Ray2

Ray2 (from scenerystack/dot) is a minimal 2D ray: an origin position and a unit-length direction, both Vector2 instances. It's the type Transform3's transformRay2/inverseRay2 carry through a transform, and the natural representation for hit-testing/intersection queries (e.g. "does this pointer ray hit that shape").

import { Ray2 } from 'scenerystack/dot';
import { Vector2 } from 'scenerystack/dot';

const ray = new Ray2( new Vector2( 0, 0 ), new Vector2( 1, 0 ) ); // origin at (0,0), pointing along +x

ray.pointAtDistance( 5 );  // Vector2(5, 0) — the point 5 units along the ray
ray.shifted( 5 );          // a new Ray2 with the same direction, origin moved to (5, 0)

Constructing

new Ray2( position: Vector2, direction: Vector2 )

Both fields are plain public properties, not getter/setter pairs. direction must be a unit vector (magnitude 1) — an assertion in development builds checks Math.abs( direction.magnitude - 1 ) < 0.01 and throws if it's off. Passing a non-normalized vector is a common mistake; call .normalized() on it first if you're not sure it's already unit length.

Methods

Method	Effect
pointAtDistance( distance )	Returns position.plus( direction.timesScalar( distance ) ) as a new Vector2 — the point reached by walking distance along the ray
shifted( distance )	Returns a new Ray2 with the same direction, whose origin is pointAtDistance( distance )
toString()	Debug string showing position and direction

That's the full public surface on Ray2 itself — it's deliberately a thin data holder. Most of the interesting ray behavior (transforming a ray, or intersecting it against a shape) lives on the other object: Transform3.transformRay2/inverseRay2 carry a Ray2 through a matrix transform, and kite Shapes expose their own intersection methods that accept a Ray2.

direction is not automatically kept normalized

Because position and direction are plain mutable fields, nothing stops you from reassigning ray.direction to a non-unit vector after construction — only the constructor asserts unit length, and only in assertion-enabled (development) builds. If you mutate a ray's direction after creating it, normalize it yourself first, or construct a fresh Ray2 instead.

Related

• Vector2 — both position and direction are Vector2 instances.
• Transform3 — transformRay2/inverseRay2 carry a Ray2 through a Matrix3-based transform.