Clock24 is the 24-hour analog clock for those programmers who have to get their work done before midnight. The short hand travels around in a day, whereas those on conventional analog clocks do so in half a day. The biggest reasons why I wrote this are that I often write code in the basement to find myself not sure whether it's nighttime or daytime, and that I prefer analog clocks to digital clocks.

This program uses OpenGL to draw an analog clock, and GLUT to do UI stuff. It works well with X11 utilities like Devil's Pie.


16:52 It's 16:52. Still have some time before the deadline.


All these options can also be turned on/off using a pop-up menu.

How to compile

I checked this program to compile and run on Ubuntu 8.04(AMD64) and MacOS X 10.5.4(ppc).


This is a public domain software. clock24-1.01.tar.bz2(2008/08/06)

Changes from 1.0(2008/08/04)

External Link

  1. Project page at


While writing this program, I noticed that Intel's GMA X3100 on their Santa Rosa platform(with all BIOS updates) does very poor OpenGL compared to years-old ATI Mobility RADEON 9700. First, GL_LINE_SMOOTH is painfully ugly even with GL_NICEST. Second, with antialiasing turned on, glLineWidth(1.0f) and glRotatef, lines parallel to one of window edges disappear without any trace. Even if their cards are not targeted at OpenGL-savvy users, isn't this a bit too rough? Anyway, lucky is that it's not me that directly paid for this machine, which the university lends me. Oh, I hear someone knocking on my door...