60 lines
2.1 KiB
GLSL
Executable file
60 lines
2.1 KiB
GLSL
Executable file
uniform sampler3D voxels;
|
|
const float voxelGridWorldSize = 150.0;
|
|
const int voxelDimensions = 512;
|
|
const float maxDist = 30.0;
|
|
const float alphaThreshold = 0.95;
|
|
const int numCones = 6;
|
|
vec3 coneDirections[6] = vec3[](
|
|
vec3(0, 1, 0),
|
|
vec3(0, 0.5, 0.866025),
|
|
vec3(0.823639, 0.5, 0.267617),
|
|
vec3(0.509037, 0.5, -0.700629),
|
|
vec3(-0.509037, 0.5, -0.700629),
|
|
vec3(-0.823639, 0.5, 0.267617));
|
|
float coneWeights[6] = float[](0.25, 0.15, 0.15, 0.15, 0.15, 0.15);
|
|
|
|
vec4 sampleVoxels(vec3 worldPosition, float lod) {
|
|
vec3 offset = vec3(1.0 / voxelDimensions, 1.0 / voxelDimensions, 0);
|
|
vec3 texco = worldPosition / (voxelGridWorldSize * 0.5);
|
|
texco = texco * 0.5 + 0.5 + offset;
|
|
return textureLod(voxels, texco, lod);
|
|
}
|
|
|
|
// See https://github.com/Cigg/Voxel-Cone-Tracing
|
|
vec4 coneTrace(vec3 posWorld, vec3 direction, vec3 norWorld, float tanHalfAngle, out float occlusion) {
|
|
const float voxelWorldSize = voxelGridWorldSize / voxelDimensions;
|
|
float dist = voxelWorldSize; // Start one voxel away to avoid self occlusion
|
|
vec3 startPos = posWorld + norWorld * voxelWorldSize;
|
|
|
|
vec3 color = vec3(0.0);
|
|
float alpha = 0.0;
|
|
occlusion = 0.0;
|
|
while (dist < maxDist && alpha < alphaThreshold) {
|
|
// Smallest sample diameter possible is the voxel size
|
|
float diameter = max(voxelWorldSize, 2.0 * tanHalfAngle * dist);
|
|
float lodLevel = log2(diameter / voxelWorldSize);
|
|
vec4 voxelColor = sampleVoxels(startPos + dist * direction, lodLevel);
|
|
// Front-to-back compositing
|
|
float a = (1.0 - alpha);
|
|
color += a * voxelColor.rgb;
|
|
alpha += a * voxelColor.a;
|
|
occlusion += (a * voxelColor.a) / (1.0 + 0.03 * diameter);
|
|
dist += diameter * 0.5; // * 2.0
|
|
}
|
|
return vec4(color, alpha);
|
|
}
|
|
|
|
vec4 coneTraceIndirect(vec3 posWorld, mat3 tanToWorld, vec3 norWorld, out float occlusion) {
|
|
vec4 color = vec4(0);
|
|
occlusion = 0.0;
|
|
|
|
for (int i = 0; i < numCones; i++) {
|
|
float coneOcclusion;
|
|
const float tanangle = tan(30):
|
|
color += coneWeights[i] * coneTrace(posWorld, tanToWorld * coneDirections[i], norWorld, tanangle, coneOcclusion);
|
|
occlusion += coneWeights[i] * coneOcclusion;
|
|
}
|
|
occlusion = 1.0 - occlusion;
|
|
return color;
|
|
}
|