glPolygonMode( GL_FRONT_AND_BACK, GL_LINE ) not working with vertex arrays on laptop

[Carl Bateman]

I'm learning and playing around with OpenGL vertex arrays.

Working with some sample code from the codesampler.com site
(ogl_indexed_geometry, if it's relevant), I'm trying to show a wireframe
cube.

I've added the line to the render function and it works fine on my desktop,
glPolygonMode( GL_FRONT_AND_BACK, GL_LINE );

but when I do the same on my laptop (Fujitsu-Siemens Amilo L7300) nothing is
displayed. Removing the line renders a solid cube on both machines.

Oddly glutWireCube works fine, but sadly isn't any real use to me since I
want to extend this for other 3d models.

Anyone have any ideas why this might be so?

TIA

Carl Bateman

[jbwest]

Post by Carl Bateman
I'm learning and playing around with OpenGL vertex arrays.
Working with some sample code from the codesampler.com site
(ogl_indexed_geometry, if it's relevant), I'm trying to show a wireframe
cube.
I've added the line to the render function and it works fine on my desktop,
glPolygonMode( GL_FRONT_AND_BACK, GL_LINE );
but when I do the same on my laptop (Fujitsu-Siemens Amilo L7300) nothing is
displayed. Removing the line renders a solid cube on both machines.
Oddly glutWireCube works fine, but sadly isn't any real use to me since I
want to extend this for other 3d models.
Anyone have any ideas why this might be so?
TIA
Carl Bateman

Do you have backface/frontface culling on ?

jbw

[Carl Bateman]

Post by jbwest
Do you have backface/frontface culling on ?
jbw

Short answer, I don't know, I'm a noob. However, I've tried variations of
glEnable/glDisable (GL_CULL_FACE)
but to no avail.

However,
glDrawElements(GL_LINE_STRIP, 4, GL_UNSIGNED_INT, cube_indexes);
and
glDrawElements(GL_LINES, 4, GL_UNSIGNED_INT, cube_indexes);
do give me lines.


I program during my daily commute, but since OpenGL doesn't seem to properly
implemented I have a problem. It slows dev work, but nothing catastrophic.
I'm asking about this more out of curiosity than anything else, I was
wondering whether this is a known issue and what the cause might be.


Sorry for delay in replying I have limited access to news servers I can post
from.

CB

[jbwest]

Post by Carl Bateman

Post by jbwest
Do you have backface/frontface culling on ?
jbw

Short answer, I don't know, I'm a noob. However, I've tried variations of
glEnable/glDisable (GL_CULL_FACE)
but to no avail.
However,
glDrawElements(GL_LINE_STRIP, 4, GL_UNSIGNED_INT, cube_indexes);
and
glDrawElements(GL_LINES, 4, GL_UNSIGNED_INT, cube_indexes);
do give me lines.
I program during my daily commute, but since OpenGL doesn't seem to
properly implemented I have a problem. It slows dev work, but nothing
catastrophic.
I'm asking about this more out of curiosity than anything else, I was
wondering whether this is a known issue and what the cause might be.
Sorry for delay in replying I have limited access to news servers I can
post from.
CB

Do you have a real driver on your laptop, or are you getting the broken
M$oft implementation ?
(do a getString on GL_RENDERER). If it says GDI -- annnnnkkkk!

jbw

[Carl Bateman]

Post by jbwest
Do you have a real driver on your laptop, or are you getting the broken
M$oft implementation ?
(do a getString on GL_RENDERER). If it says GDI -- annnnnkkkk!
jbw

I get "VIA/S3G UniChrome Pro IGP/MMX/SSE"...

[jbwest]

Post by Carl Bateman

Post by jbwest
Do you have a real driver on your laptop, or are you getting the broken
M$oft implementation ?
(do a getString on GL_RENDERER). If it says GDI -- annnnnkkkk!
jbw

I get "VIA/S3G UniChrome Pro IGP/MMX/SSE"...

Well, must be a buggy driver. If GL_LINES (GL_LINE_LOOP?) works...

jbw