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Eevee: Use textureGather for minmaxZbuffer downsampling. 

I haven't noticed any performance improvement but it could be more important
for other hardware. At least it's not slower!
This commit is contained in:
Clément Foucault 2018-04-17 22:25:53 +02:00
parent 38399c0b10
commit b40f5be01f
1 changed files with 41 additions and 20 deletions
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61
source/blender/draw/engines/eevee/shaders/effect_minmaxz_frag.glsl
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@ -4,6 +4,8 @@
* Adapted from http://rastergrid.com/blog/2010/10/hierarchical-z-map-based-occlusion-culling/
**/
#extension GL_ARB_texture_gather : enable
#ifdef LAYERED
uniform sampler2DArray depthBuffer;
uniform int depthLayer;
@ -12,15 +14,21 @@ uniform sampler2D depthBuffer;
#endif
#ifdef LAYERED
#define sampleLowerMip(t) texelFetch(depthBuffer, ivec3(t, depthLayer), 0).r
# define sampleLowerMip(t) texelFetch(depthBuffer, ivec3(t, depthLayer), 0).r
# define gatherLowerMip(t) textureGather(depthBuffer, vec3(t, depthLayer))
#else
#define sampleLowerMip(t) texelFetch(depthBuffer, t, 0).r
# define sampleLowerMip(t) texelFetch(depthBuffer, t, 0).r
# define gatherLowerMip(t) textureGather(depthBuffer, t)
#endif
#ifdef MIN_PASS
#define minmax(a, b) min(a, b)
#define minmax2(a, b) min(a, b)
#define minmax3(a, b, c) min(min(a, b), c)
#define minmax4(a, b, c, d) min(min(min(a, b), c), d)
#else /* MAX_PASS */
#define minmax(a, b) max(a, b)
#define minmax2(a, b) max(a, b)
#define minmax3(a, b, c) max(max(a, b), c)
#define minmax4(a, b, c, d) max(max(max(a, b), c), d)
#endif
/* On some AMD card / driver conbination, it is needed otherwise,
@ -38,32 +46,45 @@ void main()
texelPos *= 2;
#endif
#ifdef COPY_DEPTH
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);
#else
vec4 samp;
# ifdef GL_ARB_texture_gather
samp = gatherLowerMip(vec2(texelPos) / vec2(mipsize));
# else
samp.x = sampleLowerMip(texelPos);
samp.y = sampleLowerMip(texelPos + ivec2(1, 0));
samp.z = sampleLowerMip(texelPos + ivec2(1, 1));
samp.w = sampleLowerMip(texelPos + ivec2(0, 1));
# endif
float val = minmax4(samp.x, samp.y, samp.z, samp.w);
/* 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)));
samp.x = sampleLowerMip(texelPos + ivec2(2, 2));
val = minmax2(val, samp.x);
}
float val2 = sampleLowerMip(texelPos + ivec2(2, 0));
float val3 = sampleLowerMip(texelPos + ivec2(2, 1));
val = minmax(val, val2);
val = minmax(val, val3);
# ifdef GL_ARB_texture_gather
samp = gatherLowerMip((vec2(texelPos) + vec2(1.0, 0.0)) / vec2(mipsize));
# else
samp.y = sampleLowerMip(texelPos + ivec2(2, 0));
samp.z = sampleLowerMip(texelPos + ivec2(2, 1));
# endif
val = minmax3(val, samp.y, samp.z);
}
/* 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);
# ifdef GL_ARB_texture_gather
samp = gatherLowerMip((vec2(texelPos) + vec2(0.0, 1.0)) / vec2(mipsize));
# else
samp.x = sampleLowerMip(texelPos + ivec2(0, 2));
samp.y = sampleLowerMip(texelPos + ivec2(1, 2));
# endif
val = minmax3(val, samp.x, samp.y);
}
#endif