🚀 go-pugleaf

In article <1992Aug10.194049.58044@cc.usu.edu>, sl8nl@cc.usu.edu writes:
>In article <1992Aug11.002459.18167@mnemosyne.cs.du.edu>, loine@nyx.cs.du.edu (lee oine) writes:
>> anyone know of a good routine to rotate a bitmap picture?
>> i know that bitmap shrinking and zooming can be done quite easily, but
>> cant figure how to rotate.
>> take zooming for example, it can be done using only ADDition and the 
>> overflow bit. that is done in Wolf3D, i think, so as to make it very fast!
>> 
>
>The perspective mapper routine can be easily modified to do this...

Now, you can't just post something like that without giving us a better
explanation...

It sounds like you are claiming that it is possible to do real-time 
sprite rotations without multiplies.

I don't believe that is possible on a PC (even a 386), but I would love
to be proven wrong.

I'm planning on doing some sprite rotation stuff for a game, and my plan
was to pre-compute it all which would be fast but take tons of space.

and while you are at it, how is scaling done in Wolf3D using only adds?