Chapter 368: Triangle

Core Idea

A geometric triangle as defined by three vectors representing its three corners.

Key Concepts

• a : Vector3: The first corner of the triangle.
• b : Vector3: The second corner of the triangle.
• c : Vector3: The third corner of the triangle.

Reference Tables

Constructor

Signature
new Triangle( a : Vector3, b : Vector3, c : Vector3 )

Properties

Property	Description
.a : Vector3	The first corner of the triangle.
.b : Vector3	The second corner of the triangle.
.c : Vector3	The third corner of the triangle.

Methods

Method	Description
.clone() : Triangle	Returns a new triangle with copied values from this instance.
.closestPointToPoint( p : Vector3, target : Vector3 ) : Vector3	Returns the closest point on the triangle to the given point.
.containsPoint( point : Vector3 ) : boolean	Returns true if the given point, when projected onto the plane of the triangle, lies within the triangle.
.copy( triangle : Triangle ) : Triangle	Copies the values of the given triangle to this instance.
.equals( triangle : Triangle ) : boolean	Returns true if this triangle is equal with the given one.
.getArea() : number	Computes the area of the triangle.
.getBarycoord( point : Vector3, target : Vector3 ) : Vector3	Computes a barycentric coordinates from the given vector. Returns null if the triangle is degenerate.
.getInterpolation( point : Vector3, v1 : Vector3, v2 : Vector3, v3 : Vector3, target : Vector3 ) : Vector3	Computes the value barycentrically interpolated for the given point on the triangle. Returns null if the triangle is degenerate.
.getMidpoint( target : Vector3 ) : Vector3	Computes the midpoint of the triangle.
.getNormal( target : Vector3 ) : Vector3	Computes the normal of the triangle.
.getPlane( target : Plane ) : Plane	Computes a plane the triangle lies within.
.intersectsBox( box : Box3 ) : boolean	Returns true if this triangle intersects with the given box.
.isFrontFacing( direction : Vector3 ) : boolean	Returns true if the triangle is oriented towards the given direction.
.set( a : Vector3, b : Vector3, c : Vector3 ) : Triangle	Sets the triangle's vertices by copying the given values.
.setFromAttributeAndIndices( attribute : BufferAttribute, i0 : number, i1 : number, i2 : number ) : Triangle	Sets the triangle's vertices by copying the given attribute values.
.setFromPointsAndIndices( points : Array.<Vector3>, i0 : number, i1 : number, i2 : number ) : Triangle	Sets the triangle's vertices by copying the given array values.

Key Takeaways

1. Most relevant properties: a, b, c.
2. Key methods: clone, closestPointToPoint, containsPoint, copy.

Connects To

• Source: src/math/Triangle.js