On 2001-01-24 13:17, Warp <war### [at] tagpovrayorg> wrote:
>Peter J. Holzer <hjp### [at] sikituwsracat> wrote:
>: Actually, basic scanline rendering is quite simple, even simpler than
>: raytracing.
>
>  It depends on whether you want a working scanline rendering or not.
>
>  For example, I consider hidden surface removal to be essential in
>scanline rendering (if you don't remove hidden surfaces your image will look
>just plain wrong).
[painter's algorithm vs. zbuffering, etc.]

>  If you want any texturing at all on your polygons, that's a whole story
>in itself. Perspective correction, mipmapping, bilinear or trilinear
>filtering... The list of features is endless.

As is the list of possible features for raytracing. Povray isn't a
trivial program either.

I found my old zbuffer demo on a backup tape. It is about 400 lines of
C code, about half of which is the z buffer algorithm and half is the
application (open an X11 window, tesselate a sphere and a cylinder,
render both using the Z buffer and draw them into the window). Written
in a single afternoon, if I rememer correctly.

Of course the thing is very simple. It can draw only triangles,
there is no support for textures, the shading is quite wrong. And
I did not perspective-correct the z value. I've put the thing on
http://www.hjp.at/programs/zbuffer/, if anyone is interested.

BTW, does anyone know where the name "scanline rendering" comes from?
It is quite wrong. Unlike raytracing (which does generally follow
the scanlines), these rendering algorithms do not create the picture
scanline by scanline, but polygon by polygon.

	hp

-- 
   _  | Peter J. Holzer    | All Linux applications run on Solaris,
|_|_) | Sysadmin WSR       | which is our implementation of Linux.
| |   | hjp### [at] wsracat      | 
__/   | http://www.hjp.at/ |	-- Scott McNealy, Dec. 2000

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