45 lines
1.9 KiB
WebGPU Shading Language
45 lines
1.9 KiB
WebGPU Shading Language
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// HDRBloom closest-hit (runs in SHADE). Half the cubes are "emitters" that
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// accumulate a strongly super-1.0 radiance (the HDR signal a bloom pass
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// extracts); the rest are dim Lambert-shaded fillers near/below 1.0 that the
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// threshold rejects. The linear accumulator is what RESOLVE writes into the
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// rgba16float scene target — no tonemap here.
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//
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// Payload declared here so the assembler sees it before wfPayload / SHADE.
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struct Payload {
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color: vec3<f32>,
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};
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const SUN_DIR_TO_LIGHT: vec3<f32> = vec3<f32>(0.40, 0.85, 0.35);
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const AMBIENT_COLOR: vec3<f32> = vec3<f32>(0.10, 0.11, 0.16);
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// Distinct per-instance hue so emitters read as different coloured glows.
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fn instanceAlbedo(i: u32) -> vec3<f32> {
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let h = i * 2654435761u;
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return vec3<f32>(
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0.35 + 0.6 * f32((h >> 0u) & 255u) / 255.0,
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0.35 + 0.6 * f32((h >> 8u) & 255u) / 255.0,
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0.35 + 0.6 * f32((h >> 16u) & 255u) / 255.0);
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}
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fn closesthit_main(ray: RayDesc, hit: HitInfo, payload: ptr<function, Payload>) {
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let meshRec = meshRecords[tlasEntries[hit.instanceId].blasMeshIdx];
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let verts = _rtFetchTri(meshRec, hit.primitiveId);
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let nObj = normalize(cross(verts[1] - verts[0], verts[2] - verts[0]));
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let nWorld = normalize(vec3<f32>(
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dot(hit.objectToWorldR0.xyz, nObj),
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dot(hit.objectToWorldR1.xyz, nObj),
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dot(hit.objectToWorldR2.xyz, nObj)));
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let albedo = instanceAlbedo(hit.customIndex);
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let viewDir = -ray.direction;
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let nFacing = select(-nWorld, nWorld, dot(nWorld, viewDir) > 0.0);
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let nDotL = max(0.0, dot(nFacing, normalize(SUN_DIR_TO_LIGHT)));
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// Every third cube is a bright emitter (HDR, > 1.0); the rest stay dim.
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if ((hit.customIndex % 3u) == 0u) {
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// View-independent emission so the whole face glows uniformly.
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rtAccumulate(albedo * 9.0);
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} else {
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rtAccumulate(albedo * (AMBIENT_COLOR + vec3<f32>(0.55 * nDotL)));
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}
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}
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