annotate src/audio/SDL_audiomem.c @ 1295:c3e36ac8a94c

Date: Sun, 6 Mar 2005 17:06:20 +0100 From: Per Inge Mathisen Subject: [SDL] Fullscreen refresh on win32 Windows has a terrible default for fullscreen 3D apps of 60mhz refresh rate. This can be fixed by the user by going into his driver's control panel and forcing the refresh rate higher. However, this not a very user friendly way about it, and in any case SDL contains no code that could figure out this that condition has afflicted the user. So the question is, could SDL fix this for the user? It is possible under Windows to request a higher refresh rate. The danger is of course that if the user has an old monitor, and you request a too high refresh rate, the monitor could be damaged. However, I believe there might be a way around that: Check before switching what refresh rate the user's desktop runs in, and if our fullscreen dimensions are equal or less than those of the desktop, use the higher refresh rate of 60 and the desktop rate. Since most users run their desktops in the same or higher resolution something sane, this should fix this problem for most users. Thoughts? An alternative is to add an SDL_GL_GetAttribute(SDL_GL_REFRESH_RATE) option so that programs can bitch at their users at their own convenience. - Per
author Sam Lantinga <slouken@libsdl.org>
date Mon, 30 Jan 2006 06:56:10 +0000
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1 /*
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2 SDL - Simple DirectMedia Layer
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3 Copyright (C) 1997-2004 Sam Lantinga
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4
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5 This library is free software; you can redistribute it and/or
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6 modify it under the terms of the GNU Library General Public
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7 License as published by the Free Software Foundation; either
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8 version 2 of the License, or (at your option) any later version.
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9
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10 This library is distributed in the hope that it will be useful,
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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13 Library General Public License for more details.
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14
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15 You should have received a copy of the GNU Library General Public
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16 License along with this library; if not, write to the Free
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17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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18
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19 Sam Lantinga
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20 slouken@libsdl.org
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21 */
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22
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23 #ifdef SAVE_RCSID
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24 static char rcsid =
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25 "@(#) $Id$";
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26 #endif
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27
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28 /* Functions to allocate audio buffer memory, shareable across threads
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29 (necessary because SDL audio emulates threads with fork()
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30 */
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31
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32 #include <stdlib.h>
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33 #ifdef FORK_HACK
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34 #include <sys/types.h>
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35 #include <sys/ipc.h>
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36 #include <sys/shm.h>
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37 #include <stddef.h>
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38 #endif
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39
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40 #include "SDL_audiomem.h"
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41
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42 /* Allocate memory that will be shared between threads (freed on exit) */
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43 void *SDL_AllocAudioMem(int size)
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44 {
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45 void *chunk;
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46
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47 #ifdef FORK_HACK
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48 int semid;
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49
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50 /* Create and get the address of a shared memory segment */
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51 semid = shmget(IPC_PRIVATE, size, (IPC_CREAT|0600));
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52 if ( semid < 0 ) {
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53 return(NULL);
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54 }
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55 chunk = shmat(semid, NULL, 0);
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56
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57 /* Set the segment for deletion when it is detatched */
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58 shmctl(semid, IPC_RMID, NULL); /* Delets semid if shmat() fails */
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59 #else
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60 chunk = malloc(size);
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61 #endif
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62 return((void *)chunk);
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63 }
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64
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65 void SDL_FreeAudioMem(void *chunk)
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66 {
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67 #ifdef FORK_HACK
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68 shmdt(chunk);
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69 #else
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70 free(chunk);
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71 #endif
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72 }