Fixed bug #611

From  Tim Angus   2008-08-12 11:18:06

I'm one of the maintainers of ioquake3.org, an updated version of the
Quake 3 engine. Relatively recently, we moved ioq3 to use SDL as a
replacement for 95% of the platform specific code that was there. On the
whole it's doing a great job but unfortunately since the move we've been
getting complaints about the quality of the mouse input on the Windows
platform to the point where for many the game is unplayable. Put in
other terms, the current stable SDL 1.2 is basically not fit for purpose
if you need high quality mouse input as you do in a first person shooter.

Over the weekend I decided to pull my finger out and actually figure out
what's going on. There are basically two major problems. Firstly, when
using the "windib" driver, mouse input is gathered via the WM_MOUSEMOVE
message. Googling for this indicates that often this is known to result
in "spurious" and/or "missing" mouse movement events; this is the
primary cause of the poor mouse input. The second problem is that the
"directx" driver does not work at all in combination with OpenGL meaning
that you can't use DirectInput if your application also uses OpenGL. In
other words you're locked into using the "windib" driver and its poor
mouse input.

In order to address these problems I've done the following:

* Remove WM_MOUSEMOVE based motion event generation and replace with
calls to GetCursorPos which seems much more reliable. In order to
achieve this I've moved mouse motion out into a separate function that
is called once per DIB_PumpEvents.

* Remove the restriction on the "directx" driver being inoperable in
combination with OpenGL. There is a bug for this issues that I've
hijacked to a certain extent
(http://bugzilla.libsdl.org/show_bug.cgi?id=265). I'm the first to admit
I don't really understand why this restriction is there in the first
place. The commit message for the bug fix that introduced this
restriction (r581) isn't very elaborate and I couldn't see any other bug
tracking the issue. If anyone has more information on the bug that was
avoided by r581 it would be helpful as I/someone could then look into
addressing the problem without disabling the "directx" driver.

* I've also removed the restriction on not being allowed to use
DirectInput in windowed mode. I couldn't see any reason for this, at
least not from our perspective. I have my suspicions that it'll be
something like matching up the cursor with the mouse coordinates...

* I bumped up the DirectInput API used to version 7 in order to get
access to mouse buttons 4-7. I've had to inject a little bit of the DX7
headers into SDL there as the MinGW ones aren't up to date in this respect.

Author: slouken

configure.in

@@ -2470,7 +2470,7 @@ case "$host" in
         # Set up the system libraries we need
         EXTRA_LDFLAGS="$EXTRA_LDFLAGS -luser32 -lgdi32 -lwinmm"
         if test x$have_directx = xyes; then
-            EXTRA_LDFLAGS="$EXTRA_LDFLAGS -ldxguid"
+            EXTRA_LDFLAGS="$EXTRA_LDFLAGS -ldxguid -ldinput8"
         fi
         # The Win32 platform requires special setup
         SOURCES="$SOURCES $srcdir/src/main/win32/*.rc"

src/video/wincommon/SDL_lowvideo.h

@@ -51,23 +51,32 @@
 /* Hidden "this" pointer for the video functions */
 #define _THIS	SDL_VideoDevice *this
 
+#define FULLSCREEN() \
+	((SDL_VideoSurface->flags & SDL_FULLSCREEN) == SDL_FULLSCREEN)
+
 #define WINDIB_FULLSCREEN()						\
 (									\
 	SDL_VideoSurface &&						\
-	((SDL_VideoSurface->flags & SDL_FULLSCREEN) == SDL_FULLSCREEN) && \
+	FULLSCREEN() && \
 	(((SDL_VideoSurface->flags & SDL_OPENGL   ) == SDL_OPENGL    ) || \
 	((SDL_strcmp(this->name, "windib") == 0) || \
 	 (SDL_strcmp(this->name, "gapi") == 0))) \
 )
 #define DDRAW_FULLSCREEN() 						\
 (									\
 	SDL_VideoSurface &&						\
-	((SDL_VideoSurface->flags & SDL_FULLSCREEN) == SDL_FULLSCREEN) && \
+	FULLSCREEN() && \
 	((SDL_VideoSurface->flags & SDL_OPENGL    ) != SDL_OPENGL    ) && \
 	(SDL_strcmp(this->name, "directx") == 0)				\
 )
 
-#define DINPUT_FULLSCREEN()	DDRAW_FULLSCREEN()
+#define DINPUT_FULLSCREEN() 						\
+(									\
+	FULLSCREEN() && \
+	(strcmp(this->name, "directx") == 0)				\
+)
+
+#define DINPUT() (strcmp(this->name, "directx") == 0)
 
 /* The main window -- and a function to set it for the audio */
 #ifdef _WIN32_WCE

src/video/wincommon/SDL_sysevents.c

@@ -363,7 +363,6 @@ LRESULT CALLBACK WinMessage(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 {
 	SDL_VideoDevice *this = current_video;
 	static int mouse_pressed = 0;
-	static int in_window = 0;
 #ifdef WMMSG_DEBUG
 	fprintf(stderr, "Received windows message:  ");
 	if ( msg > MAX_WMMSG ) {
@@ -508,7 +507,7 @@ LRESULT CALLBACK WinMessage(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 		case WM_XBUTTONDOWN:
 		case WM_XBUTTONUP: {
 			/* Mouse is handled by DirectInput when fullscreen */
-			if ( SDL_VideoSurface && ! DINPUT_FULLSCREEN() ) {
+			if ( SDL_VideoSurface && ! DINPUT() ) {
 				WORD xbuttonval = 0;
 				Sint16 x, y;
 				Uint8 button, state;
@@ -606,7 +605,7 @@ LRESULT CALLBACK WinMessage(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 
 #if (_WIN32_WINNT >= 0x0400) || (_WIN32_WINDOWS > 0x0400)
 		case WM_MOUSEWHEEL: 
-			if ( SDL_VideoSurface && ! DINPUT_FULLSCREEN() ) {
+			if ( SDL_VideoSurface && ! DINPUT() ) {
 				int move = (short)HIWORD(wParam);
 				if ( move ) {
 					Uint8 button;

