diff options
Diffstat (limited to 'source/blender/draw/engines/eevee/shaders/effect_minmaxz_frag.glsl')
-rw-r--r-- | source/blender/draw/engines/eevee/shaders/effect_minmaxz_frag.glsl | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/source/blender/draw/engines/eevee/shaders/effect_minmaxz_frag.glsl b/source/blender/draw/engines/eevee/shaders/effect_minmaxz_frag.glsl new file mode 100644 index 00000000000..3d580d0ce39 --- /dev/null +++ b/source/blender/draw/engines/eevee/shaders/effect_minmaxz_frag.glsl @@ -0,0 +1,64 @@ +/** + * Shader that downsample depth buffer, + * saving min and max value of each texel in the above mipmaps. + * Adapted from http://rastergrid.com/blog/2010/10/hierarchical-z-map-based-occlusion-culling/ + **/ + +#ifdef LAYERED +uniform sampler2DArray depthBuffer; +uniform int depthLayer; +#else +uniform sampler2D depthBuffer; +#endif + +float sampleLowerMip(ivec2 texel) +{ +#ifdef LAYERED + return texelFetch(depthBuffer, ivec3(texel, depthLayer), 0).r; +#else + return texelFetch(depthBuffer, texel, 0).r; +#endif +} + +void minmax(inout float out_val, float in_val) +{ +#ifdef MIN_PASS + out_val = min(out_val, in_val); +#else /* MAX_PASS */ + out_val = max(out_val, in_val); +#endif +} + +void main() +{ + ivec2 texelPos = ivec2(gl_FragCoord.xy); + ivec2 mipsize = textureSize(depthBuffer, 0).xy; + +#ifndef COPY_DEPTH + texelPos *= 2; +#endif + + float val = sampleLowerMip(texelPos); +#ifndef COPY_DEPTH + minmax(val, sampleLowerMip(texelPos + ivec2(1, 0))); + minmax(val, sampleLowerMip(texelPos + ivec2(1, 1))); + minmax(val, sampleLowerMip(texelPos + ivec2(0, 1))); + + /* if we are reducing an odd-width texture then fetch the edge texels */ + if (((mipsize.x & 1) != 0) && (int(gl_FragCoord.x) == mipsize.x-3)) { + /* if both edges are odd, fetch the top-left corner texel */ + if (((mipsize.y & 1) != 0) && (int(gl_FragCoord.y) == mipsize.y-3)) { + minmax(val, sampleLowerMip(texelPos + ivec2(-1, -1))); + } + minmax(val, sampleLowerMip(texelPos + ivec2(0, -1))); + minmax(val, sampleLowerMip(texelPos + ivec2(1, -1))); + } + /* if we are reducing an odd-height texture then fetch the edge texels */ + else if (((mipsize.y & 1) != 0) && (int(gl_FragCoord.y) == mipsize.y-3)) { + minmax(val, sampleLowerMip(texelPos + ivec2(0, -1))); + minmax(val, sampleLowerMip(texelPos + ivec2(1, -1))); + } +#endif + + gl_FragDepth = val; +}
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