This is more a theoretical question, no code has been written down yet. Let's assume I want to create a dynamic environment and I want to use vertex buffers to draw things so I will be able to use vertex shaders to create some effects. Of course there is going to be a need to have many different textures and the game will have to swap between them alot. And my question is - how expensive is this operation? Let's say that in the worst scenario I could possible have even 20+ separated texture pages. Would it be worth to build some kind of a priority system which would draw all things that use the same texture page so the game doesn't need to swap that much?