finetuning of the Win32 simulator

simulator/winmain.c

@@ -50,23 +50,24 @@
 /** Height of the canvas. */
 #define WND_Y_EXTENTS (NUM_ROWS * LED_EXTENT)
 
-
 /* string constants */
 LPCSTR g_strWindowClass = "BorgSimulatorWindowClass";
 LPCSTR g_strWindowTitle = "Borg Simulator";
 
-LPCSTR g_strError = "Error";
-LPCSTR g_strErrorRegisterWindow = "Could not register window class.";
-LPCSTR g_strErrorCreateWindow   = "Could not create window.";
-LPCSTR g_strErrorCreateEvent    = "Could not create wait event.";
-LPCSTR g_strErrorCreateThread   = "Could not create display loop thread.";
-LPCSTR g_strErrorCreateUITimer  = "Could not create UI Timer.";
+LPCSTR g_strErr                = "Error";
+LPCSTR g_strErrTimerResolution = "Could not retrieve minimum timer resolution.";
+LPCSTR g_strErrRegisterWindow  = "Could not register window class.";
+LPCSTR g_strErrCreateWindow    = "Could not create window.";
+LPCSTR g_strErrCreateEvent     = "Could not create wait event.";
+LPCSTR g_strErrCreateThread    = "Could not create display loop thread.";
+LPCSTR g_strErrCreateUITimer   = "Could not create UI Timer.";
 
+/** Minimum timer resolution the system is capable of. */
+UINT g_uResolution;
 
 /** Event object for the multimedia timer (wait() function). */
 HANDLE g_hWaitEvent;
 
-
 /** Fake port for simulating joystick input. */
 volatile unsigned char fakeport;
 /** Flag which indicates if wait should jump to the menu if fire is pressed. */
@@ -82,7 +83,6 @@ LRESULT CALLBACK simWndProc(HWND hWnd,
                             WPARAM wParam,
                             LPARAM lParam);
 
-
 /**
  * Creates a new window and makes it visible.
  * @param hInstance Handle of the instance where this window should belong to.
@@ -133,13 +133,12 @@ HWND simCreateWindow(HINSTANCE hInstance,
 	}
 	else
 	{
-		fprintf(stderr, g_strErrorRegisterWindow);
+		fprintf(stderr, g_strErrRegisterWindow);
 	}
 
 	return hWnd;
 }
 
-
 /**
  * Closes windows and unregisters its associated window class.
  * @param lphWnd Pointer to window handle.
@@ -152,7 +151,6 @@ void simDestroyWindow(HWND hWnd,
 	UnregisterClassA(g_strWindowClass, hInstance);
 }
 
-
 /**
  * Draws the LED matrix on the given device context.
  * @param hdc The device context where the LED matrix should be drawn on.
@@ -216,7 +214,6 @@ void simDrawMatrix(HDC hdc)
 	}
 }
 
-
 /**
  * Retrieves device context from given window, creates a compatible memory
  * device context for double buffering and hands that thing over to
@@ -411,7 +408,6 @@ LRESULT CALLBACK simWndProc(HWND hWnd,
 	return lResult;
 }
 
-
 /**
  * Entry point for starting the the display loop in a thread.
  * @param lpParam Free style arguments for the thread function (not used here).
@@ -423,19 +419,36 @@ DWORD WINAPI simLoop(LPVOID lpParam)
 	return 0;
 }
 
+/**
+ * Retrieves and enforces the minimum timer resolution of the current system.
+ * @return Result of the multimedia timer operations.
+ */
+MMRESULT simSetMinimumTimerResolution()
+{
+	TIMECAPS tc;
+	MMRESULT mmresult;
+
+	mmresult = timeGetDevCaps(&tc, sizeof(tc));
+	if (mmresult == TIMERR_NOERROR)
+	{
+		/* retrieve best resolution and configure timer services accordingly */
+		g_uResolution = min(max(tc.wPeriodMin, 0), tc.wPeriodMax);
+		mmresult = timeBeginPeriod(g_uResolution);
+	}
+
+	return mmresult;
+}
 
