[Freeciv-Dev] Re: OpenGL

[Raimar Falke <i-freeciv-lists@xxxxxxxxxxxxx>]

On Tue, Feb 03, 2004 at 05:52:47PM +0000, Vasco Alexandre Da Silva Costa wrote:
> On Tue, 3 Feb 2004, Raimar Falke wrote:
> 
> > Looks like I have no luck. First running my OpenGL program crashed
> > randomly two times my X server. No other program "achieved" this so
> > far. Than I search long times why the output doesn't look like it
> > should. It turns out that the OpenGL implementation I used created the
> > wrong results. Compare
> > http://freeciv.org/~rfalke/fs6_pics/opengl-correct.png with
> > http://freeciv.org/~rfalke/fs6_pics/opengl-wrong.png.
> 
> You sure they are the wrong results?

Yes. There were some more distored results which I didn't capture.

> This is a 3D API with optional lighting and shading. From the looks
> of the second image, it looks like you turned lighting on.

Yes it looks so. But it isn't the case. I don't have an
glEnable(GL_LIGHTING) call.


> Try only setting the ambient light color component for the text.

> The line also seems to be there, at least I note that the small 'a'
> and 'm' seem to be slashed in the right places. It is just the color
> which is all wrong, compared to what you want.

Yes. The line is visible in the first drawing of both outputs. But in
subsequent redraws it is drawed in the background color. It _was_ ok
in the mesa outputs. But this is also no longer the case. Ahh. I
attached the source code and an example output. 

(in redraw()) I set the color white IMHO correct here:

    glNewList(1, GL_COMPILE);

    glColor3f(1, 1, 1);

    glBegin(GL_LINES);
    glVertex3f(0, 0, 1.0);
    glVertex3f(640, 480, 1.0);

    glVertex3f(0, 480, 1.0);
    glVertex3f(640, 0, 1.0);

    glEnd();
    glEndList();

for the list 1. Later this list is called and is drawn as you see in
the screenshot. But not in white.

> > So can someone confirm that one of the following components is buggy
> > (should all come from XFree86)?
> >
> >   server glx vendor string: SGI
> >   server glx version string: 1.2
> >
> >   client glx vendor string: NVIDIA Corporation
> >   client glx version string: 1.3
> 
> I don't think you will manage to use NVIDIA 3D DRI hardware drivers on an
> ATI graphics card. You should download 3D ATI drivers either from the ATI
> website or from http://dri.sf.net . I do not know which will be best for
> you.

I wonder why these NVIDIA drivers are still there.

> >   OpenGL vendor string: Mesa project: www.mesa3d.org
> >   OpenGL renderer string: Mesa GLX Indirect
> >   OpenGL version string: 1.3 Mesa 4.0.4
> >
> > Does anybody has an advice what OpenGL implementation should be used
> > for a "ATI Radeon 9200 SE" card in compination with XFree86 4.3?
> >
> > For now I'm using MESA. Does anybody has an numbers on performance to
> > share?
> 
> I suspect Mesa is falling back to a software 3D rendering mode since you
> have the wrong 3D hardware driver installed. Hence the "Mesa GLX Indirect"
> string.

Software rendering is ok since I can expect that it rather bugfree and
doesn't depend on the driver-hardware combo.

        Raimar

-- 
 email: rf13@xxxxxxxxxxxxxxxxx
 "Reality? That's where the pizza delivery guy comes from!"

back_end_opengl_glx.c
Description: Text document

opengl-lines.png
Description: PNG image