19c793af35
Metal shading language follows the C++ 14 standard and in some cases requires a greater level of explicitness than GLSL. There are also some small language differences: - Explicit type-casts (C++ requirements) - Explicit constant values (C++ requirements, e.g. floating point values using 0.0 instead of 0). - Metal/OpenGL compatibility paths - GLSL Function prototypes - Explicit accessors for vector types when sampling textures. Authored by Apple: Michael Parkin-White Ref T96261 Reviewed By: fclem Maniphest Tasks: T96261 Differential Revision: https://developer.blender.org/D14378
82 lines
2.4 KiB
GLSL
82 lines
2.4 KiB
GLSL
/**
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* Shader that down-sample depth buffer,
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* saving min and max value of each texel in the above mipmaps.
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* Adapted from http://rastergrid.com/blog/2010/10/hierarchical-z-map-based-occlusion-culling/
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*
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* Major simplification has been made since we pad the buffer to always be bigger than input to
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* avoid mipmapping misalignment.
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*/
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#ifdef LAYERED
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uniform sampler2DArray depthBuffer;
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uniform int depthLayer;
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#else
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uniform sampler2D depthBuffer;
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#endif
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#ifndef COPY_DEPTH
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uniform vec2 texelSize;
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#endif
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#ifdef LAYERED
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# define sampleLowerMip(t) texture(depthBuffer, vec3(t, depthLayer)).r
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# define gatherLowerMip(t) textureGather(depthBuffer, vec3(t, depthLayer))
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#else
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# define sampleLowerMip(t) texture(depthBuffer, t).r
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# define gatherLowerMip(t) textureGather(depthBuffer, t)
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#endif
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#ifdef MIN_PASS
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# define minmax2(a, b) min(a, b)
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# define minmax3(a, b, c) min(min(a, b), c)
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# define minmax4(a, b, c, d) min(min(min(a, b), c), d)
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#else /* MAX_PASS */
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# define minmax2(a, b) max(a, b)
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# define minmax3(a, b, c) max(max(a, b), c)
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# define minmax4(a, b, c, d) max(max(max(a, b), c), d)
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#endif
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/* On some AMD card / driver combination, it is needed otherwise,
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* the shader does not write anything. */
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#if (defined(GPU_INTEL) || defined(GPU_ATI)) && defined(GPU_OPENGL)
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out vec4 fragColor;
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#endif
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void main()
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{
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vec2 texel = gl_FragCoord.xy;
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#ifdef COPY_DEPTH
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vec2 uv = texel / vec2(textureSize(depthBuffer, 0).xy);
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float val = sampleLowerMip(uv);
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#else
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/* NOTE(@fclem): textureSize() does not work the same on all implementations
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* when changing the min and max texture levels. Use uniform instead (see T87801). */
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vec2 uv = texel * 2.0 * texelSize;
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vec4 samp;
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# ifdef GPU_ARB_texture_gather
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samp = gatherLowerMip(uv);
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# else
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samp.x = sampleLowerMip(uv + vec2(-0.5, -0.5) * texelSize);
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samp.y = sampleLowerMip(uv + vec2(-0.5, 0.5) * texelSize);
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samp.z = sampleLowerMip(uv + vec2(0.5, -0.5) * texelSize);
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samp.w = sampleLowerMip(uv + vec2(0.5, 0.5) * texelSize);
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# endif
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float val = minmax4(samp.x, samp.y, samp.z, samp.w);
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#endif
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#if (defined(GPU_INTEL) || defined(GPU_ATI)) && defined(GPU_OPENGL)
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/* Use color format instead of 24bit depth texture */
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fragColor = vec4(val);
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#endif
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#if !(defined(GPU_INTEL) && defined(GPU_OPENGL))
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/* If using Intel workaround, do not write out depth as there will be no depth target and this is
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* invalid. */
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gl_FragDepth = val;
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#endif
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}
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