solarpunk-raymarch.glsl

 float smallNumber = 0.01;
 
 float scene(vec3 p){
     vec3 q = fract(p) *4. -1.;
     float sphere = length(p)-abs(sin(time*0.1)*2.);
     
     float planeDist =p.y +2.;
    
    
    
    return min(sphere,planeDist);
}

 vec3 estimateNormal(vec3 p) {
    vec2 e = vec2 (smallNumber, 0.);
    
    vec3 n = scene(p)- vec3(
        scene(p-e.xyy),
        scene(p-e.yxy),
        scene(p-e.yyx));

    return normalize(n);
}

const float MD = 30.;

float trace(vec3 origin, vec3 r){
    vec3 lightDirection = vec3(0.5);
    float roughness = 3.5;
    float albedo = .1;
    float t = 0.;
    for(int i=0; i < 32; ++i){
        vec3 p = origin + r * t;
        float d = scene(p);
        t += d;
        if (t > MD || d < 0.01) break; 
     }
    
    return t;
}

float getLight(vec3 p){
    vec3 lightPos = vec3(cos(time/2.)*2.,4.,  sin(time/2.)*2.);
    
    vec3 l = normalize(lightPos-p);
    vec3 n = estimateNormal(p);
    float d = trace(p+n*0.2, l);
    float dif = clamp(dot(n,l),0.,1.);
    
    if (d<length(lightPos - p)) dif *= .5;
    
    return dif;
}


void main()
{
    vec3 pos = vec3(uv(),.8);
    vec4 color;
    vec3 camOrigin = vec3(0.,3., -9.);
    vec3 rayOrigin = normalize(pos);
    
    float t = trace(camOrigin, rayOrigin);
    
    vec3 p = camOrigin + rayOrigin *t;
    float dif = getLight(p);

    color = vec4(dif);
   
    
    gl_FragColor = color;
}