So I'm trying to apply a bloom to a UISprite background at the beginning of a scene and store the result in a RenderTexture and then on a separate camera have a draggable UISprite- in an OnRenderImage function on that camera I take the static background RenderTexture and composite the source of the camera onto it with a special shader using Graphics.Blit, sending the result to the destination. The problem is, the fps seems to be in the 1-2 range on iPads, higher generations being worse than the lower. It has been suggested that this is due to the poor fill rate to resolution ratio on the iPads and that seems plausible- it is significantly faster on iPhones- however I am having a hard time believing that one Graphics.Blit basically destroys the performance. I am new to iOS development but I thought I've seen post processing effects on iOS games before but would that even be possible if you can't blit once per frame?
I would appreciate your thoughts on this issue because I am completely stumpted. I've tried setting the textures involved to RGBA PVRTC 4 bit and messing with lots of miscellaneous settings that I've read may improve performance but nothing makes a significant enough difference.
Thanks.
