Thanks for anticipation! MatrixMode is not the problem , even i tried. The current matrix mode is already in ModelviewMode.

the problem i have is, i want some thing like this

---------------
Do standard intialization of OpenGL...
Create and BeginList list1;
Add some drawing commands in the display list1 with default transformation Modelview matrix (1)
Load a custom Modelview matrix
add more more drawing commands with custom modelview in the same display list1 (this draws fine)(2)
End Display list1
---------------

The paint function, which is called on each paintwindow call,
--------------------
do some translation/transformation
Call list1;
---------------------

And later, on a mouse handler function ,

-----------------
Clear every thing ;
some calls to gltranslate, glRotate, etc
Call the display list1 again
----------------------


Now in the mouse handler function, the rotation/scaling/transformation applied to the Current modelview matrix are reflected in the drawing at level. But not in the drawing drawn at level 2.
The drawing at level 2 remeins always static..does not moves or accepts any transformation further applied.
How could i do so ?

The problem seem to me that, the modelview matrix i load, does not accept transformations later, like calls to glRotate etc. Why could it be so ?

Any idea?

Ah, now I see the problem :)

Notice that glLoadMatrix function _replaces_ the current matrix! Perhaps you want to apply a glMultMatrix instead, hence applying the 2nd transformation w/o dropping the 1st one. But notice that in that case the transformation of stage (2) local, i.e. it is applied before the current MODELVIEW matrix when entering the routine.

Quote:Original post by Tahir
The problem seem to me that, the modelview matrix i load, does not accept transformations later, like calls to glRotate etc. Why could it be so ?

To clarify my previous post a bit: If you apply a composed transformation like this one (notice the order!)
glTranslatef(...);
glRotatef(...);
glVertex3f(p.x,p.y,p.z);
to a point p then its mathematical equivalent is (notice that I use column vectors as usual for OpenGL)
T * R * p
where T denotes the translation and R the rotation, then the effect is that the point p is 1st rotated by R and the result is then translated by T (although OpenGL does this in 1 step).

Hence, if you do this
glTranslatef(...);
glRotatef(...);
glMultMatrix(...);
glVertex3f(p.x,p.y,p.z);
then your own matrix is applied 1st, and the already pushed translation and rotation acts on the result your own transformation has left.

[Edited by - haegarr on November 24, 2006 7:19:58 AM]

Great !

It works now :)


Thanks alot haegarr.

[Edited by - Tahir on November 24, 2006 8:46:19 AM]