我做了Breakout并且它工作正常，但是因为大量的点击检查而有点滞后。有谁知道如何重做我的命中检查以提高速度/效率？ （仅供参考didCollide [Direction]方法检查它是否在那一侧 - didCollideTop（）检查它是否位于该块的顶部）
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Canvas;
import java.awt.event.KeyListener;
import java.awt.event.KeyEvent;
import static java.lang.Character.*;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
public class Breakout extends Canvas implements KeyListener, Runnable, Frame
{
private Ball ball;
private Paddle paddle;
private boolean[] keys;
private BufferedImage back;
private ArrayList<Wall> walls = new ArrayList<Wall>();
private ArrayList<Square> squares = new ArrayList<Square>();
private final int SIDEBORDER = 20;
private final int BOTTOMBORDER = 60;
private final int BALL_SPEED = 20;
private final int WALL_SIZE = 20;
public Breakout()
{
ball = new Ball((int) (Frame.WIDTH / 2.1), (int) (Frame.HEIGHT / 1.15), 20, 20, Color.green, BALL_SPEED, -BALL_SPEED); //instantiate a Ball
paddle = new Paddle((int) (Frame.WIDTH / 2.2), Frame.HEIGHT - 80, 100, 25, Color.blue, 20); //instantiate a Paddle
//makes the left walls
for (int i = 20; i < Frame.HEIGHT - BOTTOMBORDER; i += 20)
walls.add(new Wall(0, i, WALL_SIZE, WALL_SIZE));
//makes the top walls
for (int i = 0; i < Frame.WIDTH - SIDEBORDER; i += 20)
walls.add(new Wall(i, 0, WALL_SIZE, WALL_SIZE));
//makes the right walls
for (int i = 20; i < Frame.HEIGHT - BOTTOMBORDER; i += 20)
walls.add(new Wall(Frame.WIDTH - 40, i, WALL_SIZE, WALL_SIZE));
//makes the squares (the ones you hit)
for (int i = 80; i < Frame.HEIGHT / 2; i += 40)
for (int j = 80; j < Frame.WIDTH / 1.1; j += 70)
squares.add(new Square(j, i, 60, 30));
keys = new boolean[2];
setBackground(Color.WHITE);
setVisible(true);
addKeyListener(this);
new Thread(this).start();
}
public void update(Graphics window)
{paint(window);}
public void paint(Graphics window)
{
Graphics2D twoDGraph = (Graphics2D) window;
back = null;
//take a snap shop of the current screen and save it as an image
if (back == null)
back = (BufferedImage)(createImage(getWidth(), getHeight()));
//create a graphics reference to the back ground image
//draw all changes on the background image
Graphics graphToBack = back.createGraphics();
ball.moveAndDraw(graphToBack);
paddle.draw(graphToBack);
for (int i = 0; i < walls.size(); i++) //draw walls
walls.get(i).draw(graphToBack);
for (int i = 0; i < squares.size(); i++) //draw squares
squares.get(i).draw(graphToBack);
//see if the paddle can move
if (keys[0] == true && paddle.getX() > WALL_SIZE + 15)
paddle.moveLeftAndDraw(window); //move paddle left and draw it
if (keys[1] == true && paddle.getX() + paddle.getWidth() < walls.get(walls.size() - 1).getX() - 15)
paddle.moveRightAndDraw(window); //move paddle right and draw it
//see if the ball hits the top walls
if (ball.getY() + ball.getYSpeed() <= WALL_SIZE)
ball.setYSpeed(-ball.getYSpeed());
//see if the ball hits the left walls
if (ball.getX() + ball.getXSpeed() <= WALL_SIZE)
ball.setXSpeed(-ball.getXSpeed());
//see if the ball hits the right walls
if (ball.getX() + ball.getWidth() + ball.getXSpeed() >= walls.get(walls.size() - 1).getX())
ball.setXSpeed(-ball.getXSpeed());
//see if the ball hits the paddle
if (ball.didCollideTop(paddle)) //top of paddle
ball.setYSpeed(-ball.getYSpeed());
else if (ball.didCollideLeft(paddle) || ball.didCollideRight(paddle)) //sides of paddle
ball.setXSpeed(-ball.getXSpeed());
//checks if the ball hits a square
for (int i = squares.size() - 1; i >= 0; i--)
{
if (ball.didCollideLeft(squares.get(i)) || ball.didCollideRight(squares.get(i)))
{
squares.remove(i);
ball.setXSpeed(-ball.getXSpeed());
}
else if (ball.didCollideTop(squares.get(i)) || ball.didCollideBottom(squares.get(i)))
{
squares.remove(i);
ball.setYSpeed(-ball.getYSpeed());
}
}
if (ball.getY() + ball.getHeight() > Frame.HEIGHT) //resets ball if it goes off screen
resetBall();
if (squares.size() == 0)
{
ball.setColor(Color.white);
graphToBack.setColor(randomColor());
graphToBack.setFont(window.getFont().deriveFont(200f));
graphToBack.drawString("You Win!", (int) (Frame.WIDTH / 6.5), (int) (Frame.HEIGHT / 2.5));
}
twoDGraph.drawImage(back, null, 0, 0);
}
/**
* Randomly generates true or false
* Used to randomize ball direction on reset
* @return true or false
*/
public boolean genRandom()
{
if ((int) (Math.random() * 2) == 0)
return true;
else
return false;
}
/**
* Generates a random color
* @return a random color
*/
public Color randomColor()
{
int r = (int) (1 + Math.random() * 255);
int g = (int) (1 + Math.random() * 255);
int b = (int) (1 + Math.random() * 255);
return new Color(r, g, b);
}
/**
* Resets the ball in middle
* Resets the ball's speed
* Chooses a random direction
*/
public void resetBall()
{
ball.setPos((int) (Frame.WIDTH / 2.1), (int) (Frame.HEIGHT / 1.15)); //reset position
ball.setXSpeed(BALL_SPEED); //reset speeds
ball.setYSpeed(-BALL_SPEED);
if (genRandom()) //random X direction
ball.setXSpeed(-BALL_SPEED);
}
public void keyPressed(KeyEvent e)
{
switch(toUpperCase(e.getKeyChar()))
{
case 'D' : keys[0] = true; break; //left
case 'J' : keys[1] = true; break; //right
}
}
public void keyReleased(KeyEvent e)
{
switch(toUpperCase(e.getKeyChar()))
{
case 'D' : keys[0] = false; break;
case 'J' : keys[1] = false; break;
}
}
public void run()
{
try
{
while(true)
{
Thread.currentThread().sleep(8);
repaint();
}
}
catch(Exception e){}
}
public void keyTyped(KeyEvent e) {}
}
答案 0 :(得分：2)
您的块排列在网格中。如果将块存储在2D数组中（由网格行和列编号索引），则可以直接计算球的网格坐标（划分球X /块宽度和球Y /块高度）然后检查是否存在该网格单元格中的一个块（或相邻的单元格，注意到球可能位于最多4个单元格的边界上 [假设其直径小于单元格的较小维度 - 但是您可以轻松适应情况并非如此] ）。这将是O（1）;你会直接确定球可能重叠的可能块。
然后你只需要对最多4个块（球的网格单元中的那些块）而不是每个块进行实际的碰撞检测 - 并且在任何时候你都不必迭代所有块。 / p>
你的墙细胞也可以在这个网格中工作。