Articles by Retro Ports

Whilst I’ve been waiting for Miro to digest the previous posts and hopefully develop his framework to the point I have described, I’ve actually been doing a little bit of the transcode. I’m not going to go into any specifics here as I’d like to document it in some form …

Before we dive into the actual transcode, I wanted to document a few things about the goals and aims of the project, along with some notes about the process. Goals and Aims First and foremost, the aim of the project is to document and preserve both the behaviour and the …

Some of what I’ll discuss is more pertinent to C than it is to Javascript. But there’s no reason why you couldn’t adopt the same architecture in Javascript anyway. In fact, it may still be a good idea for a couple of reasons, including future porting, or even enhancement much …

Before we can create a framework for the transcoded game, we need to understand the architecture of the original. Every single arcade game that I have reverse-engineered thus far has been driven by the 60Hz VBLANK interrupt. Not only does this allow the game to update the sprites without any …

The format of the graphics in an arcade game like Galaxian is optimised for the video circuitry rendering the image as the raster beam scans down the screen. Specifically for Galaxian, the graphics data for each bitplane is stored in a separate device (ROM chip) so that colour data for …

A fellow retro enthusiast by the name of Miro expressed interest in the porting (transcoding) of Sean Riddle’s Galaxian dissassembly to a higher level language and asked if anyone was willing to collaborate. Given that the codebase is very similar to Scramble, and the hardware identical, I thought I’d be …

Well, once you lose momentum on a project when Real Life intervenes, you can very quickly forget about it completely, which is pretty much what happened on Scramble. I must admit, I haven’t even thought about it for several weeks now, only reminded about it now by a 68K post …

Stars are still WIP, I’ve been coding the algorithm to produce the tile data and also the data for optimal palette cycling. However work has gotten very busy (plus the Giro d’Italia is currently running) so I haven’t done a lot lately. Work will still be busy for another work …

 So I have a plan for the stars. There are 124 stars, and using 16×16 tiles would require 103 tiles to contain them. Tiles have no more than 3 stars in them. Tiles will also have their own palette (16 colour entries). There are 4 blink cycles. Rather than use …