TI-99/4A: Leaning More on the Firmware
5 days ago
- #Graphics Programming
- #Retro Computing
- #TI-99/4A
- The author revisited the TI-99/4A home computer, focusing on mastering its graphics chip and exploring enhanced support for sound and sprites.
- The Graphics Programming Language (GPL) was used extensively, with attention to its integration with the system's firmware capabilities.
- The TI-99/4A's memory structure includes ROM and GROM (Graphics ROM), with specific address spaces and conventions for hexadecimal constants.
- Sound lists were explored for music playback, but limitations were noted, such as the lack of looping and large data requirements.
- An alternative approach using explicit I/O in GROM was discussed, though it offered minimal advantages over manual sound list management.
- Sprite motion and collision detection were implemented, with detailed explanations of the VDP's memory layout and sprite attribute tables.
- A collision detection system was developed using the COINC instruction, which checks for overlaps between sprites based on a collision mask.
- The author highlighted challenges with GROM code, including limitations and wonky features, and suggested hybrid ROM/GROM cartridges as a solution.