我一直在线跟踪CS106A讲座并完成作业。虽然在突破游戏中我已经被困了几天，因为我无法理解它的行为。
基本上，我已经建立了环境，砖块，球，桨，边缘，我可以让球在环境中反弹。我可以让球甚至从砖块上反弹，我甚至可以移除砖块。但是我无法让球从砖块上反弹并同时移除砖块。
如果查看我的代码，你会看到我有一种方法可以反转球的方向。此方法从我的方法中获取一个布尔值，该值检查球是否与环境中的任何对象发生碰撞。如果我不包括方法'remove（）'，那么球将按照预期从砖块上反弹。如果我确实包括那种方法，那么球会移除砖块但不会从它们上弹开。这向我表明正在读取代码并返回布尔值，但该值并未改变球移动的方向。
/*
* File: Breakout.java
* -------------------
* Name:
* Section Leader:
*
* This file will eventually implement the game of Breakout.
*/
import java.awt.Color;
import java.awt.event.MouseEvent;
import acm.graphics.GArc;
import acm.graphics.GLine;
import acm.graphics.GObject;
import acm.graphics.GOval;
import acm.graphics.GRect;
import acm.program.GraphicsProgram;
import acm.util.RandomGenerator;
public class Breakout extends GraphicsProgram {
/** Width and height of application window in pixels */
public static final int APPLICATION_WIDTH = 400;
public static final int APPLICATION_HEIGHT = 600;
/** Dimensions of game board (usually the same) */
private static final int WIDTH = APPLICATION_WIDTH;
private static final int HEIGHT = APPLICATION_HEIGHT;
/** Dimensions of the paddle */
private static final int PADDLE_WIDTH = 60;
private static final int PADDLE_HEIGHT = 10;
/** Offset of the paddle up from the bottom */
private static final int PADDLE_Y_OFFSET = 30;
/** Number of bricks per row */
private static final int NBRICKS_PER_ROW = 10;
/** Number of rows of bricks */
private static final int NBRICK_ROWS = 10;
/** Separation between bricks */
private static final int BRICK_SEP = 4;
/** Width of a brick */
private static final int BRICK_WIDTH =
(WIDTH - (NBRICKS_PER_ROW - 1) * BRICK_SEP) / NBRICKS_PER_ROW;
/** Height of a brick */
private static final int BRICK_HEIGHT = 8;
/** Radius of the ball in pixels */
private static final int BALL_RADIUS = 10;
/** Offset of the top brick row from the top */
private static final int BRICK_Y_OFFSET = 70;
/** Number of turns */
/** private static final int NTURNS = 3;*/
/* Method: run() */
/** Runs the Breakout program. */
public void run() {
init();
createBall();
createSides();
createBlocks();
createPaddle();
addMouseListeners();
waitForClick();
while (BALL.getY() <= HEIGHT){
play();
}
}
public void init(){
setSize(500,700);
}
private void createBlocks(){
int BRICKS = 0;
int ROWS = 0;
while (ROWS != NBRICK_ROWS) {
while (BRICKS != NBRICKS_PER_ROW){
GRect BRICK = new GRect (BRICK_WIDTH, BRICK_HEIGHT);
BRICK.setLocation((BRICKS*(BRICK_SEP + BRICK_WIDTH)+BRICK_SEP), BRICK_Y_OFFSET + (ROWS*(BRICK_HEIGHT + BRICK_SEP)));
BRICK.setFilled(true);
if (ROWS == 0 || ROWS == 1){
BRICK.setColor(Color.RED);
BRICK.setFilled(true);}
else if (ROWS == 2 || ROWS == 3) {
BRICK.setColor(Color.ORANGE);
}
else if (ROWS == 4 || ROWS == 5){
BRICK.setColor(Color.YELLOW);
}
else if (ROWS == 6 || ROWS == 7){
BRICK.setColor(Color.GREEN);
}
else if (ROWS == 8 || ROWS == 9){
BRICK.setColor(Color.CYAN);
}
add(BRICK);
BRICKS++;
}
ROWS++;
BRICKS = 0;
}
}
private void createSides(){
add(rightSide);
add(leftSide);
add(topSide);
add(bottomSide);
}
private void createPaddle(){
PADDLE.setFilled(true);
add(PADDLE, WIDTH/2 - (PADDLE_WIDTH/2), HEIGHT - PADDLE_Y_OFFSET);
}
private void createBall(){
BALL.setFilled(true);
BALL.setLocation(WIDTH/2 - 18, HEIGHT/2);
add(BALL);
}
private void play(){
/* Add Title Text or Lives or Score */
ballMovement();
}
