SillyVenture 2k12 invitro

Screenshot of SillyVenture 2k12 invitro

Prod pages: [] []
Date: 2012-10-26
Platform: Atari VCS
Group: Me together with Grey/MSB and Jakub Husak

This one was quite fun to write, since it features a little animation with Pitfall Harry kicking the screen to get a logo to descend. The main effect is a variant of the tried and tested fullscreen plasma, but with XOR instead of additions to make up the pixel values. It also features Huffman based text compression, and packs part of the text data into the font data. Finally, it seems to have started a minor trend with having Pitfall Harry in Atari invites, see Lapin Kulta by Dentifrice.


     SillyVenture 2k12

Invitro by these fine gentlemen:

   Code/GFX:    Tjoppen^DSS
Invite text:    Grey/MSB
      Music:    Jakub Husak

For scroller text with party details, see sv2k12.nfo.

Programming notes from Tjoppen, for those interested:

The text is Huffman encoded, which saves quite a bit of space.
After getting the compressor, decompressor and text kernel to work I realized
that none of the glyphs in the font use the rightmost two pixels. This meant
that if these bits could be masked off in the kernel then that space could be
used for other purposes.
Luckily the SAX instruction is well suited for this task when X is loaded with a
suitable mask, meaning this space was indeed freed.
In other words, part of the Huffman coded text data is stored in the font
glyphs, which saves two bytes per glyphs (2*8 bits).