jointBilateral (`lygia`/`filter`/`jointBilateral`)

Joint Bilateral Filter This is a joint bilateral filter that uses a 2D gaussian kernel to approximate the bilateral filter. It is based on the paper "Fast Bilateral Filtering for the GPU" Interesting article about it and their uses: https://bartwronski.com/2019/09/22/local-linear-models-guided-filter/

Dependencies:

Use:

``````bilateralBlur(<SAMPLER_TYPE> texture, <vec2> st, <vec2> duv)
``````

Check it on Github

``````

#ifndef JOINTBILATERAL_TYPE
#define JOINTBILATERAL_TYPE vec4
#endif

#ifndef JOINTBILATERAL_SAMPLE_FNC
#define JOINTBILATERAL_SAMPLE_FNC(TEX, UV) sampleClamp2edge(TEX, UV)
#endif

#ifndef JOINTBILATERAL_TYPEGUIDE
#define JOINTBILATERAL_TYPEGUIDE vec3
#endif

#ifndef JOINTBILATERAL_SAMPLEGUIDE_FNC
#define JOINTBILATERAL_SAMPLEGUIDE_FNC(TEX, UV) sampleClamp2edge(TEX, UV).rgb
#endif

// #ifndef JOINTBILATERAL_KERNELSIZE
// #define JOINTBILATERAL_KERNELSIZE 9
// #endif

#ifndef JOINTBILATERAL_INTENSITY_SIGMA
#define JOINTBILATERAL_INTENSITY_SIGMA 0.026
#endif

#ifndef FNC_JOINTBILATERAL
#define FNC_JOINTBILATERAL

JOINTBILATERAL_TYPE jointBilateral(SAMPLER_TYPE tex, SAMPLER_TYPE guide, vec2 uv, vec2 pixel, const int kernelSize) {
JOINTBILATERAL_TYPEGUIDE centerGuide = JOINTBILATERAL_SAMPLEGUIDE_FNC(guide, uv);

#ifndef JOINTBILATERAL_KERNELSIZE

#if defined(PLATFORM_WEBGL)
#define JOINTBILATERAL_KERNELSIZE 20
float kernelSizef = float(kernelSize);
#else
#define JOINTBILATERAL_KERNELSIZE kernelSize
float kernelSizef = float(JOINTBILATERAL_KERNELSIZE);
#endif

#else
float kernelSizef = float(JOINTBILATERAL_KERNELSIZE);
#endif

JOINTBILATERAL_TYPE sum = JOINTBILATERAL_TYPE(0.0);
float weight = 0.0;
const float k = 0.15915494; // 1 / (2*PI)
for (int j = 0; j < JOINTBILATERAL_KERNELSIZE; j++) {
#if defined(PLATFORM_WEBGL)
if (j >= kernelSize)
break;
#endif
float y = -.5 * (kernelSizef - 1.) + float(j);
for (int i = 0; i < JOINTBILATERAL_KERNELSIZE; i++) {
#if defined(PLATFORM_WEBGL)
if (i >= kernelSize)
break;
#endif
float x = -.5 * (kernelSizef - 1.) + float(i);

vec2 xy = uv + vec2(x, y) * pixel;
JOINTBILATERAL_TYPE sample = JOINTBILATERAL_SAMPLE_FNC(tex, xy);
JOINTBILATERAL_TYPEGUIDE sampleGuide = JOINTBILATERAL_SAMPLEGUIDE_FNC(guide, xy);

float w = 1.0;
// w *= (k / kernelSizef) * exp(-(x * x + y * y) / (2. * kernelSize2));
w = (k / kernelSizef) * gaussian(vec2(x, y), kernelSizef);
w *= gaussian(centerGuide - sampleGuide, JOINTBILATERAL_INTENSITY_SIGMA);
sum += sample * w;
weight += w;
}
}

return sum / weight;
}

#endif

``````