PhaseMachine Performance in Game Loops

[dsriseah]

Currently, PhaseMachine has overhead in its invocation loops. Consider this example from an SNA app implementing a game loop:

async function Start() {
  const { frameRate, frameDurMS } = GSTATE.GetTimeState();
  const { RunPhaseGroup } = CLASS.PhaseMachine;
  // start
  await RunPhaseGroup('SNA_GAME/INIT');
  // loop
  GAME_TIMER = setInterval(async () => {
    if (frameRate > 0) {
      GSTATE.UpdateStateTimers();
      await RunPhaseGroup('SNA_GAME/LOOP_BEGIN');
      await RunPhaseGroup('SNA_GAME/LOOP_CALC');
      await RunPhaseGroup('SNA_GAME/LOOP_THINK');
      await RunPhaseGroup('SNA_GAME/LOOP_RENDER');
    }
  }, frameDurMS);
}

The game loop defined in the interval timers uses the static method RunPhaseGroup which has a couple of performance problems:

• the string-based lookup runs through DecodeHookSelector to look-up the machine name, then invokes each phase in the group one-by-one
• the invocation wraps the phase group execution in promises, which isn't desirable in a realtime game loop

It should be possible to write a dereferencing method that returns stacks of functions without the async-await default behavior, which could result in less overhead.