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 CAD / MLCad / 1205
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Subject: 
Re: 3D Myst III viewer of a castle
Newsgroups: 
lugnet.cad.mlcad, lugnet.cad
Date: 
Fri, 25 Jan 2002 14:58:09 GMT
Viewed: 
3947 times
  
In lugnet.cad, Travis Cobbs writes:
In lugnet.cad.mlcad, Chuck Sommerville writes:
Here is the new simplified camera:

camera {
spherical
location <-320,-239,0>        // position
look_at  <-320,-239,1>        // view
scale <0,0,-1>                // flip it rightside up
}

I'm not sure why the flip works, or why it is needed.  I think it is because
or handedness.

I actually had to do something similar in LDView in order to get models to
view properly using OpenGL (although I used a 180 degree rotation about Z
followed by one about Y).  I wonder if any of the other programmers out
there had similar trouble getting things to display correctly.

Yes, I'm pretty sure ldglite negates both the y and z coords just before
calling any OpenGL functions.  If I remember right, the reason the LDRAW
coordinate system is so odd is because it started out in 2D screen pixel
coords and the 3D view was added later.  I wonder if this explains the
weird LDRAW oblique transformation matrix?  Was the shearing introduced
to overcome the non-square aspect ratio of the pixels on those old VGA
display modes?

Don



Message is in Reply To:
  Re: 3D Myst III viewer of a castle
 
(...) I actually had to do something similar in LDView in order to get models to view properly using OpenGL (although I used a 180 degree rotation about Z followed by one about Y). I wonder if any of the other programmers out there had similar (...) (23 years ago, 25-Jan-02, to lugnet.cad.mlcad, lugnet.cad)

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