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General => General discussions => Topic started by: takatalvi on December 22, 2015, 04:14:06 pm

Title: sf::View as a minimap.
Post by: takatalvi on December 22, 2015, 04:14:06 pm

I've recently started working on a new project that uses sf::View as a camera to a Scene. Then I started messing around with using a 2nd view as a mini map, but positioning and sizing the thing was a pain. I read through the Documentation, and the numerous tutorials all over the internet, and I haven't seen anyone do this yet, so here it is.

I do admit this is just a simple hack that I threw in, but it took me awhile to think to do it this way. Hopefully I can save someone else the trouble. I created a camera class that is a wrapper for sf::View. For positioning and/or sizing I made some helper functions with terrible names, but they work well enough for now.

Here is the declaration.

(click to show/hide)

class Camera {
private:
    sf::View view;
public:
// I wanted to change this to setSize(...) but view already has a setSize method
    void setViewportSize(const sf::Vector2f& size, const sf::Vector2u& targetSize);
    void setViewportSize(float width, float height, const sf::Vector2u& targetSize);

// I'm still thinking about changing this to set position
    void setViewportPosition(const sf::Vector2f& position, const sf::Vector2u& targetSize);
    void setViewportPosition(float x, float y, const sf::Vector2u& targetSize);


// ... the rest of the interface goes here
// ... I cut it from the post for sake of space, but it's just setter and getting methods for the sf::View
};
 

And here is the simple implementation.

(click to show/hide)

// EDIT: Changed implementation as per Hapax's reply.
void Camera::setViewportSize(const sf::Vector2f& size, const sf::Vector2u& targetSize) {
    auto viewport = view.getViewport();
    viewport.width = size.x / targetSize.x;
    viewport.height = size.y / targetSize.y;
    view.setViewport(viewport);
}

void Camera::setViewportSize(float width, float height, const sf::Vector2u& targetSize) {
    auto viewport = view.getViewport();
    viewport.width = width / targetSize.x;
    viewport.height = height / targetSize.y;
    view.setViewport(viewport);
}


void Camera::setViewportPosition(const sf::Vector2f& position, const sf::Vector2u& targetSize) {
    auto viewport = view.getViewport();
    viewport.left = position.x / targetSize.x;
    viewport.top = position.y / targetSize.y;
    view.setViewport(viewport);
}

void Camera::setViewportPosition(float x, float y, const sf::Vector2u& targetSize) {
    auto viewport = view.getViewport();
    viewport.left = x / targetSize.x;
    viewport.top = y / targetSize.y;
    view.setViewport(viewport);
}
 

I registered to the forums just for this, so I hope it helps someone!

Title: Re: sf::View as a minimap.
Post by: SpeCter on December 22, 2015, 06:05:39 pm

What about http://www.sfml-dev.org/tutorials/2.3/graphics-view.php?
There is a minimap example in there.

Title: Re: sf::View as a minimap.
Post by: Hapax on December 22, 2015, 10:29:01 pm

(1.f / targetSize.x) * x
is equal to:
x / targetSize.x
 ;)

Title: Re: sf::View as a minimap.
Post by: takatalvi on December 23, 2015, 01:50:59 pm

Quote from: SpeCter on December 22, 2015, 06:05:39 pm

What about http://www.sfml-dev.org/tutorials/2.3/graphics-view.php?
There is a minimap example in there.

That's just a demonstration, no actual code for accurately positioning a sf::View.

Quote from: Hapax on December 22, 2015, 10:29:01 pm

(1.f / targetSize.x) * x
is equal to:
x / targetSize.x
 ;)

Hurray for math! Thanks for that, I posted this after one of those "Wow this day was too long" kinda days.