Loot dropping upon death

[IsaacLic]

Description

This PR adds a system for creating Loot objects when an entity with a DropsLoot component dies. Loot is the DS object that is created when certain SolObjects (e.g. ships) are destroyed. The logic was pulled from Asteroid, although SolShip uses a similar structure.

This is built upon PRs #519 and #522. It makes use of the DestroyEvent from 519, as well as Position and Velocity from 522.

Testing

First, copy/paste the following three fields to SolApplication:

private boolean madeLootEntity = false;
    private int counter = 0;
    EntityRef entity;

Next, add the following code after line 231 (inside the if statement that confims that solGame isn't null):

            if (!madeLootEntity) {

            entity = entitySystemManager.getEntityManager().createEntity(new DropsLootOnDeath(), new Position(), new Velocity(), new Size());

            Position position = entity.getComponent(Position.class).get();
            position.position = solGame.getHero().getPosition().cpy();
            position.position.x += 1;
            position.position.y += 3;
            entity.setComponent(position);

            Size size = new Size();
            size.size = 20;
            entity.setComponent(size);

            madeLootEntity = true;
        }
        counter++;
        if (counter == 500) {
            entitySystemManager.sendEvent(new DestroyEvent(), entity);
        }

That code does a few things:

• Creates an entity with the requisite components to drop loot upon dying
• Moves the entity one unit down and three to the right, so that the loot won't be absorbed by the station
• After several seconds, the EntitySystemManager will send a DestroyEvent to the entity, causing loot to appear on screen

[skaldarnar]

I read "loot dropping" I post links:

• https://lostgarden.home.blog/2014/12/08/loot-drop-tables/
• https://gamedev.stackexchange.com/questions/140979/modern-loot-table-concepts

These are basically two resources I found while briefly looking into loot tables for Terasology. Maybe they are helpful, maybe not - I honestly didn't look at the PR 🙈

[NicholasBatesNZ]

Sorry for the delay on this, seems to work 👍