当球到达左侧球拍正上方的某个位置时，它会在球拍内部产生弹跳并反弹并继续下降。它必须与下面的功能有关，但我无法弄明白。
public static boolean intervallContains(int low,int high, int n) { //determines if something is in a certain range
return n >= low && n <= high;
}
public void detectPaddle(){ //determines if ball is close enough to paddle for detection
int withinY = (paddleStart+y) - (ballStartY+randomBally);
int withinY2 = (paddleStartTwo+ytwo) - (ballStartY+randomBally);
//System.out.println(withinY +" paddle - ball" );
// System.out.println(ballStartY+randomBally +" ball" );
if (ballStartX+randomBallx <= paddleFace1 && intervallContains(-50,50,withinY)){
dx = -dx;
}
if(ballStartX+randomBallx >= paddleFace2 && intervallContains(-50,50,withinY2)){
dx = -dx;
}
}
public void points(){
if(ballStartX+randomBallx >= jpW-30){
score1++;
randomBallx = 30;
randomBally = 30;
dx = -dx;
}
else if(ballStartX+randomBallx <= 0){
score2++;
randomBallx = 0;
randomBally = 0;
dx = -dx;
}
if(score1 == Pong.points){
//JOptionPane.showMessageDialog(null, "Player one wins? maybe?...");
//choose to continue or close to reset game
//System.exit(0);
}
}
这是完整的代码
import java.awt.Color;
import java.awt.Event;
import java.awt.Graphics;
import java.util.Random;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
public class Pong extends JFrame implements ActionListener{
//implement constants
PongPanel pongPanel = new PongPanel();
//JFrame pong x and y coordinates
static final int jfpX = 150;
static final int jfpY = 20;
// JFrame pong width and height
static final int jfpW = 800;
static final int jfpH = 600;
String pointStr;
static int points;
Thread thrd;
public static void main(String[] args) {
Pong jfp = new Pong();
jfp.setVisible(true);
}
public Pong(){
setBounds(jfpX,jfpY,jfpW,jfpH);
setTitle("Pong");
setResizable(false);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setBackground(Color.black);
pointStr = JOptionPane.showInputDialog("Enter how many points you want to play to. The limit is 25, And must be at least 5.");
try{
points = Integer.parseInt(pointStr);
}
catch(NumberFormatException e){
pointStr = JOptionPane.showInputDialog("Please enter digits only.");
}
add(pongPanel);
addKeyListener(pongPanel);
thrd = new Thread (pongPanel);
thrd.start();
}
public void actionPerformed(ActionEvent e) {
}
}
class PongPanel extends JPanel implements Runnable, KeyListener{
Random random = new Random();
static final int jpW = 800;
static final int jpH = 600;
int paddleStart = (jpH/2)-60;
int paddleStartTwo = (jpH/2)-60;
int ballStartX = (jpW/2)-30;
int ballStartY = (jpH/2)-30;
int ytwo,x,y;
int paddleFace1 = 40;
int paddleFace2 = 730;
int ballD = 30;
int paddleW1 = 20;
int paddleH1 = 100;
int paddleW2 = 20;
int paddleH2 = 100;
boolean play = true;
boolean leftWall1 = true;
boolean leftWall2 = true;
boolean rightWall1 = true;
boolean rightWall2 = true;
int min = -2;
int max = 2;
int score1, score2;
int randomBallx = random.nextInt(max-min+1)+min;
int randomBally = random.nextInt(max-min+1)+min;
int dx = 7;
int dy = 7; //direction of y
public void ballNotZero(){// makes sure the ball doesnt go straight up and down
if (randomBallx == 0){
randomBallx = random.nextInt(max-min)+min;
}
if(randomBally == 0){
randomBally=random.nextInt(max-min)+min;
}
}
public PongPanel(){
}
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
Color ball,score,paddleOne,paddleTwo;
score = new Color(0,255,0);
ball = new Color(255,0,255);
