Rotating sprite towards mouse.

[tiago221]

I was using the following code to do it (found the code here, I take no credit for it), but now, after I successfully got the camera to follow the sprite, the code only works when I start the program, if I move the sprite, it's like the center is out of position, re-setting the center didn't work.

Code: [Select]


#include <SFML/Graphics.hpp>
#define PI 3.1415926535

int WINAPI WinMain(      
    HINSTANCE hInstance,
    HINSTANCE hPrevInstance,
    LPSTR lpCmdLine,
    int nCmdShow
)
{

sf::RenderWindow Window(sf::VideoMode(800, 600, 32), "Zombie Game Alpha");

sf::Image PlayerImage;
sf::Image Background;
Background.LoadFromFile("background.png");
PlayerImage.LoadFromFile("player.png");
sf::Sprite Player(PlayerImage);
sf::Sprite BackgroundS(Background);
sf::Sprite* follow = &Player;
Player.SetPosition(400,300);

sf::View Camera(sf::Vector2f(400.f, 300.f), sf::Vector2f(400.f, 300.f));  
sf::Vector2f PPos = Player.GetPosition();


while(Window.IsOpened())
{
sf::Event Event;
while (Window.GetEvent(Event))
{
if (Event.Type == sf::Event::Closed)
Window.Close();
if ((Event.Type == sf::Event::KeyPressed) && (Event.Key.Code == sf::Key::Escape))
Window.Close();
}

float ElapsedTime = Window.GetFrameTime();


if (Window.GetInput().IsKeyDown(sf::Key::W))  Player.Move(0, -425 * ElapsedTime);  
        if (Window.GetInput().IsKeyDown(sf::Key::S))  Player.Move(0,  425 * ElapsedTime);  
if (Window.GetInput().IsKeyDown(sf::Key::A))  Player.Move(-425 * ElapsedTime, 0);
if (Window.GetInput().IsKeyDown(sf::Key::D))  Player.Move(425 * ElapsedTime, 0);  

Player.SetCenter(Player.GetSize() / 2.f);


if (Window.GetInput().GetMouseX() <= Player.GetPosition().x) {
Player.SetRotation(((-1* 360 / PI * (atan2(static_cast<double>(Player.GetPosition().y - Window.GetInput().GetMouseY()), static_cast<double>(Player.GetPosition().x - Window.GetInput().GetMouseX()))))/2)+90);
} else {
Player.SetRotation(((-1* 360 / PI *(atan2(static_cast<double>(Player.GetPosition().y - Window.GetInput().GetMouseY()), static_cast<double>(Player.GetPosition().x - Window.GetInput().GetMouseX()))))/2)+90);
}


Window.Clear();
Camera.SetCenter(follow->GetPosition());
Window.SetView(Camera);
Window.Draw(BackgroundS);
Window.Draw(Player);

Window.Display();
}
}


[tiago221]

Anyone?

[e_barroga]

The mouse position is relative to the window and not the 2D plane (which is the space that the sprites are in).

For instance, if you positioned the mouse in the center of the screen and move the player around, the mouse position will remain the same but the sprite position will be different.

This makes your calculation incorrect.

What you need to do is convert from the window space to the global space that the sprites use. You need to calculate the mouse position in relation to the position of the view.

[tiago221]

Thanks a lot, it's working now.