src/video/wincommon/SDL_sysmouse.c

@@ -188,8 +188,7 @@ int WIN_ShowWMCursor(_THIS, WMcursor *cursor)
 {
 	POINT mouse_pos;
 
-	/* The fullscreen cursor must be done in software with DirectInput */
-	if ( !this->screen || DDRAW_FULLSCREEN() ) {
+	if ( !this->screen ) {
 		return(0);
 	}
 
@@ -208,15 +207,20 @@ int WIN_ShowWMCursor(_THIS, WMcursor *cursor)
 
 void WIN_WarpWMCursor(_THIS, Uint16 x, Uint16 y)
 {
-	if ( DDRAW_FULLSCREEN() ) {
-		SDL_PrivateMouseMotion(0, 0, x, y);
-	} else if ( mouse_relative) {
+	if ( mouse_relative) {
 		/*	RJR: March 28, 2000
 			leave physical cursor at center of screen if
 			mouse hidden and grabbed */
 		SDL_PrivateMouseMotion(0, 0, x, y);
 	} else {
 		POINT pt;
+
+		/* With DirectInput the position doesn't follow
+		 * the cursor, so it is set manually */
+		if ( DINPUT() ) {
+			SDL_PrivateMouseMotion(0, 0, x, y);
+		}
+
 		pt.x = x;
 		pt.y = y;
 		ClientToScreen(SDL_Window, &pt);
@@ -227,20 +231,15 @@ void WIN_WarpWMCursor(_THIS, Uint16 x, Uint16 y)
 /* Update the current mouse state and position */
 void WIN_UpdateMouse(_THIS)
 {
-	RECT rect;
 	POINT pt;
 
-	if ( ! DDRAW_FULLSCREEN() ) {
-		GetClientRect(SDL_Window, &rect);
-		GetCursorPos(&pt);
-		MapWindowPoints(NULL, SDL_Window, &pt, 1);
-		if (PtInRect(&rect, pt) && (WindowFromPoint(pt) == SDL_Window)){
-			SDL_PrivateAppActive(1, SDL_APPMOUSEFOCUS);
-			SDL_PrivateMouseMotion(0,0, (Sint16)pt.x, (Sint16)pt.y);
-		} else {
-			SDL_PrivateAppActive(0, SDL_APPMOUSEFOCUS);
-		}
-	}
+	/* Always unset SDL_APPMOUSEFOCUS to give the WM_MOUSEMOVE event
+	 * handler a chance to install a TRACKMOUSEEVENT */
+	SDL_PrivateAppActive(0, SDL_APPMOUSEFOCUS);
+
+	GetCursorPos(&pt);
+	ScreenToClient(SDL_Window, &pt);
+	SDL_PrivateMouseMotion(0,0, (Sint16)pt.x, (Sint16)pt.y);
 }
 
 /* Check to see if we need to enter or leave mouse relative mode */

src/video/windib/SDL_dibevents.c

@@ -271,6 +271,36 @@ LRESULT DIB_HandleMessage(_THIS, HWND hwnd, UINT msg, WPARAM wParam, LPARAM lPar
 	return(DefWindowProc(hwnd, msg, wParam, lParam));
 }
 
+static void DIB_GenerateMouseMotionEvent(void)
+{
+	extern int mouse_relative;
+	extern int posted;
+
+	POINT mouse;
+	GetCursorPos( &mouse );
+
+	if ( mouse_relative ) {
+		POINT center;
+		center.x = (SDL_VideoSurface->w/2);
+		center.y = (SDL_VideoSurface->h/2);
+		ClientToScreen(SDL_Window, &center);
+
+		mouse.x -= (Sint16)center.x;
+		mouse.y -= (Sint16)center.y;
+		if ( mouse.x || mouse.y ) {
+			SetCursorPos(center.x, center.y);
+			posted = SDL_PrivateMouseMotion(0, 1, mouse.x, mouse.y);
+		}
+	} else if ( SDL_GetAppState() & SDL_APPMOUSEFOCUS ) {
+		ScreenToClient(SDL_Window, &mouse);
+#ifdef _WIN32_WCE
+		if (SDL_VideoSurface)
+			GapiTransform(this->hidden->userOrientation, this->hidden->hiresFix, &mouse.x, &mouse.y);
+#endif
+		posted = SDL_PrivateMouseMotion(0, 0, mouse.x, mouse.y);
+	}
+}
+
 void DIB_PumpEvents(_THIS)
 {
 	MSG msg;
@@ -280,6 +310,10 @@ void DIB_PumpEvents(_THIS)
 			DispatchMessage(&msg);
 		}
 	}
+
+	if ( SDL_GetAppState() & SDL_APPINPUTFOCUS ) {
+		DIB_GenerateMouseMotionEvent( );
+	}
 }
 
 static HKL hLayoutUS = NULL;