A Different Lighting Tutorial?

[locker]

Box-light is artificial. It lits a boxed volume with no attenuation. Kinda like
an ambient light with limits.
Point light is a "point in space" that emits light to every direction from the point. Usually it has attenuation. I think Amnesia has quadratic attenuation , but it could be linear(not very natural) and other types of non linear attenuation based on some funky formulas
Spot light is point light that has limits and direction. Basically if the dot product between the ray from pixel in world space to the light position and the direction ray of the light itself is greater than some value, then the pixel is not lit. There could some attenuation by distance from the light and distance from the center of the light spot etc.
Directional light (sun light) has no position, only a direction, but I think HPL2 does not expose these.