iOS: Check FBO status and return failure from QIOSContext::makeCurrent()

The Khronos documentation for glCheckFramebufferStatus recommends calling
the function to see if the framebuffer is complete prior to rendering.

We now give more info to clients that call makeCurrent(), by storing the
state of the default FBO and returning that, instead of always returning
true and leaving the clients vulnerable to calling OpenGL functions on a
non-complete FBO.

Change-Id: Ia99c21f811ac799b350f07e73b2ae4b173d71120
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/src/plugins/platforms/ios/qioscontext.h b/src/plugins/platforms/ios/qioscontext.h
index c48a0251a9..52357a5d58 100644
--- a/src/plugins/platforms/ios/qioscontext.h
+++ b/src/plugins/platforms/ios/qioscontext.h
@@ -85,10 +85,12 @@ private:
         GLuint depthRenderbuffer;
         GLint renderbufferWidth;
         GLint renderbufferHeight;
+        bool isComplete;
     };
 
     static void deleteBuffers(const FramebufferObject &framebufferObject);
 
+    FramebufferObject &backingFramebufferObjectFor(QPlatformSurface *) const;
     mutable QHash<QIOSWindow *, FramebufferObject> m_framebufferObjects;
 };