playcanvas/build/playcanvas/src/scene/shader-lib/wgsl/chunks/render-pass/frag/volumetricFogCombine.d.ts

Open-source WebGL/WebGPU 3D engine for the web

declare const _default: "\n    #include \"screenDepthPS\"\n\n    varying uv0: vec2f;\n\n    var uFogTexture: texture_2d<f32>;\n    var uFogTextureSampler: sampler;\n    uniform uFogTextureSize: vec4f; // xy: fog texture resolution, zw: inverse resolution\n\n    @fragment\n    fn fragmentMain(input: FragmentInput) -> FragmentOutput {\n        var output: FragmentOutput;\n\n        let depth: f32 = getLinearScreenDepth(input.uv0);\n\n        // 4 nearest texel centers of the low resolution fog texture\n        let texel: vec2f = input.uv0 * uniform.uFogTextureSize.xy - 0.5;\n        let base: vec2f = (floor(texel) + 0.5) * uniform.uFogTextureSize.zw;\n        let f: vec2f = fract(texel);\n\n        var uvs: array<vec2f, 4>;\n        uvs[0] = base;\n        uvs[1] = base + vec2f(uniform.uFogTextureSize.z, 0.0);\n        uvs[2] = base + vec2f(0.0, uniform.uFogTextureSize.w);\n        uvs[3] = base + uniform.uFogTextureSize.zw;\n\n        let bilinear: vec4f = vec4f((1.0 - f.x) * (1.0 - f.y), f.x * (1.0 - f.y), (1.0 - f.x) * f.y, f.x * f.y);\n\n        // depth-aware upsample - weight the low resolution fog samples by depth similarity to\n        // avoid fog leaking across geometry edges\n        var sum: vec4f = vec4f(0.0);\n        var sumWeight: f32 = 0.0;\n        for (var i: i32 = 0; i < 4; i += 1) {\n            let sampleDepth: f32 = getLinearScreenDepth(uvs[i]);\n            let w: f32 = bilinear[i] / (1.0 + 16.0 * abs(sampleDepth - depth) / max(depth, 0.001));\n            sum += textureSampleLevel(uFogTexture, uFogTextureSampler, uvs[i], 0.0) * w;\n            sumWeight += w;\n        }\n\n        // rgb: in-scattered light, a: transmittance. Blended over the scene using\n        // scene * transmittance + inscatter.\n        output.color = sum / max(sumWeight, 0.0001);\n        return output;\n    }\n";
export default _default;