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Circular Movement

The Circular Movement behavior makes the associated entity perform a circular orbit on the 2D plane. Its basic parameters are:

  • A radius, given in pixels
  • A movement rate, given in cycles per second

Other parameters include: a movement scale in both X and Y axes (making it an elliptic orbit), a flag telling whether the movement should be clockwise or not, and so on.


// The example below shows how to make an entity move along
// a circle of 128 pixels of radius at a rate of 0.25 cycles
// per second (i.e., it takes one second to complete 25% of
// a cycle, or 4 seconds to complete a cycle)
using SurgeEngine.Actor;
using SurgeEngine.Vector2;
using SurgeEngine.Behaviors.CircularMovement;

object "Simple Ball" is "entity"
    actor = Actor("Simple Ball");
    movement = CircularMovement();

    state "main"
        movement.radius = 128;
        movement.rate = 0.25;
        //movement.scale = Vector2.up; // uncomment to move along the y-axis only




Spawns a CircularMovement.


A CircularMovement object.



radius: number.

The radius of the movement, in pixels.


rate: number.

The rate of the movement, given in cycles per second.


clockwise: boolean.

Indicates whether the movement is clockwise (true) or counterclockwise (false). Defaults to false.


scale: Vector2 object.

Specifies the scale of the movement in both X and Y axes. It is used to distort the circle. Vector2(1, 1) means no distortion (default).


center: Vector2 object | null.

If not null, forces the center of the movement to be at a particular position in world space. Defaults to null.


phaseOffset: number.

A value in degrees that offsets the current phase. Defaults to zero (180 means opposite phase relative to zero).


phase: number, read-only.

A value in degrees that indicates the current phase of the movement.