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Graphics / Help with Co-ordinate system

« on: January 27, 2018, 02:53:13 am »

Hello,

I am writing a small program using SFML which draws a 5 x 5 rectangle at any point specified by clicking the mouse.

I am using mapPixelToCoords() to map the mouse coordinates to the pixels as recommended in the documentation, however I am still encountering a weird offset between the coordinates and the actual shape which is drawn.
The offset varies on different parts of the window (it is not a constant x,y value).

I would like the rectangle to be drawn precisely under the mouse pointer, how do I go about removing this offset?

(I have also attached screenshots to help clarify the issue I'm encountering)

This is the code I'm using to draw the rectangle on click:

int main(){

        sf::RenderWindow window(sf::VideoMode(800, 720), "SFML window");

        sf::Event event;

        //Rectangle to be drawn on the screen
        sf::RectangleShape someRect;
        someRect.setFillColor(sf::Color(0, 0, 0));
        someRect.setSize({ 5, 5 });
        someRect.setPosition(100, 120);

        while (window.isOpen())
        {
                if (!windowStarted) {
                        event.type = sf::Event::Closed;
                }

                while (window.pollEvent(event))
                {
                        // Close window: exit
                        if (event.type == sf::Event::Closed) {
                                window.close();
                        }

                        if (event.type == sf::Event::MouseButtonPressed) {
                                someRect.setPosition(window.mapPixelToCoords(sf::Mouse::getPosition(window)));
                        }
                }

                window.clear(sf::Color(255, 255, 255));

                window.draw(someRect);

                window.display();

        }

         return 0;
}