shadermeh/shaders/mandelbrot.frag

#define MAX_ITERATIONS 1024

void mainImage(out vec4 fragColor, in vec2 fragCoord)
{
    float s = exp(-iTime / 2.0);
    vec2 c = vec2(-0.770007,0.100001);
    vec2 z = vec2(0.0);
    vec2 del = (2.0 * fragCoord/iResolution.xy - 1.0) * s;
    del.x /= (iResolution.y / iResolution.x);
    vec2 eps = vec2(0.0);
    
    int iterations = 0;
    while (length(z + eps) < 2.0 && iterations < MAX_ITERATIONS) {
        eps = 2.0*vec2(z.x*eps.x - z.y*eps.y, z.x*eps.y + z.y*eps.x) + vec2(eps.x*eps.x - eps.y*eps.y, 2.0*eps.x*eps.y) + del;
        z = vec2(z.x*z.x - z.y*z.y, 2.0*z.x*z.y) + c;
        if (length(eps) > 100.0) {
            z += eps;
            eps = vec2(0.0);
            }
        iterations += 1;
    }
    
    
    // Output to screen
    fragColor = vec4(vec3(float(iterations) / float(MAX_ITERATIONS)), 1.0);
}