neercs/neercs/video/noise.lolfx

[vert.glsl]

#version 120

void main()
{
    gl_Position = gl_Vertex;
}

[frag.glsl]

#version 120

uniform sampler2D texture;
uniform vec2 screen_size;
uniform float time;
uniform vec2 offset;
uniform float noise;
uniform vec3 retrace;

float rand(in vec2 p, in float t, in float v)
{
    return fract(sin(dot(p + mod(t, 1.0), vec2(12.9898, 78.2333))) * v);
}

void main(void)
{
    vec2 p=gl_FragCoord.xy/screen_size.xy;

    float r1=rand(p,time,43758.5453);
    float r2=rand(p,time,70425.2854);
    vec2 o=(offset-offset*2.0*r1)/screen_size;

    vec3 c=texture2D(texture,p+o).xyz;                          // offset
    c*=1.0+(noise-noise*2.0*r1);                                // noise
    c-=retrace.x*0.01*mod(p.y*retrace.y+time*retrace.z,1.0);    // retrace
    gl_FragColor=vec4(c,1.0);
}