debanding used in bit-crush demo

debanding.frag

#version 330 core

noperspective in vec2 vTexCoord;
uniform sampler2D uTexColor;
out vec4 FragColor;

float GradientNoise(in vec2 fragCoord)
{
  // from: https://www.shadertoy.com/view/lfyBWK
	return fract(52.9829189 * fract(dot(fragCoord, vec2(0.06711056, 0.00583715))));
}

void main()
{
    vec3 color = texture(uTexColor, vTexCoord).rgb;

    const float DITHER_AMOUNT = 1.0 / 255.0;
    color += DITHER_AMOUNT * GradientNoise(gl_FragCoord.xy);

    FragColor = vec4(color, 1.0);
}