WM: Event simulation support for Python

This feature is intended only for testing,
to automate simulating user input.

- Enabled by '--enable-event-simulate'.
- Disables handling all real input events.
- Access by calling `Window.event_simulate(..)`
- Disabling `bpy.app.use_event_simulate`
  to allow handling real events (can only disable).

Currently only mouse & keyboard events work well,
NDOF, IME... etc could be added as needed.

See D4286 for example usage.

3 files changed, 24 insertions, 0 deletions

diff --git a/source/blender/windowmanager/WM_api.h b/source/blender/windowmanager/WM_api.h
index 613374dc1df..7d8f5c1c0b2 100644
--- a/source/blender/windowmanager/WM_api.h
+++ b/source/blender/windowmanager/WM_api.h
@@ -616,6 +616,9 @@ bool        WM_event_is_tablet(const struct wmEvent *event);
 bool        WM_event_is_ime_switch(const struct wmEvent *event);
 #endif
 
+/* For testing only 'G_FLAG_EVENT_SIMULATE' */
+struct wmEvent *WM_event_add_simulate(struct wmWindow *win, const struct wmEvent *event_to_add);
+
 const char *WM_window_cursor_keymap_status_get(const struct wmWindow *win, int button_index, int type_index);
 void WM_window_cursor_keymap_status_refresh(struct bContext *C, struct wmWindow *win);
 
diff --git a/source/blender/windowmanager/intern/wm_event_system.c b/source/blender/windowmanager/intern/wm_event_system.c
index 8ccc2457a90..a2ee5f04449 100644
--- a/source/blender/windowmanager/intern/wm_event_system.c
+++ b/source/blender/windowmanager/intern/wm_event_system.c
@@ -127,6 +127,18 @@ wmEvent *wm_event_add(wmWindow *win, const wmEvent *event_to_add)
 	return wm_event_add_ex(win, event_to_add, NULL);
 }
 
+wmEvent *WM_event_add_simulate(wmWindow *win, const wmEvent *event_to_add)
+{
+	if ((G.f & G_FLAG_EVENT_SIMULATE) == 0) {
+		BLI_assert(0);
+		return NULL;
+	}
+	wmEvent *event = wm_event_add(win, event_to_add);
+	win->eventstate->x = event->x;
+	win->eventstate->y = event->y;
+	return event;
+}
+
 void wm_event_free(wmEvent *event)
 {
 	if (event->customdata) {
@@ -3899,6 +3911,10 @@ void wm_event_add_ghostevent(wmWindowManager *wm, wmWindow *win, int type, int U
 {
 	wmWindow *owin;
 
+	if (UNLIKELY(G.f & G_FLAG_EVENT_SIMULATE)) {
+		return;
+	}
+
 	/* Having both, event and evt, can be highly confusing to work with, but is necessary for
 	 * our current event system, so let's clear things up a bit:
 	 * - data added to event only will be handled immediately, but will not be copied to the next event
diff --git a/source/blender/windowmanager/intern/wm_window.c b/source/blender/windowmanager/intern/wm_window.c
index fa11979e39e..79e6b5104a3 100644
--- a/source/blender/windowmanager/intern/wm_window.c
+++ b/source/blender/windowmanager/intern/wm_window.c
@@ -1049,6 +1049,11 @@ void wm_cursor_position_to_ghost(wmWindow *win, int *x, int *y)
 
 void wm_get_cursor_position(wmWindow *win, int *x, int *y)
 {
+	if (UNLIKELY(G.f & G_FLAG_EVENT_SIMULATE)) {
+		*x = win->eventstate->x;
+		*y = win->eventstate->y;
+		return;
+	}
 	GHOST_GetCursorPosition(g_system, x, y);
 	wm_cursor_position_from_ghost(win, x, y);
 }