* Tablet support fixup

This commit should hopefully fix some of the problems some people were
having with tablet support in sculpt mode, and also the problems I made
visible with my previous commit related to number field dragging.

Now, all the ghost related stuff is tucked away in ghostwinlay.c and a
simple Blender API, similar to the existing get_mbut() for example, is
provided to access the tablet data. As with the other mouse related data in
Blender, the tablet data is cached upon each mouse move or click, in the
Window struct.

You can now just use:

float get_pressure(void);
void get_tilt(float *xtilt, float *ytilt);
short get_activedevice(void);

to get such data from the tablet. Documentation on the returned data
is in ghostwinlay.c in the _Window struct definition.


Brecht and Nicholas, I've updated the painting and sculpt code and it works
just fine here, you may want to give it a check though to make sure I
haven't done anything silly.

1 files changed, 55 insertions, 11 deletions

diff --git a/source/blender/src/ghostwinlay.c b/source/blender/src/ghostwinlay.c
index ff0e3727370..a19ce2c6b7e 100644
--- a/source/blender/src/ghostwinlay.c
+++ b/source/blender/src/ghostwinlay.c
@@ -75,22 +75,36 @@ void getMacAvailableBounds(short *, short *, short *, short *);
 struct _Window {
 	GHOST_WindowHandle	ghostwin;
 	
-		/* Handler and private data for handler */
+	/* Handler and private data for handler */
 	WindowHandlerFP		handler;
 	void				*user_data;
 	
-		/* Window state */
+	/* Window state */
 	int		size[2], position[2];
 	int		active, visible;
 	
-		/* Last known mouse/button/qualifier state */
+	/* Last known mouse/button/qualifier state */
 	int		lmouse[2];
 	int		lqual;		/* (LR_SHFTKEY, LR_CTRLKEY, LR_ALTKEY, LR_COMMANDKEY) */
 	int		lmbut;		/* (L_MOUSE, M_MOUSE, R_MOUSE) */
 
-		/* Tracks the faked mouse button, if non-zero it is
-		 * the event number of the last faked button.
-		 */
+	/* xtilt and ytilt represent how much the pen is tilted away from 
+	 * vertically upright in either the X or Y direction, with X and Y the
+	 * axes of the tablet surface.
+	 * In other words, Xtilt and Ytilt are components of a vector created by projecting
+	 * the pen's angle in 3D space vertically downwards on to the XY plane
+	 * --Matt
+	 */
+	float pressure;			/* tablet pressure - 0.0 (no pressure) to 1.0 (full pressure) */
+							/* mouse clicks and non-contacting stylus buttons generate pressure of 0.0. */
+	float xtilt, ytilt;		/* tablet tilt value - x and y components of 3D angle 
+							 * ranging from 0.0 (pen upright) to 1.0 (pen fully leaning over) */
+	short activedevice;		/* Active input device currently in use (DEV_MOUSE, DEV_STYLUS, DEV_ERASER) */
+	
+	
+	/* Tracks the faked mouse button, if non-zero it is
+	 * the event number of the last faked button.
+	 */
 	int		faked_mbut;
 
 	GHOST_TimerTaskHandle	timer;
@@ -488,6 +502,24 @@ static int change_bit(int val, int bit, int to_on) {
 	return to_on?(val|bit):(val&~bit);
 }
 
+static void update_tablet_data(Window *win, Window *ghostwin) {
+	const GHOST_TabletData *td= GHOST_GetTabletData(ghostwin);
+	
+	/* if there's tablet data from an active tablet device then use it,
+	 * otherwise set all tablet related data to default */
+	if ((td != NULL) && ELEM(td->Active, DEV_STYLUS, DEV_ERASER)) {
+		win->activedevice = (short)td->Active;
+		win->pressure = td->Pressure;
+		win->xtilt = td->Xtilt;
+		win->ytilt = td->Ytilt;
+	} else {
+		win->activedevice = DEV_MOUSE;
+		win->pressure = 0.0;
+		win->xtilt = win->ytilt = 0.0;
+	}
+}
+
+
 static int event_proc(GHOST_EventHandle evt, GHOST_TUserDataPtr private) 
 {
 	GHOST_TEventType type= GHOST_GetEventType(evt);
@@ -517,12 +549,14 @@ static int event_proc(GHOST_EventHandle evt, GHOST_TUserDataPtr private)
 		case GHOST_kEventCursorMove: {
 			if(win->active == 1) {
 				GHOST_TEventCursorData *cd= data;
+				
 				int cx, cy;
 				
 				GHOST_ScreenToClient(win->ghostwin, cd->x, cd->y, &cx, &cy);
 				win->lmouse[0]= cx;
 				win->lmouse[1]= (win->size[1]-1) - cy;
 				
+				update_tablet_data(win, ghostwin);			
 				window_handle(win, MOUSEX, win->lmouse[0]);
 				window_handle(win, MOUSEY, win->lmouse[1]);
 			}
@@ -557,6 +591,8 @@ static int event_proc(GHOST_EventHandle evt, GHOST_TUserDataPtr private)
 			} else {
 				win->lmbut= change_bit(win->lmbut, R_MOUSE, val);
 			}
+			
+			update_tablet_data(win, ghostwin);
 			window_handle(win, bbut, val);
 			
 			break;
@@ -709,16 +745,24 @@ void window_get_mouse(Window *win, short *mval) {
 	mval[1]= win->lmouse[1];
 }
 
+float window_get_pressure(Window *win) {
+	return win->pressure;
+}
+
+void window_get_tilt(Window *win, float *xtilt, float *ytilt) {
+	*xtilt= win->xtilt;
+	*ytilt= win->ytilt;
+}
+
+short window_get_activedevice(Window *win) {
+	return win->activedevice;
+}
+
 void window_get_position(Window *win, int *posx_r, int *posy_r) {
 	*posx_r= win->position[0];
 	*posy_r= win->position[1];
 }
 
-const GHOST_TabletData* window_get_tablet_data(Window *win)
-{
-	return GHOST_GetTabletData(win->ghostwin);
-}
-
 void window_get_size(Window *win, int *width_r, int *height_r) {
 	*width_r= win->size[0];
 	*height_r= win->size[1];