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Rifat Aras
01-15-2008, 04:07 PM
Hi Everyone,

I am trying to texture a line segment with a 2-D texture element. In other words, I am providing same u value and increasing v value for my line.

I try to do this in Cg (with this piece of code:


kd = (half3)tex2D(hairTexture, uv).xyz;), what I want to know is that whether this is possible with the OpenGL part.

If it is possible to texture a line primitive with a 2-D texture element with pure OpenGL, then I would know that the problem is with Cg part. (Recommendations with the Cg part are also welcomed :) )

Thanks in advance

Rifat

-NiCo-
01-15-2008, 05:44 PM
glColor4f(1.0,1.0,1.0,1.0);
glEnable(GL_TEXTURE_2D);
glBegin(GL_LINES);
glTexcoord2f(u,v1);
glVertex3f(x1,y1,z1);
glTexcoord2f(u,v2);
glVertex3f(x2,y2,z2);
glEnd();

Rifat Aras
01-16-2008, 02:06 AM
Then I understand that it is possible to texture a line primitive with GL_TEXTURE_2D and glTexcoord2f.

I am loading the texture, passing the texture identifier to Cg's sampler2D variable and try to access texture information with
(half3)tex2D(hairTexture, uv).xyz; Unfortunately, it does not seem to be reading correct color information; I cannot see texture drawn onto the line primitive.

Am I doing something wrong?

-NiCo-
01-16-2008, 02:17 AM
Am I doing something wrong?

I guess so..the question is 'what' ;)

Did you try the fixed function path? Are your sampler states correct? Try writing out the uv coords, maybe there's something wrong with them, etc.

N.

Rifat Aras
01-16-2008, 02:29 AM
Hmm "uv coords" may be the problem... I dynamically calculate them at vertex shader. I thought they were correct, but maybe... When I get to home I will give it a try and let you know...

Thanks anyway...

ZbuffeR
01-16-2008, 04:08 AM
Maybe you did not build mipmaps for your texture, by default mipmaps are needed.