RussellMc wrote:
> Trivia:         Bresenham was alive and friendly when I tracked him
> down and emailed him - probably between 5 & 10 years ago now.

Yeah, he's a nice guy.  I met him a few times at SIGGRAPH conferences back
when I was a graphics guy.

> I told Bresenham that I'd invented his algorithm - BUT a decade or two
> after he did :-) - but had never heard of it until then. by the time I
> did it it was probably largely unneeded in its original context except
> on very bottom end systems.

I came up with a way to extend his algorithm to do subpixel addressing.  Hi=
s
original algorithm started and ended the line segments at pixel centers.
This was fine for his original purposes, and mostly fine if you're just
drawing lines.  When you're using the vector generator to walk the edges of
polygons filled with a read-modify-write operation, it's not so fine.  He
wrote a very nice introduction in the journal I wrote up the subpixel
algorithm in.

By the way, subpixel addressing doesn't require any changes to the inner
loop, and therefore the vector generating hardware.  The difference is only
in setup of the initial values.


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