common.glsl

@@ -462,12 +462,17 @@ layout (constant_id = 1) const int MAX_SAMPLES_LOG2 = 0;
 
 #include <nbl/builtin/glsl/random/xoroshiro.glsl>
 
-vec3 rand3d(in uint protoDimension, in uint _sample, inout nbl_glsl_xoroshiro64star_state_t scramble_state)
+mat2x3 rand3d(in uint protoDimension, in uint _sample, inout nbl_glsl_xoroshiro64star_state_t scramble_state)
 {
+    mat2x3 retval;
     uint address = bitfieldInsert(protoDimension,_sample,MAX_DEPTH_LOG2,MAX_SAMPLES_LOG2);
-	uvec3 seqVal = texelFetch(sampleSequence,int(address)).xyz;
-	seqVal ^= uvec3(nbl_glsl_xoroshiro64star(scramble_state),nbl_glsl_xoroshiro64star(scramble_state),nbl_glsl_xoroshiro64star(scramble_state));
-    return vec3(seqVal)*uintBitsToFloat(0x2f800004u);
+    for (int i=0; i<2u; i++)
+    {
+	    uvec3 seqVal = texelFetch(sampleSequence,int(address)+i).xyz;
+	    seqVal ^= uvec3(nbl_glsl_xoroshiro64star(scramble_state),nbl_glsl_xoroshiro64star(scramble_state),nbl_glsl_xoroshiro64star(scramble_state));
+        retval[i] = vec3(seqVal)*uintBitsToFloat(0x2f800004u);
+    }
+    return retval;
 }
 
 bool traceRay(in ImmutableRay_t _immutable);
@@ -511,7 +516,7 @@ void main()
             // apply stochastic reconstruction filter
             const float gaussianFilterCutoff = 2.5;
             const float truncation = exp(-0.5*gaussianFilterCutoff*gaussianFilterCutoff);
-            vec2 remappedRand = rand3d(0u,i,scramble_state).xy;
+            vec2 remappedRand = rand3d(0u,i,scramble_state)[0].xy;
             remappedRand.x *= 1.0-truncation;
             remappedRand.x += truncation;
             tmp.xy += pixOffsetParam*nbl_glsl_BoxMullerTransform(remappedRand,1.5);

examples_tests/42.FragmentShaderPathTracer/litByRectangle.frag

@@ -287,7 +287,7 @@ void closestHitProgram(in ImmutableRay_t _immutable, inout nbl_glsl_xoroshiro64s
             rayStack[stackPtr]._immutable.origin = intersection+_sample.L*(doNEE ? maxT:1.0/*kSceneSize*/)*getStartTolerance(depth);
             rayStack[stackPtr]._immutable.maxT = maxT;
             rayStack[stackPtr]._immutable.direction = _sample.L;
-            rayStack[stackPtr]._immutable.typeDepthSampleIx = bitfieldInsert(sampleIx,depth+1,DEPTH_BITS_OFFSET,DEPTH_BITS_COUNT)|(doNEE ? ANY_HIT_FLAG:0);
+            rayStack[stackPtr]._immutable.typeDepthSampleIx = bitfieldInsert(sampleIx,depth+2,DEPTH_BITS_OFFSET,DEPTH_BITS_COUNT)|(doNEE ? ANY_HIT_FLAG:0);
             rayStack[stackPtr]._immutable.normalAtOrigin = interaction.isotropic.N;
             rayStack[stackPtr]._immutable.wasBSDFAtOrigin = isBSDF;
             stackPtr++;

examples_tests/42.FragmentShaderPathTracer/litBySphere.frag

@@ -155,10 +155,10 @@ void closestHitProgram(in ImmutableRay_t _immutable, inout nbl_glsl_xoroshiro64s
 
 
         const float bsdfGeneratorProbability = BSDFNode_getMISWeight(bsdf);    
-        vec3 epsilon = rand3d(depth,sampleIx,scramble_state);
+        mat2x3 epsilon = rand3d(depth,sampleIx,scramble_state);
 
         float rcpChoiceProb;
-        const bool doNEE = nbl_glsl_partitionRandVariable(bsdfGeneratorProbability,epsilon.z,rcpChoiceProb);
+        const bool doNEE = nbl_glsl_partitionRandVariable(bsdfGeneratorProbability,epsilon[0].z,rcpChoiceProb);
 
