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java – 了解BufferStrategy

我是java的新手.我想做一个游戏.经过大量的研究,我无法理解bufferstrategy的工作原理.

我知道基础知识..它创建了一个屏幕外图像,您可以稍后将其放入您的 Windows

对象..我得到了这个

public class Marco extends JFrame {
    private static final long serialVersionUID = 1L;
    BufferStrategy bs; //create an strategy for multi-buffering.

    public Marco() {
       basicFunctions(); //just the clasics setSize,setVisible,etc
       createBufferStrategy(2);//jframe extends windows so i can call this method 
       bs = this.getBufferStrategy();//returns the buffer strategy used by this component
    }

   @Override
   public void paint(Graphics g){
      g.drawString("My game",20,40);//some string that I don't know why it does not show
      //guess is 'couse g2 overwrittes all the frame..
      Graphics2D g2=null;//create a child object of Graphics
      try{
         g2 = (Graphics2D) bs.getDrawGraphics();//this new object g2,will get the
         //buffer of this jframe?
         drawWhatEver(g2);//whatever I draw in this method will show in jframe,
         //but why??
      }finally{
         g2.dispose();//clean memory,but how? it cleans the buffer after
         //being copied to the jframe?? when did I copy to the jframe??
      }
      bs.show();//I never put anything on bs, so, why do I need to show its content??
      //I think it's a reference to g2, but when did I do this reference??
   }

   private void drawWhatEver(Graphics2D g2){
       g2.fillRect(20, 50, 20, 20);//now.. this I can show..
   }
  }

我不知道..我已经研究了很长时间了……而且根本没有运气……我不知道……也许它就在那里,而且它非常简单明了,我我看起来太傻了..

感谢所有的帮助..

以下是它的工作原理：

>当您调用createBufferStrategy(2);时,JFrame构造一个BufferStrategy. BufferStrategy知道它属于JFrame的特定实例.您正在检索它并将其存储在bs字段中.

>当你需要绘制你的东西时,你正在从bs中检索Graphics2D.此Graphics2D对象绑定到bs拥有的内部缓冲区之一.在绘制时,一切都进入缓冲区.

>当你最终调用bs.show()时,bs将导致你刚绘制的缓冲区成为JFrame的当前缓冲区.它知道如何做到这一点,因为(见第1点)它知道它正在服务的JFrame.

这就是所有这一切.

通过对代码的评论……你应该稍微改变你的绘图程序.而不是这个：

try{
    g2 = (Graphics2D) bs.getDrawGraphics();
    drawWhatEver(g2);
} finally {
       g2.dispose();
}
bs.show();

你应该有一个像这样的循环：

do {
    try{
        g2 = (Graphics2D) bs.getDrawGraphics();
        drawWhatEver(g2);
    } finally {
           g2.dispose();
    }
    bs.show();
} while (bs.contentsLost());

这将防止丢失的缓冲帧,根据 the docs ,偶尔会发生这种情况.

翻译自：https://stackoverflow.com/questions/13590002/understand-bufferstrategy

原文 https://codeday.me/bug/20190112/519944.html

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