Rendering in orthographic projection

Blender's renderer and external renderer export

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BloB
Posts: 6
Joined: Fri Mar 07, 2003 1:38 pm

Rendering in orthographic projection

Postby BloB » Fri Mar 07, 2003 1:59 pm

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.

Jamesk
Posts: 239
Joined: Mon Oct 14, 2002 8:15 am
Location: Sweden

Postby Jamesk » Fri Mar 07, 2003 3:34 pm

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...

BloB
Posts: 6
Joined: Fri Mar 07, 2003 1:38 pm

Postby BloB » Fri Mar 07, 2003 3:57 pm

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.

BloB
Posts: 6
Joined: Fri Mar 07, 2003 1:38 pm

Well, well, well...

Postby BloB » Wed Mar 12, 2003 10:29 am

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: Select all

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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