WASM

All I wanted was to make Nintendo DS games in Rust...

This is a work-in-progress Fantasy Console that targets embedded systems and allows users to create games in any language that compiles to WebAssembly.

Roadmap

• Learn some Docker
• Get WASM on NDS running in a reproducible environment
• Have it run a wasm file compiled from a different language than AssemblyScript
• Have it load a file from file storage instead of embedding it
  • File picker (needs work)
• Support sprites
• Define functions for game engine to expose
• Port build system to CMake
  • Create NDS implementation
  • Create Desktop implementation (Raylib probably) went with SDL3
  • Create Wii implementation
• Build tool
• Sprite/map editing solution
• Support background tiles
• Memory mapping for tilemap/sprite manipulation
• Printing text on the screen

Stretch Goals

• Networking
• In-engine editor
• Port to GBA?
  • Would require including the wasm as part of ROM data
  • Some heavy source code customization would be in order
  • Look into Butano for graphics

Engine Spec

Graphics

• 256 sprite tiles (8x8 pixels)
• 256 BG tiles (8x8 pixels)
• 16 color global palette
• Screen can be any dimensions up to 256x256

ROM Layout

Section	Bytes	Address range
Header	16	0x00000-0x0000F
Global Palette	48	0x00010-0x0003F
Sprite Tiles	8192	0x00040-0x0203F
BG Tiles	8192	0x02040-0x0403F
Tile Map (256x256 tiles)	65536	0x04040-0x1403F
Program Code	<=966592	0x14040-0xFFFFF

Functions

Graphics

Done	Function/Usage	Description
❌	circle(x, y, rad)	Render a circle
❌	circleFill(x, y, rad)	Render a filled circle
✅	clearScreen(color)	Clear the screen to the specified color
❌	ellipse(x, y, xRad, yRad)	Render an ellipse
❌	ellipseFill(x, y, xRad, yRad)	Render a filled ellipse
❌	print(x, y, text)	Print a string of text to the display
✅	pixel(x, y, color)	Draw a single pixel at the specified location
✅	rect(x, y, w, h, color)	Draw an outlined rectangle at the specified position and size
✅	rectFill(x, y, w, h, color)	Draw a filled rectangle at the specified position and size
✅	sprite(x, y, id)	Render a sprite of the designated id
❌	tileMap(x, y, tileX, tileY, mapW, mapH)	Display a tilemap

Input

Done	Function/Usage	Description
✅	button(btn)	Check if a given button ID is being held
✅	buttonPressed(btn)	Check if a given button ID was just pressed

Miscellaneous

Done	Function/Usage	Description
✅	debugPrint(text)	Output a string to a debug console (stdout, log file, etc.)
✅	rand()	Calculate a pseudo-random 32-bit integer

Thanks

This project stands on the backs of giants. During my work, I felt a need to give special thanks to:

• Martin Moxon for his WebAssembly On Your Nintendo DS blog post, which gave me just the right kind of inspiration I needed to start this thing!
• AntonioND for his superhuman work put into the NDS and GBA development scene, particularly through BlocksDS
• Asie for giving us Wonderful Toolchain, which included very up-to-date compilers and other build tools for the Nintendo DS.
• vshymanskyy for creating wasm3
• Anyone else who has contributed to WebAssembly, Nintendo DS Homebrew, and SDL3! You rock!