Mercurial > sdl-ios-xcode
view Xcode-iPhoneOS/Template/SDL Application/main.c @ 5053:b5b42be9333c
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.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Wed, 19 Jan 2011 23:56:16 -0800 |
parents | 20326ba2bda2 |
children | b6c7a6b07ebf |
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/* * rectangles.c * written by Holmes Futrell * use however you want */ #include "SDL.h" #include <time.h> #define SCREEN_WIDTH 320 #define SCREEN_HEIGHT 480 int randomInt(int min, int max) { return min + rand() % (max - min + 1); } void render(void) { Uint8 r, g, b; /* Come up with a random rectangle */ SDL_Rect rect; rect.w = randomInt(64, 128); rect.h = randomInt(64, 128); rect.x = randomInt(0, SCREEN_WIDTH); rect.y = randomInt(0, SCREEN_HEIGHT); /* Come up with a random color */ r = randomInt(50, 255); g = randomInt(50, 255); b = randomInt(50, 255); /* Fill the rectangle in the color */ SDL_RenderFill(r, g, b, 255, &rect); /* update screen */ SDL_RenderPresent(); } int main(int argc, char *argv[]) { SDL_WindowID windowID; int done; SDL_Event event; /* initialize SDL */ if (SDL_Init(SDL_INIT_VIDEO) < 0) { printf("Could not initialize SDL\n"); } /* seed random number generator */ srand(time(NULL)); /* create window and renderer */ windowID = SDL_CreateWindow(NULL, 0, 0, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_OPENGL | SDL_WINDOW_SHOWN); if (windowID == 0) { printf("Could not initialize Window\n"); } if (SDL_CreateRenderer(windowID, -1, 0) != 0) { printf("Could not create renderer\n"); } /* Fill screen with black */ SDL_RenderFill(0, 0, 0, 0, NULL); /* Enter render loop, waiting for user to quit */ done = 0; while (!done) { while (SDL_PollEvent(&event)) { if (event.type == SDL_QUIT) { done = 1; } } render(); SDL_Delay(1); } /* shutdown SDL */ SDL_Quit(); return 0; }