Created attachment 2862[details]
Initialize depth buffer on startup.
The menu and loading screen are (randomly) corrupted on IRIX until a game is started. The corruption only affects (some random parts of) the (black) background areas, where the mouse cursor sometimes leaves trails. The corrupted areas may flicker terribly, possibly showing some parts of the id logo video shown before.
This is reported e.g. here:
http://forums.nekochan.net/viewtopic.php?f=15&t=12556&view=unread#p133490
It turns out that the depth buffer is not properly initialized.The enclosed patch initializes the depth buffer of both front and back buffers to 1.0, however it would probably be better to perform this when clearing the screen to show the menu.
This is strange. Have a look at RB_BeginDrawingView() in tr_backend.c
It clears the depth buffer there, after qglClearDepth( 1.0f ); in GL_SetDefaultState() from tr_init.c
I feel uncomfortable with this patch. This code doesn't seem to belong where it is right now.
You're of course correct that RB_BeginDrawingView() is a much more suitable place to clear the depth buffer, however, the way it's set up now, It only clears the top part with the Quake III Arena logo. If one moves the SetViewportAndScissor(); after the qglClear(), the entire screen's depth buffer is cleared and no corruption occurs.
(In reply to comment #6)
> Do you have any other ideas how/where this bug could be fixed more selectively,
> i.e. just for the black area in the main menu?
How about the function: GL_SetDefaultState()?
I would go with your first version of the patch then, just that it's added in GL_SetDefaultState() function inside the renderer.
Would that be okay?
A screenshot of e4227d1cd59f3a6877e1f18dc4c500fe499dc199 showing the remains of the intro video, a few left behind mouse pointers and some noise is at http://canavan.de/ioquake_irix_menu_corrupted.jpg
Comment 15Zachary J. Slater
2013-10-08 16:35:39 EDT
(In reply to comment #14)
> A screenshot of e4227d1cd59f3a6877e1f18dc4c500fe499dc199 showing the remains
> of the intro video, a few left behind mouse pointers and some noise is at
> http://canavan.de/ioquake_irix_menu_corrupted.jpg
Are you sure that the glClear calls are necessary? It smells to me like some state is not set properly when the background is cleared. My advice is to look into what (if anything) is drawing the background and figure out why it's not taking effect in your case. Like I say my guess would be that there is some GL state that's wrong at that point.
Adding code to actually do drawing to GL_SetDefaultState is probably the wrong way to fix it.
It's quite possible that glClear() calls are uneccesary. A single call before drawing the Menu may be sufficient, however I'm not ver well versed in either OpenGL or ioquake.
If anyone with sufficient knowledge in both of those is interested in helping out, I may be able to provide ssh and VNC access to a computer that's not terribly slow.
Comment 18Zachary J. Slater
2013-10-09 18:45:10 EDT
Please do not reopen this issue. I do not believe it makes sense for ioquake3 to continue supporting irix. If you would like to continue discussing this feel free to email me directly zachary@ioquake.org
I recommend that you fork ioquake3 on GitHub for continued irix support and issue tracking:
https://help.github.com/articles/fork-a-repo
Created attachment 2864 [details] SetViewportAndScissor() after qglClear()Created attachment 3251 [details] GL_SetDefaultState Attempt to clear all buffers in GL_SetDefaultState()