Logan's flailing re: a scene adapter using FP

three-adapter.js

const move = (obj) => {
  if(obj.moving) {
    const newLocation = new Vector3(
        obj.transform.x + obj.speed.x
      , obj.transform.y + obj.speed.y
      , obj.transform.z + obj.speed.z
    );
    var newTransform = new Transform(obj.transform, {location: newLocation}) * Time.delta});
    return new SceneObj(obj, {transform: newTransform});
  }
  else {
    return obj;
  }
};
  
const checkCollision = (obj) => {
  // need sceneObjs
  // can we just make a getSceneObjs()? Doesn't that mean the function doesn't get all inputs at start?
  // Doesn't that violate the principles of FP? What if bigCollisionCheck() is decomposed with the sceneObjs in it already?
  const check = /* big collision check */;
  // maybe otherObj is null when not provided? Maybe we have a SceneObj.none we can use.
  return new SceneObj(obj, {collidedThisFrame: true, collidedWith: otherObj});
};
  
const startFallingIfCollided = (obj) => {
  if(obj.collidedThisFrame) {
    return new SceneObj(obj, {speed: {x: 0, y: -1, z: 0}});
  }
  else {
    return obj;
  }
}

// try to move a ball across a scene, hit a wall, and then fall to the ground
const gimmehBall = () => {
  // this is a very 'wind up' style where all of the ball's interactions are defined up-front as part of the ball's creation.
  
  // Lots of new SceneObj. Should probably just be a createSceneObj so we're not stuffing behavior into the SceneObj itself.
  const ball = new SceneObj(SceneObj.none, {moving: true});
  
  // This looks maybe-ish. Is that supposed to be a smell? Maybe it should just be a maybe in the first place.
  // That way we can handle errors when they inevitably come up.
  const ballUpdate = (ball) => {
    ball = move(ball);
    ball = checkCollision(ball);
    // I want to put the transition to falling here, but this feels like another function should be called instead.
    ball = startFallingIfCollided(ball);
    return ball;
  }
  
  // pretend for a moment that .push returns a new list
  return sceneObjUpdates.push(ballUpdate);
}
 
gimmehBall();
 
// later in the scene manager
 
// the tires have to hit the pavement somewhere, right? Mutating the ref but only in this one dirty, secret place.
// ...dirty...
virtualSceneObjs = sceneObjs.map(sceneObjUpdates);

// do the delta somehow
...
// apply scene changes from the delta
...