poisson noise

Author: azer89

HelloVulkan/HelloVulkan.vcxproj

@@ -154,6 +154,7 @@
     <None Include="..\Shaders\PBRPushConstants.glsl" />
     <None Include="..\Shaders\Radiance.glsl" />
     <None Include="..\Shaders\ShadowMapping\Depth.frag" />
+    <None Include="..\Shaders\ShadowMapping\Poisson.glsl" />
     <None Include="..\Shaders\SlotBased\Mesh.frag" />
     <None Include="..\Shaders\SlotBased\Mesh.vert" />
     <None Include="..\Shaders\TangentNormalToWorld.glsl" />

HelloVulkan/HelloVulkan.vcxproj.filters

@@ -168,6 +168,9 @@
     <None Include="..\Shaders\ShadowMapping\Depth.frag">
       <Filter>Shaders\ShadowMapping</Filter>
     </None>
+    <None Include="..\Shaders\ShadowMapping\Poisson.glsl">
+      <Filter>Shaders\ShadowMapping</Filter>
+    </None>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="Header\Camera.h">

Shaders/ShadowMapping/PCF.glsl

@@ -1,3 +1,5 @@
+#include <ShadowMapping//Poisson.glsl>
+
 float ShadowPCF(vec4 shadowCoord, uint cascadeIndex)
 {
 	vec3 N = normalize(normal);
@@ -13,8 +15,8 @@ float ShadowPCF(vec4 shadowCoord, uint cascadeIndex)
 
 	float bias = max(shadowUBO.shadowMaxBias * (1.0 - NoL), shadowUBO.shadowMinBias);
 
-	// TODO Find out a better blurring technique concerning multiple shadow maps
-	const int range = 1;
+	// PCF
+	/*const int range = 1;
 	float shadow = 0.0;
 	int count = 0;
 	for (int x = -range; x <= range; x++)
@@ -27,5 +29,15 @@ float ShadowPCF(vec4 shadowCoord, uint cascadeIndex)
 			count++;
 		}
 	}
-	return shadow / count;
+	return shadow / count;*/
+
+	float shadow = 0.0;
+	int numSamples = 8;
+	for (int i = 0; i < numSamples; ++i)
+	{
+		vec2 coord = GetPoissonDiskCoord(shadowCoord.xy, i);
+		float dist = texture(shadowMap, vec3(coord, cascadeIndex)).r;
+		shadow += (shadowCoord.z - bias) > dist ? 0.1 : 1.0;
+	}
+	return shadow / float(numSamples);
 }

Shaders/ShadowMapping/Poisson.glsl

@@ -0,0 +1,35 @@
+const float DISK_RADIUS = 2500;
+const int NUM_ELEMENTS_DISK = 16;
+
+const vec2 poissonDisk[NUM_ELEMENTS_DISK] = vec2[](
+	vec2(-0.94201624, -0.39906216),
+	vec2(0.94558609, -0.76890725),
+	vec2(-0.094184101, -0.92938870),
+	vec2(0.34495938, 0.29387760),
+	vec2(-0.91588581, 0.45771432),
+	vec2(-0.81544232, -0.87912464),
+	vec2(-0.38277543, 0.27676845),
+	vec2(0.97484398, 0.75648379),
+	vec2(0.44323325, -0.97511554),
+	vec2(0.53742981, -0.47373420),
+	vec2(-0.26496911, -0.41893023),
+	vec2(0.79197514, 0.19090188),
+	vec2(-0.24188840, 0.99706507),
+	vec2(-0.81409955, 0.91437590),
+	vec2(0.19984126, 0.78641367),
+	vec2(0.14383161, -0.14100790)
+	);
+
+// Returns a pseudo random number based on a vec3 and an int.
+float PseudoRandom(vec3 seed, int i)
+{
+	vec4 seed4 = vec4(seed, i);
+	float dotValue = dot(seed4, vec4(12.9898, 78.233, 45.164, 94.673));
+	return fract(sin(dotValue) * 43758.5453);
+}
+
+vec2 GetPoissonDiskCoord(vec2 projCoords, int i)
+{
+	int index = int(float(NUM_ELEMENTS_DISK) * PseudoRandom(projCoords.xyy, i)) % NUM_ELEMENTS_DISK;
+	return projCoords.xy + poissonDisk[index] / DISK_RADIUS;
+}