iPhone openGLES performance tuning
- by genesys
Hey there!
I'm trying now for quite a while to optimize the framerate of my game without really making progress. I'm running on the newest iPhone SDK and have a iPhone 3G 3.1.2 device.
I invoke arround 150 drawcalls, rendering about 1900 Triangles in total (all objects are textured using two texturelayers and multitexturing. most textures come from the same textureAtlasTexture stored in pvrtc 2bpp compressed texture).
This renders on my phone at arround 30 fps, which appears to me to be way too low for only 1900 triangles.
I tried many things to optimize the performance, including batching together the objects, transforming the vertices on the CPU and rendering them in a single drawcall. this yelds 8 drawcalls (as oposed to 150 drawcalls), but performance is about the same (fps drop to arround 26fps)
I'm using 32byte vertices stored in an interleaved array (12bytes position, 12bytes normals, 8bytes uv). I'm rendering triangleLists and the vertices are ordered in TriStrip order.
I did some profiling but I don't really know how to interprete it.
instruments-sampling
using Instruments and Sampling yelds this result:
http://neo.cycovery.com/instruments_sampling.gif
telling me that a lot of time is spent in "mach_msg_trap". I googled for it and it seems this function is called in order to wait for some other things. But wait for what??
instruments-openGL
instruments with the openGL module yelds this result:
http://neo.cycovery.com/intstruments_openglES_debug.gif
but here i have really no idea what those numbers are telling me
shark profiling:
profiling with shark didn't tell me much either:
http://neo.cycovery.com/shark_profile_release.gif
the largest number is 10%, spent by DrawTriangles - and the whole rest is spent in very small percentage functions
Can anyone tell me what else I could do in order to figure out the bottleneck and could help me to interprete those profiling information?
Thanks a lot!
