Resolve "Voxel cone tracing"

Closes #82 (closed)

projects/voxelization/resources/shaders/shadowBlur.inc

+#ifndef SHADOW_BLUR_INC
+#define SHADOW_BLUR_INC
+
+vec4 blurMomentShadowMap1D(ivec2 coord, ivec2 blurDirection, texture2D srcTexture, sampler depthSampler){
+    
+    int blurRadius  = 9;
+    int minOffset   = -(blurRadius-1) / 2;
+    int maxOffset   = -minOffset;
+    
+    vec2 pixelSize = vec2(1) / textureSize(sampler2D(srcTexture, depthSampler), 0);
+    
+    float wTotal = 0;
+    vec4 moments = vec4(0);
+    
+    float weights1D[4] = { 0.5, 0.25, 0.125, 0.0625 };    // gaussian
+    
+    for(int i = minOffset; i <= maxOffset; i++){
+        vec2 uv = (coord + i * blurDirection) * pixelSize;
+        uv      += 0.5 * pixelSize * blurDirection * sign(i); // half pixel shift to take advantage of bilinear filtering
+        float w = weights1D[abs(i)];
+        moments += w * texture(sampler2D(srcTexture, depthSampler), uv);
+        wTotal  += w;
+    }
+    return moments / wTotal;
+}
+
+#endif // #ifndef SHADOW_BLUR_INC
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