37 lines
1.4 KiB
WebGPU Shading Language
37 lines
1.4 KiB
WebGPU Shading Language
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// RTVolume closest-hit (runs in SHADE). Shades the procedural sphere by
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// its surface normal with a fixed sun + ambient, tinted per instance.
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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 SUN_COLOR: vec3<f32> = vec3<f32>(1.20, 1.10, 0.95);
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const AMBIENT_COLOR: vec3<f32> = vec3<f32>(0.16, 0.18, 0.24);
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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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// Object-space hit point on the unit sphere is its object-space normal.
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let posObj = hit.objectRayOrigin + hit.objectRayDirection * hit.t;
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let nObj = normalize(posObj);
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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 sunDir = normalize(SUN_DIR_TO_LIGHT);
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let nDotL = max(0.0, dot(nFacing, sunDir));
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rtAccumulate(albedo * (AMBIENT_COLOR + SUN_COLOR * nDotL));
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}
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