SDL_systimer.c
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/*
Simple DirectMedia Layer
Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
#include "../../SDL_internal.h"
#ifdef SDL_TIMER_WINDOWS
#include "../../core/windows/SDL_windows.h"
#include <mmsystem.h>
#include "SDL_timer.h"
#include "SDL_hints.h"
/* The first (low-resolution) ticks value of the application */
static DWORD start = 0;
static BOOL ticks_started = FALSE;
/* Store if a high-resolution performance counter exists on the system */
static BOOL hires_timer_available;
/* The first high-resolution ticks value of the application */
static LARGE_INTEGER hires_start_ticks;
/* The number of ticks per second of the high-resolution performance counter */
static LARGE_INTEGER hires_ticks_per_second;
static void
SDL_SetSystemTimerResolution(const UINT uPeriod)
{
#ifndef __WINRT__
static UINT timer_period = 0;
if (uPeriod != timer_period) {
if (timer_period) {
timeEndPeriod(timer_period);
}
timer_period = uPeriod;
if (timer_period) {
timeBeginPeriod(timer_period);
}
}
#endif
}
static void SDLCALL
SDL_TimerResolutionChanged(void *userdata, const char *name, const char *oldValue, const char *hint)
{
UINT uPeriod;
/* Unless the hint says otherwise, let's have good sleep precision */
if (hint && *hint) {
uPeriod = SDL_atoi(hint);
} else {
uPeriod = 1;
}
if (uPeriod || oldValue != hint) {
SDL_SetSystemTimerResolution(uPeriod);
}
}
void
SDL_TicksInit(void)
{
if (ticks_started) {
return;
}
ticks_started = SDL_TRUE;
/* if we didn't set a precision, set it high. This affects lots of things
on Windows besides the SDL timers, like audio callbacks, etc. */
SDL_AddHintCallback(SDL_HINT_TIMER_RESOLUTION,
SDL_TimerResolutionChanged, NULL);
/* Set first ticks value */
/* QueryPerformanceCounter has had problems in the past, but lots of games
use it, so we'll rely on it here.
*/
if (QueryPerformanceFrequency(&hires_ticks_per_second) == TRUE) {
hires_timer_available = TRUE;
QueryPerformanceCounter(&hires_start_ticks);
} else {
hires_timer_available = FALSE;
#ifndef __WINRT__
start = timeGetTime();
#endif /* __WINRT__ */
}
}
void
SDL_TicksQuit(void)
{
SDL_DelHintCallback(SDL_HINT_TIMER_RESOLUTION,
SDL_TimerResolutionChanged, NULL);
SDL_SetSystemTimerResolution(0); /* always release our timer resolution request. */
start = 0;
ticks_started = SDL_FALSE;
}
Uint32
SDL_GetTicks(void)
{
DWORD now = 0;
LARGE_INTEGER hires_now;
if (!ticks_started) {
SDL_TicksInit();
}
if (hires_timer_available) {
QueryPerformanceCounter(&hires_now);
hires_now.QuadPart -= hires_start_ticks.QuadPart;
hires_now.QuadPart *= 1000;
hires_now.QuadPart /= hires_ticks_per_second.QuadPart;
return (DWORD) hires_now.QuadPart;
} else {
#ifndef __WINRT__
now = timeGetTime();
#endif /* __WINRT__ */
}
return (now - start);
}
Uint64
SDL_GetPerformanceCounter(void)
{
LARGE_INTEGER counter;
if (!QueryPerformanceCounter(&counter)) {
return SDL_GetTicks();
}
return counter.QuadPart;
}
Uint64
SDL_GetPerformanceFrequency(void)
{
LARGE_INTEGER frequency;
if (!QueryPerformanceFrequency(&frequency)) {
return 1000;
}
return frequency.QuadPart;
}
void
SDL_Delay(Uint32 ms)
{
/* Sleep() is not publicly available to apps in early versions of WinRT.
*
* Visual C++ 2013 Update 4 re-introduced Sleep() for Windows 8.1 and
* Windows Phone 8.1.
*
* Use the compiler version to determine availability.
*
* NOTE #1: _MSC_FULL_VER == 180030723 for Visual C++ 2013 Update 3.
* NOTE #2: Visual C++ 2013, when compiling for Windows 8.0 and
* Windows Phone 8.0, uses the Visual C++ 2012 compiler to build
* apps and libraries.
*/
#if defined(__WINRT__) && defined(_MSC_FULL_VER) && (_MSC_FULL_VER <= 180030723)
static HANDLE mutex = 0;
if (!mutex) {
mutex = CreateEventEx(0, 0, 0, EVENT_ALL_ACCESS);
}
WaitForSingleObjectEx(mutex, ms, FALSE);
#else
if (!ticks_started) {
SDL_TicksInit();
}
Sleep(ms);
#endif
}
#endif /* SDL_TIMER_WINDOWS */
/* vi: set ts=4 sw=4 expandtab: */
SDL_TRUE
Definition: SDL_stdinc.h:142
SDL_FALSE
Definition: SDL_stdinc.h:141
SDL_GetPerformanceFrequency
Uint64 SDL_GetPerformanceFrequency(void)
Get the count per second of the high resolution counter.
start
GLuint start
Definition: SDL_opengl.h:1571
Uint32
uint32_t Uint32
Definition: SDL_stdinc.h:181
mutex
static SDL_mutex * mutex
Definition: testlock.c:23
SDL_HINT_TIMER_RESOLUTION
#define SDL_HINT_TIMER_RESOLUTION
A variable that controls the timer resolution, in milliseconds.
Definition: SDL_hints.h:492
Uint64
uint64_t Uint64
Definition: SDL_stdinc.h:194
name
GLuint const GLchar * name
Definition: SDL_opengl_glext.h:660
SDL_GetTicks
Uint32 SDL_GetTicks(void)
Get the number of milliseconds since the SDL library initialization.
TRUE
#define TRUE
Definition: edid-parse.c:33
SDL_hints.h
SDL_atoi
#define SDL_atoi
Definition: SDL_dynapi_overrides.h:410
SDL_GetPerformanceCounter
#define SDL_GetPerformanceCounter
Definition: SDL_dynapi_overrides.h:484
SDL_Delay
#define SDL_Delay
Definition: SDL_dynapi_overrides.h:486
NULL
#define NULL
Definition: begin_code.h:164
SDL_AddHintCallback
#define SDL_AddHintCallback
Definition: SDL_dynapi_overrides.h:192
SDL_TicksInit
void SDL_TicksInit(void)
SDL_DelHintCallback
#define SDL_DelHintCallback
Definition: SDL_dynapi_overrides.h:193
counter
GLuint counter
Definition: SDL_opengl_glext.h:4992
SDL_TicksQuit
void SDL_TicksQuit(void)
SDL_timer.h
FALSE
#define FALSE
Definition: edid-parse.c:34
SDLCALL
#define SDLCALL
Definition: SDL_internal.h:45