[Cogl] [PATCH] sdl: Bind the default window when currently bound window is destroyed

[Neil Roberts]

Cogl always needs to have the context bound to something so that it
can freely create resources such as textures even if there is no
current window. When the currently bound SDLWindow is destroyed, SDL
apparently explicitly unbinds the GL context. If something then later
for example tries to create a texture Cogl would start getting GL
errors and fail. To fix this the SDL winsys now just binds the dummy
window before deiniting the currently bound onscreen.
---
 cogl/winsys/cogl-winsys-sdl2.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/cogl/winsys/cogl-winsys-sdl2.c b/cogl/winsys/cogl-winsys-sdl2.c
index 8c0c256..ca4f5fd 100644
--- a/cogl/winsys/cogl-winsys-sdl2.c
+++ b/cogl/winsys/cogl-winsys-sdl2.c
@@ -388,7 +388,18 @@ _cogl_winsys_onscreen_deinit (CoglOnscreen *onscreen)
       CoglContextSdl2 *sdl_context = context->winsys;
 
       if (sdl_context->current_window == sdl_onscreen->window)
-        sdl_context->current_window = NULL;
+        {
+          CoglDisplaySdl2 *sdl_display = context->display->winsys;
+
+          /* SDL explicitly unbinds the context when the currently
+           * bound window is destroyed. Cogl always needs a context
+           * bound so that for example it can create texture resources
+           * at any time even without flushing a framebuffer.
+           * Therefore we'll bind the dummy window. */
+          SDL_GL_MakeCurrent (sdl_display->dummy_window,
+                              sdl_display->context);
+          sdl_context->current_window = sdl_display->dummy_window;
+        }
 
       SDL_DestroyWindow (sdl_onscreen->window);
       sdl_onscreen->window = NULL;
-- 
1.7.11.3.g3c3efa5