sample_photon

Context(s)	displace fog light shadow surface

int  sample_photon(light lp, vector &pos, vector &dir, float &scale, float time)

Spawns a photon from the given light source and returns the information for the first intersection in the scene. The pos, dir and scale are filled out with the information about where the photon hit in the scene.

The returned integer represents the bounce type mask (this is determined by the types of illumination labels on the light source).

The function returns 0 if the photon didn’t intersect any geometry.