Relative SDF operations: 

• Limited repeat

  • Symmetric

  • Smooth Edge

Reference:

https://youtu.be/Ff0jJyyiVyw?si=S7J2ojxUnMRxJbk1

https://iquilezles.org/articles/distfunctions/

vec3 subsurfaceColor(vec3 lightDir, vec3 normal, vec3 viewVec, float thin) {

    vec3 scatterDir = lightDir + normal * DISTORTION; // Last term is tunable

    float lightReachingEye = pow(clamp(dot(viewVec, -scatterDir),

                                 0.0, 1.0), GLOW) * SCALE;

    float attenuation = max(0.0, dot(normal, lightDir)

                             + dot(viewVec, -lightDir));

    float totalLight = attenuation * (lightReachingEye + AMBIENT) * thin;

    return material.albedo * light.color * totalLight;

}