playcanvas/build/playcanvas.dbg/src/scene/shader-lib/chunks/lightmapper/frag/bilateralDeNoise.js

PlayCanvas WebGL game engine

var bilateralDeNoisePS = "\n// bilateral filter, based on https://www.shadertoy.com/view/4dfGDH# and\n// http://people.csail.mit.edu/sparis/bf_course/course_notes.pdf\n\n// A bilateral filter is a non-linear, edge-preserving, and noise-reducing smoothing filter for images.\n// It replaces the intensity of each pixel with a weighted average of intensity values from nearby pixels.\n// This weight can be based on a Gaussian distribution. Crucially, the weights depend not only on\n// Euclidean distance of pixels, but also on the radiometric differences (e.g., range differences, such\n// as color intensity, depth distance, etc.). This preserves sharp edges.\n\nfloat normpdf3(in vec3 v, in float sigma) {\n    return 0.39894 * exp(-0.5 * dot(v, v) / (sigma * sigma)) / sigma;\n}\n\nvec3 decodeRGBM(vec4 rgbm) {\n    vec3 color = (8.0 * rgbm.a) * rgbm.rgb;\n    return color * color;\n}\n\nfloat saturate(float x) {\n    return clamp(x, 0.0, 1.0);\n}\n\nvec4 encodeRGBM(vec3 color) { // modified RGBM\n    vec4 encoded;\n    encoded.rgb = pow(color.rgb, vec3(0.5));\n    encoded.rgb *= 1.0 / 8.0;\n\n    encoded.a = saturate( max( max( encoded.r, encoded.g ), max( encoded.b, 1.0 / 255.0 ) ) );\n    encoded.a = ceil(encoded.a * 255.0) / 255.0;\n\n    encoded.rgb /= encoded.a;\n    return encoded;\n}\n\nvec3 decode(vec4 pixel) {\n    #if HDR\n        return pixel.rgb;\n    #else\n        return decodeRGBM(pixel);\n    #endif\n}\n\nbool isUsed(vec4 pixel) {\n    #if HDR\n        return any(greaterThan(pixel.rgb, vec3(0.0)));\n    #else\n        return pixel.a > 0.0;\n    #endif\n}\n\n// filter size\n#define MSIZE 15\n\nvarying vec2 vUv0;\nuniform sampler2D source;\nuniform vec2 pixelOffset;\nuniform vec2 sigmas;\nuniform float bZnorm;\nuniform float kernel[MSIZE];\n\nvoid main(void) {\n    \n    vec4 pixel = texture2DLod(source, vUv0, 0.0);\n\n    // lightmap specific optimization - skip pixels that were not baked\n    // this also allows dilate filter that work on the output of this to work correctly, as it depends on .a being zero\n    // to dilate, which the following blur filter would otherwise modify\n    if (!isUsed(pixel)) {\n        gl_FragColor = pixel;\n        return ;\n    }\n\n    // range sigma - controls blurriness based on a pixel distance\n    float sigma = sigmas.x;\n\n    // domain sigma - controls blurriness based on a pixel similarity (to preserve edges)\n    float bSigma = sigmas.y;\n\n    vec3 pixelHdr = decode(pixel);\n    vec3 accumulatedHdr = vec3(0.0);\n    float accumulatedFactor = 0.000001;  // avoid division by zero\n\n    // read out the texels\n    const int kSize = (MSIZE-1)/2;\n    for (int i = -kSize; i <= kSize; ++i) {\n        for (int j = -kSize; j <= kSize; ++j) {\n            \n            // sample the pixel with offset\n            vec2 coord = vUv0 + vec2(float(i), float(j)) * pixelOffset;\n            vec4 pix = texture2DLod(source, coord, 0.0);\n\n            // lightmap - only use baked pixels\n            if (isUsed(pix)) {\n                vec3 hdr = decode(pix);\n\n                // bilateral factors\n                float factor = kernel[kSize + j] * kernel[kSize + i];\n                factor *= normpdf3(hdr - pixelHdr, bSigma) * bZnorm;\n\n                // accumulate\n                accumulatedHdr += factor * hdr;\n                accumulatedFactor += factor;\n            }\n        }\n    }\n\n    vec3 finalHDR = accumulatedHdr / accumulatedFactor;\n\n    #if HDR\n        gl_FragColor = vec4(finalHDR, 1.0);\n    #else\n        gl_FragColor = encodeRGBM(finalHDR);\n    #endif\n}\n";

export { bilateralDeNoisePS as default };