b7435a3ad3
Coriiander
In src\timer\windows\SDL_systimer.c there is an error with regards to timeBeginPeriod and timeEndPeriod. These functions typically get called when no high resolution timer is available, and GetTickCount is not used.
According to MSDN (link: dd757624(v=vs.85).aspx), for every call to timeBeginPeriod a subsequent call to timeEndPeriod is required. While SDL is currently doing this, it fails to call timeEndPeriod when cleaning up/shutting down SDL. Please note that these functions affect things on a system level. Failing to call timeEndPeriod, disables applications for using WINMM-timers after usage&shutdown of SDL, as effectively they the mechanism is now broken.
Solution:
Ensure this code gets called when shutting down the timer subsystem:
#ifndef USE_GETTICKCOUNT
if (!hires_timer_available)
{
timeSetPeriod(0);
}
#endif
185 lines
4.3 KiB
C
185 lines
4.3 KiB
C
/*
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Simple DirectMedia Layer
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Copyright (C) 1997-2014 Sam Lantinga <slouken@libsdl.org>
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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#include "../../SDL_internal.h"
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#ifdef SDL_TIMER_WINDOWS
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#include "../../core/windows/SDL_windows.h"
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#include <mmsystem.h>
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#include "SDL_timer.h"
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#include "SDL_hints.h"
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/* The first (low-resolution) ticks value of the application */
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static DWORD start;
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static BOOL ticks_started = FALSE;
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#ifndef USE_GETTICKCOUNT
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/* Store if a high-resolution performance counter exists on the system */
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static BOOL hires_timer_available;
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/* The first high-resolution ticks value of the application */
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static LARGE_INTEGER hires_start_ticks;
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/* The number of ticks per second of the high-resolution performance counter */
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static LARGE_INTEGER hires_ticks_per_second;
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static void
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timeSetPeriod(UINT uPeriod)
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{
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static UINT timer_period = 0;
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if (uPeriod != timer_period) {
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if (timer_period) {
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timeEndPeriod(timer_period);
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}
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timer_period = uPeriod;
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if (timer_period) {
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timeBeginPeriod(timer_period);
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}
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}
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}
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static void
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SDL_TimerResolutionChanged(void *userdata, const char *name, const char *oldValue, const char *hint)
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{
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UINT uPeriod;
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/* Unless the hint says otherwise, let's have good sleep precision */
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if (hint && *hint) {
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uPeriod = SDL_atoi(hint);
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} else {
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uPeriod = 1;
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}
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if (uPeriod || oldValue != hint) {
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timeSetPeriod(uPeriod);
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}
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}
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#endif /* !USE_GETTICKCOUNT */
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void
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SDL_TicksInit(void)
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{
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if (ticks_started) {
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return;
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}
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ticks_started = SDL_TRUE;
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/* Set first ticks value */
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#ifdef USE_GETTICKCOUNT
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start = GetTickCount();
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#else
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/* QueryPerformanceCounter has had problems in the past, but lots of games
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use it, so we'll rely on it here.
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*/
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if (QueryPerformanceFrequency(&hires_ticks_per_second) == TRUE) {
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hires_timer_available = TRUE;
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QueryPerformanceCounter(&hires_start_ticks);
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} else {
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hires_timer_available = FALSE;
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timeSetPeriod(1); /* use 1 ms timer precision */
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start = timeGetTime();
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SDL_AddHintCallback(SDL_HINT_TIMER_RESOLUTION,
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SDL_TimerResolutionChanged, NULL);
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}
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#endif
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}
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void
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SDL_TicksQuit(void)
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{
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#ifndef USE_GETTICKCOUNT
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if (!hires_timer_available) {
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SDL_DelHintCallback(SDL_HINT_TIMER_RESOLUTION,
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SDL_TimerResolutionChanged, NULL);
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timeSetPeriod(0);
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}
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#endif
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ticks_started = SDL_FALSE;
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}
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Uint32
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SDL_GetTicks(void)
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{
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DWORD now;
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#ifndef USE_GETTICKCOUNT
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LARGE_INTEGER hires_now;
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#endif
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if (!ticks_started) {
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SDL_TicksInit();
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}
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#ifdef USE_GETTICKCOUNT
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now = GetTickCount();
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#else
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if (hires_timer_available) {
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QueryPerformanceCounter(&hires_now);
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hires_now.QuadPart -= hires_start_ticks.QuadPart;
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hires_now.QuadPart *= 1000;
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hires_now.QuadPart /= hires_ticks_per_second.QuadPart;
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return (DWORD) hires_now.QuadPart;
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} else {
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now = timeGetTime();
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}
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#endif
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return (now - start);
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}
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Uint64
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SDL_GetPerformanceCounter(void)
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{
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LARGE_INTEGER counter;
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if (!QueryPerformanceCounter(&counter)) {
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return SDL_GetTicks();
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}
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return counter.QuadPart;
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}
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Uint64
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SDL_GetPerformanceFrequency(void)
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{
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LARGE_INTEGER frequency;
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if (!QueryPerformanceFrequency(&frequency)) {
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return 1000;
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}
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return frequency.QuadPart;
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}
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void
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SDL_Delay(Uint32 ms)
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{
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Sleep(ms);
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}
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#endif /* SDL_TIMER_WINDOWS */
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/* vi: set ts=4 sw=4 expandtab: */
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