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1

General / comparing shapes position to each other (detect collision)

« on: June 29, 2012, 12:49:07 pm »

hello i am making a pong game and i need to compare the x position of the panel to the x position of the ball. but if i use GetPosition() the x value for the panels is always 0 so i can't really compare them that way. i believe i need some kind of conversion. but i don't know which. i have tried to use TransformToGlobal but that didn't work.
below is the code (minimalisezed)

sf::Vector2f pos = ball.TransformToGlobal(ball.GetPosition());
sf::Vector2f pos1 = panel1.TransformToGlobal(panel1.GetPosition());
sf::Vector2f pos2 = panel2.TransformToGlobal(panel2.GetPosition());
std::cout<<pos1.x<<","<<pos1.y<<std::endl;
std::cout<<pos2.x<<","<<pos2.y<<std::endl;
 

it outputs always something like this
0,122
0,-101
full code under this if someone wants to test:

#include "stdafx.h"
#include <SFML/System.hpp>
#include <SFML/Window.hpp>
#include <SFML/Graphics.hpp>
#include <iostream>

int main()
{
    // Create main window
    sf::RenderWindow App(sf::VideoMode(800, 600), "SFML Shapes"/*, sf::Style::Fullscreen*/);

        //define shapes
        sf::Shape panel1=sf::Shape::Rectangle(20, 300, 30, 360, sf::Color::White);
        sf::Shape panel2=sf::Shape::Rectangle(770, 300, 780, 360, sf::Color::White);
        sf::Shape ball=sf::Shape::Circle(395, 330, 10, sf::Color(200,200,200));
    ball.SetCenter(0,0);
        bool game=false;
        int direction=0;

    // 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();

                        if ((Event.Type == sf::Event::KeyPressed) && (Event.Key.Code == sf::Key::Escape))
                                App.Close();

                        if (Event.Type == sf::Event::KeyPressed && Event.Key.Code==sf::Key::Space)
                game=true;
        }

        // Clear screen
        App.Clear();

        // Draw shapes
                App.Draw(panel1);
                App.Draw(panel2);
                App.Draw(ball);
       
                //elapsed time
                float ElapsedTime = App.GetFrameTime();
               
                //move panels
                if (App.GetInput().IsKeyDown(sf::Key::Up))    {
                       
                        panel2.Move(0, -110 * ElapsedTime);
                       
                                sf::Vector2f pos1 = panel1.TransformToGlobal(panel1.GetPosition());
                                sf::Vector2f pos2 = panel2.TransformToGlobal(panel2.GetPosition());
                                std::cout<<pos1.x<<","<<pos1.y<<std::endl;
                                std::cout<<pos2.x<<","<<pos2.y<<std::endl;
                }
                if (App.GetInput().IsKeyDown(sf::Key::Down))  panel2.Move(0, 110 * ElapsedTime);

                if (App.GetInput().IsKeyDown(sf::Key::U))     panel1.Move(0, -110 * ElapsedTime);
                if (App.GetInput().IsKeyDown(sf::Key::J))     panel1.Move(0, 110 * ElapsedTime);

                if (game) {
                        if (direction==0) {
                                                sf::Vector2f pos = ball.TransformToGlobal(ball.GetPosition());
                                if (pos.x+(-49.1934955f * ElapsedTime)<-320) {
                                        direction=1;
                                } /*else if (pos.x) {
                               
                                }*/ else {
                                ball.Move(-49.1934955f * ElapsedTime, -98.386991f * ElapsedTime);
                                }
                        }
                        if (direction==1) {
                                sf::Vector2f pos = ball.TransformToGlobal(ball.GetPosition());
                                if (pos.x+(49.1934955f * ElapsedTime)>320) {
                                        direction=1;
                                } else {
                                ball.Move(-98.386991f * ElapsedTime, 49.1934955f * ElapsedTime);
                                }
                        }
                }

        // Finally, display the rendered frame on screen
        App.Display();
    }

    return EXIT_SUCCESS;
}

2

General / how to get the position of a cirlce.

« on: June 28, 2012, 09:38:20 pm »

hello i am making an pong game but when i can't get the position of the ball. i have tried to use ball.GetPosition() but that didn't work. so could someone tell me how to do that.
 this is my code:

sf::Shape ball=sf::Shape::Circle(395, 330, 10, sf::Color(200,200,200));
ball.Move(-49.1934955f * ElapsedTime, -98.386991f * ElapsedTime);
std::cout<<ball.GetPosition()<<std::endl;
 

full code under this if someone wants to test.

#include "stdafx.h"
#include <SFML/System.hpp>
#include <SFML/Window.hpp>
#include <SFML/Graphics.hpp>
#include <iostream>

int main()
{
    // Create main window
    sf::RenderWindow App(sf::VideoMode(800, 600), "SFML Shapes"/*, sf::Style::Fullscreen*/);

        //define shapes
        sf::Shape panel1=sf::Shape::Rectangle(20, 300, 30, 360, sf::Color::White);
        sf::Shape panel2=sf::Shape::Rectangle(770, 300, 780, 360, sf::Color::White);
        sf::Shape ball=sf::Shape::Circle(395, 330, 10, sf::Color(200,200,200));
     
        bool game=false;
        int direction=0;

    // 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();

                        if ((Event.Type == sf::Event::KeyPressed) && (Event.Key.Code == sf::Key::Escape))
                                App.Close();

                        if (Event.Type == sf::Event::KeyPressed && Event.Key.Code==sf::Key::Space)
                game=true;
        }

        // Clear screen
        App.Clear();

        // Draw shapes
                App.Draw(panel1);
                App.Draw(panel2);
                App.Draw(ball);
       
                //elapsed time
                float ElapsedTime = App.GetFrameTime();
               
                //move panels
                if (App.GetInput().IsKeyDown(sf::Key::Up))    panel2.Move(0, -110 * ElapsedTime);
                if (App.GetInput().IsKeyDown(sf::Key::Down))  panel2.Move(0, 110 * ElapsedTime);

                if (App.GetInput().IsKeyDown(sf::Key::U))     panel1.Move(0, -110 * ElapsedTime);
                if (App.GetInput().IsKeyDown(sf::Key::J))     panel1.Move(0, 110 * ElapsedTime);

                if (game) {
                        if (direction==0) {
                                ball.Move(-49.1934955f * ElapsedTime, -98.386991f * ElapsedTime);
                                               //sqrt(110²/5)                     <-- *2
                                std::cout<<ball.GetPosition()<<std::endl;
                        }
                }

        // Finally, display the rendered frame on screen
        App.Display();
    }

    return EXIT_SUCCESS;
}