TI-89 Height-Mapped Raycaster

A custom height-mapped raycasting engine and dungeon crawler game for the TI-89 graphing calculator, built on top of the 2002 FAT Engine. Renders textured walls, stair geometry, billboard enemy sprites, and procedurally generated dungeons on a 10MHz Motorola 68000 with a 160x100 4-shade grayscale LCD.

Descend (fatd_dungeon.c) is a procedural dungeon crawler with:

• Height-mapped raycaster with per-tile floor elevations and stair-step rendering
• Textured walls and doors using the FAT Engine's texture system
• Billboard enemy sprites with mask-based transparency and per-column Z-buffer occlusion
• Procedural level generation (rooms, L-shaped corridors, triangle-wave staircases)
• Bump-to-attack combat, HP/level tracking, blinking minimap
• Smooth Z interpolation when walking up and down stairs

Also included:

• fatd_stairs.c: standalone height-mapped raycaster demo
• fatd_hw4.c: self-contained version for HW4 Titanium
• fatd_life.c: Conway's Game of Life with bitwise parallel neighbor counting (50-100x faster)
• fatd_plasma.c: real-time grayscale plasma effect
• ti_send.c / ti_dbus_send.c: USB transfer tools

Requirements:

• A TI-89 (standard HW2 recommended) or TI-89 Titanium
• SilverLink cable or direct USB cable
• libusb installed

Note: The full FAT Engine only works on standard TI-89 (HW1/HW2). The Titanium HW4 blocks heap code execution; use the standalone flat-shaded version (descend.89z) instead.

History: The FAT Engine ("Fixed Angle Texturing") is a Wolfenstein 3D-style raycasting engine for TI-89/TI-92+ calculators, written by Thomas Nussbaumer and released in 2002. It renders 3D environments at 560-825 frames per minute on the 10MHz Motorola 68000.