Resource management

[PearCoding]

We have the luxury to handle all resource input and output via an interface. The GPU is quite memory limited. It would be a great enhancement (and the only option for some scenes) to load and unload resources depending their use.

Each shader instance is synchronized. So, build a resource map for each shader stage and only unload from "idle" resources if they are not in the current shader resource map and free memory is low. This can be done fully automatic without changing the scene loading process.