diff options
Diffstat (limited to 'modules/lightmapper_rd/lm_compute.glsl')
-rw-r--r-- | modules/lightmapper_rd/lm_compute.glsl | 46 |
1 files changed, 34 insertions, 12 deletions
diff --git a/modules/lightmapper_rd/lm_compute.glsl b/modules/lightmapper_rd/lm_compute.glsl index 158cd960c4..7bb8346c47 100644 --- a/modules/lightmapper_rd/lm_compute.glsl +++ b/modules/lightmapper_rd/lm_compute.glsl @@ -235,19 +235,39 @@ uint trace_ray(vec3 p_from, vec3 p_to return RAY_MISS; } +// https://www.reedbeta.com/blog/hash-functions-for-gpu-rendering/ +uint hash(uint value) { + uint state = value * 747796405u + 2891336453u; + uint word = ((state >> ((state >> 28u) + 4u)) ^ state) * 277803737u; + return (word >> 22u) ^ word; +} + +uint random_seed(ivec3 seed) { + return hash(seed.x ^ hash(seed.y ^ hash(seed.z))); +} + +// generates a random value in range [0.0, 1.0) +float randomize(inout uint value) { + value = hash(value); + return float(value / 4294967296.0); +} + const float PI = 3.14159265f; -const float GOLDEN_ANGLE = PI * (3.0 - sqrt(5.0)); - -vec3 vogel_hemisphere(uint p_index, uint p_count, float p_offset) { - float r = sqrt(float(p_index) + 0.5f) / sqrt(float(p_count)); - float theta = float(p_index) * GOLDEN_ANGLE + p_offset; - float y = cos(r * PI * 0.5); - float l = sin(r * PI * 0.5); - return vec3(l * cos(theta), l * sin(theta), y); + +// http://www.realtimerendering.com/raytracinggems/unofficial_RayTracingGems_v1.4.pdf (chapter 15) +vec3 generate_hemisphere_uniform_direction(inout uint noise) { + float noise1 = randomize(noise); + float noise2 = randomize(noise) * 2.0 * PI; + + float factor = sqrt(1 - (noise1 * noise1)); + return vec3(factor * cos(noise2), factor * sin(noise2), noise1); } -float quick_hash(vec2 pos) { - return fract(sin(dot(pos * 19.19, vec2(49.5791, 97.413))) * 49831.189237); +vec3 generate_hemisphere_cosine_weighted_direction(inout uint noise) { + float noise1 = randomize(noise); + float noise2 = randomize(noise) * 2.0 * PI; + + return vec3(sqrt(noise1) * cos(noise2), sqrt(noise1) * sin(noise2), sqrt(1.0 - noise1)); } float get_omni_attenuation(float distance, float inv_range, float decay) { @@ -404,8 +424,9 @@ void main() { #endif vec3 light_average = vec3(0.0); float active_rays = 0.0; + uint noise = random_seed(ivec3(params.ray_from, atlas_pos)); for (uint i = params.ray_from; i < params.ray_to; i++) { - vec3 ray_dir = normal_mat * vogel_hemisphere(i, params.ray_count, quick_hash(vec2(atlas_pos))); + vec3 ray_dir = normal_mat * generate_hemisphere_cosine_weighted_direction(noise); uint tidx; vec3 barycentric; @@ -550,8 +571,9 @@ void main() { vec4(0.0), vec4(0.0)); + uint noise = random_seed(ivec3(params.ray_from, probe_index, 49502741 /* some prime */)); for (uint i = params.ray_from; i < params.ray_to; i++) { - vec3 ray_dir = vogel_hemisphere(i, params.ray_count, quick_hash(vec2(float(probe_index), 0.0))); + vec3 ray_dir = generate_hemisphere_uniform_direction(noise); if (bool(i & 1)) { //throw to both sides, so alternate them ray_dir.z *= -1.0; |