LYGIA Shader Library

Dependencies:

• lygia/v1.1.4/math/absi.glsl
• lygia/v1.1.4/sample.glsl

Use:

<vec4> convolutionPyramidDownscale(<sampler2D> tex, <vec2> st, <vec2> pixel)

Check it on Github

#ifndef POISSONFILL_H1
#define POISSONFILL_H1 1.0334, 0.6836, 0.1507
#endif

#ifndef FNC_POISSONFILL_DOWNSCALE
#define FNC_POISSONFILL_DOWNSCALE
vec4 poissonFillDownscale(sampler2D tex, vec2 st, vec2 pixel) {
    const vec3 h1 = vec3(POISSONFILL_H1);

    vec4 color = vec4(0.0);
    for (int dy = -2; dy <= 2; dy++) {
        for (int dx = -2; dx <= 2; dx++) {
            vec2 uv = st + vec2(float(dx), float(dy)) * pixel;
            if (uv.x <= 0.0 || uv.x >= 1.0 || uv.y <= 0.0 || uv.y >= 1.0)
                continue;
            color += SAMPLER_FNC(tex, uv) * h1[ absi(dx) ] * h1[ absi(dy) ];
        }
    }

    return color;
}
#endif