private void ballMovement(){
BRICK_COUNT = (NBRICKS_PER_ROW*NBRICK_ROWS);
while (BRICK_COUNT != 0){
BALL.move(ballXVelocity(), ballYVelocity());
pause(5);
checkXCollision();
checkYCollision();
}
}
public int ballXVelocity(){
boolean x = checkXCollision();
if (x == true){
BALL_X_VELOCITY = -INITIAL_X_VELOCITY;
INITIAL_X_VELOCITY = BALL_X_VELOCITY;
}
else {BALL_X_VELOCITY = INITIAL_X_VELOCITY;}
return BALL_X_VELOCITY;
}
public int ballYVelocity(){
boolean y = checkYCollision();
if (y == true){
BALL_Y_VELOCITY = -INITIAL_Y_VELOCITY;
INITIAL_Y_VELOCITY = BALL_Y_VELOCITY;
}
else {BALL_Y_VELOCITY = INITIAL_Y_VELOCITY;}
return BALL_Y_VELOCITY;
}
private boolean checkXCollision(){
double ballX = BALL.getX();
double ballY = BALL.getY();
GObject colObjLeft = getElementAt(ballX, ballY - BALL_RADIUS);
GObject colObjRight = getElementAt(ballX + BALL_RADIUS*2, ballY- BALL_RADIUS);
if (ballX <= 0 || ballX + (BALL_RADIUS*2) >= APPLICATION_WIDTH){
return true;
}
else if (colObjLeft != null){
return true;
}
else if (colObjRight != null){
return true;
}
else {return false;}
}
private boolean checkYCollision(){
double ballX = BALL.getX();
double ballY = BALL.getY();
GObject colObjTop = getElementAt(ballX+ BALL_RADIUS, ballY - 1);
GObject colObjBot = getElementAt(ballX + BALL_RADIUS, ballY + (BALL_RADIUS*2) + 1);
if(colObjBot == PADDLE){
return true;
}
else if (ballY <= 0){
return true;
}
else if (colObjTop != null && colObjTop != BALL){
remove(colObjTop);
return true;
}
else if (colObjBot != null && colObjBot != PADDLE && colObjBot != BALL){
remove(colObjBot);
return true;
}
else {return false;}
}
public void mouseMoved(MouseEvent e){
if (e != null){
int x = e.getX();
PADDLE.setLocation(x - (PADDLE_WIDTH/2), HEIGHT - PADDLE_Y_OFFSET);
}
}
/*public void paddleLocation(dx,dy);*/
/*int x = */
public GRect PADDLE = new GRect(PADDLE_WIDTH, PADDLE_HEIGHT);
private GArc BALL = new GArc(BALL_RADIUS*2, BALL_RADIUS*2, 0,360);
/*private GOval BALL = new GOval(BALL_RADIUS*2, BALL_RADIUS*2);*/
private int BRICK_COUNT;
private int BALL_Y_VELOCITY;
private int BALL_X_VELOCITY;
private int INITIAL_Y_VELOCITY = 1;
private RandomGenerator rgen = RandomGenerator.getInstance();
private int INITIAL_X_VELOCITY = rgen.nextInt(2);
private GLine rightSide = new GLine (WIDTH, 0, WIDTH, HEIGHT );
private GLine leftSide = new GLine (0, 0, 0, HEIGHT);
private GLine topSide = new GLine (0, 0, WIDTH, 0);
private GLine bottomSide = new GLine (0, HEIGHT, WIDTH, HEIGHT);
}
答案 0 :(得分：2)
看起来您对checkXCollision和checkYCollision的额外电话是个问题。
您可以直接将它们作为ballMovement的一部分进行调用，并且每个方法也会在Velocity方法中调用。
要获取Ball.move的参数，请调用Velocity方法，检查碰撞并移除砖块。但是，在移动球之后，你正在检查碰撞并再次移除。因此，当ballMovement下次运行时，砖块已被移除，Velocity方法内的碰撞检测不起作用。
由于你没有对ballMovement中的碰撞返回值做任何事情，你可能不需要它们。
答案 1 :(得分：1)
欢迎来到SO，这是第一个问题。
while (BRICK_COUNT != 0){
BALL.move(ballXVelocity(), ballYVelocity());
pause(5);
checkXCollision();
checkYCollision();
}
我认为错误是在您的check*Collision()方法的主循环和中调用ball*Velocity()。
如果在其中一个ball*Velocity()方法中发现了碰撞，那么砖被移除，当然也会被逆转，并且看起来很好。
但是如果在check*Collision()的直接调用中发现了碰撞，那么你就无法反转方向。
但我担心修复不仅仅是删除这两行。 （但是试一试。:)当球在角落碰撞时，会发生什么？X和Y ？我认为你正在检查两个不同函数中的球速度，可能在两个不同的函数中改变方向，而不是在它们之间传递知识'，当你击中一个球时你的碰撞代码角落不正确。 （checkXCollision()，通过ballXVelocity()调用，可能会删除checkYCollision()通过ballYVelocity()调用所需的块，以确定是否需要更改方向。）
您可能需要重新编写函数来同时计算X和Y碰撞 ，这样您就可以根据需要删除一个或两个砖块。
我希望这会有所帮助。