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Cleanup GI

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JMS55 2025-07-06 11:20:31 -04:00
parent c12670b0be
commit cb2a1fdddb
1 changed files with 70 additions and 53 deletions
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123
crates/bevy_solari/src/realtime/restir_gi.wgsl
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@ -43,61 +43,13 @@ fn initial_and_temporal(@builtin(global_invocation_id) global_id: vec3<u32>) {
let base_color = pow(unpack4x8unorm(gpixel.r).rgb, vec3(2.2));
let diffuse_brdf = base_color / PI;
let temporal_reservoir = load_temporal_reservoir(global_id.xy, depth, world_position, world_normal, &rng);
let ray_direction = sample_uniform_hemisphere(world_normal, &rng);
let ray_hit = trace_ray(world_position, ray_direction, RAY_T_MIN, RAY_T_MAX, RAY_FLAG_NONE);
if ray_hit.kind == RAY_QUERY_INTERSECTION_NONE {
gi_reservoirs_b[pixel_index] = temporal_reservoir;
return;
}
let sample_point = resolve_ray_hit_full(ray_hit);
if all(sample_point.material.emissive != vec3(0.0)) {
gi_reservoirs_b[pixel_index] = temporal_reservoir;
return;
}
let sample_point_diffuse_brdf = sample_point.material.base_color / PI;
let direct_lighting = sample_random_light(sample_point.world_position, sample_point.world_normal, &rng);
let sample_point_radiance = direct_lighting.radiance * sample_point_diffuse_brdf;
let cos_theta = dot(ray_direction, world_normal);
let inverse_uniform_hemisphere_pdf = PI_2;
var combined_reservoir = empty_reservoir();
combined_reservoir.confidence_weight = 1.0 + temporal_reservoir.confidence_weight;
let mis_weight_denominator = 1.0 / combined_reservoir.confidence_weight;
let new_mis_weight = mis_weight_denominator;
let new_target_function = luminance(sample_point_radiance * diffuse_brdf * cos_theta);
let new_inverse_pdf = direct_lighting.inverse_pdf * inverse_uniform_hemisphere_pdf;
let new_resampling_weight = new_mis_weight * (new_target_function * new_inverse_pdf);
let temporal_mis_weight = temporal_reservoir.confidence_weight * mis_weight_denominator;
let temporal_cos_theta = dot(normalize(temporal_reservoir.sample_point_world_position - world_position), world_normal);
let temporal_target_function = luminance(temporal_reservoir.radiance * diffuse_brdf * temporal_cos_theta);
let temporal_resampling_weight = temporal_mis_weight * (temporal_target_function * temporal_reservoir.unbiased_contribution_weight);
combined_reservoir.weight_sum = new_resampling_weight + temporal_resampling_weight;
if rand_f(&rng) < temporal_resampling_weight / combined_reservoir.weight_sum {
combined_reservoir.sample_point_world_position = temporal_reservoir.sample_point_world_position;
combined_reservoir.radiance = temporal_reservoir.radiance;
let inverse_target_function = select(0.0, 1.0 / temporal_target_function, temporal_target_function > 0.0);
combined_reservoir.unbiased_contribution_weight = combined_reservoir.weight_sum * inverse_target_function;
} else {
combined_reservoir.sample_point_world_position = sample_point.world_position;
combined_reservoir.radiance = sample_point_radiance;
let inverse_target_function = select(0.0, 1.0 / new_target_function, new_target_function > 0.0);
combined_reservoir.unbiased_contribution_weight = combined_reservoir.weight_sum * inverse_target_function;
}
let initial_reservoir = generate_initial_reservoir(world_position, world_normal, diffuse_brdf, &rng);
let temporal_reservoir = load_temporal_reservoir(global_id.xy, depth, world_position, world_normal, diffuse_brdf, &rng);
let combined_reservoir = merge_reservoirs(initial_reservoir, temporal_reservoir, &rng);
gi_reservoirs_b[pixel_index] = combined_reservoir;
}
@compute @workgroup_size(8, 8, 1)
fn spatial_and_shade(@builtin(global_invocation_id) global_id: vec3<u32>) {
if any(global_id.xy >= vec2u(view.viewport.zw)) { return; }
@ -127,7 +79,39 @@ fn spatial_and_shade(@builtin(global_invocation_id) global_id: vec3<u32>) {
textureStore(view_output, global_id.xy, pixel_color);
}
fn load_temporal_reservoir(pixel_id: vec2<u32>, depth: f32, world_position: vec3<f32>, world_normal: vec3<f32>, rng: ptr<function, u32>) -> Reservoir {
