​

uniform vec2 resolution;

uniform float time;

uniform vec2 mouse;

uniform sampler2D backbuffer;

​

vec2 map(vec3 p){

    vec2 o = vec2(10.,0.);

    o.x = length(p) - 1.;

    return o;

}

​

vec2 march(vec3 cp , vec3 rd){

    float depth = 0.;

    for(int i = 0 ; i < 99; i++){

        vec2 d = map(cp + rd * depth);

        if(abs(d.x) < 0.001){

            return vec2(depth , d.y);

        }

        depth += d.x;

    }

    return vec2(-depth);

}

​

void main(void) {

    vec2 p = (gl_FragCoord.xy * 2.0 - resolution.xy) / min(resolution.x, resolution.y);

    vec3 cp = vec3(0.,0.,-5.);

    vec3 target = vec3(0.,0.,0.);

    vec3 cd = normalize(target - cp);

    vec3 cu = normalize(vec3(0.,1.,0.) );

    vec3 cs = normalize(cross(cu,cd));

    float fov = 2.5;

    vec3 rd = normalize(cs * p.x + cu * p.y + cd * fov);

    vec3 color = vec3(0.);