precision mediump float;

#endif

​

uniform vec2 iResolution;

uniform int iFrame;

uniform vec2 iMouse;

uniform float iTime;

​

uniform float zoom;

​

​

// Anaglyph Structure

// Framed for https://fanzine.cookie.paris/

// Licensed under hippie love conspiracy

// Leon Denise (ponk) 2019.10.24

// Using code from Inigo Quilez

​

mat2 rot (float a) { float c=cos(a),s=sin(a); return mat2(c,-s,s,c); }

float random (in vec2 st) { return fract(sin(dot(st.xy,vec2(12.9898,78.233)))*43758.5453123); }

​

vec3 look (vec3 eye, vec3 target, vec2 anchor) {

    vec3 forward = normalize(target-eye);

    vec3 right = normalize(cross(forward, vec3(0,1,0)));

    vec3 up = normalize(cross(right, forward));

    return normalize(forward * .5 + right * anchor.x + up * anchor.y);

}

​

​

float map (vec3 pos) {

    float scene = 2.0;

    float r = 1.0;

    const float count = 5.0;

    for (float index = count; index > 0.0; --index)

    {

        pos.xz = abs(pos.xz)-1.5*r;

        pos.xz *= rot(0.4/r + iTime * 0.1);

        pos.yz *= rot(1.5/r + iTime * 0.05);

        pos.yx *= rot(.2/r + iTime * 0.05);

        // pos.yz -=  zoom*.01;

        scene = min(scene, length(pos.xy)-0.001);

        scene = min(scene, length(pos)-0.3*r);

        r /= 1.8;

    }

    return scene;

}

​

vec4 raymarch (vec3 eye, vec3 ray) {

    float dither = random(ray.xy+fract(iTime));

    vec4 result = vec4(eye, 0);

    float total = 0.0;

    float maxt = 20.0;

    const float count = 30.;

    for (float index = count; index > 0.0; --index) {

        result.xyz = eye + ray * total;

        float dist = map(result.xyz);

        if (dist < 0.001 + total * .002 || total > maxt) {

            result.w = index / count;

            break;

        }

        dist *= 0.9 + 0.1 * dither;

        total += dist;

    }

    result.w *= step(total, maxt);

    return result;

}

​

​

  void main()

{

//void mainImage( out vec4 fragColor, in vec2 fragCoord ){

    vec2 uv = (gl_FragCoord.xy-0.5*iResolution.xy)/iResolution.y;

    vec3 eye = vec3(.13,0.95,-2. );

   // eye = vec3(iMouse.x*.01,iMouse.y*.01,.2);

     uv.x += (iMouse.x-.5)*-.952;

    uv.y += (iMouse.y-.5)*-.952;

    vec3 at = vec3(0);

    vec3 ray = look(eye, at, uv);

    vec3 eyeoffset = 0.01*normalize(cross(normalize(at-eye), vec3(0,1,0)));

​

    vec4 resultLeft = raymarch(eye-eyeoffset, ray);

    vec4 resultRight = raymarch(eye+eyeoffset, ray);

     gl_FragColor = vec4(resultLeft.w,vec2(resultRight.w),1);

}