Messages

1

Graphics / Re: Detecting when an object is no longer visible to the use

« on: September 02, 2011, 07:49:14 pm »

Code: [Select]

  if (ball.GetPosition().y > 460) {
      ballIsVisible == false;
   }

You gotta have that in your main loop.
The rest goes as follows;
[code]
if(ball.y < 0){
 bouncedown
}
if(ball.x < 0){
bounceright
}

if(ball.x > 640){
bounceleft
}

[/code

You, sir, are a genius. Thanks!!

2

Graphics / Detecting when an object is no longer visible to the user

« on: September 02, 2011, 05:36:59 pm »

I'm trying to create a very simple Pong game on my own before I get into anything more complex. However, I can't seem to get the ball to bounce off of the sides of the screen. No matter what I've tried, it just goes offscreen every time. Can anyone help a noob out? The ball is 20x20px so I wanted it to bounce when its center is within 20 units of the edge of the screen. In the code below I've only (unsuccessfully) implemented a bounce for when it goes past the y-maximum as that is where it goes by default in the example so far.

Code: [Select]



////////////////////////////////////////////////////////////
// Headers
////////////////////////////////////////////////////////////
#include <SFML/Graphics.hpp>


////////////////////////////////////////////////////////////
/// Entry point of application
///
/// \return Application exit code
///
////////////////////////////////////////////////////////////
int main()
{
    // Create main window
srand ( time(NULL) );
sf::RenderWindow App(sf::VideoMode(640, 480), "Pong");
sf::Image playerimg;
if (!playerimg.LoadFromFile("paddle.png"))
{
// Error...
}

sf::Image computerimg;
if (!computerimg.LoadFromFile("paddle.png"))
{
// Error...
}

sf::Image ballimg;
if (!ballimg.LoadFromFile("ball.png"))
{
// Error...
}

int ball_x=300;
int ball_y=220;
int ball_start = 2;
int ball_count = 1;

sf::Sprite player;
sf::Sprite computer;
sf::Sprite ball;
player.SetImage(playerimg);
computer.SetImage(computerimg);
ball.SetImage(ballimg);
player.SetPosition(0,160);
computer.SetPosition(625,160);
ball.SetPosition(ball_x,ball_y);

bool ballIsVisible = true;
if (ball.GetPosition().y > 460) {
ballIsVisible == false;
}


    // Start game loop
    while (App.IsOpened())
    {
        // Process events
        sf::Event Event;
        while (App.GetEvent(Event))
        {
            // Close window : exit
            if (Event.Type == sf::Event::Closed)
                App.Close();
        }

float ElapsedTime = App.GetFrameTime();
if (App.GetInput().IsKeyDown(sf::Key::Up))    player.Move(0, -100 * ElapsedTime);
if (App.GetInput().IsKeyDown(sf::Key::Down))  player.Move(0,  100 * ElapsedTime);
if (ball_start==2)  ball.Move(150 * ElapsedTime,  150 * ElapsedTime);
if (ballIsVisible==false) ball.Move((-1 * (150 * ElapsedTime)),  (-1 * (150 * ElapsedTime)));



        App.Clear();

App.Draw(player);
App.Draw(ball);
App.Draw(computer);
App.Display();
    }

    return EXIT_SUCCESS;
}