Remove hardcoded uniform directions add whitepoint param
This commit is contained in:
Máté Homolya
parent
937c738591
commit
b9374ee6f3
@ -1,4 +1,4 @@
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#import bevy_render::maths::{PI, PI_2};
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#import bevy_render::maths::{PI, PI_2, fast_sqrt};
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#import bevy_pbr::lighting::perceptualRoughnessToRoughness;
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struct FilteringConstants {
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@ -6,6 +6,7 @@ struct FilteringConstants {
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sample_count: u32,
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roughness: f32,
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blue_noise_size: vec2f,
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white_point: f32,
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}
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@group(0) @binding(0) var input_texture: texture_2d_array<f32>;
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@ -15,90 +16,11 @@ struct FilteringConstants {
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@group(0) @binding(4) var blue_noise_texture: texture_2d<f32>;
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// Tonemapping functions to reduce fireflies
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const white_point: f32 = 1.0;
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fn rcp(x: f32) -> f32 { return 1.0 / x; }
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fn max3(x: vec3f) -> f32 { return max(x.r, max(x.g, x.b)); }
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fn tonemap(color: vec3f) -> vec3f {
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return color / (color + vec3(white_point));
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return color / (color + vec3(constants.white_point));
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}
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fn reverse_tonemap(color: vec3f) -> vec3f {
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return white_point * color / (vec3(1.0) - color);
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}
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// Predefined set of uniform directions
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fn get_uniform_direction(index: u32) -> vec3f {
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var dir = vec3f(0.0);
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switch(index % 64u) {
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case 0u: { dir = vec3f(0.91593, -0.347884, 0.200123); }
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case 1u: { dir = vec3f(-0.244493, -0.710186, -0.660196); }
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case 2u: { dir = vec3f(-0.838322, 0.259442, 0.479484); }
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case 3u: { dir = vec3f(0.245473, 0.891464, -0.380835); }
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case 4u: { dir = vec3f(0.632533, -0.155099, 0.758846); }
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case 5u: { dir = vec3f(-0.20644, -0.973183, -0.101474); }
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case 6u: { dir = vec3f(-0.269471, 0.0483681, -0.961793); }
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case 7u: { dir = vec3f(0.143331, 0.973557, 0.177887); }
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case 8u: { dir = vec3f(0.725872, -0.086002, -0.682432); }
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case 9u: { dir = vec3f(-0.076835, -0.886014, 0.457249); }
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case 10u: { dir = vec3f(-0.913781, 0.0503775, -0.403071); }
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case 11u: { dir = vec3f(0.0159914, 0.676129, 0.73661); }
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case 12u: { dir = vec3f(0.992288, 0.00772121, -0.12371); }
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case 13u: { dir = vec3f(0.00641109, -0.177892, -0.984029); }
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case 14u: { dir = vec3f(-0.985566, -0.0665794, 0.155651); }
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case 15u: { dir = vec3f(-0.0700448, 0.706071, -0.704668); }
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case 16u: { dir = vec3f(0.89279, 0.117001, 0.435013); }
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case 17u: { dir = vec3f(0.142896, -0.893697, -0.425307); }
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case 18u: { dir = vec3f(-0.687174, -0.132142, 0.714374); }
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case 19u: { dir = vec3f(-0.217251, 0.965143, -0.145946); }
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case 20u: { dir = vec3f(0.108209, 0.0279573, 0.993735); }
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case 21u: { dir = vec3f(0.274912, -0.952168, 0.133416); }
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case 22u: { dir = vec3f(-0.653478, -0.211134, -0.726904); }
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case 23u: { dir = vec3f(-0.307126, 0.85749, 0.412777); }
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case 24u: { dir = vec3f(0.831999, 0.327845, -0.447543); }
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case 25u: { dir = vec3f(0.283463, -0.663772, 0.692138); }
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case 26u: { dir = vec3f(-0.893939, -0.415437, -0.168182); }
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case 27u: { dir = vec3f(-0.106605, 0.211719, 0.971499); }
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case 28u: { dir = vec3f(0.873146, 0.474611, 0.11118); }
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case 29u: { dir = vec3f(0.332658, -0.572825, -0.74914); }
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case 30u: { dir = vec3f(-0.781162, -0.487098, 0.390541); }
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case 31u: { dir = vec3f(-0.490404, 0.734038, -0.469779); }
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case 32u: { dir = vec3f(0.604084, 0.431641, 0.669902); }
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case 33u: { dir = vec3f(0.593065, -0.782314, -0.190417); }
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case 34u: { dir = vec3f(-0.244516, -0.197766, 0.949263); }
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case 35u: { dir = vec3f(-0.650394, 0.754372, 0.0889437); }
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case 36u: { dir = vec3f(0.468682, 0.430484, -0.771376); }
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case 37u: { dir = vec3f(0.647992, -0.666677, 0.368305); }
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case 38u: { dir = vec3f(-0.604909, -0.626104, -0.492015); }
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case 39u: { dir = vec3f(-0.564322, 0.511928, 0.647666); }
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case 40u: { dir = vec3f(0.633455, 0.743985, -0.212653); }
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case 41u: { dir = vec3f(0.292272, -0.234942, 0.927027); }
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case 42u: { dir = vec3f(-0.600382, -0.796926, 0.0667077); }
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case 43u: { dir = vec3f(-0.497216, 0.350652, -0.793612); }
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case 44u: { dir = vec3f(0.516356, 0.783334, 0.346069); }
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case 45u: { dir = vec3f(0.729109, -0.451604, -0.514251); }
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case 46u: { dir = vec3f(-0.389822, -0.675926, 0.62543); }
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case 47u: { dir = vec3f(-0.856868, 0.458917, -0.234889); }
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case 48u: { dir = vec3f(0.189162, 0.381537, 0.904791); }
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case 49u: { dir = vec3f(0.907219, -0.4183, 0.0444719); }
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case 50u: { dir = vec3f(-0.225508, -0.532484, -0.815848); }