 /**
  * Wait function which utilizes multimedia timers and thread synchronization
  * objects. Although this is much more complicated than calling the Sleep()
  * function, it is also much more precise.
  * @param ms The requested delay in milliseconds.
+ * @param uResolution The minimum timer resolution the system is capable of.
  */
 void wait(int ms)
 {
-	TIMECAPS tc;
-	MMRESULT mmresult;
 	MMRESULT mmTimerEventId;
-	UINT uResolution;
 
 	/* check if fire button is pressed (and if it is, jump to the menu) */
 	if (waitForFire)
@@ -446,17 +459,8 @@ void wait(int ms)
 		}
 	}
 
-	/* retrieve timer resolution capabilities of the current system */
-	mmresult = timeGetDevCaps(&tc, sizeof(tc));
-	if (mmresult == TIMERR_NOERROR)
-	{
-		/* retrieve best resolution and configure timer services accordingly */
-		uResolution = min(max(tc.wPeriodMin, 0), tc.wPeriodMax);
-		mmresult = timeBeginPeriod(uResolution);
-		if (mmresult == TIMERR_NOERROR)
-		{
-			/* actually retrieve a multimedia timer */
-			mmTimerEventId = timeSetEvent(ms, uResolution, g_hWaitEvent, 0,
+	/* retrieve a multimedia timer */
+	mmTimerEventId = timeSetEvent(ms, g_uResolution, g_hWaitEvent, 0,
 	    TIME_ONESHOT | TIME_CALLBACK_EVENT_SET);
 	if (mmTimerEventId != 0)
 	{
@@ -467,13 +471,7 @@ void wait(int ms)
 		/* relieve the timer from its duties */
 		timeKillEvent(mmTimerEventId);
 	}
-
-			/* relax timer service constraints */
-			timeEndPeriod (uResolution);
 }
-	}
-}
-
 
 /**
  * Main function of the windows simulator.
@@ -495,6 +493,9 @@ int APIENTRY WinMain(HINSTANCE hInstance,
 	int nExitCode = 0;
 
 	if ((hWnd = simCreateWindow(hInstance, nCmdShow)) != NULL)
+	{
+		/* retrieve minimum timer resolution */
+		if (simSetMinimumTimerResolution() == TIMERR_NOERROR)
 		{
 			/* event handle for multimedia timer (for the wait() function) */
 			g_hWaitEvent = CreateEventA(NULL, TRUE, FALSE, "Local\\WaitEvent");
@@ -504,7 +505,8 @@ int APIENTRY WinMain(HINSTANCE hInstance,
 				hLoopThread = CreateThread(NULL, 0, simLoop, NULL, 0, NULL);
 				if (hLoopThread != NULL)
 				{
-				SetThreadPriority(hLoopThread, THREAD_PRIORITY_TIME_CRITICAL);
+					SetThreadPriority(hLoopThread,
+					THREAD_PRIORITY_TIME_CRITICAL);
 
 					/* issue a UI timer message every 40 ms (roughly 25 fps) */
 					uTimerId = SetTimer(hWnd, 23, 40, NULL);
@@ -522,14 +524,14 @@ int APIENTRY WinMain(HINSTANCE hInstance,
 					}
 					else
 					{
-					fprintf(stderr, g_strErrorCreateUITimer);
+						fprintf(stderr, g_strErrCreateUITimer);
 					}
 
 					TerminateThread(hLoopThread, 0);
 				}
 				else
 				{
-				fprintf(stderr, g_strErrorCreateThread);
+					fprintf(stderr, g_strErrCreateThread);
 				}
 
 				/* relieve wait event object from its duties */
@@ -537,14 +539,22 @@ int APIENTRY WinMain(HINSTANCE hInstance,
 			}
 			else
 			{
-			fprintf(stderr, g_strErrorCreateEvent);
+				fprintf(stderr, g_strErrCreateEvent);
+			}
+
+			/* relieve timer resolution constraints */
+			timeEndPeriod(g_uResolution);
+		}
+		else
+		{
+			fprintf(stderr, g_strErrTimerResolution);
 		}
 
 		simDestroyWindow(hWnd, hInstance);
 	}
 	else
 	{
-		fprintf(stderr, g_strErrorCreateWindow);
+		fprintf(stderr, g_strErrCreateWindow);
 	}
 
 	return nExitCode;