__device__ Spectrum SampleLi(const Interaction& it, const float u[2], glm::vec3* wi, float* pdf)
{
	*wi = glm::normalize(position - it.point);
	*pdf = 1.0f;
	return I / glm::pow(glm::length(position - it.point), 2); //Irradiance / DistanceSquared -> radiance decreases over distance
}