如何让球从桨上弹起来

Question

import pygame

BLACK = pygame.color.Color('Black')
YELLOW = pygame.color.Color('Yellow')
BLUE = pygame.color.Color('Blue')

pygame.init()
screen = pygame.display.set_mode([700,500])
screen_rect = screen.get_rect()

pygame.display.set_caption("Trial to make PONG")

blue_rect = pygame.Rect(10, 250, 20, 60)
yellow_rect = pygame.Rect(670, 250, 20, 60)
ball_rect = pygame.Rect(50, 50, 50, 50)

ball_x_speed = 5
ball_y_speed = 5

clock = pygame.time.Clock()

done = False
while not done:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            done = True

    # check all pressed keys and move the paddles
    pressed = pygame.key.get_pressed()
    if pressed[pygame.K_UP]: blue_rect.move_ip(0, -5)
    if pressed[pygame.K_DOWN]: blue_rect.move_ip(0, 5)
    if pressed[pygame.K_w]: yellow_rect.move_ip(0, -5)
    if pressed[pygame.K_s]: yellow_rect.move_ip(0, 5)

    # ensure paddles stay on screen
    blue_rect.clamp_ip(screen_rect)
    yellow_rect.clamp_ip(screen_rect)

    # move the ball
    ball_rect.move_ip(ball_x_speed, ball_y_speed)

    # check if the ball needs to change direction
    if ball_rect.x  + ball_rect.width > screen_rect.width or ball_rect.x < 0:
        ball_x_speed = ball_x_speed * -1
    if ball_rect.y  + ball_rect.height> screen_rect.height or ball_rect.y < 0:
        ball_y_speed = ball_y_speed * -1


    # draw everything
    screen.fill(BLACK)
    pygame.draw.ellipse(screen, BLUE, ball_rect)
    pygame.draw.rect(screen,BLUE, blue_rect)
    pygame.draw.rect(screen,YELLOW, yellow_rect)
    pygame.display.flip()
    clock.tick(60)

pygame.quit()

我在比赛中有两个球，一个球在弹跳。当球撞到球拍时，我试图制造一个碰撞点。我试图重建乒乓球。碰撞点没有用（可能是因为我没有正确地构造它）。

我想知道如何在球拍（长方形蓝色和黄色）和球（ball_rect）之间形成一个碰撞点，以便球从球拍中反弹？

Answer 1

这应该有效：

# Inside the main loop.
if ball_rect.collidelist([blue_rect, yellow_rect]) > -1:
    ball_x_speed = -ball_x_speed

希望它有所帮助！

Answer 2

这是我在Java中的ball类...........

public class Ball {

public int width = 30;
public int height = 30;
public int motionX;
public int motionY;
public int x, y;
private RectAnimation pong;
public Random random;

public int amountOfHits;

public Ball(RectAnimation pong) {
    this.random = new Random();
    this.pong = pong;
    spawn();
}

public void update(paddle paddle1, paddle paddle2) {

    int speed = 5;

    this.x += motionX * speed;
    this.y += motionY * speed;
    if (this.y + height > pong.height || this.y < 0) {
        if (this.motionY < 0) {
            this.y = 0;
            this.motionY = random.nextInt(4);
            if (motionY == 0) {
                motionY = 1;
            }
        } else {
            this.y = pong.height - height - motionY;
            this.motionY = -random.nextInt(4);
            if (motionY == 0) {
                motionY = -1;
            }

        }
    }
    if (checkCollision(paddle1) == 1) {
        this.motionX = 1 + (amountOfHits / 5);
        this.motionY = -2 + random.nextInt(4);
        if (motionY == 0) {
            motionY = 1;
        }
        amountOfHits++;
    } else if (checkCollision(paddle2) == 1) {
        this.motionX = -1 - (amountOfHits / 5);
        this.motionY = -2 + random.nextInt(4);
        if (motionY == 0) {
            motionY = -1;
        }
    }

    if (checkCollision(paddle1) == 2) {
        paddle2.score++;
        spawn();
    } else if (checkCollision(paddle2) == 2) {
        paddle1.score++;
        spawn();
    }
}

public void spawn() {
    this.amountOfHits = 0;
    this.x = pong.width / 2 - this.width / 2;
    this.y = pong.height / 2 - this.height / 2;
    this.motionX = -1 + random.nextInt(4);

    if (motionY == 0) {
        motionY = 1;
    }
    if (random.nextBoolean()) {
        motionX = 1;
    } else {
        motionX = -1;
    }

}

public int checkCollision(paddle pad) {

    if (this.x < pad.x + pad.width && this.x + width > pad.x && this.y < pad.y + pad.height && this.y + height > pad.y) {
        return 1; //bounce
    } else if (pad.x > x + width && pad.paddleNumber == 1 || pad.x < x && pad.paddleNumber == 2) {
        return 2; //score
    }

    return 0;

