pyopengl-users

[PyOpenGL-Users] Re: [PyOpenGL-Devel] rotation problem

[Mike C. F. <mcf...@ro...>]

You'll want to push and pop a matrix stack to do rotation.  You can find 
demo code for glPushMatrix linked here:

http://pyopengl.sourceforge.net/documentation/manual/glPushMatrix.3G.xml

BTW, most OpenGL tutorials, such as the red book or NeHe will cover 
matrix-stack manipulations.

HTH,
Mike

Drishti Integra wrote:

> hi,
>  
> i am a newbee to pyopengl.
> would be very kind if any one can guide me for the following:
>  
> i am trying to rotate a few objects using glRotate(). but this seems 
> to rotate the whole coordinates system as well as any lightings i have 
> used. is there a way to rotate only objects and not the coordinate 
> system and lights.
>  
> thanks and regards

_______________________________________
  Mike C. Fletcher
  Designer, VR Plumber, Coder
  http://members.rogers.com/mcfletch/

[PyOpenGL-Users] Re: [PyOpenGL-Devel] rotation problem

[<dri...@ya...>]

hi,
 
thanks a lot for help!
 
i tried using the glPushMatrix() and glPopMatrix() as suggested by the examples, but the coordinate system still seems to rotate. 
 
like when i rotate at initial position along x and y the rotation seems to be proper, but now after doing so if i rotate along z then my z axis seems to have changed ... giving a feeling that the coordiante system has changed?

also is there a way to get the updated coordinates of the rotated object?
 
regards

"Mike C. Fletcher" <mcf...@ro...> wrote:
You'll want to push and pop a matrix stack to do rotation. You can find 
demo code for glPushMatrix linked here:

http://pyopengl.sourceforge.net/documentation/manual/glPushMatrix.3G.xml

BTW, most OpenGL tutorials, such as the red book or NeHe will cover 
matrix-stack manipulations.

HTH,
Mike

Drishti Integra wrote:

> hi,
> 
> i am a newbee to pyopengl.
> would be very kind if any one can guide me for the following:
> 
> i am trying to rotate a few objects using glRotate(). but this seems 
> to rotate the whole coordinates system as well as any lightings i have 
> used. is there a way to rotate only objects and not the coordinate 
> system and lights.
> 
> thanks and regards

_______________________________________
Mike C. Fletcher
Designer, VR Plumber, Coder
http://members.rogers.com/mcfletch/



Yahoo! India Mobile: Ringtones, Wallpapers, Picture Messages and more.Download now.

Re: [PyOpenGL-Users] Re: [PyOpenGL-Devel] rotation problem

[Rene D. <il...@ya...>]

You can do this, and it is a tiny insy bit quicker than push/pop too, 
but may be prone to small float errors if you do it lots.

a = 30.
x,y,z = 1., 0., 0.

# rotate to your place in the gl universe.
glRotatef(a, x,y,z)
something_rotated()
# rotate back
glRotatef(a,-x,-y,-z)

You can get the current matrix with glLoadMatrix(...) but not the 
transformed coordinates.  Well it is possible with shaders, with a bit 
of effort.


Have fun!
http://www.holepit.com/