vec3 Mandelbox()

in src/elm_src/Algorithm/fractals.c [335:375]

• 21 lines of code
• 3 McCabe index (conditional complexity)

vec3 Mandelbox(vec3 w)
{
    w *= objectRotation;
    float md = 1000.0;
    vec3 c = w;

    // distance estimate
    vec4 p = vec4(w.xyz, 1.0),
        p0 = vec4(w.xyz, 1.0);  // p.w is knighty's DEfactor

    for (int i = 0; i < int(maxIterations); i++) {
        // box fold:
        // if (p > 1.0) {
        //   p = 2.0 - p;
        // } else if (p < -1.0) {
        //   p = -2.0 - p;
        // }
        p.xyz = clamp(p.xyz, -boxFold, boxFold) * 2.0 * boxFold - p.xyz;  // box fold
        p.xyz *= fractalRotation1;

        // sphere fold:
        // if (d < minRad2) {
        //   p /= minRad2;
        // } else if (d < 1.0) {
        //   p /= d;
        // }
        float d = dot(p.xyz, p.xyz);
        p.xyzw *= clamp(max(fR2 / d, mR2), 0.0, 1.0);  // sphere fold

        p.xyzw = p * scaleFactor.xxxy + p0 + vec4(offset, 0.0);
        p.xyz *= fractalRotation2;

        if (i < colorIterations) {
            md = min(md, d);
            c = p.xyz;
        }
    }

    // Return distance estimate, min distance, fractional iteration count
    return vec3((length(p.xyz) - fudgeFactor) / p.w, md, 0.33 * log(dot(c, c)) + 1.0);
}