webcam_backbuffer_final_theforce.glsl

float circ( vec2 p){
    
    return length(p) - 0.3;
}
void pR(inout vec2 p, float a) {
    p = cos(a)*p + sin(a)*vec2(p.y, -p.x);
}
// Repeat in two dimensions
vec2 pMod2(inout vec2 p, vec2 size) {
    vec2 c = floor((p + size*0.5)/size);
    p = mod(p + size*0.5,size) - size*0.5;
    return c;
}
// http://www.iquilezles.org/www/articles/palettes/palettes.htm
// As t runs from 0 to 1 (our normalized palette index or domain), 
//the cosine oscilates c times with a phase of d. 
//The result is scaled and biased by a and b to meet the desired constrast and brightness.
vec3 cosPalette( float t, vec3 a, vec3 b, vec3 c, vec3 d )
{
    return a + b*cos( 6.28318*(c*t+d) );
}

void main () {
    vec2 pos = uv();

    pR(pos,time);
    
    pMod2(pos, vec2(2.0,2.0));
    
    pos = pos + vec2(0.4,0.);
    
    float shape = circ(pos);
    
    vec3 brightness = vec3(0.3);
    vec3 contrast = bands.xyz;
    vec3 osc = vec3(0.5,1.0,0.0);
    vec3 phase = vec3(0.4,0.9,0.2);
    
    vec4 web = texture2D(channel0,uvN());
    
    vec3 col = cosPalette((time/4.0) + shape, brightness, contrast, osc, phase );
    
    col = col * shape;
    
    vec4 prev = texture2D(backbuffer, uvN() + .002);
    
   col = mix(web,prev, col.x ).rgb;
    
    if (web.x < 0.4){
        col = prev.rbg;
        
    }
    
    gl_FragColor = vec4(col,1.) ;
    
}