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.

/* Print out all the scancodes we have, just to verify them */

#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>

#include "SDL.h"

int
main(int argc, char *argv[])
{
    SDL_scancode scancode;

    if (SDL_Init(SDL_INIT_VIDEO) < 0) {
        fprintf(stderr, "Couldn't initialize SDL: %s\n", SDL_GetError());
        exit(1);
    }
    for (scancode = 0; scancode < SDL_NUM_SCANCODES; ++scancode) {
        printf("Scancode #%d, \"%s\"\n", scancode,
               SDL_GetScancodeName(scancode));
    }
    SDL_Quit();
    return (0);
}