java游戏开发杂谈 - 有限状态机

package game6;

import java.awt.Color;
import java.awt.Graphics;

import javax.swing.JPanel;
/**
 * java游戏开发杂谈
 * ---demo6：有限状态机
 * 
 * @author 台哥编程课堂
 * https://www.cnblogs.com/chaohi/
 * 
 * @date 2019-04-25
 */

public class GamePanel extends JPanel{
	/** 屏幕的宽和高 */
	private int width,height;
	
	public GamePanel(int width, int height) {
		this.width = width;
		this.height = height;
		this.setSize(width, height);
		
		//设置当前画布可以获得焦点。
		this.setFocusable(true);
	}
	
	/**方块的位置*/
	private int fk_x = 60;
	private int fk_y = 60;
	
	/**
	 * 画布的绘制
	 */
	public void paintComponent(Graphics g) {
		super.paintComponent(g);
		
		//画绿色背景
		g.setColor(new Color(0x9391d6));
		g.fillRect(0, 0, width, height);
		
		//绘制方块，大小为80
		g.setColor(Color.red);
		g.fillRect(fk_x, fk_y, 80, 80);
	}

	
	//四个状态，对应四个方向的运动
	private static final int stage_left = 0;
	private static final int stage_right = 1;
	private static final int stage_up = 2;
	private static final int stage_down = 3;
	
	//当前状态，初始为向右
	private int stage = stage_right;
	
	/**
	 * 游戏逻辑，处理方块的运动，每次横纵坐标都移动1个像素
	 */
	public void logic()
	{
		switch(stage)
		{
		case stage_right:
			if(fk_x < 260){
				fk_x = fk_x + 1; //右移一个像素
			}else{
				stage = stage_down; //超出指定范围，改为向下状态
			}
			break;
		case stage_down:
			if(fk_y < 260){
				fk_y = fk_y + 1;
			}else{
				stage = stage_left;
			}
			break;
		case stage_left:
			if(fk_x > 60){
				fk_x = fk_x - 1; 
			}else{
				stage = stage_up;
			}
			break;
		case stage_up:
			if(fk_y > 60){
				fk_y = fk_y - 1; 
			}else{
				stage = stage_right;
			}
			break;
		}
		
	}
	
	
}