luboslenco
78 lines
2.7 KiB
GLSL
78 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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uniform float cone_offset;
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uniform float cone_aperture;
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const int voxelgi_resolution = 256;
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const vec3 voxelgi_half_extents = vec3(1, 1, 1);
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const float voxelgi_occ = 1.0;
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const float voxelgi_step = 1.0;
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const float voxelgi_range = 2.0;
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const float MAX_DISTANCE = 1.73205080757 * voxelgi_range;
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const float VOXEL_SIZE = (2.0 / voxelgi_resolution.x) * voxelgi_step;
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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 trace_cone_ao(sampler3D voxels, const vec3 origin, vec3 dir, const float aperture, const float max_dist) {
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dir = normalize(dir);
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float sample_col = 0.0;
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float dist = 1.5 * VOXEL_SIZE * cone_offset;
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float diam = dist * aperture;
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vec3 sample_pos;
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while (sample_col < 1.0 && dist < max_dist) {
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sample_pos = dir * dist + origin;
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float mip = max(log2(diam * voxelgi_resolution.x), 0);
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float mip_sample = textureLod(voxels, sample_pos * 0.5 + vec3(0.5, 0.5, 0.5), mip).r;
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sample_col += (1 - sample_col) * mip_sample;
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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 sample_col;
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}
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float trace_shadow(sampler3D voxels, const vec3 origin, const vec3 dir) {
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return trace_cone_ao(voxels, origin, dir, 0.14 * cone_aperture, 2.5 * voxelgi_range);
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}
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float trace_ao(const vec3 origin, const vec3 normal, sampler3D voxels) {
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const float angle_mix = 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 = voxelgi_occ * 0.93;
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#else
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const float factor = voxelgi_occ * 0.90;
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#endif
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float col = trace_cone_ao(voxels, origin, normal, aperture, MAX_DISTANCE);
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col += trace_cone_ao(voxels, origin, mix(normal, o1, angle_mix), aperture, MAX_DISTANCE);
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col += trace_cone_ao(voxels, origin, mix(normal, o2, angle_mix), aperture, MAX_DISTANCE);
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col += trace_cone_ao(voxels, origin, mix(normal, -c1, angle_mix), aperture, MAX_DISTANCE);
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col += trace_cone_ao(voxels, origin, mix(normal, -c2, angle_mix), 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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