Hi!

I draw text with the following routine, but glColor and glRasterPos are 
being ignored:

     glColor3f(r, g, b);        // text is always red
     glRasterPos2f(x, y);       // text is always at same position
     glPushAttrib(GL_LIST_BIT);
     glListBase(fonts[index].listBase - 32);
     glCallLists(strlen(text), GL_UNSIGNED_BYTE, text);
     glPopAttrib();

The lower left corner of the text is always at the center of the 
viewport and the color is always red.

Am I missing something?

Thanks, Ingo

Unless the display lists that render each character have compiled
glRasterPos and glColor calls, it may work.
Other considered issues are :
- position : the modelview matrix's scale factor is too small compared to x
and y arguments (for instance the modelview matrix is identity and
x=y=0.00001)
- color : either texturing or lighting is enabled, and texturing and/or
lighting is not configured to take color into account (GL_REPLACE in case
of texturing, no COLOR_MATERIAL in case of lighting).

Vincent


Ingo Schulz wrote:

> Hi!
>
> I draw text with the following routine, but glColor and glRasterPos are
> being ignored:
>
>      glColor3f(r, g, b);        // text is always red
>      glRasterPos2f(x, y);       // text is always at same position
>      glPushAttrib(GL_LIST_BIT);
>      glListBase(fonts[index].listBase - 32);
>      glCallLists(strlen(text), GL_UNSIGNED_BYTE, text);
>      glPopAttrib();
>
> The lower left corner of the text is always at the center of the
> viewport and the color is always red.
>
> Am I missing something?
>
> Thanks, Ingo

Ingo Schulz wrote:
> 
>     glColor3f(r, g, b);        // text is always red
>     glRasterPos2f(x, y);       // text is always at same position
>     glPushAttrib(GL_LIST_BIT);
>     glListBase(fonts[index].listBase - 32);
>     glCallLists(strlen(text), GL_UNSIGNED_BYTE, text);
>     glPopAttrib();
> 
> The lower left corner of the text is always at the center of the 
> viewport and the color is always red.
> 
> Am I missing something?
> 

What's your view and projection matrices?

glRasterPos() transforms the coordinate using the
modelview and projection matrices. If the result
is invalid the the function will be ignored, also
the color won't be sent down the pipeline (color
is only sent down when a valid vertex is sent).


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fungus schrieb:
> What's your view and projection matrices?

Camera is at 0,0,0 pointing to 0,0,-1
Viewport is 1005 x 1005 pixels

I'm using my own Camera class that worked without problems on another 
project. But here I'm getting these matrices:

model view:
0  0  0  0
0  0  0  0
0  0  1  0
0  0 -1  1

projection:
2.414  0      0      0
0      2.414  0      0
0      0      -1.02  -1
0      0      -0.2   0

> glRasterPos() transforms the coordinate using the
> modelview and projection matrices. If the result
> is invalid the the function will be ignored, also
> the color won't be sent down the pipeline (color
> is only sent down when a valid vertex is sent).

glGet says that the current raster position is valid.


Ingo

Vincent DAVID schrieb:
> Unless the display lists that render each character have compiled
> glRasterPos and glColor calls, it may work.
> Other considered issues are :
> - position : the modelview matrix's scale factor is too small compared to x
> and y arguments (for instance the modelview matrix is identity and
> x=y=0.00001)

See reply to fungus.

> - color : either texturing or lighting is enabled, and texturing and/or
> lighting is not configured to take color into account (GL_REPLACE in case
> of texturing, no COLOR_MATERIAL in case of lighting).

Texturing and lighting are disabled and text is still red.

Ingo Schulz wrote:
> 
> I'm using my own Camera class that worked without problems on another 
> project. But here I'm getting these matrices:
> 
> model view:
> 0  0  0  0
> 0  0  0  0
> 0  0  1  0
> 0  0 -1  1
> 

That doesn't look very valid to me...


-- 
<\___/>          For email, remove my socks.
/ O O \
\_____/  FTB.    Why isn't there mouse-flavored cat food?

you probably set up view like this:
glOrtho(-width/2, width/2, -height/2, height/2, NearClip, FarClip);
where width and height are your windows width and height. This makes
center of the window (0,0,0). So if you draw text at 0,0,0 that would
come up in center.
Try 
glOrtho(0, width, 0, height, NearClip, FarClip);
which will set lower left corner to (0,0,0)

eymre

> I'm using my own Camera class that worked without problems on another
> project. But here I'm getting these matrices:
>
> model view:
> 0  0  0  0
> 0  0  0  0
> 0  0  1  0
> 0  0 -1  1

That explains why the text corner is always at the center of the screen.
Because the 2x2 upper-left part of the matrix is zero, every x and y
coordinate in object-space (sent to glVertex or glRasterPos) will output
a zero-valued x and y coordinates in eye-space.

Vincent

fungus wrote:

> glRasterPos() transforms the coordinate using the
> modelview and projection matrices. If the result
> is invalid the the function will be ignored, also
> the color won't be sent down the pipeline (color
> is only sent down when a valid vertex is sent).

The pedant here again.

If the given coordinate is *clipped* by any clip plane, including the 
user defined clip planes,  the current raster position is marked as 
"invalid". The function will not be "ignored".