Texture Swapping and Efficiency


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?


On today's PCs you shouldn't have any problem even with 30 swaps. Mobile and certain other handheld devices may struggle though.