- fixed: The light buffer index must not be reset between rendering a camera texture and the main scene.

Since rendering is asynchronous, the camera texture scene may not be finished once the main scene's lights get filled in. Unfortunately forcing a synchronization with glFinisg has bad side effects on performance the only remaining option is to use separate parts of the buffer for both scenes, which in extreme cases may increase the light buffer's size - but on modern hardware that shouldn't be a problem.