BGE resize callback

This patch allows callbacks (both C/C++ side and Python side) to be registered for resize events. When the size of the canvas changes, the callbacks will be called. As a demonstration of where this can be used on the C++ side, I've updated the 2D Filters to use a callback. From the Python side it's handy for updating gui libraries such as bgui:
https://code.google.com/p/bgui/

I wasn't sure who to add as "Reviewers". Dalai and Benoit originally discussed resize callbacks some time ago.

[dfelinto, 2011-06-17 17:24:40]

Hi Mitchell,

I never implemented callbacks, but it seems like you did the right way (assuming
GHOST resize event is really not reliable).

I added some code syntax comments along the patch.
(adding bf-codereview as CC)

https://codereview.appspot.com/4639043/diff/1/source/gameengine/Ketsji/KX_Ket...
File source/gameengine/Ketsji/KX_KetsjiEngine.cpp (right):

https://codereview.appspot.com/4639043/diff/1/source/gameengine/Ketsji/KX_Ket...
source/gameengine/Ketsji/KX_KetsjiEngine.cpp:111: * ResizeCallback functions
use a tab between instead of space here (doxygen style along the rest of the
file)

https://codereview.appspot.com/4639043/diff/1/source/gameengine/Ketsji/KX_Ket...
source/gameengine/Ketsji/KX_KetsjiEngine.cpp:209: m_prevWidth(0),
I would not include "prev" in the variable name (i.e. call it m_width and
m_height or m_viewWidth, m_windowsWidth, m_canvasWidth. ...)

https://codereview.appspot.com/4639043/diff/1/source/gameengine/Ketsji/KX_Ket...
source/gameengine/Ketsji/KX_KetsjiEngine.cpp:239: 
don't you also need to clear m_pyfunc?

https://codereview.appspot.com/4639043/diff/1/source/gameengine/Ketsji/KX_Sce...
File source/gameengine/Ketsji/KX_Scene.cpp (right):

https://codereview.appspot.com/4639043/diff/1/source/gameengine/Ketsji/KX_Sce...
source/gameengine/Ketsji/KX_Scene.cpp:129: // This callback is used to update
the 2D filter manager
I don't think we need this comment here.

[Moguri, 2011-06-17 19:25:20]

On 2011/06/17 17:24:40, dfelinto wrote:
> Hi Mitchell,
> 
> I never implemented callbacks, but it seems like you did the right way
(assuming
> GHOST resize event is really not reliable).
> 
> I added some code syntax comments along the patch.
> (adding bf-codereview as CC)
> 
>
https://codereview.appspot.com/4639043/diff/1/source/gameengine/Ketsji/KX_Ket...
> File source/gameengine/Ketsji/KX_KetsjiEngine.cpp (right):
> 
>
https://codereview.appspot.com/4639043/diff/1/source/gameengine/Ketsji/KX_Ket...
> source/gameengine/Ketsji/KX_KetsjiEngine.cpp:111: * ResizeCallback functions
> use a tab between instead of space here (doxygen style along the rest of the
> file)
> 
>
https://codereview.appspot.com/4639043/diff/1/source/gameengine/Ketsji/KX_Ket...
> source/gameengine/Ketsji/KX_KetsjiEngine.cpp:209: m_prevWidth(0),
> I would not include "prev" in the variable name (i.e. call it m_width and
> m_height or m_viewWidth, m_windowsWidth, m_canvasWidth. ...)
> 
>
https://codereview.appspot.com/4639043/diff/1/source/gameengine/Ketsji/KX_Ket...
> source/gameengine/Ketsji/KX_KetsjiEngine.cpp:239: 
> don't you also need to clear m_pyfunc?
> 
>
https://codereview.appspot.com/4639043/diff/1/source/gameengine/Ketsji/KX_Sce...
> File source/gameengine/Ketsji/KX_Scene.cpp (right):
> 
>
https://codereview.appspot.com/4639043/diff/1/source/gameengine/Ketsji/KX_Sce...
> source/gameengine/Ketsji/KX_Scene.cpp:129: // This callback is used to update
> the 2D filter manager
> I don't think we need this comment here.

The m_pyfunc reference is dealt with in ResizeCallback's destructor, so it
doesn't need to be handled in KX_KetsjiEngine's destructor. As for the comment
in KX_Scene, I added it because it was a 2d filter callback placed in KX_Scene.
Since this seemed a touch out of place, I decided to add a comment. I'll create
a new patch addressing some of the other comments.

[Moguri, 2011-06-17 19:25:42]

https://codereview.appspot.com/4639043/diff/1/source/gameengine/Ketsji/KX_Ket...
File source/gameengine/Ketsji/KX_KetsjiEngine.cpp (right):

https://codereview.appspot.com/4639043/diff/1/source/gameengine/Ketsji/KX_Ket...
source/gameengine/Ketsji/KX_KetsjiEngine.cpp:239: 
On 2011/06/17 17:24:41, dfelinto wrote:
> don't you also need to clear m_pyfunc?

decrefing m_pyfunc is handled in ResizseCallback's destructor.