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case 51u: { dir = vec3f(-0.882371, 0.341401, 0.323833); }
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case 52u: { dir = vec3f(0.279638, 0.796232, -0.536486); }
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case 53u: { dir = vec3f(0.759697, -0.242935, 0.603194); }
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case 54u: { dir = vec3f(-0.265275, -0.929255, -0.257125); }
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case 55u: { dir = vec3f(-0.455978, 0.114803, 0.882555); }
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case 56u: { dir = vec3f(0.213508, 0.976688, 0.0222359); }
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case 57u: { dir = vec3f(0.536034, -0.10141, -0.838084); }
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case 58u: { dir = vec3f(-0.147707, -0.941925, 0.301597); }
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case 59u: { dir = vec3f(-0.822975, 0.102675, -0.558722); }
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case 60u: { dir = vec3f(0.0753368, 0.810439, 0.580958); }
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case 61u: { dir = vec3f(0.958193, -0.0618399, -0.279361); }
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case 62u: { dir = vec3f(-0.0168296, -0.509477, 0.860319); }
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case 63u: { dir = vec3f(-0.999999, 0.00159255, 0.0); }
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default: { dir = vec3f(0.0, 0.0, 1.0); }
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}
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return normalize(dir);
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return constants.white_point * color / (vec3(1.0) - color);
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}
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// Convert UV and face index to direction vector
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@ -197,7 +119,6 @@ fn hammersley_2d(i: u32, n: u32) -> vec2f {
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// Blue noise randomization
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fn sample_noise(pixel_coords: vec2u) -> vec4f {
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// Get a stable random offset for this pixel
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let noise_size = vec2u(u32(constants.blue_noise_size.x), u32(constants.blue_noise_size.y));
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let noise_coords = pixel_coords % noise_size;
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let uv = vec2f(noise_coords) / constants.blue_noise_size;
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@ -222,8 +143,8 @@ fn importance_sample_ggx(xi: vec2f, roughness: f32, normal: vec3f) -> vec3f {
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let phi = 2.0 * PI * xi.x;
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// GGX mapping from uniform random to GGX distribution
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let cos_theta = sqrt((1.0 - xi.y) / (1.0 + (a * a - 1.0) * xi.y));
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let sin_theta = sqrt(1.0 - cos_theta * cos_theta);
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let cos_theta = fast_sqrt((1.0 - xi.y) / (1.0 + (a * a - 1.0) * xi.y));
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let sin_theta = fast_sqrt(1.0 - cos_theta * cos_theta);
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// Convert to cartesian
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let h = vec3f(
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@ -351,6 +272,30 @@ fn generate_radiance_map(@builtin(global_invocation_id) global_id: vec3u) {
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textureStore(output_texture, coords, face, vec4f(radiance, 1.0));
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}
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// Calculate spherical coordinates using spiral pattern
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// and golden angle to get a uniform distribution
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fn uniform_sample_sphere(i: u32, normal: vec3f) -> vec3f {
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// Get stratified sample index
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let strat_i = i % constants.sample_count;
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let golden_angle = 2.4;
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let full_sphere = f32(constants.sample_count) * 2.0;
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let z = 1.0 - (2.0 * f32(strat_i) + 1.0) / full_sphere;
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let r = fast_sqrt(1.0 - z * z);
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let phi = f32(strat_i) * golden_angle;
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// Create the direction vector
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let dir_uniform = vec3f(
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r * cos(phi),
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r * sin(phi),
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z
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);
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let tangent_frame = calculate_tangent_frame(normal);
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return normalize(tangent_frame * dir_uniform);
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}
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@compute
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@workgroup_size(8, 8, 1)
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fn generate_irradiance_map(@builtin(global_invocation_id) global_id: vec3u) {
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@ -368,54 +313,41 @@ fn generate_irradiance_map(@builtin(global_invocation_id) global_id: vec3u) {
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let uv = (vec2f(coords) + 0.5) * invSize;
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let normal = sample_cube_dir(uv, face);
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// Create tangent space matrix
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let tangent_frame = calculate_tangent_frame(normal);
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var irradiance = vec3f(0.0);
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var total_weight = 0.0;
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let sample_count = min(constants.sample_count, 64u);
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for (var i = 0u; i < sample_count; i++) {
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// Using a predefined set of directions provides good hemisphere coverage for diffuse
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var dir = get_uniform_direction((i + u32(coords.x * 7u + coords.y * 11u + face * 5u)) % 64u);
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// Use uniform sampling on a hemisphere
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for (var i = 0u; i < constants.sample_count; i++) {
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// Get a uniform direction on unit sphere
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var sample_dir = uniform_sample_sphere(i, normal);
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// Ensure the direction is in the hemisphere defined by the normal
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let NoL = dot(normal, dir);
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// Calculate the cosine weight (N·L)
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let weight = max(dot(normal, sample_dir), 0.0);
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// Flip the direction if it's in the wrong hemisphere
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if (NoL < 0.0) {
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dir = -dir;
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// Skip samples below horizon or at grazing angles
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if (weight <= 0.001) {
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continue;
