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Help => Graphics => Topic started by: smguyk on January 13, 2015, 02:46:07 am

Title: How to rotate a rectangle (or another shape) around its center?
Post by: smguyk on January 13, 2015, 02:46:07 am

I have a RectangleShape

sf::RectangleShape rect;

and I want it to continuously rotate around its own center.

When I use this code in the loop:

float rotation = rect.getRotation() + 1.0f;
if (rotation >= 360.0f) {
  rotation = 0.0f;
}

rect.setRotation(rotation);

it rotates around its top left corner.

So I tried to alter its origin:

rect.setOrigin(rect.getSize().x * 0.5f, rect.getSize().y * 0.5f);

and now it does rotate around its center, but the center is now where its original top left corner was.

What am I doing wrong, please?

Title: Re: How to rotate a rectangle (or another shape) around its center?
Post by: Gambit on January 13, 2015, 02:53:17 am

After you set the origin you need to offset the shape by half the size.

Title: Re: How to rotate a rectangle (or another shape) around its center?
Post by: smguyk on January 13, 2015, 07:33:04 am

Thanks it's working. This is how I'm doing it now:

rect.setPosition(rect.getPosition().x + rect.getOrigin().x, rect.getPosition().y + rect.getOrigin().y);