annotate src/video/uikit/jumphack.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
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1 /*
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2 * jumphack.c
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3 * SDLiPhoneOS
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4 *
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5 */
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6
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7 #include "jumphack.h"
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8
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9 /* see SDL_uikitevents.m for more info */
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10
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11 /* stores the information we need to jump back */
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12 jmp_buf env;
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13
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14 /* returns the jump environment for setting / getting purposes */
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15 jmp_buf *
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16 jump_env(void)
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17 {
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18 return &env;
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19 }