Rendering GUI in multiple viewports - OGRE

[Jabberwocky]

As far as the flickering goes

Here's a bit of additional information that may be relevant to the flickering issue.

Even using a single viewport, I've noticed some flakiness with the following:

1. FRAPS
The fraps number overlay is sometimes displayed, sometimes not. The FRAPS overlay visibility seems to change as different windows are activated or deactivated. This was not a problem previous to 0.7.x

2. Ogre Overlays
I use ogre overlays for a small number of things in my game, including playing video, and for an in-game console. (I like having the console non-CEGUI based so that I can access in-game testing commands even when I've disabled CEGUI for performance testing purposes).

These ogre overlays exhibit the exact same problem as the FRAPS overlay, which is sometimes they are drawn correctly, other times they are completely invisible. Similarly, these overlays seem to pop in and out as I toggle the visibility on CEGUI windows.

Neither of these are critical issues, although a CEGUI/FRAPS incompatibility would be noticed by both devs and end users.

Once CE is back, I'd be happy to provide any more information that might help diagnose this issue.

[eugen]

Thanks for the anwsers, ill look more into it in the next weeks!

[eugen]

i encountered the FRAPS behavior as well, i sometimes even have the FPS counter shown only partly at a margin of a CEGUI window.
Im using as well some Ogre Overlays at the same time with CEGUI controls. They dont flicker however, only CEGUI controls flicker. The thing is this is only happening in the editor (MFC app, 4 Ogre windows each having one viewport) and not ingame (which is a big releaf cause the editor flickering is not a critical thing for us currently)

[Jabberwocky]

As far as the flickering goes

Here's a bit of additional information that may be relevant to the flickering issue.

Even using a single viewport, I've noticed some flakiness with the following:

1. FRAPS
The fraps number overlay is sometimes displayed, sometimes not. The FRAPS overlay visibility seems to change as different windows are activated or deactivated. This was not a problem previous to 0.7.x

2. Ogre Overlays
I use ogre overlays for a small number of things in my game, including playing video, and for an in-game console. (I like having the console non-CEGUI based so that I can access in-game testing commands even when I've disabled CEGUI for performance testing purposes).

These ogre overlays exhibit the exact same problem as the FRAPS overlay, which is sometimes they are drawn correctly, other times they are completely invisible. Similarly, these overlays seem to pop in and out as I toggle the visibility on CEGUI windows.

Neither of these are critical issues, although a CEGUI/FRAPS incompatibility would be noticed by both devs and end users.

Once CE is back, I'd be happy to provide any more information that might help diagnose this issue.

I just thought I'd post an update to my above issues with ogre overlays and FRAPS.

I've now solved the issue, with a bit of extra code in my CEGUI integration. I believe the problem was a general issue rendering anything after CEGUI. This issue may not be new, I found an old Ogre3D post that discusses a similar problem with an earlier version of CEGUI: Ogre3D: Render *anything* over CEGUI [Solved].

at the moment my best guess is that OgreCEGUIRenderer is doing some state changes that prevent anything from being rendered properly after it

I've noted that this problem doesn't always manifest itself - for example FRAPS seems to work in the CEGUI samples I've tested. I believe it may depend on the properties of the last CEGUI window you've drawn.

Anyway, my fix looks something like this:
(This is my Ogre3D based game, using some game-specific classes, but it should be decipherable):

Code: Select all

      Camera* pCamera = CameraSys()->GetOgreCamera();
      if ( pCamera && pCamera->getViewport() )
      {
         GraphicsSys()->GetOgreRoot()->getRenderSystem()->_setProjectionMatrix( pCamera->getProjectionMatrixRS() );
         GraphicsSys()->GetOgreRoot()->getRenderSystem()->_setViewMatrix( pCamera->getViewMatrix() );
         GraphicsSys()->GetOgreRoot()->getRenderSystem()->_setViewport( pCamera->getViewport() );
      }


If this code is called per-frame, after CEGUI renders, then any subsequent rendering (FRAPS, ogre3D overlays, etc) work just fine.

Hopefully that may help anyone else who stumbles across this somewhat obscure issue.

[CrazyEddie]

Thanks for all this info, testing and what have you regarding this issue.

One of the situations we have when we test is that most of our testing is done using our own samples framework - which is by it's very nature a little bit contrived. What I plan for the future is for the base application for each engine or API to have something a little more substantial in the background, I believe this will enable us to better test the interaction of CEGUI with some 'regular' output from the various engines or APIs - because while everything looks and works great over a blank / static display, it may not under more realistic conditions, so this is something we need to move towards in the new new year

CE.