GamePanel.java

package main;

import entity.Player;
import tile.TileManager;

import javax.swing.JPanel;
import java.awt.*;

public class GamePanel extends JPanel implements Runnable{

    //screen
    final int originalTileSize = 16;
    final int scale = 3;

    public final int tileSize = originalTileSize * scale;
    public final int maxScreenCol = 16;
    public final int maxScreenRow = 12;
    public final int screenWidth = tileSize * maxScreenCol;
    public final int screenHeight = tileSize * maxScreenRow;

    //world setting
    public final int maxWorldCol = 50;
    public final int maxWorldRow = 50;
    public final int worldWidth = tileSize * maxWorldCol;
    public final int worldHeight = tileSize * maxWorldRow;

    int FPS = 60;

    TileManager tileM = new TileManager(this);
    KeyHandler keyH = new KeyHandler();
    Thread gameThread;
    public CollisionCheck cChecker = new CollisionCheck(this);
    public Player player = new Player(this, keyH);

    public GamePanel(){

        this.setPreferredSize(new Dimension(screenWidth, screenHeight));
        this.setBackground(Color.black);
        this.setDoubleBuffered(true);
        this.addKeyListener(keyH);
        this.setFocusable(true);
    }

    public void startGameThread(){

        gameThread = new Thread(this);
        gameThread.start();
    }

    @Override
    public void run() {

        double drawInterval = 1000000000/FPS;
        double delta = 0;
        double lastTime = System.nanoTime() + drawInterval;
        long currentTime;
        long timer = 0;
        int drawCount = 0;

        while(gameThread != null) {

            currentTime = System.nanoTime();

            delta += (currentTime - lastTime) / drawInterval;
            timer += (currentTime - lastTime);
            lastTime = currentTime;

            if(delta >= 1) {
                update();
                repaint();
                delta--;
                drawCount++;
            }

            if(timer >= 1000000000) {
                System.out.println("FPS" + drawCount);
                drawCount = 0;
                timer = 0;
            }
        }
    }

    public void update(){

        player.update();
    }
    public void paintComponent(Graphics g){

        super.paintComponent(g);

        Graphics2D g2 = (Graphics2D)g;

        tileM.draw(g2);
        player.draw(g2);
        g2.dispose();


    }
}