Best way to handle entity loading!

syszee · June 14, 2014, 2:45am

Hi there,

EDIT* - Whenever I add “handler = new Handler();” in the MenuState class it works. Oddly enough. This is fine… I just don’t understand it. I still want a better system though!

I am looking for the best way to load map objects (entitys, gameobjects (coins, players, enemies, blocks, etc.)). Currently, I am using this type of system:

Main Class > GameStateManager > 1. STATE 1 > Render > Handler Render > GameObject
2. STATE 2 > Render > Handler Render > GameObject

Hopefully, this isn’t confusing. Lets break it down. First, I am using a “gameStateManager” class to cycle through the selected state (ex: menu, intro, playstate, etc.) and render/tick that state.

GameStateManager Class


package net.austinh.dot.gears;

import java.awt.Graphics;

import net.austinh.dot.states.AboutState;
import net.austinh.dot.states.MenuState;
import net.austinh.dot.states.PlayState;

public class GameStateManager {
	
	
	@SuppressWarnings("unused")
	private boolean paused;
	
	public GameState[] gameStates;
	public int currentState;
	public int previousState;
	
	public static final int NUM_STATES = 3;
	public static final int MENU = 0;
	public static final int PLAY = 1;
	public static final int ABOUT = 2;
	
	public GameStateManager() {
		
		paused = false;
		
		gameStates = new GameState[NUM_STATES];
		setState(MENU);
		
		
	}
	
	public void setState(int i) {
		previousState = currentState;
		unloadState(previousState);
		currentState = i;
		if(i == MENU) {
			gameStates[i] = new MenuState(this);
			gameStates[i].init();
		}
		else if(i == PLAY) {
			gameStates[i] = new PlayState(this);
			gameStates[i].init();
		}
		else if(i == ABOUT) {
			gameStates[i] = new AboutState(this);
			gameStates[i].init();
		}
	}
	
	public void unloadState(int i) {
		gameStates[i] = null;
	}
	
	public void setPaused(boolean b) {
		paused = b;
	}
	
	public void tick() {
		if(gameStates[currentState] != null) {
			gameStates[currentState].tick();
		}
	}
	
	public void render(Graphics g) {
		if(gameStates[currentState] != null) {
			gameStates[currentState].render(g);
		}
	}

	public int getCurrentState() {
		return currentState;
	}

	public void setCurrentState(int currentState) {
		this.currentState = currentState;
	}
	
}

Next, on the selected state, it renders everything needed:

PlayState Class

package net.austinh.dot.states;

import java.awt.Graphics;

import net.austinh.dot.gears.GameState;
import net.austinh.dot.gears.GameStateManager;
import net.austinh.dot.main.Game;
import net.austinh.dot.main.Handler;
import net.austinh.dot.objects.ObjectId;
import net.austinh.dot.objects.Player;

public class PlayState extends GameState{

	Game game;
	Handler handler;
	
	public PlayState(GameStateManager gsm) {
		super(gsm);
	}

	public void init() {
		
		game = new Game();
		handler = new Handler();
		
		handler.addObject(new Player(50, 50, ObjectId.Player));
		
		
	}

	public void tick() {
		handler.tick();
	}

	public void render(Graphics g) {
	
		g.fillRect(0, 0, 650, 450);
		
		handler.render(g);
		
	}

}

After that, it renders an object through the handler class:

Handler Class:

package net.austinh.dot.main;

import java.awt.Graphics;
import java.util.LinkedList;

import net.austinh.dot.objects.GameObject;

public class Handler {

	public LinkedList<GameObject> object = new LinkedList<GameObject>();
	private GameObject tempObject;
	
	public void tick(){
		
		for(int i = 0; i < object.size(); i++){
			tempObject = object.get(i);
			tempObject.tick(object);
		}
	}
	
	public void render(Graphics g){
		
		for(int i = 0; i < object.size(); i++){
			tempObject = object.get(i);
			tempObject.render(g);
		}
	}
	
	public void addObject(GameObject object){
		this.object.add(object);
	}
	
	public void removeObject(GameObject object){
		this.object.remove(object);
	}
	
}

(Here is the gameobject super class):

package net.austinh.dot.objects;

import java.awt.Graphics;
import java.awt.Rectangle;
import java.util.LinkedList;

public abstract class GameObject {

	protected float x, y;
	protected static float velX = 0, velY = 0;
	protected ObjectId id;

	public GameObject(float x, float y, ObjectId id){
		this.x = x;
		this.y = y;
		this.id = id;
	}
	
	public abstract void tick(LinkedList<GameObject> object);
	public abstract void render(Graphics g);
	public abstract Rectangle getBounds();

	public float getX() {
		return x;
	}

	public void setX(float x) {
		this.x = x;
	}

	public float getY() {
		return y;
	}

	public void setY(float y) {
		this.y = y;
	}

	public ObjectId getId() {
		return id;
	}

	public void setId(ObjectId id) {
		this.id = id;
	}
	
	
	
}

Then, through the handler class… it displays the object through
handler.addObject(new Player(50, 50, ObjectId.Player));

Player Class

package net.austinh.dot.objects;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.util.LinkedList;

import net.austinh.dot.main.Handler;

public class Player extends GameObject{

	public int w = 32, h = 32;
	
	
	public Player(float x, float y, ObjectId id) {
		super(x, y, id);
	}

	public void tick(LinkedList<GameObject> object) {
		x+=velX;
		y+=velY;
	}

	public void render(Graphics g) {
		
		g.setColor(Color.white);
		g.drawRect((int)x, (int)y, w, h);
		
	}

	public Rectangle getBounds() {
		return new Rectangle((int)x, (int)y, w, h);
	}

}

The error I am having is in the playstate class.
This is the error:

What in the world is wrong with my system??

& What would be a similar, yet better, system for handling objects. (This includes locations, collisions, etc.)

Thanks!

A