Fixed bug #1026 Vittorio Giovara 2010-07-16 19:09:28 PDT i was reading SDL_renderer_gles and i noticed that every time we there is some gl call the gl state is modified with a couple of glEnableClientState()/glDisableClientState. While this is completely fine for desktops systems, this is a major performace kill on mobile devices, right where opengles is implemented. Normal practice in this case is to update the glstate once, keep it always the same and disable/enable other states only in very special occasions. On the web there's plenty of documentation (on the top of my head http://developer.apple.com/iphone/library/documentation/3DDrawing/Conceptual/OpenGLES_ProgrammingGuide/Performance/Performance.html#//apple_ref/doc/uid/TP40008793-CH105-SW5 ) and i personally tried this. I modified my code and got a 10 fps boost, then modified SDL_render_gles and shifted from 40 fps to 50 fps alone -- considering that i started from ~30fps i got an 80% performance increase with this technique. I have attached a dif of my changes, hope that it will be included in mainstream.

To compile and install SDL:

    0.  If you have downloaded this from the website, skip to the next step.
        If you have checked this out from subversion, you'll need to run
        ./autogen.sh to build the configure script. 

    1.  Run './configure; make; make install'

        If you are compiling for Windows using gcc, read the FAQ at:
        http://www.libsdl.org/faq.php?action=listentries&category=4#42

        If you are compiling using Visual C++ on Win32, you should read
        the file VisualC.html

    2.  Look at the example programs in ./test, and check out the HTML
        documentation in ./docs to see how to use the SDL library.

    3.  Join the SDL developer mailing list by sending E-mail to
    	sdl-request@libsdl.org
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That's it!
Sam Lantinga <slouken@libsdl.org>