Just a quick update - finally finished the deferred rendering system for Battle Balloons! Guerilla Games has a good presentation for Killzone 2 on the theory behind it - but mine is not as advanced. Not much to show as it's pretty much all under-the-hood at the moment. But this excites me because I no longer need to worry about how to limit the number of lights in the game - they can now be practically unlimited. I went with a fairly simple approach:
- the scene normals are rendered in RGB as-is (if it's good enough precision for Insomniac Games' Resistance 2, then it's good enough for me!),
- pixel world position is derived from the 2D screen co-ordinates and depth buffer value, and
- lighting happens in two stages: a spherical mesh is first rendered for each light onto the stencil buffer and the light shading is then calculated for each pixel not masked out by the stencil.