| /* |
| Simple DirectMedia Layer |
| Copyright (C) 1997-2013 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_config.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; |
| |
| #ifndef USE_GETTICKCOUNT |
| /* 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; |
| #endif |
| |
| static void |
| timeSetPeriod(UINT uPeriod) |
| { |
| static UINT timer_period = 0; |
| |
| if (uPeriod != timer_period) { |
| if (timer_period) { |
| timeEndPeriod(timer_period); |
| } |
| |
| timer_period = uPeriod; |
| |
| if (timer_period) { |
| timeBeginPeriod(timer_period); |
| } |
| } |
| } |
| |
| static void |
| 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) { |
| timeSetPeriod(uPeriod); |
| } |
| } |
| |
| void |
| SDL_StartTicks(void) |
| { |
| /* Set first ticks value */ |
| #ifdef USE_GETTICKCOUNT |
| start = GetTickCount(); |
| #else |
| /* 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; |
| timeSetPeriod(1); /* use 1 ms timer precision */ |
| start = timeGetTime(); |
| } |
| #endif |
| |
| SDL_AddHintCallback(SDL_HINT_TIMER_RESOLUTION, |
| SDL_TimerResolutionChanged, NULL); |
| } |
| |
| Uint32 |
| SDL_GetTicks(void) |
| { |
| DWORD now; |
| #ifndef USE_GETTICKCOUNT |
| LARGE_INTEGER hires_now; |
| #endif |
| |
| #ifdef USE_GETTICKCOUNT |
| now = GetTickCount(); |
| #else |
| 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 { |
| now = timeGetTime(); |
| } |
| #endif |
| |
| 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(ms); |
| } |
| |
| #endif /* SDL_TIMER_WINDOWS */ |
| |
| /* vi: set ts=4 sw=4 expandtab: */ |