Fix #34997: when starting the game engine in one window and switching to a second

window, the game would stop drawing in the first and mess up the OpenGL state of
the second.

Also fixes glPushAttrib/glPopAttrib getting out of sync in some cases.

5 files changed, 32 insertions, 20 deletions

diff --git a/source/gameengine/BlenderRoutines/BL_KetsjiEmbedStart.cpp b/source/gameengine/BlenderRoutines/BL_KetsjiEmbedStart.cpp
index 38302a51a45..dbb7cbc1816 100644
--- a/source/gameengine/BlenderRoutines/BL_KetsjiEmbedStart.cpp
+++ b/source/gameengine/BlenderRoutines/BL_KetsjiEmbedStart.cpp
@@ -210,6 +210,7 @@ static int BL_KetsjiPyNextFrame(void *state0)
 extern "C" void StartKetsjiShell(struct bContext *C, struct ARegion *ar, rcti *cam_frame, int always_use_expand_framing)
 {
 	/* context values */
+	struct wmWindowManager *wm= CTX_wm_manager(C);
 	struct wmWindow *win= CTX_wm_window(C);
 	struct Scene *startscene= CTX_data_scene(C);
 	struct Main* maggie1= CTX_data_main(C);
@@ -276,7 +277,7 @@ extern "C" void StartKetsjiShell(struct bContext *C, struct ARegion *ar, rcti *c
 		if (animation_record) usefixed= false; /* override since you don't want to run full-speed for sim recording */
 
 		// create the canvas, rasterizer and rendertools
-		RAS_ICanvas* canvas = new KX_BlenderCanvas(win, area_rect, ar);
+		RAS_ICanvas* canvas = new KX_BlenderCanvas(wm, win, area_rect, ar);
 		
 		// default mouse state set on render panel
 		if (mouse_state)
diff --git a/source/gameengine/BlenderRoutines/KX_BlenderCanvas.cpp b/source/gameengine/BlenderRoutines/KX_BlenderCanvas.cpp
index b6c41064282..3bd1c02f12e 100644
--- a/source/gameengine/BlenderRoutines/KX_BlenderCanvas.cpp
+++ b/source/gameengine/BlenderRoutines/KX_BlenderCanvas.cpp
@@ -37,7 +37,8 @@
 #include <assert.h>
 
 
-KX_BlenderCanvas::KX_BlenderCanvas(struct wmWindow *win, RAS_Rect &rect, struct ARegion *ar) :
+KX_BlenderCanvas::KX_BlenderCanvas(wmWindowManager *wm, wmWindow *win, RAS_Rect &rect, struct ARegion *ar) :
+m_wm(wm),
 m_win(win),
 m_frame_rect(rect)
 {
@@ -81,20 +82,29 @@ bool KX_BlenderCanvas::GetFullScreen()
 	return false;
 }
 
+bool KX_BlenderCanvas::BeginDraw()
+{
+	// in case of multi-window we need to ensure we are drawing to the correct
+	// window always, because it may change in window event handling
+	BL_MakeDrawable(m_wm, m_win);
+	return true;
+}
+
+
+void KX_BlenderCanvas::EndDraw()
+{
+	// nothing needs to be done here
+}
+
 void KX_BlenderCanvas::BeginFrame()
 {
 	glEnable(GL_DEPTH_TEST);
 	glDepthFunc(GL_LEQUAL);
-
 }
 
 
 void KX_BlenderCanvas::EndFrame()
 {
-		// this is needed, else blender distorts a lot
-	glPopAttrib();
-	glPushAttrib(GL_ALL_ATTRIB_BITS);
-		
 	glDisable(GL_FOG);
 }
 
diff --git a/source/gameengine/BlenderRoutines/KX_BlenderCanvas.h b/source/gameengine/BlenderRoutines/KX_BlenderCanvas.h
index bc487504eeb..c201d866efe 100644
--- a/source/gameengine/BlenderRoutines/KX_BlenderCanvas.h
+++ b/source/gameengine/BlenderRoutines/KX_BlenderCanvas.h
@@ -49,6 +49,7 @@
 
 struct ARegion;
 struct wmWindow;
+struct wmWindowManager;
 
 /**
  * 2D Blender device context abstraction. 
@@ -69,7 +70,7 @@ public:
 	 * 
 	 * \param area The Blender ARegion to run the game within.
 	 */
-	KX_BlenderCanvas(struct wmWindow* win, class RAS_Rect &rect, struct ARegion* ar);
+	KX_BlenderCanvas(struct wmWindowManager *wm, struct wmWindow* win, class RAS_Rect &rect, struct ARegion* ar);
 	~KX_BlenderCanvas();
 
 		void 
@@ -186,25 +187,17 @@ public:
 		const char* filename
 	);
 	
-	/**
-	 * Nothing needs be done for BlenderCanvas
-	 * Begin/End Draw, as the game engine GL context
-	 * is always current/active.
-	 */
-
 		bool 
 	BeginDraw(
-	) {
-			return true;
-	};
+	);
 
 		void 
 	EndDraw(
-	) {
-	};
+	);
 
 private:
 	/** Blender area the game engine is running within */
+	struct wmWindowManager *m_wm;
 	struct wmWindow* m_win;
 	RAS_Rect	m_frame_rect;
 	RAS_Rect 	m_area_rect;
diff --git a/source/gameengine/BlenderRoutines/KX_BlenderGL.cpp b/source/gameengine/BlenderRoutines/KX_BlenderGL.cpp
index f43f8c30d57..61598995040 100644
--- a/source/gameengine/BlenderRoutines/KX_BlenderGL.cpp
+++ b/source/gameengine/BlenderRoutines/KX_BlenderGL.cpp
@@ -93,6 +93,11 @@ void BL_SwapBuffers(wmWindow *win)
 	wm_window_swap_buffers(win);
 }
 
+void BL_MakeDrawable(wmWindowManager *wm, wmWindow *win)
+{
+	wm_window_make_drawable(wm, win);
+}
+
 static void DisableForText()
 {
 	glPolygonMode(GL_FRONT_AND_BACK, GL_FILL); /* needed for texture fonts otherwise they render as wireframe */
diff --git a/source/gameengine/BlenderRoutines/KX_BlenderGL.h b/source/gameengine/BlenderRoutines/KX_BlenderGL.h
index 0f35494c73a..54e76ff6489 100644
--- a/source/gameengine/BlenderRoutines/KX_BlenderGL.h
+++ b/source/gameengine/BlenderRoutines/KX_BlenderGL.h
@@ -36,13 +36,16 @@
 extern "C" {
 #endif  /* __cplusplus */
 
-struct wmWindow;
 struct ARegion;
 struct bScreen;
+struct wmWindow;
+struct wmWindowManager;
 
 // special swapbuffers, that takes care of which area (viewport) needs to be swapped
 void	BL_SwapBuffers(struct wmWindow *win);
 
+void	BL_MakeDrawable(struct wmWindowManager *wm, struct wmWindow *win);
+
 void	BL_warp_pointer(struct wmWindow *win,int x,int y);
 
 void	BL_MakeScreenShot(struct bScreen *screen, struct ScrArea *curarea, const char *filename);