Generated Noise pattern for dithering

NoiseDithering.glsl

vec2 rand(vec2 coord, vec2 uv, float noiseamount, bool noise) {
        float noiseX = ((fract(1.0-coord.s*(uv.x/2.0))*0.25)+(fract(coord.t*(uv.y/2.0))*0.75))*2.0-1.0;
        float noiseY = ((fract(1.0-coord.s*(uv.x/2.0))*0.75)+(fract(coord.t*(uv.y/2.0))*0.25))*2.0-1.0;
        if (noise) {
                noiseX = clamp(fract(sin(dot(coord ,vec2(12.9898,78.233))) * 43758.5453),0.0,1.0)*2.0-1.0;
                noiseY = clamp(fract(sin(dot(coord ,vec2(12.9898,78.233)*2.0)) * 43758.5453),0.0,1.0)*2.0-1.0;
        }
        return vec2(noiseX,noiseY)*noiseamount;
}