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Solari: Improve spatial sample finding #22617

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Merged
alice-i-cecile merged 1 commit into from
Jan 21, 2026
Merged

Solari: Improve spatial sample finding #22617

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8 changes: 5 additions & 3 deletions crates/bevy_solari/src/realtime/restir_di.wgsl
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Original file line number Diff line number Diff line change
Expand Up @@ -184,13 +184,15 @@ fn load_temporal_reservoir_inner(temporal_pixel_id: vec2<u32>, depth: f32, world
}

fn load_spatial_reservoir(pixel_id: vec2<u32>, depth: f32, world_position: vec3<f32>, world_normal: vec3<f32>, rng: ptr<function, u32>) -> NeighborInfo {
var search_radius = SPATIAL_REUSE_RADIUS_PIXELS;
for (var i = 0u; i < 5u; i++) {
let spatial_pixel_id = get_neighbor_pixel_id(pixel_id, rng);
let spatial_pixel_id = get_neighbor_pixel_id(pixel_id, search_radius, rng);

let spatial_depth = textureLoad(depth_buffer, spatial_pixel_id, 0);
let spatial_surface = gpixel_resolve(textureLoad(gbuffer, spatial_pixel_id, 0), spatial_depth, spatial_pixel_id, view.main_pass_viewport.zw, view.world_from_clip);
let spatial_diffuse_brdf = spatial_surface.material.base_color / PI;
if pixel_dissimilar(depth, world_position, spatial_surface.world_position, world_normal, spatial_surface.world_normal, view) {
search_radius /= 2.0;
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@HugoPeters1024 HugoPeters1024 Jan 21, 2026

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What's the reasoning behind halving the search radius each iteration? Is this part of the original restir literature that we missed earlier, or is this a novel finding?

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@JMS55 JMS55 Jan 21, 2026

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Just a random idea I had. Seems to work well in practice.

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@SparkyPotato SparkyPotato Jan 21, 2026

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Could this not lead to correlations because the search radius at the end is around 2 pixels? Or does the temporal permutation hide it?

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@JMS55 JMS55 Jan 21, 2026

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I didn't notice issues when I was testing, but please test yourself and confirm! The archway on the left is a good candidate.

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@JMS55 JMS55 Jan 21, 2026

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We can also clamp to a minimum radius if needed.

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@SparkyPotato SparkyPotato Jan 21, 2026

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Seems to be fine in my testing too

continue;
}

Expand All @@ -201,8 +203,8 @@ fn load_spatial_reservoir(pixel_id: vec2<u32>, depth: f32, world_position: vec3<
return NeighborInfo(empty_reservoir(), world_position, world_normal, vec3(0.0));
}

fn get_neighbor_pixel_id(center_pixel_id: vec2<u32>, rng: ptr<function, u32>) -> vec2<u32> {
var spatial_id = vec2<f32>(center_pixel_id) + sample_disk(SPATIAL_REUSE_RADIUS_PIXELS, rng);
fn get_neighbor_pixel_id(center_pixel_id: vec2<u32>, search_radius: f32, rng: ptr<function, u32>) -> vec2<u32> {
var spatial_id = vec2<f32>(center_pixel_id) + sample_disk(search_radius, rng);
spatial_id = clamp(spatial_id, vec2(0.0), view.main_pass_viewport.zw - 1.0);
return vec2<u32>(spatial_id);
}
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8 changes: 5 additions & 3 deletions crates/bevy_solari/src/realtime/restir_gi.wgsl
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Original file line number Diff line number Diff line change
Expand Up @@ -150,13 +150,15 @@ fn load_temporal_reservoir_inner(temporal_pixel_id: vec2<u32>, depth: f32, world
}

fn load_spatial_reservoir(pixel_id: vec2<u32>, depth: f32, world_position: vec3<f32>, world_normal: vec3<f32>, rng: ptr<function, u32>) -> NeighborInfo {
var search_radius = SPATIAL_REUSE_RADIUS_PIXELS;
for (var i = 0u; i < 5u; i++) {
let spatial_pixel_id = get_neighbor_pixel_id(pixel_id, rng);
let spatial_pixel_id = get_neighbor_pixel_id(pixel_id, search_radius, rng);

let spatial_depth = textureLoad(depth_buffer, spatial_pixel_id, 0);
let spatial_surface = gpixel_resolve(textureLoad(gbuffer, spatial_pixel_id, 0), spatial_depth, spatial_pixel_id, view.main_pass_viewport.zw, view.world_from_clip);
let spatial_diffuse_brdf = spatial_surface.material.base_color / PI;
if pixel_dissimilar(depth, world_position, spatial_surface.world_position, world_normal, spatial_surface.world_normal, view) {
search_radius /= 2.0;
continue;
}

Expand All @@ -168,8 +170,8 @@ fn load_spatial_reservoir(pixel_id: vec2<u32>, depth: f32, world_position: vec3<
return NeighborInfo(empty_reservoir(), world_position, world_normal, vec3(0.0));
}

fn get_neighbor_pixel_id(center_pixel_id: vec2<u32>, rng: ptr<function, u32>) -> vec2<u32> {
var spatial_id = vec2<f32>(center_pixel_id) + sample_disk(SPATIAL_REUSE_RADIUS_PIXELS, rng);
fn get_neighbor_pixel_id(center_pixel_id: vec2<u32>, search_radius: f32, rng: ptr<function, u32>) -> vec2<u32> {
var spatial_id = vec2<f32>(center_pixel_id) + sample_disk(search_radius, rng);
spatial_id = clamp(spatial_id, vec2(0.0), view.main_pass_viewport.zw - 1.0);
return vec2<u32>(spatial_id);
}
Expand Down