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}
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// Recalculate NoL after possible flipping
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let weight = max(dot(normal, dir), 0.0);
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// Sample environment with level 0 (no mip)
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var sample_color = sample_environment(sample_dir, 0.0).rgb;
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if (weight > 0.0) {
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// Lambert PDF
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let pdf = weight / PI;
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let width = f32(size.x);
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// Filtered importance sampling
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let mip_level = clamp(
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calculate_environment_map_lod(pdf, width, f32(sample_count)),
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1.0,
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constants.roughness * 3.0
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);
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// Sample environment with the calculated mip level
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let sample_color = sample_environment(dir, mip_level).rgb;
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// Accumulate the sample
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irradiance += sample_color * weight;
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total_weight += weight;
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}
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// Apply tonemapping to reduce fireflies
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sample_color = tonemap(sample_color);
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// Accumulate the contribution
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irradiance += sample_color * weight;
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total_weight += weight;
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}
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// Normalize and scale by PI for diffuse BRDF
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if (total_weight > 0.0) {
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irradiance = irradiance / total_weight * PI;
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}
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// Normalize by total weight
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irradiance = irradiance / total_weight;
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// Scale by PI to account for the Lambert BRDF normalization factor
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irradiance *= PI;
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// Reverse tonemap to restore HDR range
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irradiance = reverse_tonemap(irradiance);
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// Write result to output texture
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textureStore(output_texture, coords, face, vec4f(irradiance, 1.0));
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@ -325,6 +325,7 @@ pub struct GeneratedEnvironmentMapLight {
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pub intensity: f32,
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pub rotation: Quat,
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pub affects_lightmapped_mesh_diffuse: bool,
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pub white_point: f32,
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}
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impl Default for GeneratedEnvironmentMapLight {
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@ -334,6 +335,7 @@ impl Default for GeneratedEnvironmentMapLight {
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intensity: 0.0,
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rotation: Quat::IDENTITY,
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affects_lightmapped_mesh_diffuse: true,
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white_point: 2.0,
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}
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}
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}
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@ -372,6 +374,7 @@ pub fn extract_generator_entities(
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intensity: filtered_env_map.intensity,
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rotation: filtered_env_map.rotation,
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affects_lightmapped_mesh_diffuse: filtered_env_map.affects_lightmapped_mesh_diffuse,
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white_point: filtered_env_map.white_point,
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};
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commands
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.get_entity(entity)
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@ -389,6 +392,7 @@ pub struct RenderEnvironmentMap {
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pub intensity: f32,
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pub rotation: Quat,
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pub affects_lightmapped_mesh_diffuse: bool,
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pub white_point: f32,
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}
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#[derive(Component)]
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@ -448,6 +452,7 @@ pub struct FilteringConstants {
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sample_count: u32,
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roughness: f32,
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blue_noise_size: Vec2,
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white_point: f32,
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}
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/// Stores bind groups for the environment map generation pipelines
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@ -586,6 +591,7 @@ pub fn prepare_generator_bind_groups(
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vector2_uniform.size.width as f32,
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vector2_uniform.size.height as f32,
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),
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white_point: env_map_light.white_point,
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};
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let mut radiance_constants_buffer = UniformBuffer::from(radiance_constants);
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@ -614,12 +620,14 @@ pub fn prepare_generator_bind_groups(
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// Create irradiance bind group
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let irradiance_constants = FilteringConstants {
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mip_level: 0.0,
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sample_count: 64,
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// 32 phi, 32 theta = 1024 samples total
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sample_count: 1024,
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roughness: 1.0,
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blue_noise_size: Vec2::new(
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sphere_cosine_weights.size.width as f32,
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sphere_cosine_weights.size.height as f32,
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),
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white_point: env_map_light.white_point,
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};
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let mut irradiance_constants_buffer = UniformBuffer::from(irradiance_constants);
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