engine-psx

• About
• Recommended tools
• Running on real hardware
• Running on your browser
• Gallery
• License

Open source platformer engine built for the Original PlayStation.

Uses PSn00bSDK.

Engine short video running on DuckStation, dated [2024-08-05].

About

This is a platformer game engine build for the PlayStation 1, heavily inspired by Sonic The Hedgehog. The focus here is on experimentation, attempting to build a sane 2D engine in pure C while taking advantage of what the PlayStation has to offer in terms of hardware.

This engine is opensource and can be built by anyone. Also, since it uses Psn00bSDK, it also contains no copyrighted material. Plus, any tools used in this project are modern, opensource or cheap to acquire.

Some assets use different formats than common formats. This is because I needed a better way to process these files, or the PlayStation recognizes different formats.

All code is tested under emulators PCSX-Redux and DuckStation, and are also tested on real hardware (a PlayStation model SCPH-5501).

Recommended tools

Here are some tools I've been using:

• GIMP with G'Mic plugin (to reduce image colormaps to 256 colors with no dithering);
• Aseprite (for handling sprite sheets and tilemaps), plus some useful script files (tweak export_tileset.lua so it only exports with a row_len of 32, since all tiles are 8x8);
• mkpsxiso, to build the ISO files;
• gcc-mipsel compiler toolchain;
• timedit, to import images and convert them to .TIM format;
• wav2vag, to convert .WAV sound effects to .VAG audio;
• psxavenc, to convert music to a preliminary .XA format;
• xainterleave, to interleave .XA files into a single, ready-for-production .XA file;
• cdrdao, if you intend on burning your ISO on a CD-R;
• CMake and GNU Make, for build scripts.

Some of these tools are already available when you properly install PSn00bSDK. Just follow this guide.

Running on real hardware

Engine short video running on a PlayStation SCPH-5501, dated [2024-08-05].

In theory, to burn the disc, you would need a Sony license file which comes bundled with the Psy-Q SDK (which I AM NOT using). I WILL NOT provide these files for obvious legal reasons. But if you manage to obtain them, tweak iso.xml to add such a license file. I cannot guarantee that the ISO will work on real hardware if this file is omitted.

You most likely will need a PlayStation console that allows you to run homebrew software – I did not do anything on my model, but again, I bought it from someone else, and I didn't open it up to check if it was still intact from day one.

You will also need a CD drive capable of burning CD images to physical disks, and you will also need good quality CD-R disks. Do not ignore this. If you're a fellow brazillian, I recommend Multilaser.

Remember also that this method was tested in an SCPH-5501 model.

Use a command such as this to burn your image into the disk by using cdrdao (do not use other software, unless you know what you're doing):

cd build/
cdrdao write --speed 1 --driver generic-mmc-raw --swap -n --eject "engine.cue"

If you're on Windows or you need more information on other methods, check out this awesome guide.

Running on your browser

NOTE: As of now, for some reason, EmulatorJS won't load the game. You can still play it on an offline emulator such as DuckStation or pcsx-redux.

If you're using a browser emulator such as EmulatorJS and you need your .ISO + .CUE to be a single file, you might want to use something to convert it to .CHD format. You can do this by using a tool called tochd:

tochd -d . -- ./build/engine.cue

Gallery

Screenshot	Description
	Alpha engine [2024-08-05]. Same as screenshot below, but on a physical PlayStation (SCPH-5501).
	Alpha engine [2024-08-05]. First implementation of collision, camera and level data.
	Alpha engine [2024-07-22]. Running on DuckStation.
	Alpha engine [2024-07-21]. Running on a physical PlayStation (SCPH-5501).

License

Licensed under the Mozilla Public License 2.0.