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chat icon Rendering in orthographic projection

BloB

Posted: Fri Mar 07, 2003 1:59 pm
Joined: 07 Mar 2003
Posts: 6
Hi.

Is there anyone who can confirm that some rendering features are disabled when the camera is performing an orthographic projection ? For instance no mist is rendered whereas in a 'standard 3d" projection, I see the mist perfectly.

The underlying question is : can I produce an image of the Z-buffer of a scene in ortho-projection? I tried to used the mist for this. Is there another recommended way?

BloB.
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Jamesk

Posted: Fri Mar 07, 2003 3:34 pm
Joined: 14 Oct 2002
Posts: 239
For some reason it sounds perfectly logical that mist doesn't work in ortho mode... Don't ask me why, but it feels like one of those zen things... That didn't help of course...
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BloB

Posted: Fri Mar 07, 2003 3:57 pm
Joined: 07 Mar 2003
Posts: 6
I wonder what 'some' reason might be...

You still get a Z-distance from the camera, you still can do Z-buffering, the faces are still rendered almost the same way. There seems to be also a problem with texture coordinates in ortho-projection (not UV-edited but the other ones).

It's just the projection matrix that changes (theoretically).

BloB.
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BloB

Posted: Wed Mar 12, 2003 10:29 am
Joined: 07 Mar 2003
Posts: 6
Now that the sources are open, anyone can have a peek. Can anyone explain me why the mist is treated differently in orthographic projection?
Namely, in v2.25 sources, in file source/blender/blenkernel/intern/world.c,
line 191, I can read:
Code:

if(cam->type==CAM_ORTHO) {
   /* dit is maar ongeveer */
   R.wrld.miststa+= (float)fabs(R.viewmat[3][2]);
}


Has anyone a clue on this one ? The starting position of the mist is 'pushed' further by a distance found in the view projection matrix ?


BloB.
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