fn generate_initial_reservoir(world_position: vec3<f32>, world_normal: vec3<f32>, diffuse_brdf: vec3<f32>, rng: ptr<function, u32>) -> Reservoir{
var reservoir = empty_reservoir();
let ray_direction = sample_uniform_hemisphere(world_normal, rng);
let ray_hit = trace_ray(world_position, ray_direction, RAY_T_MIN, RAY_T_MAX, RAY_FLAG_NONE);
if ray_hit.kind == RAY_QUERY_INTERSECTION_NONE {
return reservoir;
}
let sample_point = resolve_ray_hit_full(ray_hit);
if all(sample_point.material.emissive != vec3(0.0)) {
return reservoir;
}
reservoir.sample_point_world_position = sample_point.world_position;
reservoir.confidence_weight = 1.0;
let sample_point_diffuse_brdf = sample_point.material.base_color / PI;
let direct_lighting = sample_random_light(sample_point.world_position, sample_point.world_normal, rng);
reservoir.radiance = direct_lighting.radiance * sample_point_diffuse_brdf;
let inverse_uniform_hemisphere_pdf = PI_2;
reservoir.unbiased_contribution_weight = direct_lighting.inverse_pdf * inverse_uniform_hemisphere_pdf;
let cos_theta = dot(ray_direction, world_normal);
reservoir.target_function = luminance(reservoir.radiance * diffuse_brdf * cos_theta);
return reservoir;
}
fn load_temporal_reservoir(pixel_id: vec2<u32>, depth: f32, world_position: vec3<f32>, world_normal: vec3<f32>, diffuse_brdf: vec3<f32>, rng: ptr<function, u32>) -> Reservoir {
let motion_vector = textureLoad(motion_vectors, pixel_id, 0).xy;
let temporal_pixel_id_float = vec2<f32>(pixel_id) - (motion_vector * view.viewport.zw);
@ -181,6 +165,9 @@ fn load_temporal_reservoir(pixel_id: vec2<u32>, depth: f32, world_position: vec3
temporal_reservoir.confidence_weight = min(temporal_reservoir.confidence_weight, CONFIDENCE_WEIGHT_CAP);
let temporal_cos_theta = dot(normalize(temporal_reservoir.sample_point_world_position - world_position), world_normal);
temporal_reservoir.target_function = luminance(temporal_reservoir.radiance * diffuse_brdf * temporal_cos_theta);
return temporal_reservoir;
}
@ -224,7 +211,7 @@ struct Reservoir {
radiance: vec3<f32>,
confidence_weight: f32,
unbiased_contribution_weight: f32,
padding1: f32,
target_function: f32,
padding2: f32,
padding3: f32,
}
@ -241,3 +228,33 @@ fn empty_reservoir() -> Reservoir {
0.0,
);
}
fn merge_reservoirs(canonical_reservoir: Reservoir,other_reservoir: Reservoir,rng: ptr<function, u32>) -> Reservoir {
// TODO: Balance heuristic MIS weights
let mis_weight_denominator = 1.0 / (canonical_reservoir.confidence_weight + other_reservoir.confidence_weight);
let canonical_mis_weight = canonical_reservoir.confidence_weight * mis_weight_denominator;
let canonical_resampling_weight = canonical_mis_weight * (canonical_reservoir.target_function * canonical_reservoir.unbiased_contribution_weight);
let other_mis_weight = other_reservoir.confidence_weight * mis_weight_denominator;
let other_resampling_weight = other_mis_weight * (other_reservoir.target_function * other_reservoir.unbiased_contribution_weight);
var combined_reservoir = empty_reservoir();
combined_reservoir.weight_sum = canonical_resampling_weight + other_resampling_weight;
combined_reservoir.confidence_weight = canonical_reservoir.confidence_weight + other_reservoir.confidence_weight;
if rand_f(rng) < other_resampling_weight / combined_reservoir.weight_sum {
combined_reservoir.sample_point_world_position = other_reservoir.sample_point_world_position;
combined_reservoir.radiance = other_reservoir.radiance;
combined_reservoir.target_function = other_reservoir.target_function;
} else {
combined_reservoir.sample_point_world_position = canonical_reservoir.sample_point_world_position;
combined_reservoir.radiance = canonical_reservoir.radiance;
combined_reservoir.target_function = canonical_reservoir.target_function;
}
let inverse_target_function = select(0.0, 1.0 / combined_reservoir.target_function, combined_reservoir.target_function > 0.0);
combined_reservoir.unbiased_contribution_weight = combined_reservoir.weight_sum * inverse_target_function;
return combined_reservoir;
}