Uploaded August 2023 | Updated September 2026, 2 weeks ago

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I show implementations of ellipse routines, including horizontal ellipses and diagonal/general ellipses on a vintage 386 computer, all assembly optimised for maximum performance.

I talk about how scan conversion of lines, circles and ellipses actually works at a high level and talk about all the issues I ran into trying to get my final animation to work.

Code repository for this episode:

github.com/wbhart/ellipse

PC-Key-Draw:

pcjs.org/software/pcx86/sw/misc/pcsig/0001-0999/DISK0344

Minsky circle algorithm:

cabezal.com/misc/minsky-circles.html

Da Silva Ellipse algorithm:

https://cs.brown.edu/research/pubs/theses/masters/1989/dasilva.pdf

Van Aken's algorithm:

arxiv.org/pdf/2009.03434.pdf

Kappel's algorithm is unfortunately behind a paywall.