ioccc/2004/gavare/README.md

To build:

    make

There are three alternate versions; see Alternate code below for more details.

To use:

    ./gavare > ioccc_ray.ppm

Open ioccc_ray.ppm with a viewer capable of viewing PPM files. Alternatively, if you have ImageMagick installed, you can convert it to a jpeg:

    convert ioccc_ray.ppm ioccc_ray.jpg

and then view ioccc_ray.jpg in a graphics viewer, editor or web browser.

NOTE: if you do not have ImageMagick installed, see the FAQ on "ImageMagick" for help.

Try:

If you have xv(1) you can do:

    ./gavare | xv -

to not worry about writing it to a file and just viewing the image it creates.

Alternate code:

The alternate code gavare.alt.c allows you to change the size of the image as well as the anti-alias setting, when compiling.

The author also provided on their web page for the entry an unobfuscated version that was used during development, which we have included in the file gavare.r3.c (named such because that is what they called it).

Finally, the file gavare.alt2.c sets binary mode on stdout which theoretically should work in Windows (if anything works in Windows :-) ).

Alternate build:

To build the configurable and unobfuscated versions:

    make alt

To change the default size from 1024x768 try:

    make clobber XX=640 YY=480 alt

You might also wish to change the anti-alias setting:

    make clobber AA=2 alt

You may of course combine the above two commands and give any combination you wish.

This is not possible with the author's version but it is with the alt versions (Windows - see below).

As the Windows version will not compile on most viewers' systems we do not build it with make alt; instead try:

    make alt2

Alternate use:

Use gavare.alt, gavare.r3 or gavare.alt2 as you would gavare above.

Judges' remarks:

For users of systems that distinguish between text and binary mode (you know who you are), add a library call that specifies binary mode for stdout as the first statement of main(), or use freopen("ioccc_ray.ppm", "wb", stdout); and do not use redirection (or see Alternate code above).

A freely distributable command-line version of Microsoft Visual C exhibits an optimizer bug when compiling this entry. Disable /Og for best results.

The judges were able to figure out how to control position (in all 3 coordinates), size, and color (to some extent) of the balls.

Author's remarks:

It is possible to write some kinds of programs in C without using reserved words. For very short and trivial programs, it usually isn't very hard to write a variant using no reserved words, but with this program I want to show that also non-trivial programs can be written this way. This IOCCC entry contains no reserved words (I don't count main as a reserved word, although the compiler gives it special meaning) and no preprocessor directives.

This program is a small ray-tracer. The first line of the source code may be modified if you want the resulting image to be of some other resolution than the predefined. The A value is an anti-alias factor. Setting it to 1 disables the anti-aliasing feature which makes the output look bad, but setting it too high makes the trace take a lot more time to complete.

The ppm image can then be viewed using an image viewer of your own choice. (Running the ray-tracer may take several minutes, even on fast machines, so be patient.)

I am very much aware about the fact that I'm breaking the guidelines. For example, the word int is a reserved word and therefore all variable declarations are implicit. There will no doubt be lots of warnings, no matter which compiler is used. Still, the source code should be word- length-independent and endianness-independent.

Humor

Another reason for writing code without using reserved words is that many text editors will make all reserved words turn BOLD when printed on paper. Since I care for the global environment, we shouldn't waste any more laser toner, or ink, than necessary. Everyone should write C code with no reserved words, and our world will be a better place.