Wasmcraft Preview Simulator

This tool is part of the Wasmcraft Suite. See the link for more details on the project.

The Wasmcraft Preview Simulator is a debugging tool intended to make editing programs for Wasmcraft faster and easier.

Simulating an actual datapack (or running it in a real Minecraft world) can be slow and difficult to debug, especially in the presence of miscompilations. This simulator runs the WebAssembly directly and presents a simplified version of the output from the program, which makes quickly verifying changes much easier.

Output

The simulator will print chat messages to stdout (e.g. from print or mc_putc). It can also display placed blocks on an X-Y plane, making it useful for previewing games.

By default, blocks placed at Z=-60 will appear on-screen with one block representing one pixel. The Z coordinate used for the plane can be configured using a command-line argument.

As an additional feature for simulating games, printing a magic value (specifiable on the command line) will signal to the simulator that a "frame" has been completed, which will immediately update the block display (which can sometimes lag behind) and sleep for a short duration to show the completed frame.

Usage

Use cargo run to run the simulator on a file, as shown below:

cargo run -- /my/compiled/program.wasm

Running the program without any arguments will print usage information that details the various arguments that are available.

cargo run

Limitations

This simulator...

• ... cannot check that mc_sleep() calls are inserted at the proper intervals.
• ... cannot guarantee that a webassembly file will compile correctly using Wasmcraft
• ... currently has no way of taking user input
• ... only supports a single X-Y display plane