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The resulting texture isn't used yet, but it's being written to.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,152 @@ | ||
| #import bevy_core_pipeline::fullscreen_vertex_shader::FullscreenVertexOutput | ||
| #import bevy_render::view::View | ||
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| fn world_to_ndc(world_position: vec2<f32>) -> vec2<f32> { | ||
| return (view.clip_from_world * vec4(world_position, 0.0, 1.0)).xy; | ||
| } | ||
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| fn ndc_to_world(ndc_position: vec2<f32>) -> vec2<f32> { | ||
| return (view.world_from_clip * vec4(ndc_position, 0.0, 1.0)).xy; | ||
| } | ||
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| fn frag_coord_to_uv(frag_coord: vec2<f32>) -> vec2<f32> { | ||
| return (frag_coord - view.viewport.xy) / view.viewport.zw; | ||
| } | ||
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| fn frag_coord_to_ndc(frag_coord: vec2<f32>) -> vec2<f32> { | ||
| return uv_to_ndc(frag_coord_to_uv(frag_coord.xy)); | ||
| } | ||
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| fn uv_to_ndc(uv: vec2<f32>) -> vec2<f32> { | ||
| return uv * vec2(2.0, -2.0) + vec2(-1.0, 1.0); | ||
| } | ||
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| fn ndc_to_uv(ndc: vec2<f32>) -> vec2<f32> { | ||
| return ndc * vec2(0.5, -0.5) + vec2(0.5); | ||
| } | ||
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| // We're currently only using a single uniform binding for point lights in | ||
| // WebGL2, which is limited to 4kb in BatchedUniformBuffer, so we need to | ||
| // ensure our point lights can fit in 4kb. | ||
| const MAX_POINT_LIGHTS: u32 = 82u; | ||
|
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| struct PointLight2d { | ||
| center: vec2f, | ||
| radius: f32, | ||
| color: vec4<f32>, | ||
| intensity: f32, | ||
| falloff: f32 | ||
| } | ||
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| struct AmbientLight2d { | ||
| color: vec4<f32> | ||
| } | ||
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| @group(0) @binding(0) | ||
| var<uniform> view: View; | ||
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| @group(0) @binding(1) | ||
| var<uniform> ambient_light: AmbientLight2d; | ||
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| // WebGL2 does not support storage buffers, so we fall back to a fixed length | ||
| // array in a uniform buffer. | ||
| #if AVAILABLE_STORAGE_BUFFER_BINDINGS >= 6 | ||
| @group(0) @binding(2) | ||
| var<storage> point_lights: array<PointLight2d>; | ||
| #else | ||
| @group(0) @binding(2) | ||
| var<uniform> point_lights: array<PointLight2d, MAX_POINT_LIGHTS>; | ||
| #endif | ||
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| @group(0) @binding(3) | ||
| var sdf: texture_2d<f32>; | ||
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| @group(0) @binding(4) | ||
| var sdf_sampler: sampler; | ||
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| @fragment | ||
| fn fragment(in: FullscreenVertexOutput) -> @location(0) vec4<f32> { | ||
| let pos = ndc_to_world(frag_coord_to_ndc(in.position.xy)); | ||
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| var lighting_color = ambient_light.color; | ||
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| if get_distance(pos) <= 0.0 { | ||
| return lighting_color; | ||
| } | ||
|
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| // WebGL2 does not support storage buffers (or runtime sized arrays), so we | ||
| // need to use a fixed number of point lights. | ||
| #if AVAILABLE_STORAGE_BUFFER_BINDINGS >= 6 | ||
| let point_light_count = arrayLength(&point_lights); | ||
| #else | ||
| let point_light_count = MAX_POINT_LIGHTS; | ||
| #endif | ||
|
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| for (var i = 0u; i < point_light_count; i++) { | ||
| let light = point_lights[i]; | ||
| let dist = distance(light.center, pos); | ||
|
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| if dist < light.radius { | ||
| let raymarch = raymarch(pos, light.center); | ||
|
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| if raymarch > 0.0 { | ||
| lighting_color += light.color * attenuation(light, dist); | ||
| } | ||
| } | ||
| } | ||
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| return lighting_color; | ||
| } | ||
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| fn square(x: f32) -> f32 { | ||
| return x * x; | ||
| } | ||
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| fn attenuation(light: PointLight2d, dist: f32) -> f32 { | ||
| let s = dist / light.radius; | ||
| if s > 1.0 { | ||
| return 0.0; | ||
| } | ||
| let s2 = square(s); | ||
| return light.intensity * square(1 - s2) / (1 + light.falloff * s2); | ||
| } | ||
|
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| fn get_distance(pos: vec2<f32>) -> f32 { | ||
| let uv = ndc_to_uv(world_to_ndc(pos)); | ||
| let dist = textureSample(sdf, sdf_sampler, uv).r; | ||
| return dist; | ||
| } | ||
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| fn distance_squared(a: vec2<f32>, b: vec2<f32>) -> f32 { | ||
| let c = a - b; | ||
| return dot(c, c); | ||
| } | ||
|
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| fn raymarch(ray_origin: vec2<f32>, ray_target: vec2<f32>) -> f32 { | ||
| let ray_direction = normalize(ray_target - ray_origin); | ||
| let stop_at = distance_squared(ray_origin, ray_target); | ||
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| var ray_progress: f32 = 0.0; | ||
| var pos = vec2<f32>(0.0); | ||
|
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| for (var i = 0; i < 32; i++) { | ||
| pos = ray_origin + ray_progress * ray_direction; | ||
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| if (ray_progress * ray_progress >= stop_at) { | ||
| // ray found target | ||
| return 1.0; | ||
| } | ||
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| let dist = get_distance(pos); | ||
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| if dist <= 0.0 { | ||
| break; | ||
| } | ||
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| ray_progress += dist; | ||
| } | ||
|
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| // ray found occluder | ||
| return 0.0; | ||
| } | ||
|
|
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