Re: Introduction to to Graphics in C on the Apple II

[DaveSchmenk <dschmenk@gmail.com>]

On Jan 6, 6:14 pm, Bill Buckels <bbuck...@escape.ca> wrote:
> For your perusal and viewing pleasure I am pleased to announce the
> following addition to the AppleOldies website:
>
> http://www.appleoldies.ca/azgraphics33/index.htm
>
> Please visit the above link.
>
> Single and Double
> Lo-Res and Hi-Res Graphics in the
> C Programming Language
> Introduction to to Graphics in C on the Apple II
>
SNIP
> Happy New Year and Have Fun!
>
> Bill Buckels
> bbuck...@mts.net
> January 2010

Bill-
I am impressed with the effort that went into these demos.  I thought
I woke up in an alternate reality when I saw the cc65 versions ;-)

On Jan 8, 6:57 pm, sicklittlemonkey <nick.westg...@gmail.com> wrote:
> On Jan 9, 8:56 am, "Michael J. Mahon" <mjma...@aol.com> wrote:
>
> > Bit fiddling of this kind has always been the "poster child" for
> > high-level language inefficiency, though it is seldom needed in
> > practice.
>
> True, and Woz made perhaps the best effort in Disassembly Lines:http://www.txbobsc.com/aal/1986/aal8612.html#a9
>
> Cheers,
> Nick.

I had not seen this version either.  Wow.  Time to revisit this
routine again.  Both the calculated address and table lookup address
routines have their place.  Based on the type of graphics operation
I'm performing, I will decide to use the calculated address if it is
only a small percentage of the total time.  Fill routines will
generally get the calculated version.  Line drawing will generally get
the table lookup.  Of course the line address calculation is only half
the equation.  Let's not forget the divide-by-7 that is needed for
edges and horizontal offset.  Again, there is the table vs.
calculation tradeoff.  Fast hires graphics on the Apple II is one of
the most intriguing problems I've encountered in graphics programming.

Dave...