Perspective Transform (was: Screen shots for Squeak.org)
Bert Freudenberg
bert at isgnw.CS.Uni-Magdeburg.De
Sun Jun 20 11:00:58 UTC 1999
On 19 Jun 1999, Lawson English wrote:
> One thing missing from all the current graphics engines is the ability to
> apply perspective.
I'm not really sure what you mean by this - almost every 3D graphics
engine has this ability: it's called texture mapping. And why would we
want to have perspective distortion if we do not go three-dimensional?
> I have a rough idea how to do it*, but I'm not sure how useable it would
> be in Squeak without creating C-primitives that support it.
>
> However, it if IS doable, it would certainly make Squeak more powerful
> than anything else out there.
It's already there! Almost, that is. Balloon3D is able to display a
bitmap (Form) with perspective. So you could have it display a window's
form as easily as a loaded bitmap. What's missing is the ability to make
this view respond to mouse/key events in the same way as it does in the
2D-World. Just imagine some arbitrary Morph being dropped into a
Wonderland and living there happily on ...
> *cache the line-segments of a bezier path as it would be drawn without
> perspective, and then apply the perspective to each line segment. This
> strategy works well, but probably requires efficient (C-based) access to
> the cached info in order to run in real-time.
IMHO this would be too specific, the texture mapping approach is more
general.
Cheers,
/bert
--
Bert Freudenberg Department of
Simulation and
Computer Graphics
http://isgwww.cs.uni-magdeburg.de/isg/bert.html Univ. of Magdeburg
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