xfy
ed6639738f
Adds BlurMaterial + blur.wgsl with a 13-tap weighted Gaussian kernel (var<private> arrays — naga rejects dynamic indexing of const arrays), run in downsample then upsample passes. For the 3-level pyramid: bloom_0 (half, from brightpass) → bloom_1 (quarter) → bloom_2 (eighth), then upsample to bloom_final (half). Camera orders -18/-17/-16/-15. The bloom output is not yet composited (Task 6); this commit only wires the passes and confirms they run in sequence without crashing.
53 lines
1.9 KiB
WebGPU Shading Language
53 lines
1.9 KiB
WebGPU Shading Language
#import bevy_sprite::mesh2d_vertex_output::VertexOutput
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struct BlurUniform {
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mode: u32, // 0 = downsample, 1 = upsample
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texel_size: vec2<f32>,
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blend: f32, // upsample blend factor (ignored for down)
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_pad0: f32,
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};
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@group(#{MATERIAL_BIND_GROUP}) @binding(0) var<uniform> u: BlurUniform;
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@group(#{MATERIAL_BIND_GROUP}) @binding(1) var tex: texture_2d<f32>;
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@group(#{MATERIAL_BIND_GROUP}) @binding(2) var samp: sampler;
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// 13-tap weighted kernel (Gaussian approximation for HDR bloom).
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// NOTE: naga rejects dynamic indexing of const arrays ("may only be indexed
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// by a constant"), so we use var<private> here — it allows runtime indexing.
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var<private> KERNEL_OFFSETS: array<vec2<f32>, 13> = array<vec2<f32>, 13>(
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vec2<f32>( 0.0, 0.0),
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vec2<f32>( 1.0, 0.0), vec2<f32>(-1.0, 0.0),
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vec2<f32>( 0.0, 1.0), vec2<f32>( 0.0, -1.0),
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vec2<f32>( 1.0, 1.0), vec2<f32>(-1.0, 1.0),
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vec2<f32>( 1.0, -1.0), vec2<f32>(-1.0, -1.0),
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vec2<f32>( 2.0, 0.0), vec2<f32>(-2.0, 0.0),
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vec2<f32>( 0.0, 2.0), vec2<f32>( 0.0, -2.0),
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);
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var<private> KERNEL_WEIGHTS: array<f32, 13> = array<f32, 13>(
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0.5,
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0.25, 0.25, 0.25, 0.25,
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0.125, 0.125, 0.125, 0.125,
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0.0625, 0.0625, 0.0625, 0.0625,
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);
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@fragment
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fn fragment(in: VertexOutput) -> @location(0) vec4<f32> {
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let uv = in.uv;
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// Downsample and upsample share the same 13-tap weighted kernel.
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// mode 0 = down (plain weighted average), mode 1 = up (scaled by blend).
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var sum = vec3<f32>(0.0);
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var wsum = 0.0;
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for (var i: i32 = 0; i < 13; i = i + 1) {
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let off = KERNEL_OFFSETS[i] * u.texel_size;
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let c = textureSample(tex, samp, uv + off).rgb;
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sum = sum + c * KERNEL_WEIGHTS[i];
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wsum = wsum + KERNEL_WEIGHTS[i];
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}
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let blurred = sum / wsum;
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if (u.mode == 0u) {
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return vec4<f32>(blurred, 1.0);
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} else {
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return vec4<f32>(blurred * u.blend, 1.0);
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}
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}
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