texture coordinates

OpenGL OpenGL: Basic Coding
1

hi,

i was wondering what the texture coordinates will dom what is the relation b/n texture coordinates and geometirc coordinates…

they are specified using:

glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f, 1.0f);
this question may appear silly but i am not able to get clear picture…help me !!!

2

You might want to read it up in the GL-spec if you are that interested.

Here is short version (for triangles):

GL calcualtes the TexCoord of every Fragments Center, out of the TexCoords you specify for each Vertex.
Depending on your Min-and Mag Filter GL calculates a Fragment Color.

In GL spec you should read through sections 3.4.1, 3.5.1, 3.8.5 and 3.8.6

Sorry that I am to lazy to cite out of for chapters of the GL-spec.

Cheers
Chris

3

hi DaViper,

thanks for the info…i am ready to read the GL-spec…can u give the link/web site where i can read GL-spec…

Thanks
ravi

4

Here you go:
http://www.opengl.org/developers/documentation/Version1.2/OpenGL_spec_1.2.1.pdf

5

Hi,

Here’s the valus for the coordinates.

0,0 down left corner
1,0 down right corner
1,1 up right corner
0,1 up left corner