From f4508fa0da294c7710a272cb87ea235d6371abee Mon Sep 17 00:00:00 2001
From: Matt Low <mattjlow94@gmail.com>
Date: Sat, 1 Feb 2020 20:40:39 +0400
Subject: [PATCH] Utilize a PLAYER tag and ASTEROIDS group

User PLAYER tag for access to the player entity
Use ASTEROIDS group to count how many asteroids there are
---
 core/src/com/me/asteroids/EntityFactory.java        |  3 +++
 .../asteroids/systems/AsteroidSpawningSystem.java   | 13 +------------
 .../com/me/asteroids/systems/GameDataSystem.java    |  2 +-
 3 files changed, 5 insertions(+), 13 deletions(-)

diff --git a/core/src/com/me/asteroids/EntityFactory.java b/core/src/com/me/asteroids/EntityFactory.java
index 9853ef9..9be54d7 100644
--- a/core/src/com/me/asteroids/EntityFactory.java
+++ b/core/src/com/me/asteroids/EntityFactory.java
@@ -73,6 +73,7 @@ public class EntityFactory {
         player.addComponent(new AccelerationComponent(0f, 1f));
         player.addComponent(COLLIDER);
         player.addComponent(new PlayerComponent(afterBurner));
+        player.setTag("PLAYER");
 
         afterBurner.addComponent(new PositionComponent(Constants.HALF_WIDTH, Constants.HALF_HEIGHT, 90));
         afterBurner.addComponent(velocity);
@@ -186,6 +187,7 @@ public class EntityFactory {
         asteroid.addComponent(model);
         asteroid.addComponent(COLLIDER);
         asteroid.addComponent(new AsteroidComponent());
+        asteroid.addGroup("ASTEROIDS");
         return asteroid;
     }
 
@@ -230,6 +232,7 @@ public class EntityFactory {
             split.addComponent(velocity);
             split.addComponent(new AsteroidComponent(ASTEROID.get(asteroid).generation + 1));
             split.addComponent(COLLIDER);
+            split.addGroup("ASTEROIDS");
             entities[i] = split;
         }
 
diff --git a/core/src/com/me/asteroids/systems/AsteroidSpawningSystem.java b/core/src/com/me/asteroids/systems/AsteroidSpawningSystem.java
index 0b59f81..e5f378d 100644
--- a/core/src/com/me/asteroids/systems/AsteroidSpawningSystem.java
+++ b/core/src/com/me/asteroids/systems/AsteroidSpawningSystem.java
@@ -2,7 +2,6 @@ package com.me.asteroids.systems;
 
 import com.badlogic.gdx.math.Rectangle;
 import com.badlogic.gdx.math.Vector2;
-import com.badlogic.gdx.utils.Array;
 import com.me.asteroids.Constants;
 import com.me.asteroids.EntityFactory;
 import com.me.asteroids.Utils;
@@ -12,7 +11,6 @@ import com.me.common.ecs.BaseSystem;
 import com.me.common.ecs.Engine;
 import com.me.common.ecs.Entity;
 
-import static com.me.asteroids.Components.ASTEROID;
 import static com.me.asteroids.Components.MODEL;
 import static com.me.asteroids.Components.POSITION;
 import static com.me.asteroids.Components.VELOCITY;
@@ -63,16 +61,7 @@ public class AsteroidSpawningSystem extends BaseSystem {
 
     @Override
     public void process(float dt) {
-        Array<Entity> entities = engine.getEntities();
-        int asteroidCount = 0;
-        for (Entity entity : entities) {
-            // It's rather inefficient to have to check our entire entity list every frame
-            // to count how many entities have a specific component. Maybe we should keep a count of
-            // how many entites a given component?
-            if (ASTEROID.has(entity)) {
-                asteroidCount++;
-            }
-        }
+        int asteroidCount = engine.getEntitiesInGroup("ASTEROIDS").size;
 
         if (asteroidCount++ < Constants.ASTEROID_SPAWN_COUNT && (asteroidSpawnDelay -= dt) <= 0) {
             spawnAsteroid();
diff --git a/core/src/com/me/asteroids/systems/GameDataSystem.java b/core/src/com/me/asteroids/systems/GameDataSystem.java
index 652ebcc..b21ecad 100644
--- a/core/src/com/me/asteroids/systems/GameDataSystem.java
+++ b/core/src/com/me/asteroids/systems/GameDataSystem.java
@@ -85,7 +85,7 @@ public class GameDataSystem extends EntitySystem implements Listener {
     }
 
     private void resetPlayer() {
-        Entity player = engine.getEntities().get(1);
+        Entity player = engine.getEntityByTag("PLAYER");
         PositionComponent position = POSITION.get(player);
         position.set(Constants.HALF_WIDTH, Constants.HALF_HEIGHT);
         position.rotation = 90;