Object pooling

We have defined our first game object, which represents our player's spaceship, but all we can do is fly around the game screen. We need to allow our player to shoot a projectile. If we created a new projectile object every time a player shot a projectile, we would quickly fill up the WASM module's memory. What we need to do is create what is known as an object pool. Object pools are used to create objects with a fixed lifespan. Our projectiles only need to be alive long enough to either hit a target or travel a fixed distance before disappearing. If we create a set number of projectiles that is a little more than we need on the screen at one time, we can keep those objects in a pool in either an active or inactive state. When we need to launch a new projectile, we scan our object pool for an inactive one, then activate it and place it at the launch point...