coral

Calculate and display an aggregating particle

Authored and Contributed by: Ronald Joe Record
Description: The idea here is to calculate and display aggregating particles. In order to accomplish this, a modified random walk algorithm is used. Initial particles are "seeded" at the "bottom" or the "sea". Particles are then "dropped" randomly from above. When a particle comes within a pixel of an already existent particle, it "sticks". After N particles have "stuck", the color is incremented. Thus, color indicates "age".
Acknowledgements: The algorithm was derived from lectures given by Dietmar Saupe at the University of California at Santa Cruz. Assistance with colormaps and spinning color wheels and X was gleaned from Hiram Clawson and Stacey Campbell.
Build: To build the coral binary, either use the Imakefile or the sample makefile, Makefile.std. If your system doesn't support prototypes, uncomment the PROTODEFINE line of the Imakefile. After modifying the Imakefile appropriately, either use "xmkmf" or "imake" to create a Makefile. Then just type "make" to compile coral. The manual page can be formatted by typing "nroff -man coral.man > coral.6X".
Install: To install coral, copy the coral binary to the desired location (the sample makefile puts it in /usr/games/X11) Copy the formatted man page to wherever you keep your local doc (i use /usr/games/X11/doc for games and imaging software), then add that location to your MANPATH.
Productivity: None
Safety: I have used this for years without harm.
Work Planned: None
Documentation: manual page.
Verification: You can test coral by just invoking it with no arguments. It should display a 512x480 image. Some workstations may be slow to calculate and display the coral growth as there are many calculations involved. Some "interesting" ways to run coral are as follows : % coral -F -n 10 -d (use the full screen, calculate 10 maps in demo mode) % coral -R (display on the root window) % coral -o coralgrowth.ppm (calculate and display with default parameters and save the resulting image as a PPM file called coralgrowth.ppm. this can be viewed later using xv or any PPM viewing utility)
Feedback: Ideas, comments, additions, deletions, suggestions, bug reports, code review,... e-mail Ronald Record at rr@ronrecord.com or ...uunet!sco!rr.