Introduces per vertex flags for chunks. This should increase the overall performance as well as the performance when using one of the higher quality settings.
Vertex flags can be used to store information about each chunk vertex on a per-block basis. Previously the chunk shader had to to utilize the available texture coordinates to look up the currently relevant texture in the texture atlas - to detect water blocks for example (and thus to enable water reflections for some of the vertices). Or a large array of texture coordinates had to be transferred to the GPU just to detect if a block is waving or not (which is REALLY slow). Using chunk flags a more or less infinite amount of waving blocks can be created on engine side at almost no costs on GPU side. Let's see how many users have the necessary GLSL version available...