 
         float maxT;
@@ -171,7 +171,7 @@ void closestHitProgram(in ImmutableRay_t _immutable, inout nbl_glsl_xoroshiro64s
             vec3 lightRemainder;
             _sample = nbl_glsl_light_generate_and_remainder_and_pdf(
                 lightRemainder,lightPdf,maxT,
-                intersection,interaction,epsilon,
+                intersection,interaction,epsilon[0],
                 depth
             );
             throughput *= lightRemainder;
@@ -190,7 +190,7 @@ void closestHitProgram(in ImmutableRay_t _immutable, inout nbl_glsl_xoroshiro64s
         else
         {
             maxT = FLT_MAX;
-            _sample = nbl_glsl_bsdf_cos_generate(interaction,epsilon,bsdf,monochromeEta,_cache);
+            _sample = nbl_glsl_bsdf_cos_generate(interaction,epsilon[0],bsdf,monochromeEta,_cache);
         }
 
         // do a cool trick and always compute the bsdf parts this way! (no divergence)
@@ -219,7 +219,7 @@ void closestHitProgram(in ImmutableRay_t _immutable, inout nbl_glsl_xoroshiro64s
             rayStack[stackPtr]._immutable.origin = intersection+_sample.L*(doNEE ? maxT:1.0/*kSceneSize*/)*getStartTolerance(depth);
             rayStack[stackPtr]._immutable.maxT = maxT;
             rayStack[stackPtr]._immutable.direction = _sample.L;
-            rayStack[stackPtr]._immutable.typeDepthSampleIx = bitfieldInsert(sampleIx,depth+1,DEPTH_BITS_OFFSET,DEPTH_BITS_COUNT)|(doNEE ? ANY_HIT_FLAG:0);
+            rayStack[stackPtr]._immutable.typeDepthSampleIx = bitfieldInsert(sampleIx,depth+2,DEPTH_BITS_OFFSET,DEPTH_BITS_COUNT)|(doNEE ? ANY_HIT_FLAG:0);
             stackPtr++;
         }
     }

examples_tests/42.FragmentShaderPathTracer/litByTriangle.frag

@@ -293,7 +293,7 @@ void closestHitProgram(in ImmutableRay_t _immutable, inout nbl_glsl_xoroshiro64s
             rayStack[stackPtr]._immutable.origin = intersection+_sample.L*(doNEE ? maxT:1.0/*kSceneSize*/)*getStartTolerance(depth);
             rayStack[stackPtr]._immutable.maxT = maxT;
             rayStack[stackPtr]._immutable.direction = _sample.L;
-            rayStack[stackPtr]._immutable.typeDepthSampleIx = bitfieldInsert(sampleIx,depth+1,DEPTH_BITS_OFFSET,DEPTH_BITS_COUNT)|(doNEE ? ANY_HIT_FLAG:0);
+            rayStack[stackPtr]._immutable.typeDepthSampleIx = bitfieldInsert(sampleIx,depth+2,DEPTH_BITS_OFFSET,DEPTH_BITS_COUNT)|(doNEE ? ANY_HIT_FLAG:0);
             rayStack[stackPtr]._immutable.normalAtOrigin = interaction.isotropic.N;
             rayStack[stackPtr]._immutable.wasBSDFAtOrigin = isBSDF;
             stackPtr++;

examples_tests/42.FragmentShaderPathTracer/main.cpp

@@ -146,7 +146,7 @@ void APIENTRY openGLCBFunc(GLenum source, GLenum type, GLuint id, GLenum severit
 
 struct ShaderParameters
 {
-	const uint32_t MaxDepthLog2 = 3; //5
+	const uint32_t MaxDepthLog2 = 4; //5
 	const uint32_t MaxSamplesLog2 = 10; //18
 } kShaderParameters;
 
@@ -261,7 +261,7 @@ int main()
 		return { gpuPipeline, gpuMeshBuffer };
 	};
 
-	E_LIGHT_GEOMETRY lightGeom = ELG_RECTANGLE;
+	E_LIGHT_GEOMETRY lightGeom = ELG_SPHERE;
 	constexpr const char* shaderPaths[] = {"../litBySphere.frag","../litByTriangle.frag","../litByRectangle.frag"};
 	auto gpuEnvmapResources = createGpuResources(shaderPaths[lightGeom]);
 	auto gpuEnvmapPipeline = gpuEnvmapResources.first;