| name | wasm-c64-bridge |
| description | Use this skill when implementing the WebAssembly C64 emulator bridge for web and iOS, including ROM loading, touch controls, and mobile-safe initialization. |
| version | 1.0.0 |
| author | 64Box |
| tags | ["wasm","c64","emulator","ios","touch"] |
WebAssembly C64 Emulator Integration
When to Use This Skill
- When building the React component that hosts the emulator canvas.
- When writing the TypeScript bridge that passes
.d64, .t64, or .tap files into the WASM module.
- When implementing touch controls or virtual gamepads for mobile and iOS.
1. Passing ROM Data To WASM
Use the Emscripten virtual file system rather than trying to pass raw arrays directly into C functions.
Strict Protocol
- Read or fetch the ROM as an
ArrayBuffer.
- Convert it to
Uint8Array.
- Ensure the target VFS directory exists.
- Write the ROM into the WASM VFS.
- Trigger emulator startup using the mounted virtual path.
const romData = new Uint8Array(arrayBuffer);
window.Module.FS.mkdir('/roms');
window.Module.FS.writeFile('/roms/game.d64', romData);
2. iOS & Mobile Browser Constraints
Audio Context
iOS requires audio initialization to happen inside a direct user interaction such as a click or touchstart. Do not initialize audio automatically on mount.
Canvas Touch Handling
- Set
touch-action: none on the emulator interaction surface.
- Use
touchstart, touchmove, and touchend handlers.
- Call
preventDefault() to stop native Safari gestures.
3. Virtual Joystick
- Prefer a circular joypad area over four discrete buttons.
- Compute angle and distance from the center on touchmove.
- Map that to 8-way joystick directions.
- Dispatch the keyboard or input events expected by the WASM emulator.
