Merge pull request #6613 from sudhanshuv1/refining-sample-numbers

refined the number of samples used in diffused and specular textures
processing · Dec 22, 2023 · ddede18 · ddede18
2 parents ce50455 + 53ec82c
commit ddede18
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Showing 2 changed files with 42 additions and 12 deletions.
diff --git a/src/webgl/shaders/imageLightDiffused.frag b/src/webgl/shaders/imageLightDiffused.frag
@@ -28,6 +28,12 @@ vec2 nTOE( vec3 v ){
   return angles;
 }
 
+float random(vec2 p) {
+  vec3 p3  = fract(vec3(p.xyx) * .1031);
+  p3 += dot(p3, p3.yzx + 33.33);
+  return fract((p3.x + p3.y) * p3.z);
+}
+
 void main()
 {   	 
 	// the sample direction equals the hemisphere's orientation
@@ -48,13 +54,15 @@ void main()
 	//  We specify a fixed sampleDelta delta value to traverse
   // the hemisphere; decreasing or increasing the sample delta
   // will increase or decrease the accuracy respectively.
-	const float sampleDelta = 0.025;
+	const float sampleDelta = 0.100;
 	float nrSamples = 0.0;
-
-	for(float phi = 0.0; phi < 2.0 * PI; phi += sampleDelta)
+  float randomOffset = random(gl_FragCoord.xy) * sampleDelta;
+	for(float rawPhi = 0.0; rawPhi < 2.0 * PI; rawPhi += sampleDelta)
 	{
-    for(float theta = 0.0; theta < ( 0.5 ) * PI; theta += sampleDelta)
+    float phi = rawPhi + randomOffset;
+    for(float rawTheta = 0.0; rawTheta < ( 0.5 ) * PI; rawTheta += sampleDelta)
     {
+      float theta = rawTheta + randomOffset;
       // spherical to cartesian (in tangent space) // tangent space to world // add each sample result to irradiance
       float x = sin(theta) * cos(phi);
       float y = sin(theta) * sin(phi);

diff --git a/src/webgl/shaders/imageLightSpecular.frag b/src/webgl/shaders/imageLightSpecular.frag
@@ -36,7 +36,8 @@ vec2 nTOE( vec3 v ){
 
 
 void main(){
-  const int SAMPLE_COUNT = 1024; // 4096
+  const int SAMPLE_COUNT = 400; // 4096
+  int lowRoughnessLimit = int(pow(2.0,(roughness+0.1)*20.0));
   float totalWeight = 0.0;
   vec3 prefilteredColor = vec3(0.0);
   float phi = vTexCoord.x * 2.0 * PI;
@@ -48,6 +49,11 @@ void main(){
   vec3 V = N;
   for (int i = 0; i < SAMPLE_COUNT; ++i)
   {
+    // break at smaller sample numbers for low roughness levels
+    if(i == lowRoughnessLimit)
+    {
+      break;
+    }
     vec2 Xi = HammersleyNoBitOps(i, SAMPLE_COUNT);
     vec3 H = ImportanceSampleGGX(Xi, N, roughness);
     vec3 L = normalize(2.0 * dot(V, H) * H - V);
@@ -88,22 +94,38 @@ vec3 ImportanceSampleGGX(vec2 Xi, vec3 N, float roughness){
 
 float VanDerCorput(int n, int base)
 {
+#ifdef WEBGL2
+
+    uint bits = uint(n);
+    bits = (bits << 16u) | (bits >> 16u);
+    bits = ((bits & 0x55555555u) << 1u) | ((bits & 0xAAAAAAAAu) >> 1u);
+    bits = ((bits & 0x33333333u) << 2u) | ((bits & 0xCCCCCCCCu) >> 2u);
+    bits = ((bits & 0x0F0F0F0Fu) << 4u) | ((bits & 0xF0F0F0F0u) >> 4u);
+    bits = ((bits & 0x00FF00FFu) << 8u) | ((bits & 0xFF00FF00u) >> 8u);
+    return float(bits) * 2.3283064365386963e-10; // / 0x100000000
+
+#else
+
   float invBase = 1.0 / float(base);
   float denom = 1.0;
   float result = 0.0;
 
+
   for (int i = 0; i < 32; ++i)
   {
-	if (n > 0)
-	{
-  	denom = mod(float(n), 2.0);
-  	result += denom * invBase;
-  	invBase = invBase / 2.0;
-  	n = int(float(n) / 2.0);
-	}
+        if (n > 0)
+        {
+        denom = mod(float(n), 2.0);
+        result += denom * invBase;
+        invBase = invBase / 2.0;
+        n = int(float(n) / 2.0);
+        }
   }
 
+
   return result;
+
+#endif
 }
 
 vec2 HammersleyNoBitOps(int i, int N)