//go:build ignore

//kage:unit pixels

package main

var Time float
var Cursor vec2

const noiseX = 80.0
const noiseY = 100.0

const colorOffsetIntensity = 1.2

func rand(co vec2) float {
    return fract(sin(dot(co.xy, vec2(12.9898,78.233))) * 43758.5453);
}

func Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {
    noiseOffset := Time / 7
    col := vec4(0)
    uv := srcPos / imageSrc0Size()

    uv.x = uv.x + (rand(vec2(Time,srcPos.y)) - 0.5) / (noiseX); 
    uv.y = uv.y + (rand(vec2(Time))-0.5) / (noiseY);

    whiteNoise := rand(vec2(floor(uv.y*80.0),floor(uv.x*50.0))+vec2(Time,0))
    off := 1.0 - mod(uv.y - noiseOffset, 1)

    if (whiteNoise > 11.5-30.0*(off)) || whiteNoise < 1.5-2.0*(off) {
        // Sample the texture.

        offsetR := vec2(0.006 * sin(Time), 0.0) * colorOffsetIntensity;
        offsetG := vec2(0.0073 * (cos(Time * 0.97)), 0.0) * colorOffsetIntensity;
        r := imageSrc0UnsafeAt((uv+offsetR) * imageSrc0Size()).r
        g := imageSrc0UnsafeAt((uv+offsetG) * imageSrc0Size()).g
        b := imageSrc0UnsafeAt(uv * imageSrc0Size()).b
        return vec4(r, g, b, 1.0)
    } else {
    	col = imageSrc2UnsafeAt(uv * imageSrc0Size());
        return col + vec4(0.8);
    }

}