这是我之前的一个问题的后续问题。我正在制作一个java游戏，它基本上是一个带有角色图像的JFrame，一些由fillRect()组成的健康栏，它们都位于背景图像的顶部。问题是生命条和角色出现了，但背景图像没有出现。
这是 Game 类的简化版本，其中包含 main() 和 render() 方法:
public class Game extends Canvas implements Runnable{
public static boolean running = false;
public Thread gameThread;
private BufferedImage playerSpriteSheet;
private ImageManager im;
private static Player player;
private static HealthBar healthBars;
private static BackgroundImage backgroundImage;
public void init(){
ImageLoader loader = new ImageLoader();
playerSpriteSheet = loader.load("/spriteSheet.png");
SpriteSheet pss = new SpriteSheet(playerSpriteSheet);
im = new ImageManager(pss);
backgroundImage = new BackgroundImage("/background.png");
player = new Player(800, 250, im);
healthBars = new HealthBar(200, 200);
this.addKeyListener(new KeyManager());
}
public synchronized void start() {
if(running)return;
running = true;
gameThread = new Thread(this);
gameThread.start();
}
public synchronized void stop() {
if(!running)return;
running = false;
try {
gameThread.join();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void run() {
init();
long lastTime = System.nanoTime();
final double amountOfTicks = 60D;
double ns = 1_000_000_000/amountOfTicks;
double delta = 0;
long now = System.nanoTime();
while(running)
{
delta += (now - lastTime)/ns;
lastTime = now;
if(delta >= 1)
{
tick();
delta--;
}
render();
}
stop();
}
public void tick() {
player.tick();
}
public void render() {
BufferStrategy bs = this.getBufferStrategy();
if(bs == null)
{
createBufferStrategy(3); //Use 5 at most
return;
}
Graphics g = bs.getDrawGraphics();
//RENDER HERE
backgroundImage.render(g);
player.render(g);
healthBars.render(g);
//END RENDER
g.dispose();
bs.show();
}
public static void main(String[] args)
{
JLabel backgroundImage;
JLabel controlKeyPanel;
JLabel statusLabel;
Game game = new Game();
game.setPreferredSize(new Dimension(WIDTH * SCALE, HEIGHT * SCALE));
game.setMaximumSize(new Dimension(WIDTH * SCALE, HEIGHT * SCALE));
game.setMinimumSize(new Dimension(WIDTH * SCALE, HEIGHT * SCALE));
JFrame frame = new JFrame("Title");
frame.setResizable(false);
frame.setSize(WIDTH * SCALE, HEIGHT * SCALE);
frame.setLayout(new BorderLayout());
backgroundImage = new JLabel(new ImageIcon("/background.png"));
String htmlButtonGuide = "words";
controlKeyPanel = new JLabel(htmlButtonGuide);
statusLabel = new JLabel("label");
frame.add(backgroundImage, BorderLayout.CENTER);
frame.add(controlKeyPanel, BorderLayout.EAST);
frame.add(statusLabel, BorderLayout.SOUTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(game);
frame.setVisible(true);
game.start();
//Program seems to continue running after ESC
}
public static Player getPlayer() {
return player;
}
}
这是 BackGroundImage 类:
public class BackgroundImage {
private Image background = null;
public BackgroundImage(String s) {
if(s == null)
{
background = getImage(s);
}
}
public void render(Graphics g) {
Graphics2D g2 = (Graphics2D)g;
g2.drawImage(background, 0, 0, 1200, 600, null);
}
public Image getImage(String path) {
Image tempImage = null;
File image2 = new File(path);
try {
tempImage = ImageIO.read(image2);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return tempImage;
}
}
我关心 render() 方法重用“g”Graphics 对象将所有 3 个东西添加到屏幕上。有人告诉我不要将轻量级的 Swing 生命值条与厚重的 AWT 背景和角色结合起来？谁能指出我正确的方向来显示背景？渲染方法是否应该不考虑背景？我只需要把背景放一次。它不需要像生命条和角色那样不断更新，对吗？
最佳答案
让我们从...开始
backgroundImage = new BackgroundImage("/background.png");
这变成了...
File image2 = new File(path);
或
File image2 = new File("/background.png");
所以你可以看到它...你能看出这个有问题吗？这是请求一个位于当前驱动器根位置的文件...这并不是我认为您想要的...
The images are stored in a folder called "res" in the main project folder
这表明您想要使用...
backgroundImage = new BackgroundImage("res/background.png");
假设图像不是嵌入资源......
下一步...
public BackgroundImage(String s) {
if (s == null) {
background = getImage(s);
}
}
因此，您只想在引用为 null 时尝试加载图像？？？
旁注...
frame.setSize(WIDTH * SCALE, HEIGHT * SCALE); 是一个坏主意，因为框架的边框占据了框架本身内部的空间。
最好重写 Canvas 的 getPreferredSize 方法并提供您要使用的默认大小值，然后在框架上调用 pack 。这将计算框架的大小作为其内容的首选大小加上框架边框要求...
你的“游戏循环”正在疯狂运行......
while (running) {
delta += (now - lastTime) / ns;
lastTime = now;
if (delta >= 1) {
tick();
delta--;
}
render();
}
基本上，这将尽可能快地运行，并将减少其他线程运行的机会，最终使您的游戏(可能还有您的电脑)崩溃
这是运行循环的“简单”概念......
public void run() {
init();
final long amountOfTicks = 60;
long ns = Math.round(1_000_000_000 / (double)amountOfTicks);
int frames = 0;
long frameStart = System.currentTimeMillis();
while (running) {
long startedAt = System.nanoTime();
tick();
render();
long completedAt = System.nanoTime();
long duration = completedAt - startedAt;
long frameEnd = System.currentTimeMillis();
if (frameEnd - frameStart >= 1000) {
System.out.println(frames);
frames = 0;
frameStart = System.currentTimeMillis();
} else {
frames++;
}
long rest = ns - duration;
if (rest > 0) {
rest = TimeUnit.MILLISECONDS.convert(rest, TimeUnit.NANOSECONDS);
try {
Thread.sleep(rest);
} catch (InterruptedException ex) {
}
}
}
stop();
}
基本上，它会尝试确保每次迭代之间有足够的延迟，以维持您试图达到的 60fps 目标...而不会让系统挨饿...
关于java - Java 游戏中不显示背景图像，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/25636507/