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 | 75 |
1 files changed, 75 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..05fef73b159 --- /dev/null +++ b/source/blender/draw/engines/eevee/shaders/effect_minmaxz_frag.glsl @@ -0,0 +1,75 @@ +/** + * 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 + +#ifdef LAYERED +#define sampleLowerMip(t) texelFetch(depthBuffer, ivec3(t, depthLayer), 0).r +#else +#define sampleLowerMip(t) texelFetch(depthBuffer, t, 0).r +#endif + +#ifdef MIN_PASS +#define minmax(a, b) min(a, b) +#else /* MAX_PASS */ +#define minmax(a, b) max(a, b) +#endif + +/* On some AMD card / driver conbination, it is needed otherwise, + * the shader does not write anything. */ +#if defined(GPU_INTEL) || defined(GPU_ATI) +out vec4 fragColor; +#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 + float val2 = sampleLowerMip(texelPos + ivec2(1, 0)); + float val3 = sampleLowerMip(texelPos + ivec2(1, 1)); + float val4 = sampleLowerMip(texelPos + ivec2(0, 1)); + val = minmax(val, val2); + val = minmax(val, val3); + val = minmax(val, val4); + + /* if we are reducing an odd-width texture then fetch the edge texels */ + if (((mipsize.x & 1) != 0) && (texelPos.x == mipsize.x - 3)) { + /* if both edges are odd, fetch the top-left corner texel */ + if (((mipsize.y & 1) != 0) && (texelPos.y == mipsize.y - 3)) { + val = minmax(val, sampleLowerMip(texelPos + ivec2(2, 2))); + } + float val2 = sampleLowerMip(texelPos + ivec2(2, 0)); + float val3 = sampleLowerMip(texelPos + ivec2(2, 1)); + val = minmax(val, val2); + val = minmax(val, val3); + } + /* if we are reducing an odd-height texture then fetch the edge texels */ + if (((mipsize.y & 1) != 0) && (texelPos.y == mipsize.y - 3)) { + float val2 = sampleLowerMip(texelPos + ivec2(0, 2)); + float val3 = sampleLowerMip(texelPos + ivec2(1, 2)); + val = minmax(val, val2); + val = minmax(val, val3); + } +#endif + +#if defined(GPU_INTEL) || defined(GPU_ATI) + /* Use color format instead of 24bit depth texture */ + fragColor = vec4(val); +#endif + gl_FragDepth = val; +}
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