#ifndef PI
#define PI          3.14159265358979
#define PI_SQUARE   ( PI * PI )
#endif

// All our vectors have been normalized
vec4 diffuseReflectionBSDF(in vec3 N, in vec3 L, in vec3 lightDiffuse)
{
    float factor = max(0.0, dot(N, L));
    return vec4(factor * lightDiffuse, 1.0);
}