- Added vid_maxfps cvar to limit the frame rate to some arbitrary rate between 35 and 1000 FPS. It

defaults to 200. Setting it to 0 will restore the previous behavior of having no frame rate
  limit. Note that vid_maxfps 35 is NOT the same as cl_capfps 1. cl_capfps caps the frame rate
  by tying the video update directly to the game timer. With vid_maxfps 35, the video update and
  game timer are running on separate timers, and results will not be as good as with cl_capfps 1,
  which uses only one timer.

SVN r3872 (trunk)

src/d_net.cpp

@@ -60,6 +60,7 @@
 #include "p_lnspec.h"
 #include "v_video.h"
 #include "p_spec.h"
+#include "hardware.h"
 #include "intermission/intermission.h"
 
 EXTERN_CVAR (Int, disableautosave)
@@ -135,7 +136,18 @@ static int	oldentertics;
 
 extern	bool	 advancedemo;
 
-CVAR (Bool, cl_capfps, false, CVAR_ARCHIVE|CVAR_GLOBALCONFIG)
+CUSTOM_CVAR (Bool, cl_capfps, false, CVAR_ARCHIVE|CVAR_GLOBALCONFIG)
+{
+	// Do not use the separate FPS limit timer if we are limiting FPS with this.
+	if (self)
+	{
+		I_SetFPSLimit(0);
+	}
+	else
+	{
+		I_SetFPSLimit(-1);
+	}
+}
 
 // [RH] Special "ticcmds" get stored in here
 static struct TicSpecial

src/sdl/hardware.cpp

@@ -177,6 +177,10 @@ void I_ClosestResolution (int *width, int *height, int bits)
 	}
 }	
 
+void I_SetFPSLimit(int limit)
+{
+}
+
 extern int NewWidth, NewHeight, NewBits, DisplayBits;
 
 CUSTOM_CVAR (Bool, fullscreen, false, CVAR_ARCHIVE|CVAR_GLOBALCONFIG)

src/sdl/hardware.h

@@ -59,6 +59,8 @@ void I_InitGraphics ();
 void I_ShutdownGraphics ();
 void I_CreateRenderer();
 
+void I_SetFPSLimit(int limit);
+
 extern IVideo *Video;
 
 #endif	// __HARDWARE_H__

src/win32/fb_d3d9.cpp

@@ -1208,6 +1208,11 @@ void D3DFB::Flip()
 			BlockSurface[BlockNum]->UnlockRect();
 		}
 	}
+	// Limiting the frame rate is as simple as waiting for the timer to signal this event.
+	if (FPSLimitEvent != NULL)
+	{
+		WaitForSingleObject(FPSLimitEvent, 1000);
+	}
 	D3DDevice->Present(NULL, NULL, NULL, NULL);
 	InScene = false;
 

src/win32/fb_ddraw.cpp

@@ -1201,6 +1201,10 @@ void DDrawFB::Update ()
 	LockCount = 0;
 	UpdatePending = false;
 
+	if (FPSLimitEvent != NULL)
+	{
+		WaitForSingleObject(FPSLimitEvent, 1000);
+	}
 	if (!Windowed && AppActive && !SessionState /*&& !UseBlitter && !MustBuffer*/)
 	{
 		HRESULT hr = PrimarySurf->Flip (NULL, FlipFlags);

src/win32/hardware.h

@@ -62,6 +62,9 @@ void I_CreateRenderer();
 void I_SaveWindowedPos ();
 void I_RestoreWindowedPos ();
 
+void I_SetFPSLimit(int limit);
+
+
 extern IVideo *Video;
 
 #endif	// __HARDWARE_H__

src/win32/win32iface.h

@@ -52,6 +52,8 @@
 
 EXTERN_CVAR (Bool, vid_vsync)
 
+extern HANDLE FPSLimitEvent;
+
 class D3DTex;
 class D3DPal;
 struct FSoftwareRenderer;

src/win32/win32video.cpp

@@ -41,6 +41,7 @@
 #define _WIN32_WINNT 0x0501
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
+#include <mmsystem.h>
 #include <ddraw.h>
 #include <d3d9.h>
 
@@ -87,6 +88,8 @@ void DoBlending (const PalEntry *from, PalEntry *to, int count, int r, int g, in
 
 // PRIVATE FUNCTION PROTOTYPES ---------------------------------------------
 
+static void StopFPSLimit();
+
 // EXTERNAL DATA DECLARATIONS ----------------------------------------------
 
 extern HWND Window;
@@ -98,20 +101,38 @@ extern bool VidResizing;
 
 EXTERN_CVAR (Bool, fullscreen)
 EXTERN_CVAR (Float, Gamma)
+EXTERN_CVAR (Bool, cl_capfps)
 
 // PRIVATE DATA DEFINITIONS ------------------------------------------------
 
 static HMODULE D3D9_dll;
 static HMODULE DDraw_dll;
+static UINT FPSLimitTimer;
 
 // PUBLIC DATA DEFINITIONS -------------------------------------------------
 
 IDirectDraw2 *DDraw;
 IDirect3D9 *D3D;
 IDirect3DDevice9 *D3Device;
+HANDLE FPSLimitEvent;
 
 CVAR (Bool, vid_forceddraw, false, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
 CVAR (Int, vid_adapter, 1, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
+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);
+	}
+}
 
 #if VID_FILE_DEBUG
 FILE *dbg;
@@ -714,4 +735,74 @@ void Win32Video::SetWindowedScale (float scale)
 	// FIXME
 }
 
-// FrameBuffer implementation -----------------------------------------------
+//==========================================================================
+//
+// 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.
+//
+//==========================================================================
+
+void I_SetFPSLimit(int limit)
+{
+	if (limit < 0)
+	{
+		limit = vid_maxfps;
+	}
+	// Kill any leftover timer.
+	if (FPSLimitTimer != 0)
+	{
+		timeKillEvent(FPSLimitTimer);
+		FPSLimitTimer = 0;
+	}
+	if (limit == 0)
+	{ // no limit
+		if (FPSLimitEvent != NULL)
+		{
+			CloseHandle(FPSLimitEvent);
+			FPSLimitEvent = NULL;
+		}
+		DPrintf("FPS timer disabled\n");
+	}
+	else
+	{
+		if (FPSLimitEvent == NULL)
+		{
+			FPSLimitEvent = CreateEvent(NULL, FALSE, TRUE, NULL);
+			if (FPSLimitEvent == NULL)
+			{ // Could not create event, so cannot use timer.
+				Printf("Failed to create FPS limitter event\n");
+				return;
+			}
+		}
+		atterm(StopFPSLimit);
+		// Set timer event as close as we can to limit/sec, in milliseconds.
+		UINT period = 1000 / limit;
+		FPSLimitTimer = timeSetEvent(period, 0, (LPTIMECALLBACK)FPSLimitEvent, 0, TIME_PERIODIC | TIME_CALLBACK_EVENT_SET);
+		if (FPSLimitTimer == 0)
+		{
+			CloseHandle(FPSLimitEvent);
+			FPSLimitEvent = NULL;
+			Printf("Failed to create FPS limitter timer\n");
+			return;
+		}
+		DPrintf("FPS timer set to %u ms\n", period);
+	}
+}
+
+//==========================================================================
+//
+// StopFPSLimit
+//
+// Used for cleanup during application shutdown.
+//
+//==========================================================================
+
+static void StopFPSLimit()
+{
+	I_SetFPSLimit(0);
+}