Add shadowing to point light shader.
Add shadowing to point light shader.

We use the same approach than for other lights, but using a cubemap and computing the light-to-point vector in world space to query the map and check which areas are occluded.


Former-commit-id: 16cc4966ed94fb0130a536054904ff663f5e2acc
kosua20/GL_Template,kosua20/GL_Template