ParticleSystem.java

package com.gdxjam.systems;

import com.badlogic.ashley.core.Engine;
import com.badlogic.ashley.core.Entity;
import com.badlogic.ashley.core.Family;
import com.badlogic.ashley.core.PooledEngine;
import com.badlogic.ashley.systems.IteratingSystem;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.graphics.g2d.ParticleEffect;
import com.badlogic.gdx.graphics.g2d.ParticleEffectPool;
import com.badlogic.gdx.graphics.g2d.ParticleEffectPool.PooledEffect;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.utils.Array;
import com.gdxjam.components.Components;
import com.gdxjam.components.ParticleComponent;

public class ParticleSystem extends IteratingSystem {

	private static final String ROOT_DIR = "particles/";

	public enum ParticleType {
		EXPLOSION("explosion.p"), HARVSET("harvest.p");

		public String file;

		private ParticleType(String file) {
			this.file = file;
		}
	}

	private Array<ParticleEffect> effectTemplates = new Array<ParticleEffect>();
	private Array<ParticleEffectPool> effectPools = new Array<ParticleEffectPool>();

	private OrthographicCamera camera;
	private SpriteBatch batch;

	private PooledEngine engine;

	@SuppressWarnings("unchecked")
	public ParticleSystem() {
		super(Family.all(ParticleComponent.class).get());
		loadTemplates();
	}

	public void loadTemplates() {
		for (int i = 0; i < ParticleType.values().length; i++) {
			ParticleEffect template = new ParticleEffect();
			template.load(Gdx.files.internal(ROOT_DIR + ParticleType.values()[i].file), Gdx.files.internal(ROOT_DIR));
			template.scaleEffect(0.02f);
			effectTemplates.add(template);

			ParticleEffectPool pool = new ParticleEffectPool(template, 4, 20);
			effectPools.add(pool);
		}
	}

	public PooledEffect createEffect(Vector2 position, ParticleType type) {
		PooledEffect effect = effectPools.get(type.ordinal()).obtain();
		effect.setPosition(position.x, position.y);
		return effect;
	}

	@Override
	public void addedToEngine(Engine engine) {
		super.addedToEngine(engine);
		this.engine = (PooledEngine) engine;
		batch = new SpriteBatch();
		camera = engine.getSystem(CameraSystem.class).getCamera();
	}

	@Override
	protected void processEntity(Entity entity, float deltaTime) {
		ParticleComponent particle = Components.PARTICLE.get(entity);
		particle.effect.update(deltaTime);
		particle.effect.draw(batch);

		if (particle.effect.isComplete()) {
			particle.effect.free();
			engine.removeEntity(entity);
		}
	}

	@Override
	public void update(float deltaTime) {
		batch.setProjectionMatrix(camera.combined);
		batch.begin();
		super.update(deltaTime);
		batch.end();
	}

}