Chapter 364: Ray

Core Idea

A ray that emits from an origin in a certain direction. The class is used by Raycaster to assist with raycasting. Raycasting is used for mouse picking (working out what objects in the 3D space the mouse is over) amongst other things.

Key Concepts

• direction : Vector3: The (normalized) direction of the ray.
• origin : Vector3: The origin of the ray.

Reference Tables

Constructor

Signature
new Ray( origin : Vector3, direction : Vector3 )

Properties

Property	Description
.direction : Vector3	The (normalized) direction of the ray.
.origin : Vector3	The origin of the ray.

Methods

Method	Description
.applyMatrix4( matrix4 : Matrix4 ) : Ray	Transforms this ray with the given 4x4 transformation matrix.
.at( t : number, target : Vector3 ) : Vector3	Returns a vector that is located at a given distance along this ray.
.clone() : Ray	Returns a new ray with copied values from this instance.
.closestPointToPoint( point : Vector3, target : Vector3 ) : Vector3	Returns the point along this ray that is closest to the given point.
.copy( ray : Ray ) : Ray	Copies the values of the given ray to this instance.
.distanceSqToPoint( point : Vector3 ) : number	Returns the squared distance of the closest approach between this ray and the given point.
.distanceSqToSegment( v0 : Vector3, v1 : Vector3, optionalPointOnRay : Vector3, optionalPointOnSegment : Vector3 ) : number	Returns the squared distance between this ray and the given line segment.
.distanceToPlane( plane : Plane ) : number	Computes the distance from the ray's origin to the given plane. Returns null if the ray does not intersect with the plane.
.distanceToPoint( point : Vector3 ) : number	Returns the distance of the closest approach between this ray and the given point.
.equals( ray : Ray ) : boolean	Returns true if this ray is equal with the given one.
.intersectBox( box : Box3, target : Vector3 ) : Vector3	Intersects this ray with the given bounding box, returning the intersection point or null if there is no intersection.
.intersectPlane( plane : Plane, target : Vector3 ) : Vector3	Intersects this ray with the given plane, returning the intersection point or null if there is no intersection.
.intersectSphere( sphere : Sphere, target : Vector3 ) : Vector3	Intersects this ray with the given sphere, returning the intersection point or null if there is no intersection.
.intersectTriangle( a : Vector3, b : Vector3, c : Vector3, backfaceCulling : boolean, target : Vector3 ) : Vector3	Intersects this ray with the given triangle, returning the intersection point or null if there is no intersection.
.intersectsBox( box : Box3 ) : boolean	Returns true if this ray intersects with the given box.
.intersectsPlane( plane : Plane ) : boolean	Returns true if this ray intersects with the given plane.
.intersectsSphere( sphere : Sphere ) : boolean	Returns true if this ray intersects with the given sphere.
.lookAt( v : Vector3 ) : Ray	Adjusts the direction of the ray to point at the given vector in world space.
.recast( t : number ) : Ray	Shift the origin of this ray along its direction by the given distance.
.set( origin : Vector3, direction : Vector3 ) : Ray	Sets the ray's components by copying the given values.

Key Takeaways

1. Most relevant properties: direction, origin.
2. Key methods: applyMatrix4, at, clone, closestPointToPoint.

Connects To

• Source: src/math/Ray.js