paddleOne = new Color(255,0,0);
paddleTwo = new Color(0,0,255);
g.setColor(ball);
g.fillOval(ballStartX+randomBallx,ballStartY+randomBally,ballD,ballD);
// g.setFont(font);
g.setColor(score);
g.drawString(Integer.toString(score1),200 ,100 );
g.drawString(Integer.toString(score2),600,100);
g.setColor(paddleOne);
g.fillRect(20,paddleStart+y,paddleW1,paddleH1);
g.setColor(paddleTwo);
g.fillRect(760,paddleStartTwo+ytwo,paddleW2,paddleH2);
g.setColor(Color.white);
g.drawLine(400,0,400,600);
}
public void run() {
while(play){
paddleWalls();
detectPaddle();
ballBounce();
points();
moveBall();
ballNotZero();
repaint();
try {Thread.sleep(75); } catch(Exception e){
};
}
}
public static boolean intervallContains(int low,int high, int n) { //determines if something is in a certain range
return n >= low && n <= high;
}
public void detectPaddle(){ //determines if ball is close enough to paddle for detection
int withinY = (paddleStart+y) - (ballStartY+randomBally);
int withinY2 = (paddleStartTwo+ytwo) - (ballStartY+randomBally);
//System.out.println(withinY +" paddle - ball" );
// System.out.println(ballStartY+randomBally +" ball" );
if (ballStartX+randomBallx <= paddleFace1 && intervallContains(-50,50,withinY)){
dx = -dx;
}
if(ballStartX+randomBallx >= paddleFace2 && intervallContains(-50,50,withinY2)){
dx = -dx;
}
}
public void moveBall(){
randomBallx+=dx;
randomBally+=dy;
}
public void ballBounce(){
if(ballStartY+randomBally >= jpH-50){
dy = -dy;
}
else if(ballStartY+randomBally <= 0){
dy = -dy;
}
}
public void paddleWalls(){
if((paddleStart+y) == 0){
leftWall1 = false;
}
else{
leftWall1 = true;
}
if((paddleStart+y) == 480){
rightWall1 = false;
}
else{
rightWall1 = true;
}
if((paddleStartTwo+ytwo) == 0){
leftWall2 = false;
}
else{
leftWall2 = true;
}
if((paddleStartTwo+ytwo) == 480){
rightWall2 = false;
}
else{
rightWall2 = true;
}
}
public void points(){
if(ballStartX+randomBallx >= jpW-30){
score1++;
randomBallx = 30;
randomBally = 30;
dx = -dx;
}
else if(ballStartX+randomBallx <= 0){
score2++;
randomBallx = 0;
randomBally = 0;
dx = -dx;
}
if(score1 == Pong.points){
//JOptionPane.showMessageDialog(null, "Player one wins? maybe?...");
//choose to continue or close to reset game
//System.exit(0);
}
}
public void keyPressed(KeyEvent e) {
//player one controls
if(e.getKeyCode() == KeyEvent.VK_A && leftWall1 == true){
y-=10;
}
else if(e.getKeyCode() == KeyEvent.VK_S && rightWall1 == true){
y+=10;
}
//player two controls
if(e.getKeyCode() == KeyEvent.VK_QUOTE && leftWall2 == true){
ytwo-=10;
}
else if(e.getKeyCode() == KeyEvent.VK_SEMICOLON && rightWall2 == true){
ytwo+=10;
}
if(e.getKeyCode() == KeyEvent.VK_ESCAPE){
System.exit(0);
}
}
public void keyTyped(KeyEvent e) {
}
public void keyReleased(KeyEvent e) {
}
public void startPong() {
play = true;
}
public void stopPong() {
play = false;
}
}
答案 0 :(得分：2)
如果无法直接看到问题，我猜您的问题出在detectPaddle()方法中。在其中，您可以看到球是否足够接近您的球拍。但是，您不会检查它是否朝正确的方向移动。
更改这些行：
if (ballStartX+randomBallx <= paddleFace1 && intervallContains(-50,50,withinY)){
dx = -dx;
}
if(ballStartX+randomBallx >= paddleFace2 && intervallContains(-50,50,withinY2)){
dx = -dx;
}
包括球方向的检查。也许是这样的：
if (dx < 0 && ballStartX+randomBallx <= paddleFace1 && intervallContains(-50,50,withinY)){
dx = -dx;
}
if(dx > 0 && ballStartX+randomBallx >= paddleFace2 && intervallContains(-50,50,withinY2)){
dx = -dx;
}
这样球不会在球拍内部反弹 - 它只能在一个方向反弹。
此外，我假设paddleFace1是你的左桨，paddleFace2是你的右桨。