192 lines
8.2 KiB
GLSL
Executable file
192 lines
8.2 KiB
GLSL
Executable file
// 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 float MAX_DISTANCE = 1.73205080757 * voxelgiRange;
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const float VOXEL_SIZE = (2.0 / voxelgiResolution.x) * voxelgiStep;
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// uniform sampler3D voxels;
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// uniform sampler3D voxelsLast;
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vec3 orthogonal(const vec3 u) {
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// Pass normalized u
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const vec3 v = vec3(0.99146, 0.11664, 0.05832); // Pick any normalized vector
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return abs(dot(u, v)) > 0.99999 ? cross(u, vec3(0.0, 1.0, 0.0)) : cross(u, v);
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}
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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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// uvec3 faceIndices(const vec3 dir) {
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// uvec3 ret;
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// ret.x = (dir.x < 0.0) ? 0 : 1;
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// ret.y = (dir.y < 0.0) ? 2 : 3;
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// ret.z = (dir.z < 0.0) ? 4 : 5;
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// return ret;
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// }
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// vec4 sampleVoxel(const vec3 pos, vec3 dir, const uvec3 indices, const float lod) {
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// dir = abs(dir);
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// return dir.x * textureLod(voxels[indices.x], pos, lod) +
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// dir.y * textureLod(voxels[indices.y], pos, lod) +
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// dir.z * textureLod(voxels[indices.z], pos, lod);
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// }
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vec4 traceCone(sampler3D voxels, vec3 origin, vec3 dir, const float aperture, const float maxDist, const vec3 normal) {
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dir = normalize(dir);
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// origin -= dir * dot(dir, normal) * VOXEL_SIZE;
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// uvec3 indices = faceIndices(dir);
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vec4 sampleCol = vec4(0.0);
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float dist = 0.04 * voxelgiOffset;
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float diam = dist * aperture;
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vec3 samplePos;
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// Step until alpha > 1 or out of bounds
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while (sampleCol.a < 1.0 && dist < maxDist) {
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samplePos = dir * dist + origin;
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// Choose mip level based on the diameter of the cone
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float mip = max(log2(diam * voxelgiResolution.x), 0);
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// vec4 mipSample = sampleVoxel(samplePos, dir, indices, mip);
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vec4 mipSample = textureLod(voxels, samplePos * 0.5 + 0.5, mip);
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// Blend mip sample with current sample color
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sampleCol += (1 - sampleCol.a) * mipSample;
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dist += max(diam / 2, VOXEL_SIZE); // Step 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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vec4 traceDiffuse(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 _VoxelCones1
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return traceCone(voxels, origin, normal, aperture, MAX_DISTANCE, normal) * voxelgiOcc;
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#endif
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#ifdef _VoxelCones3
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vec4 col = traceCone(voxels, origin, normal, aperture, MAX_DISTANCE, normal);
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col += traceCone(voxels, origin, mix(normal, -o1, angleMix), aperture, MAX_DISTANCE, normal);
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col += traceCone(voxels, origin, mix(normal, c2, angleMix), aperture, MAX_DISTANCE, normal);
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return (col / 3.0) * voxelgiOcc;
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#endif
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#ifdef _VoxelCones5
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vec4 col = traceCone(voxels, origin, normal, aperture, MAX_DISTANCE, normal);
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col += traceCone(voxels, origin, mix(normal, -o1, angleMix), aperture, MAX_DISTANCE, normal);
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col += traceCone(voxels, origin, mix(normal, -o2, angleMix), aperture, MAX_DISTANCE, normal);
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col += traceCone(voxels, origin, mix(normal, c1, angleMix), aperture, MAX_DISTANCE, normal);
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col += traceCone(voxels, origin, mix(normal, c2, angleMix), aperture, MAX_DISTANCE, normal);
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return (col / 5.0) * voxelgiOcc;
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#endif
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#ifdef _VoxelCones9
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// Normal direction
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vec4 col = traceCone(voxels, origin, normal, aperture, MAX_DISTANCE, normal);
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// 4 side cones
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col += traceCone(voxels, origin, mix(normal, o1, angleMix), aperture, MAX_DISTANCE, normal);
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col += traceCone(voxels, origin, mix(normal, -o1, angleMix), aperture, MAX_DISTANCE, normal);
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col += traceCone(voxels, origin, mix(normal, o2, angleMix), aperture, MAX_DISTANCE, normal);
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col += traceCone(voxels, origin, mix(normal, -o2, angleMix), aperture, MAX_DISTANCE, normal);
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// 4 corners
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col += traceCone(voxels, origin, mix(normal, c1, angleMix), aperture, MAX_DISTANCE, normal);
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col += traceCone(voxels, origin, mix(normal, -c1, angleMix), aperture, MAX_DISTANCE, normal);
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col += traceCone(voxels, origin, mix(normal, c2, angleMix), aperture, MAX_DISTANCE, normal);
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col += traceCone(voxels, origin, mix(normal, -c2, angleMix), aperture, MAX_DISTANCE, normal);
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return (col / 9.0) * voxelgiOcc;
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#endif
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return vec4(0.0);
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}
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float traceShadow(sampler3D voxels, const vec3 origin, const vec3 dir, const float aperture, const float targetDistance, const vec3 normal) {
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return traceCone(voxels, origin + normal * 0.04 * voxelgiOffset, dir, aperture, targetDistance, normal).a;
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}
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vec3 traceSpecular(sampler3D voxels, const vec3 pos, const vec3 normal, const vec3 viewDir, const float roughness) {
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float specularAperture = clamp(tan((3.14159265 / 2) * roughness * 0.75), 0.0174533 * 3.0, 3.14159265);
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vec3 specularDir = normalize(reflect(-viewDir, normal));
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return traceCone(voxels, pos, specularDir, specularAperture, MAX_DISTANCE, normal).xyz;
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}
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vec3 traceRefraction(sampler3D voxels, const vec3 pos, const vec3 normal, const vec3 viewDir, const float roughness) {
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const float ior = 1.440;
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const float transmittance = 1.0;
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vec3 refraction = refract(viewDir, normal, 1.0 / ior);
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float specularAperture = clamp(tan((3.14159265 / 2) * roughness), 0.0174533 * 3.0, 3.14159265);
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return transmittance * traceCone(voxels, pos, refraction, specularAperture, MAX_DISTANCE, normal).xyz;
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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 * voxelgiOffset;
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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 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 _VoxelCones1
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return traceConeAO(voxels, origin, normal, aperture, MAX_DISTANCE) * voxelgiOcc;
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#endif
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#ifdef _VoxelCones3
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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, -c2, angleMix), aperture, MAX_DISTANCE);
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return (col / 3.0) * voxelgiOcc;
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#endif
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#ifdef _VoxelCones5
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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) * voxelgiOcc;
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#endif
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#ifdef _VoxelCones9
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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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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 / 9.0) * voxelgiOcc;
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#endif
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return 0.0;
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}
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