🚀 go-pugleaf

In article <quan.726211707@sol> quan@sol.surv.utas.edu.au (Stephen Quan) writes:
>paul@ramsey.cs.laurentian.ca (Paul Lalonde) writes:
>
>>I'm working on a small 3D graphics program that takes vector images
>>and rotates them about the XY axes.
>
>There are 3 kinds of rotations in 3D :
>
>x-axis rotation :
>y' = y*cos(angle) - z*sin(angle)
>z' = y*sin(angle) + z*cos(angle)
>
>y-axis rotation :
>z' = z*cos(angle) - x*cos(angle)
>x' = z*sin(angle) + x*cos(angle)
>
>z-axis rotation :
>x' = x*cos(angle) - y*sin(angle)
>y' = x*sin(angle) + y*cos(angle)
>
>There is, of course, the more effective matrix representations of the
>above, but I didn't think Paul wanted to be bamboozled with all the
>matrix-algebra jargon.  Any good computer graphics would describe the
>3D theory rotation well.
>--
>Stephen Quan (quan@sol.surv.utas.edu.au)      Tel : 002 202844 (local)
>Research Fellow, Computer Scientist,          Fax : 002 240282 (local)
>Centre for Spatial Information Systems,       Tel : 61 02 202844
>University of Tasmania, Australia.            Fax : 61 02 240282

I don't remember the title, but there is a book including also
3D formulas with perspective, that is they are using 4 variables
instead of 3.  If you plan to develop something potentially more
powerful (like drawing boxes with perspective), you should explore
this now since it will be easier to develop now 3D-P programs than
to right some 3D programs and convert them later to 3D-P.  3D-P is
not the official name.

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