SPPD

Scriptable Parser for Portal 2 Demos. Name chosen specifically to be confused with Spinning Player Physics Deformation.

This parser enables you to interact with a demo as it's being parsed. In other words, it lets you write scripts to track changes in the game world during simulated demo playback. Compatible only with Portal 2.

Here's a simple example that logs the position of a cube over time:

const demoBytes: Uint8Array = readFileSync(demoFilePath);
const demo: Demo = new Demo(demoBytes, { onTick: (demo) => {
  // Called once per server tick (30 TPS in SP)

  // Check if entities have loaded yet
  const { entities } = demo.state;
  if (!entities) return;

  // Find the first cube by classname and print its position
  const cube = entities.FindByClassname(null, "prop_weighted_cube");
  if (cube) console.log(cube.GetOrigin()?.ToKVString());

}});

The entity interface is deliberately shaped like the VScript API to make it more familiar to those who've scripted for Portal 2 before. For more details, see the examples or the API documentation.

Acknowledgements

• UntitledParser - most of the entity handling code is derived from here.
• dem.nekz.me - guided the initial program layout and message parsing.
• mlugg - for consulting on a different project, which indirectly inspired this one.