Lubos Lenco
79 lines
2.7 KiB
GLSL
79 lines
2.7 KiB
GLSL
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#ifndef _CONETRACE_GLSL_
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#define _CONETRACE_GLSL_
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// References
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// https://github.com/Friduric/voxel-cone-tracing
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// https://github.com/Cigg/Voxel-Cone-Tracing
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// https://github.com/GreatBlambo/voxel_cone_tracing/
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// http://simonstechblog.blogspot.com/2013/01/implementing-voxel-cone-tracing.html
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// http://leifnode.com/2015/05/voxel-cone-traced-global-illumination/
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// http://www.seas.upenn.edu/%7Epcozzi/OpenGLInsights/OpenGLInsights-SparseVoxelization.pdf
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// https://research.nvidia.com/sites/default/files/publications/GIVoxels-pg2011-authors.pdf
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const ivec3 voxelgiResolution = ivec3(256, 256, 256);
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const vec3 voxelgiHalfExtents = vec3(1, 1, 1);
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const float voxelgiOcc = 1.0;
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const float voxelgiStep = 1.0;
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const float voxelgiRange = 2.0;
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const float MAX_DISTANCE = 1.73205080757 * voxelgiRange;
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const float VOXEL_SIZE = (2.0 / voxelgiResolution.x) * voxelgiStep;
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uniform float coneOffset;
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uniform float coneAperture;
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vec3 tangent(const vec3 n) {
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vec3 t1 = cross(n, vec3(0, 0, 1));
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vec3 t2 = cross(n, vec3(0, 1, 0));
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if (length(t1) > length(t2)) return normalize(t1);
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else return normalize(t2);
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}
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float traceConeAO(sampler3D voxels, const vec3 origin, vec3 dir, const float aperture, const float maxDist) {
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dir = normalize(dir);
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float sampleCol = 0.0;
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float dist = 1.5 * VOXEL_SIZE * coneOffset;
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// float dist = (0.02 + 0.02 * (1.0 - dot(dir, normal)) ) * coneOffset;
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float diam = dist * aperture;
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vec3 samplePos;
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while (sampleCol < 1.0 && dist < maxDist) {
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samplePos = dir * dist + origin;
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float mip = max(log2(diam * voxelgiResolution.x), 0);
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float mipSample = textureLod(voxels, samplePos * 0.5 + vec3(0.5), mip).r;
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sampleCol += (1 - sampleCol) * mipSample;
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dist += max(diam / 2, VOXEL_SIZE);
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diam = dist * aperture;
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}
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return sampleCol;
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}
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float traceShadow(sampler3D voxels, const vec3 origin, const vec3 dir) {
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return traceConeAO(voxels, origin, dir, 0.14 * coneAperture, 2.5 * voxelgiRange);
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}
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float traceAO(const vec3 origin, const vec3 normal, sampler3D voxels) {
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const float angleMix = 0.5f;
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const float aperture = 0.55785173935;
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vec3 o1 = normalize(tangent(normal));
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vec3 o2 = normalize(cross(o1, normal));
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vec3 c1 = 0.5f * (o1 + o2);
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vec3 c2 = 0.5f * (o1 - o2);
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#ifdef HLSL
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const float factor = voxelgiOcc * 0.93;
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#else
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const float factor = voxelgiOcc * 0.90;
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#endif
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float col = traceConeAO(voxels, origin, normal, aperture, MAX_DISTANCE);
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col += traceConeAO(voxels, origin, mix(normal, o1, angleMix), aperture, MAX_DISTANCE);
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col += traceConeAO(voxels, origin, mix(normal, o2, angleMix), aperture, MAX_DISTANCE);
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col += traceConeAO(voxels, origin, mix(normal, -c1, angleMix), aperture, MAX_DISTANCE);
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col += traceConeAO(voxels, origin, mix(normal, -c2, angleMix), aperture, MAX_DISTANCE);
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return (col / 5.0) * factor;
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return 0.0;
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}
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#endif
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