Mercurial > sdl-ios-xcode
annotate src/thread/generic/SDL_syssem.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 |
| parents | b8d311d90021 |
| children | c9b51268668f |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 SDL - Simple DirectMedia Layer | |
|
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b8d311d90021
Updated copyright information for 2004 (Happy New Year!)
Sam Lantinga <slouken@libsdl.org>
parents:
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|
3 Copyright (C) 1997-2004 Sam Lantinga |
| 0 | 4 |
| 5 This library is free software; you can redistribute it and/or | |
| 6 modify it under the terms of the GNU Library General Public | |
| 7 License as published by the Free Software Foundation; either | |
| 8 version 2 of the License, or (at your option) any later version. | |
| 9 | |
| 10 This library is distributed in the hope that it will be useful, | |
| 11 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 Library General Public License for more details. | |
| 14 | |
| 15 You should have received a copy of the GNU Library General Public | |
| 16 License along with this library; if not, write to the Free | |
| 17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
| 18 | |
| 19 Sam Lantinga | |
|
252
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Updated the source with the correct e-mail address
Sam Lantinga <slouken@libsdl.org>
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|
20 slouken@libsdl.org |
| 0 | 21 */ |
| 22 | |
| 23 #ifdef SAVE_RCSID | |
| 24 static char rcsid = | |
| 25 "@(#) $Id$"; | |
| 26 #endif | |
| 27 | |
| 28 /* An implementation of semaphores using mutexes and condition variables */ | |
| 29 | |
| 30 #include <stdlib.h> | |
| 31 | |
| 32 #include "SDL_error.h" | |
| 33 #include "SDL_timer.h" | |
| 34 #include "SDL_thread.h" | |
| 35 #include "SDL_systhread_c.h" | |
| 36 | |
| 37 | |
| 38 #ifdef DISABLE_THREADS | |
| 39 | |
| 40 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) | |
| 41 { | |
| 42 SDL_SetError("SDL not configured with thread support"); | |
| 43 return (SDL_sem *)0; | |
| 44 } | |
| 45 | |
| 46 void SDL_DestroySemaphore(SDL_sem *sem) | |
| 47 { | |
| 48 return; | |
| 49 } | |
| 50 | |
| 51 int SDL_SemTryWait(SDL_sem *sem) | |
| 52 { | |
| 53 SDL_SetError("SDL not configured with thread support"); | |
| 54 return -1; | |
| 55 } | |
| 56 | |
| 57 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) | |
| 58 { | |
| 59 SDL_SetError("SDL not configured with thread support"); | |
| 60 return -1; | |
| 61 } | |
| 62 | |
| 63 int SDL_SemWait(SDL_sem *sem) | |
| 64 { | |
| 65 SDL_SetError("SDL not configured with thread support"); | |
| 66 return -1; | |
| 67 } | |
| 68 | |
| 69 Uint32 SDL_SemValue(SDL_sem *sem) | |
| 70 { | |
| 71 return 0; | |
| 72 } | |
| 73 | |
| 74 int SDL_SemPost(SDL_sem *sem) | |
| 75 { | |
| 76 SDL_SetError("SDL not configured with thread support"); | |
| 77 return -1; | |
| 78 } | |
| 79 | |
| 80 #else | |
| 81 | |
| 82 struct SDL_semaphore | |
| 83 { | |
| 84 Uint32 count; | |
| 85 Uint32 waiters_count; | |
| 86 SDL_mutex *count_lock; | |
| 87 SDL_cond *count_nonzero; | |
| 88 }; | |
| 89 | |
| 90 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) | |
| 91 { | |
| 92 SDL_sem *sem; | |
| 93 | |
