- Ported frame rate limiting code to SDL.

SVN r3891 (trunk)

src/sdl/hardware.cpp

@@ -33,6 +33,8 @@
 */
 
 #include <SDL.h>
+#include <signal.h>
+#include <time.h>
 
 #include "hardware.h"
 #include "i_video.h"
@@ -177,8 +179,87 @@ void I_ClosestResolution (int *width, int *height, int bits)
 	}
 }
 
+//==========================================================================
+//
+// SetFPSLimit
+//
+// Initializes an event timer to fire at a rate of <limit>/sec. The video
+// update will wait for this timer to trigger before updating.
+//
+// Pass 0 as the limit for unlimited.
+// Pass a negative value for the limit to use the value of vid_maxfps.
+//
+//==========================================================================
+
+EXTERN_CVAR(Int, vid_maxfps);
+EXTERN_CVAR(Bool, cl_capfps);
+
+Semaphore FPSLimitSemaphore;
+
+static void FPSLimitNotify(sigval val)
+{
+	SEMAPHORE_SIGNAL(FPSLimitSemaphore)
+}
+
 void I_SetFPSLimit(int limit)
 {
+	static sigevent FPSLimitEvent;
+	static timer_t FPSLimitTimer;
+	static bool FPSLimitTimerEnabled = false;
+	static bool EventSetup = false;
+	if(!EventSetup)
+	{
+		EventSetup = true;
+		FPSLimitEvent.sigev_notify = SIGEV_THREAD;
+		FPSLimitEvent.sigev_signo = 0;
+		FPSLimitEvent.sigev_value.sival_int = 0;
+		FPSLimitEvent.sigev_notify_function = FPSLimitNotify;
+		FPSLimitEvent.sigev_notify_attributes = NULL;
+
+		SEMAPHORE_INIT(FPSLimitSemaphore, 0, 0)
+	}
+
+	if (limit < 0)
+	{
+		limit = vid_maxfps;
+	}
+	// Kill any leftover timer.
+	if (FPSLimitTimerEnabled)
+	{
+		timer_delete(FPSLimitTimer);
+		FPSLimitTimerEnabled = false;
+	}
+	if (limit == 0)
+	{ // no limit
+		DPrintf("FPS timer disabled\n");
+	}
+	else
+	{
+		FPSLimitTimerEnabled = true;
+		if(timer_create(CLOCK_REALTIME, &FPSLimitEvent, &FPSLimitTimer) == -1)
+			Printf("Failed to create FPS limitter event\n");
+		itimerspec period = { {0, 0}, {0, 0} };
+		period.it_value.tv_nsec = period.it_interval.tv_nsec = 1000000000 / limit;
+		if(timer_settime(FPSLimitTimer, 0, &period, NULL) == -1)
+			Printf("Failed to set FPS limitter timer\n");
+		DPrintf("FPS timer set to %u ms\n", (unsigned int) period.it_interval.tv_nsec / 1000000);
+	}
+}
+
+CUSTOM_CVAR (Int, vid_maxfps, 200, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
+{
+	if (vid_maxfps < TICRATE && vid_maxfps != 0)
+	{
+		vid_maxfps = TICRATE;
+	}
+	else if (vid_maxfps > 1000)
+	{
+		vid_maxfps = 1000;
+	}
+	else if (cl_capfps == 0)
+	{
+		I_SetFPSLimit(vid_maxfps);
+	}
 }
 
 extern int NewWidth, NewHeight, NewBits, DisplayBits;

src/sdl/hardware.h

@@ -37,6 +37,29 @@
 #include "i_video.h"
 #include "v_video.h"
 
+// Semaphores
+#ifdef __APPLE__
+#include <mach/mach_init.h>
+#include <mach/semaphore.h>
+#include <mach/task.h>
+typedef semaphore_t Semaphore;
+#define SEMAPHORE_WAIT(sem) \
+	while(semaphore_wait(sem) != KERN_SUCCESS){}
+#define SEMAPHORE_SIGNAL(sem) \
+	semaphore_signal(sem)
+#define SEMAPHORE_INIT(sem, shared, value) \
+	semaphore_create(mach_task_self(), &sem, shared, value);
+#else
+#include <semaphore.h>
+typedef sem_t Semaphore;
+#define SEMAPHORE_WAIT(sem) \
+	while(sem_wait(&sem) != 0);
+#define SEMAPHORE_SIGNAL(sem) \
+	sem_post(&sem);
+#define SEMAPHORE_INIT(sem, shared, value) \
+	sem_init(&sem, shared, value);
+#endif
+
 class IVideo
 {
  public:
@@ -59,6 +82,7 @@ void I_InitGraphics ();
 void I_ShutdownGraphics ();
 void I_CreateRenderer();
 
+extern Semaphore FPSLimitSemaphore;
 void I_SetFPSLimit(int limit);
 
 extern IVideo *Video;

src/sdl/i_system.cpp

@@ -38,14 +38,6 @@
 #include <gdk/gdkkeysyms.h>
 #endif
 
-#ifdef __APPLE__
-#include <mach/mach_init.h>
-#include <mach/semaphore.h>
-#include <mach/task.h>
-#else
-#include <semaphore.h>
-#endif
-
 #include "doomerrors.h"
 #include <math.h>
 
@@ -144,11 +136,7 @@ static DWORD BaseTime;
 static int TicFrozen;
 
 // Signal based timer.
-#ifdef __APPLE__
-static semaphore_t timerWait;
-#else
-static sem_t timerWait;
-#endif
+static Semaphore timerWait;
 static int tics;
 static DWORD sig_start, sig_next;
 
@@ -221,12 +209,7 @@ int I_WaitForTicSignaled (int prevtic)
 
 	while(tics <= prevtic)
 	{
-#ifdef __APPLE__
-		while(semaphore_wait(timerWait) != KERN_SUCCESS)
-			;
-#else
-		while(sem_wait(&timerWait) != 0);
-#endif
+		SEMAPHORE_WAIT(timerWait)
 	}
 
 	return tics;
@@ -276,11 +259,7 @@ void I_HandleAlarm (int sig)
 		tics++;
 	sig_start = SDL_GetTicks();
 	sig_next = Scale((Scale (sig_start, TICRATE, 1000) + 1), 1000, TICRATE);
-#ifdef __APPLE__
-	semaphore_signal(timerWait);
-#else
-	sem_post(&timerWait);
-#endif
+	SEMAPHORE_SIGNAL(timerWait)
 }
 
 //
@@ -290,11 +269,7 @@ void I_HandleAlarm (int sig)
 //
 void I_SelectTimer()
 {
-#ifdef __APPLE__
-	semaphore_create(mach_task_self(), &timerWait, 0, 0);
-#else
-	sem_init(&timerWait, 0, 0);
-#endif
+	SEMAPHORE_INIT(timerWait, 0, 0)
 	signal(SIGALRM, I_HandleAlarm);
 
 	struct itimerval itv;

src/sdl/sdlvideo.cpp

@@ -80,6 +80,7 @@ extern SDL_Rect cursorBlit;
 extern bool GUICapture;
 
 EXTERN_CVAR (Float, Gamma)
+EXTERN_CVAR (Int, vid_maxfps)
 
 // PUBLIC DATA DEFINITIONS -------------------------------------------------
 
@@ -374,6 +375,11 @@ void SDLFB::Update ()
 
 	DrawRateStuff ();
 
+	if(vid_maxfps)
+	{
+		SEMAPHORE_WAIT(FPSLimitSemaphore)
+	}
+
 	Buffer = NULL;
 	LockCount = 0;
 	UpdatePending = false;