Creates a new Circle Shape Game Object and adds it to the Scene.
A Circle is an Arc with no defined start and end angle, making it render as a complete circle.
Note: This method will only be available if the Arc Game Object has been built into Phaser.
The horizontal position of this Game Object in the world.
The vertical position of this Game Object in the world.
The radius of the circle.
The color the circle will be filled with, i.e. 0xff0000 for red.
The alpha the circle will be filled with. You can also set the alpha of the overall Shape using its
The Game Object that was created.