| 94 sem = (SDL_sem *)malloc(sizeof(*sem)); | |
| 95 if ( ! sem ) { | |
| 96 SDL_OutOfMemory(); | |
| 97 return(0); | |
| 98 } | |
| 99 sem->count = initial_value; | |
| 100 sem->waiters_count = 0; | |
| 101 | |
| 102 sem->count_lock = SDL_CreateMutex(); | |
| 103 sem->count_nonzero = SDL_CreateCond(); | |
| 104 if ( ! sem->count_lock || ! sem->count_nonzero ) { | |
| 105 SDL_DestroySemaphore(sem); | |
| 106 return(0); | |
| 107 } | |
| 108 | |
| 109 return(sem); | |
| 110 } | |
| 111 | |
| 112 /* WARNING: | |
| 113 You cannot call this function when another thread is using the semaphore. | |
| 114 */ | |
| 115 void SDL_DestroySemaphore(SDL_sem *sem) | |
| 116 { | |
| 117 if ( sem ) { | |
| 118 sem->count = 0xFFFFFFFF; | |
| 119 while ( sem->waiters_count > 0) { | |
| 120 SDL_CondSignal(sem->count_nonzero); | |
| 121 SDL_Delay(10); | |
| 122 } | |
| 123 SDL_DestroyCond(sem->count_nonzero); | |
| 124 SDL_mutexP(sem->count_lock); | |
| 125 SDL_mutexV(sem->count_lock); | |
| 126 SDL_DestroyMutex(sem->count_lock); | |
| 127 free(sem); | |
| 128 } | |
| 129 } | |
| 130 | |
| 131 int SDL_SemTryWait(SDL_sem *sem) | |
| 132 { | |
| 133 int retval; | |
| 134 | |
| 135 if ( ! sem ) { | |
| 136 SDL_SetError("Passed a NULL semaphore"); | |
| 137 return -1; | |
| 138 } | |
| 139 | |
| 140 retval = SDL_MUTEX_TIMEDOUT; | |
| 141 SDL_LockMutex(sem->count_lock); | |
| 142 if ( sem->count > 0 ) { | |
| 143 --sem->count; | |
| 144 retval = 0; | |
| 145 } | |
| 146 SDL_UnlockMutex(sem->count_lock); | |
| 147 | |
| 148 return retval; | |
| 149 } | |
| 150 | |
| 151 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) | |
| 152 { | |
| 153 int retval; | |
| 154 | |
| 155 if ( ! sem ) { | |
| 156 SDL_SetError("Passed a NULL semaphore"); | |
| 157 return -1; | |
| 158 } | |
| 159 | |
| 160 /* A timeout of 0 is an easy case */ | |
| 161 if ( timeout == 0 ) { | |
| 162 return SDL_SemTryWait(sem); | |
| 163 } | |
| 164 | |
| 165 SDL_LockMutex(sem->count_lock); | |
| 166 ++sem->waiters_count; | |
| 167 retval = 0; | |
| 168 while ( (sem->count == 0) && (retval != SDL_MUTEX_TIMEDOUT) ) { | |
| 169 retval = SDL_CondWaitTimeout(sem->count_nonzero, | |
| 170 sem->count_lock, timeout); | |
| 171 } | |
| 172 --sem->waiters_count; | |
| 173 --sem->count; | |
| 174 SDL_UnlockMutex(sem->count_lock); | |
| 175 | |
| 176 return retval; | |
| 177 } | |
| 178 | |
| 179 int SDL_SemWait(SDL_sem *sem) | |
| 180 { | |
| 181 return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT); | |
| 182 } | |
| 183 | |
| 184 Uint32 SDL_SemValue(SDL_sem *sem) | |
| 185 { | |
| 186 Uint32 value; | |
| 187 | |
| 188 value = 0; | |
| 189 if ( sem ) { | |
| 190 SDL_LockMutex(sem->count_lock); | |
| 191 value = sem->count; | |
| 192 SDL_UnlockMutex(sem->count_lock); | |
| 193 } | |
| 194 return value; | |
| 195 } | |
| 196 | |
| 197 int SDL_SemPost(SDL_sem *sem) | |
| 198 { | |
| 199 if ( ! sem ) { | |
| 200 SDL_SetError("Passed a NULL semaphore"); | |
| 201 return -1; | |
| 202 } | |
| 203 | |
| 204 SDL_LockMutex(sem->count_lock); | |
| 205 if ( sem->waiters_count > 0 ) { | |
| 206 SDL_CondSignal(sem->count_nonzero); | |
| 207 } | |
| 208 ++sem->count; | |
| 209 SDL_UnlockMutex(sem->count_lock); | |
| 210 | |
| 211 return 0; | |
| 212 } | |
| 213 | |
| 214 #endif /* DISABLE_THREADS */ |