Enable capturing raw Xinput2 touch events and use to flag global mouse state as dirty

- Touch events may be translated to mouse movement events without the normal Xinput2 raw motion events
  being sent. Not all touch events will necessarily move the mouse but this ensures we update the global
  mouse state just in case.

- Fix up some formatting

CR: saml

src/video/x11/SDL_x11xinput2.c

@@ -120,7 +120,7 @@ X11_InitXinput2(_THIS)
 
     int version = 0;
     XIEventMask eventmask;
-    unsigned char mask[3] = { 0,0,0 };
+    unsigned char mask[4] = { 0, 0, 0, 0 };
     int event, err;
 
     /*
@@ -149,7 +149,7 @@ X11_InitXinput2(_THIS)
     xinput2_multitouch_supported = xinput2_version_atleast(version, 2, 2);
 #endif
 
-    /* Enable  Raw motion events for this display */
+    /* Enable raw motion events for this display */
     eventmask.deviceid = XIAllMasterDevices;
     eventmask.mask_len = sizeof(mask);
     eventmask.mask = mask;
@@ -158,7 +158,16 @@ X11_InitXinput2(_THIS)
     XISetMask(mask, XI_RawButtonPress);
     XISetMask(mask, XI_RawButtonRelease);
 
-    if (X11_XISelectEvents(data->display,DefaultRootWindow(data->display),&eventmask,1) != Success) {
+#if SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_MULTITOUCH
+    /* Enable raw touch events if supported */
+    if (X11_Xinput2IsMultitouchSupported()) {
+        XISetMask(mask, XI_RawTouchBegin);
+        XISetMask(mask, XI_RawTouchUpdate);
+        XISetMask(mask, XI_RawTouchEnd);
+    }
+#endif
+
+    if (X11_XISelectEvents(data->display, DefaultRootWindow(data->display), &eventmask,1) != Success) {
         return;
     }
 #endif
@@ -168,7 +177,7 @@ int
 X11_HandleXinput2Event(SDL_VideoData *videodata,XGenericEventCookie *cookie)
 {
 #if SDL_VIDEO_DRIVER_X11_XINPUT2
-    if(cookie->extension != xinput2_opcode) {
+    if (cookie->extension != xinput2_opcode) {
         return 0;
     }
     switch(cookie->evtype) {
@@ -197,11 +206,16 @@ X11_HandleXinput2Event(SDL_VideoData *videodata,XGenericEventCookie *cookie)
             prev_rel_coords[1] = relative_coords[1];
             prev_time = rawev->time;
             return 1;
-            }
-            break;
+        }
+        break;
 
         case XI_RawButtonPress:
         case XI_RawButtonRelease:
+#if SDL_VIDEO_DRIVER_X11_XINPUT2_SUPPORTS_MULTITOUCH
+        case XI_RawTouchBegin:
+        case XI_RawTouchUpdate:
+        case XI_RawTouchEnd:
+#endif
             videodata->global_mouse_changed = SDL_TRUE;
             break;
 
@@ -214,7 +228,7 @@ X11_HandleXinput2Event(SDL_VideoData *videodata,XGenericEventCookie *cookie)
 
             if (! pointer_emulated) {
                 SDL_Mouse *mouse = SDL_GetMouse();
-                if(!mouse->relative_mode || mouse->relative_mode_warp) {
+                if (!mouse->relative_mode || mouse->relative_mode_warp) {
                     SDL_Window *window = xinput2_get_sdlwindow(videodata, xev->event);
                     if (window) {
                         SDL_SendMouseMotion(window, 0, 0, xev->event_x, xev->event_y);
@@ -222,8 +236,8 @@ X11_HandleXinput2Event(SDL_VideoData *videodata,XGenericEventCookie *cookie)
                 }
             }
             return 1;
-            }
-            break;
+        }
+        break;
 
         case XI_TouchBegin: {
             const XIDeviceEvent *xev = (const XIDeviceEvent *) cookie->data;
@@ -232,8 +246,8 @@ X11_HandleXinput2Event(SDL_VideoData *videodata,XGenericEventCookie *cookie)
             xinput2_normalize_touch_coordinates(window, xev->event_x, xev->event_y, &x, &y);
             SDL_SendTouch(xev->sourceid, xev->detail, window, SDL_TRUE, x, y, 1.0);
             return 1;
-            }
-            break;
+        }
+        break;
         case XI_TouchEnd: {
             const XIDeviceEvent *xev = (const XIDeviceEvent *) cookie->data;
             float x, y;
@@ -241,8 +255,8 @@ X11_HandleXinput2Event(SDL_VideoData *videodata,XGenericEventCookie *cookie)
             xinput2_normalize_touch_coordinates(window, xev->event_x, xev->event_y, &x, &y);
             SDL_SendTouch(xev->sourceid, xev->detail, window, SDL_FALSE, x, y, 1.0);
             return 1;
-            }
-            break;
+        }
+        break;
         case XI_TouchUpdate: {
             const XIDeviceEvent *xev = (const XIDeviceEvent *) cookie->data;
             float x, y;
@@ -250,8 +264,9 @@ X11_HandleXinput2Event(SDL_VideoData *videodata,XGenericEventCookie *cookie)
             xinput2_normalize_touch_coordinates(window, xev->event_x, xev->event_y, &x, &y);
             SDL_SendTouchMotion(xev->sourceid, xev->detail, window, x, y, 1.0);
             return 1;
-            }
-            break;
+        }
+        break;
+
 #endif
     }
 #endif