JGame2D/src/de/miaurizius/jgame2d/core/GamePanel.java

package de.miaurizius.jgame2d.core;

import de.miaurizius.jgame2d.core.enums.GameState;
import de.miaurizius.jgame2d.core.handlers.*;
import de.miaurizius.jgame2d.entity.Entity;
import de.miaurizius.jgame2d.entity.Player;
import de.miaurizius.jgame2d.tile.TileManager;

import javax.swing.*;
import java.awt.*;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.logging.Level;
import java.util.logging.Logger;

public class GamePanel extends JPanel implements Runnable {

    // SCREEN SETTINGS
    final int originalTileSize = 16; //16x16 tile
    final int scale = 3;

    public final int tileSize = originalTileSize * scale; //48x48 tile
    // 4:3 ratio
    public final int maxScreenCol = 16;
    public final int maxScreenRow = 12;
    public final int screenWidth = tileSize * maxScreenCol; // 768 pixels
    public final int screenHeight = tileSize * maxScreenRow; // 576 pixels

    // WORLD SETTINGS
    public final int maxWorldCol = 50;
    public final int maxWorldRow = 50;

    //FPS
    int FPS = 60;

    // SYSTEM
    public TileManager tileM = new TileManager(this);
    public KeyHandler keyH = new KeyHandler(this);
    Sound se = new Sound();
    Sound music = new Sound();
    public CollisionHandler collisionH = new CollisionHandler(this);
    public AssetSetter assetSetter = new AssetSetter(this);
    public UI ui = new UI(this);
    public EventHandler eventH = new EventHandler(this);
    Thread gameThread;

    // ENTITY AND OBJECT
    public Player player = new Player(this, keyH);
    public Entity[] obj = new Entity[10];
    public Entity[] npc = new Entity[10];
    ArrayList<Entity> entityList = new ArrayList<>();

    // GAME STATE
    public GameState gameState;

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

    public void setupGame() {
        assetSetter.setObject();
        assetSetter.setNPC();
        //playMusic(0); //Play main theme
        gameState = GameState.TITLE;
    }

    public void startGameThread() {
        gameThread = new Thread(this);
        gameThread.start();
    }

    @Override
    public void run() {
        double drawInterval = (double) 1000000000 / FPS;
        double delta = 0;
        double lastTime = System.nanoTime();
        long currentTime;
        long timer = 0;
        int drawCount = 0;

        while(gameThread != null) {
            currentTime = System.nanoTime();
            delta += (currentTime - lastTime) / drawInterval;
            timer += (long) (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() {
        switch(gameState) {
            case PLAY:
                player.update();
                for(Entity entity : npc) if(entity != null) entity.update();
                break;
            case PAUSE:
                break;
        }
    }

    public void paintComponent(Graphics graphics) {
        super.paintComponent(graphics);
        Graphics2D graphics2d = (Graphics2D) graphics;

        // DEBUG
        long drawStart;
        drawStart = System.nanoTime();

        // TITLE SCREEN
        if(gameState == GameState.TITLE) {
            ui.draw(graphics2d);
            return;
        }

        // GAME
        tileM.draw(graphics2d);

        // ENTITY RENDER SYSTEM
        entityList.add(player);
        for(Entity entity : npc) if(entity != null) entityList.add(entity);
        for(Entity entity : obj) if(entity != null) entityList.add(entity);
        entityList.sort(Comparator.comparingInt(o -> o.worldY));
        for(Entity entity : entityList) entity.draw(graphics2d);
        entityList.clear();

        ui.draw(graphics2d);

        long drawEnd = System.nanoTime();
        long passed = drawEnd - drawStart;

        // DEBUG
        if(keyH.checkDrawTime) {
            graphics2d.setColor(Color.white);
            graphics2d.drawString("Draw Time: " + passed, 10, 400);
            System.out.println("Draw Time: " + passed);
            Logger.getLogger("DEBUG").log(Level.FINE, "Draw Time: " + passed);
        }

        // END
        graphics.dispose();
    }

    public void playMusic(int i) {
        music.setFile(i);
        music.play();
        music.loop();
    }

    public void stopMusic() {
        music.stop();
    }

    public void playSE(int i) {
        se.setFile(i);
        se.play();
    }

}