glOrtho: How can I MOVE my text

[Structural]

Originally posted by T:
What is it you are trying to do? Place text just using 2D pixel coordinates or place text within a 3D scene.

Why do you rotate the camera 180degrees?

To the first point: I simply want to place some text with 2D coords. Nothing fancy really (exept that it's the first time I try this).

To the second point: I'm making my first game to learn things like reflections: pong3D (no comments please), and I chose for that setup in the first place. I chose that the camera should look down to the positive Z.

Here's how I do it to get the text overlayed on the scene.

/2D OVERLAY STUFF
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(0,1,0,1); //coordinates are 0,0 to 1,1 in 2D
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glColor3f(1.0f,1.0f,1.0f); //color for text
glRasterPos2f(0.02f,0.95f); //text position ( top leftish )
glPrint("vPosition.x=%7.2f);

//3D STUFF
glMatrixMode(GL_PROJECTION); // Select The Projection Matrix
glLoadIdentity(); // Reset The Projection Matrix
gluPerspective(45.0f,(GLfloat)1024/(GLfloat)768,0.1f,100.0f);
glMatrixMode(GL_MODELVIEW); // Select The Modelview Matrix
glLoadIdentity();
draw blah blah
rotate blah blah
translate blah blah

[Structural]

You rock!
Both of you

It works now with the gluOrtho2D (and with glORtho too now) and I have a slight idea of what went wrong.

What eXor did (I think) in his example code is reset the GL_PROJECTION and GL_MODELVIEW both to the origin (swith to the one, load origin, to other, load origin). I missed the part where I set the projection to the origin.

But what's beyond me is whether the projection and modelview matrix are actually two seperate matrices? I thought there was one view matrix, and that it was overwritten if you switched.

I have to note this down:
1) switch to projection matrix
2) reset to origin
3) switch to modelview matrix
4) reset to origin

Am I correct in this?

[T]

The projection and modelview matrices are separate matrices.

Its more like:
1. switch to projection
2. reset to identity
3. load a projection matrix (ortho or perspective)
4. switch to modelview
5. reset to identity
6. do stuff

[T]

Oh, and remember that any matrix command always operates on the matrix you last "activated" (i.e. used in glMatrixMode).

ortho mode is 2D There is no depth ( z axis ) that's why the text doesn't move.

Well it looks like its moving because when you move forward it's still there.

You can't outrun it

[Structural]

Thanks people, I'm finally beginning to understand this ortho stuff, though I still have a long way to go.