}

public void render(Graphics g) {

    g.setColor(Color.WHITE);
    g.fillOval(x, y, width, height);

}

}

您如何询问并实例化它。...

public class RectAnimation implements ActionListener, KeyListener {

public static RectAnimation rectAnimation;
public gamePong renderer;

public paddle player1;
public paddle player2;

public Ball ball;
public int width = 700, height = 700;

public boolean bot = false;
public boolean w = false;
public boolean s = false;
public boolean up = false;
public boolean down = false;
public int gameStatus = 0;
public int botMoves;
public int botCoolDown = 0;
public int botDifficulty = 0;
public RectAnimation() {

    Timer timer = new Timer(20, this);

    JFrame frame = new JFrame("Rectangle Animation");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    frame.setVisible(true);
    frame.setResizable(true);
    frame.setSize(width + 15, height + 30);
    frame.setLocation(375, 55);

    renderer = new gamePong();
    frame.add(renderer);

    frame.addKeyListener(this);

    timer.start();
}


public void render(Graphics2D g) {

    g.setColor(Color.BLACK);
    g.fillRect(0, 0, width, height);
    g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

    if (gameStatus == 0) {
        g.setColor(Color.WHITE);
        g.setFont(new Font("Ariel", 1, 50));
        g.drawString("PONG", width / 2 - 70, 50);

        g.setFont(new Font("Ariel", 1, 20));
        g.drawString("Press Space to Play", width / 2 - 90, height / 2 + 50);
    }

    if (gameStatus == 1 || gameStatus == 2) {
        g.setColor(Color.WHITE);
        g.setStroke(new BasicStroke(10));
        g.drawLine(width / 2, 0, width / 2, height);
        g.drawOval(width / 2 - 100, height / 2 - 100, 200, 200);
        g.setFont(new Font("Ariel", 1, 50));
        g.drawString(String.valueOf(player1.score), width / 2 - 70, 50);

        g.setFont(new Font("Ariel", 1, 50));
        g.drawString(String.valueOf(player2.score), width / 2 + 65, 50);

        player1.render(g);
        player2.render(g);
        ball.render(g);
    }
    if (gameStatus == 1) {
        g.setColor(Color.WHITE);
        g.setFont(new Font("Ariel", 1, 50));
        g.drawString("PAUSED", width / 2 - 100, 50);
    }

}

public void start() {
    player1 = new paddle(this, 1);
    player2 = new paddle(this, 2);
    ball = new Ball(this);
    gameStatus = 2;
}

public void update() {

    if (w) {
        player1.move(true);
    } else if (s) {
        player1.move(false);
    } else if (!bot) {
        if (up) {
            player2.move(true);
        }
        if (down) {
            player2.move(false);
        }
    } else {

        if (botCoolDown > 0) {
            botCoolDown--;
            if (botCoolDown == 0) {
                botMoves = 0;
            }
        }

        if (botMoves < 10) {

            if (player2.y + player2.height < ball.y) {
                player2.move(false);
                botMoves++;
            }
            if (player2.y  + player2.height  > ball.y) {
                player2.move(true);
                botMoves++;
            }
            if(botDifficulty == 0)
                botCoolDown = 30;
            else if(botDifficulty == 1)
                botCoolDown = 20;
            else if(botDifficulty == 2)
                botCoolDown = 10;
        }
    }
    ball.update(player1, player2);
}

public void actionPerformed(ActionEvent e) {
    if (gameStatus == 2) {
        update();
    }
    renderer.repaint();

}

/**
 * @param args the command line arguments
 */
public static void main(String[] args) {
    // TODO code application logic here

    rectAnimation = new RectAnimation();

}

public void keyTyped(KeyEvent e) {

}

public void keyPressed(KeyEvent e) {
    int id = e.getKeyCode();

    if (id == KeyEvent.VK_W) {
        w = true;
    } else if (id == KeyEvent.VK_S) {
        s = true;
    } else if (id == KeyEvent.VK_UP) {
        up = true;
    } else if (id == KeyEvent.VK_DOWN) {
        down = true;
    } else if (id == KeyEvent.VK_ESCAPE && gameStatus == 2) {
        gameStatus = 0;
    } else if (id == KeyEvent.VK_SHIFT && gameStatus == 0) {
        bot = true;
        start();
    }

    if (id == KeyEvent.VK_SPACE) {
        if (gameStatus == 0) {
            start();
            bot = false;
        } else if (gameStatus == 1) {
            gameStatus = 2;
        } else if (gameStatus == 2) {
            gameStatus = 1;
        }
    }
}

public void keyReleased(KeyEvent e) {

    int id = e.getKeyCode();

    if (id == KeyEvent.VK_W) {
        w = false;
    }
    if (id == KeyEvent.VK_S) {
        s = false;
    }
    if (id == KeyEvent.VK_UP) {
        up = false;
    }
    if (id == KeyEvent.VK_DOWN) {
        down = false;
    }

}

}