From: "R. William Gosper" <rwg@osots.com>
http://gosper.org/jaggies.png is a 4x blowup of a detail of a Golly (Game of Life) screen, where each pixel is 2^24 x 2^24 cells. The diagonal line marked by arrows is a row of equally spaced gliders, (dx,dy) = (14412108,16685960).
Another way of explaining that horizontal jog, even though dy > dx: +-----+-----+ | | * | glider very close to the top of a pixel | | | | * | | glider very close to the bottom +-----+-----+
From: Steve Witham <sw@tiac.net>
Yeah but Bresenham is just an optimized way of drawing the same jaggies.
I was wrong. Bresenham works by setting one of the step sizes to one pixel and the other to <= 1, instead of stepping the x and y by independent fractions. Bresenham would never get the kind of jaggy pointed to in that Golly screen (but the Golly screen is correctly showing which pixels have gliders). Trying to imagine an antialiasing method for Life that would show things with such low density (~2^-46). All I can think of is, color based on the distance from the pixel center to the closest live cell within +/- 1 pixel. Intuition can be so demanding. --Steve