Rename hint.txt and hint.text to README.md

2011/eastman/README.md

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+# Best ball
+
+Peter Eastman  
+<peter.eastman@gmail.com>  
+
+
+## Judges' comments:
+### To build:
+
+    make eastman
+
+### To run:
+
+    ./eastman
+
+### Try:
+
+    Quit the program.  Resize your terminal window.  Run it again.
+
+### Selected Judges Remarks:
+
+This round program will generate a classic spherical result!
+
+You will need a terminal capable of displaying coloured ANSI
+characters (for example an xterm or a Terminal.app window).
+
+You might also want to turn off any scrollback history. The program will
+size itself to the initial geometry of your terminal.
+
+If you are ambitious, make the font really small and the window really
+large for hi-rez graphics!
+
+## Author's comments:
+This program uses ANSI graphics to recreate the classic Boing Ball demo from
+the Commodore Amiga.  See http://www.youtube.com/watch?v=-ga41edXw3A if you
+aren't familiar with it.  Back in its day, this demo inspired lust and awe in
+geeks around the world.
+
+The graphics are raytraced, with procedural textures on the ball and the back
+wall.  I did cheat a little to simplify the calculations: it uses a parallel
+projection, but textures the back wall to look as if there were a floor being
+viewed in perspective.  The shadow is also just part of the texture, not an
+actual raytraced shadow.
+
+This program automatically adapts to the size of the terminal it is running in,
+so try enlarging the window to get higher resolution.  Don't resize while the
+program is running, though.  It only checks the size once, when it starts up.
+
+To compile:
+
+cc -lm ball.c
+
+Portability:
+
+It should be completely portable.  I've tested with gcc on Mac OS X 10.7 and
+Fedora 10.  I would expect it to work in any Unix-like environment.
+
+Obfuscation:
+
+I have merged expressions wherever possible, making extensive use of ternary
+operators, commas, return values of assignment operators, etc.  The entire
+raytracing computation, include ray intersection tests and procedural texture
+evaluations, is a single expression involving 41 operators.
+
+Variables are named alphabetically in the order they are declared.
+
+The third argument to ioctl() should really be a "struct winsize", and I should
+then look up the ws_row and ws_col fields, but that makes it way too obvious
+what I'm doing there.  Since a winsize just contains four unsigned shorts, I
+replaced it with an array.  And since all the values will be much less than
+32767, I further simplified the type to just short[].
+
+A wonderful thing about ANSI graphics is that it produces nearly unintelligible
+code.  Consider the printf spec to print a single space in a desired color:
+"\x1B[%dm ".  I could have done something to further obfuscate it, but it's
+already indistinguishable from line noise, so why bother?
+
+There are lots of other minor obfuscations to make the code less obvious.  For
+example, I could have written the outer loop as while(1), but why write a 1
+when I can calculate it from the return value of usleep() instead?  And I could
+have written usleep(80000), but usleep(79383) just looks so much better.  And
+so on.
+
+--------------------------------------------------------------------------------
+<!--
+(c) Copyright 1984-2012, [Leo Broukhis, Simon Cooper, Landon Curt Noll][judges] - All rights reserved
+This work is licensed under a [Creative Commons Attribution-ShareAlike 3.0 Unported License][cc].
+
+[judges]: http://www.ioccc.org/judges.html
+[cc]: http://creativecommons.org/licenses/by-sa/3.0/
+-->