glViewport broken

I wondering how many other users are affected by this bug.

I have observed that DoomLegacy with OpenGL, using splitscreen, will draw the lower screen over the upper screen.

My test is:

> doomlegacy -opengl -game doom2

Select two player game, and start server.  If you have the OpenGL bug, at the game start the lower screen will be drawn over the upper screen.  Turning the player2 sideways or moving him back and forth will expose the upper screen.

This works perfectly on my other machines and Linux 2.6, but is failing on my latest Linux 4.4.

I have traced this to a failing call to  glViewport.   In a test I set the viewport to a smaller window, but the call is completely ignored by OpenGL.   It appears that the draw window is only set to fullscreen size.

I have a new install of Linux 4.4, Slackware 14.2, using Nouveau for a nVidia card.   My older Linux 2.6 uses an obsolete nVidia proprietary driver that has major problems even with Linux 2.6.   They use different OpenGL packages.

Does anyone else experience this bug, because otherwise I would have to suspect it just my machine.

An internet search shows that others have experienced a failure of the glViewport function.

Thank You.

On 9/5/2017 at 11:05 PM, wesleyjohnson said:

I have a new install of Linux 4.4, Slackware 14.2, using Nouveau for a nVidia card.

 

To me that sounds like the cause here. Have you tried the latest proprietary driver?