Re: [Mesa3d-users] Getting GLUT to work with OSMesa

[Brian P. <bri...@tu...>]

Alexander Mont wrote:
> I have a GLUT-based data visualization application that allows a user to 
> view a scene and manipulate that view using a UI. I want to add a 
> “scripting mode” to the application where the user specifies an input 
> file containing a sequence of commands to execute, and then the program 
> executes those commands and then writes the contents of the display to a 
> file.
> 
>  
> 
> I am trying to use OSMesa for this by using an OSMesa rendering context 
> instead of the one generated by GLUT. I have tried to do this by calling 
> the functions needed to make the OSMesa context instead of the 
> glutCreateWindow() function. However, this doesn’t work: it gives an 
> access violation exception as soon as glutPostRedisplay() is called.
> 
>  
> 
> Is it even possible to get GLUT to recognize an OSMesa rendering 
> context, and if so, how?

GLUT doesn't know anything about OSMesa, but I think it should be 
possible to use both libraries in one app.

Basically, if you're starting with a regular GLUT app, you should be 
able to create and bind an OSMesa rendering context and draw something 
off-screen.  But then, when you're done drawing with OSMesa, you should 
try calling glutSetWindow() to re-bind the original GLUT rendering context.

If you try that and have trouble, if you could send me a simple test 
program I could look into it.


> (I am using the GLUT libraries that are generated by Mesa, not the 
> system’s native GLUT libraries.)
> 
>  
> 
> -Alexander Mont
> 
>  
> 
> (Note that I already have the scripting mode working with the system’s 
> own OpenGL libraries, and copying the contents of a window to a file 
> from there. The reason I want to use OSMesa is because I want to run the 
> scripting mode on machines which do not have windowing systems or even 
> graphics cards.)


-Brian