I'm trying to push my FPS up on iPhone 3Gs from 30 as high as possible... and I'm running into a couple of issues and thought it would be better to ask for advice.
1) What exactly do the Renderer Utilization and Tiler Utilization columns on the OpenGL ES Instrument signify? My Tiler Utiliation percentage is extremely low, and my Renderer Utilization tends to drop during user interaction and when the app is flipped to landscape mode. I noticed that my FPS tends to drop whenever the Renderer Utilization value drops as well. My FPS dropping during landscape mode is particularly odd for me, because portrait mode and landscape mode use the exact same game logic, and textures... and landscape mode actually renders fewer vertices/triangles to boot (some parts of the UI aren't drawn at all in landscape mode).
2) I've already done most of the recommended optimizations in the ngmoco/Stanford videos, and the only things I think I can do left are changing GLfloats to GLshorts and interleaving my vertices with my texture coordinates into one array. Are any of these likely to have large effects on my FPS? It's a 2D sprite game with lots of large, detailed textures...
3) Which is a faster way to hide a polygon: setting all of its vertices to the same coordinates (essentially, reducing it to a point), or setting its alpha value to 0? I'm guessing its the former, since blending is slower in general and particularly expensive on the iPhone.
4) Currently, I'm using a 2 512x512 textures, a 1024x512 texture, and a 256x256 texture. I've sought advice on how to best manage this, and I was told not to combine them into 1 1024x1024 texture because of memory problems on the iPhone 3G. I'd like to confirm that here, because if I put everything into 1 texture, I can eradicate having to call glBindTexture repeatedly...