SDF Normal calculation

sdfnormal.glsl

// Slow to compile

vec3 calcNormalA(vec3 pos){
    vec3 eps = vec3(.0001,0,0);
    vec3 nor = vec3(
        map(pos+eps.xyy).dist - map(pos-eps.xyy).dist,
        map(pos+eps.yxy).dist - map(pos-eps.yxy).dist,
        map(pos+eps.yyx).dist - map(pos-eps.yyx).dist
    );
    return normalize(nor);
}


// Fast to compile

const int NORMAL_STEPS = 6;

vec3 calcNormalB(vec3 pos){
    vec3 eps = vec3(.0001,0,0);
    vec3 nor = vec3(0);
    float invert = 1.;
    for (int i = 0; i < NORMAL_STEPS; i++){
        nor += map(pos + eps * invert).dist * eps * invert;
        eps = eps.zxy;
        invert *= -1.;
    }
    return normalize(nor);
}