(graphics): speedup depth peeling
Description
All depth peeling could be enhanced by rendering the depth at the same time as the color using multiple render targets (MRTs).
Proposal
- Enhance the depth peeling, dual depth peeling and hybrid depth peeling using MRTs
- Use the
PF_DEPTH32F
pixel format (available in Ogre > 1.12.2) for depth to avoid float packing.