How to make ball bounce off paddle

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()

I have two paddles in the game and a ball is bouncing around. I tried making a collide point when the ball hit's the paddle. Im trying to recreate pong. The collide point didn't work (maybe because I didn't structure it right).

I was wondering how can I make a collide point between the paddle (rectangle Blue and Yellow) and the ball (ball_rect) so that the ball bounces off the paddle?

It looks like you only are handling the ball bouncing off the back wall. You will need to check for the paddles as well. The code will be somewhat similar to the wall check for the ball, except you need to take into account y coordinates. — sbochins, Apr 02 '16 at 04:16

score 1 · Accepted Answer · edited Apr 02 '16 at 11:28

1

This should work:

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

Hope it helps!

edited Apr 02 '16 at 11:28

answered Apr 02 '16 at 04:15

cdonts

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Thank you so much. You rock!! – HALLOPEOPLE Apr 03 '16 at 15:04

score 0 · Answer 2 · answered Sep 09 '18 at 03:45

This is my ball class in java...........

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);

}

}

How do it move you ask and instantiated....

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;
    }

}

}

How to make ball bounce off paddle

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