IntersectionTests

Functions for computing the intersection between geometries such as rays, planes, triangles, and ellipsoids.

Methods

staticCesium.IntersectionTests.grazingAltitudeLocation(ray, ellipsoid)Cartesian3

Provides the point along the ray which is nearest to the ellipsoid.
Name Type Description
ray Ray The ray.
ellipsoid Ellipsoid The ellipsoid.
Returns:
The nearest planetodetic point on the ray.

staticCesium.IntersectionTests.lineSegmentPlane(endPoint0, endPoint1, plane, result)Cartesian3

Computes the intersection of a line segment and a plane.
Name Type Description
endPoint0 Cartesian3 An end point of the line segment.
endPoint1 Cartesian3 The other end point of the line segment.
plane Plane The plane.
result Cartesian3 optional The object onto which to store the result.
Returns:
The intersection point or undefined if there is no intersection.
Example:
var origin = Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883);
var normal = ellipsoid.geodeticSurfaceNormal(origin);
var plane = Cesium.Plane.fromPointNormal(origin, normal);

var p0 = new Cesium.Cartesian3(...);
var p1 = new Cesium.Cartesian3(...);

// find the intersection of the line segment from p0 to p1 and the tangent plane at origin.
var intersection = Cesium.IntersectionTests.lineSegmentPlane(p0, p1, plane);

staticCesium.IntersectionTests.lineSegmentSphere(p0, p1, sphere, result)Interval

Computes the intersection points of a line segment with a sphere.
Name Type Description
p0 Cartesian3 An end point of the line segment.
p1 Cartesian3 The other end point of the line segment.
sphere BoundingSphere The sphere.
result Interval optional The result onto which to store the result.
Returns:
The interval containing scalar points along the ray or undefined if there are no intersections.

staticCesium.IntersectionTests.lineSegmentTriangle(v0, v1, p0, p1, p2, cullBackFaces, result)Cartesian3

Computes the intersection of a line segment and a triangle.
Name Type Default Description
v0 Cartesian3 The an end point of the line segment.
v1 Cartesian3 The other end point of the line segment.
p0 Cartesian3 The first vertex of the triangle.
p1 Cartesian3 The second vertex of the triangle.
p2 Cartesian3 The third vertex of the triangle.
cullBackFaces Boolean false optional If true, will only compute an intersection with the front face of the triangle and return undefined for intersections with the back face.
result Cartesian3 optional The Cartesian3 onto which to store the result.
Returns:
The intersection point or undefined if there is no intersections.

staticCesium.IntersectionTests.rayEllipsoid(ray, ellipsoid)Interval

Computes the intersection points of a ray with an ellipsoid.
Name Type Description
ray Ray The ray.
ellipsoid Ellipsoid The ellipsoid.
Returns:
The interval containing scalar points along the ray or undefined if there are no intersections.

staticCesium.IntersectionTests.rayPlane(ray, plane, result)Cartesian3

Computes the intersection of a ray and a plane.
Name Type Description
ray Ray The ray.
plane Plane The plane.
result Cartesian3 optional The object onto which to store the result.
Returns:
The intersection point or undefined if there is no intersections.

staticCesium.IntersectionTests.raySphere(ray, sphere, result)Interval

Computes the intersection points of a ray with a sphere.
Name Type Description
ray Ray The ray.
sphere BoundingSphere The sphere.
result Interval optional The result onto which to store the result.
Returns:
The interval containing scalar points along the ray or undefined if there are no intersections.

staticCesium.IntersectionTests.rayTriangle(ray, p0, p1, p2, cullBackFaces, result)Cartesian3

Computes the intersection of a ray and a triangle as a Cartesian3 coordinate. Implements {@link https://cadxfem.org/inf/Fast%20MinimumStorage%20RayTriangle%20Intersection.pdf| Fast Minimum Storage Ray/Triangle Intersection} by Tomas Moller and Ben Trumbore.
Name Type Default Description
ray Ray The ray.
p0 Cartesian3 The first vertex of the triangle.
p1 Cartesian3 The second vertex of the triangle.
p2 Cartesian3 The third vertex of the triangle.
cullBackFaces Boolean false optional If true, will only compute an intersection with the front face of the triangle and return undefined for intersections with the back face.
result Cartesian3 optional The Cartesian3 onto which to store the result.
Returns:
The intersection point or undefined if there is no intersections.

staticCesium.IntersectionTests.rayTriangleParametric(ray, p0, p1, p2, cullBackFaces)Number

Computes the intersection of a ray and a triangle as a parametric distance along the input ray. The result is negative when the triangle is behind the ray. Implements {@link https://cadxfem.org/inf/Fast%20MinimumStorage%20RayTriangle%20Intersection.pdf| Fast Minimum Storage Ray/Triangle Intersection} by Tomas Moller and Ben Trumbore.
Name Type Default Description
ray Ray The ray.
p0 Cartesian3 The first vertex of the triangle.
p1 Cartesian3 The second vertex of the triangle.
p2 Cartesian3 The third vertex of the triangle.
cullBackFaces Boolean false optional If true, will only compute an intersection with the front face of the triangle and return undefined for intersections with the back face.
Returns:
The intersection as a parametric distance along the ray, or undefined if there is no intersection.

staticCesium.IntersectionTests.trianglePlaneIntersection(p0, p1, p2, plane)Object

Computes the intersection of a triangle and a plane
Name Type Description
p0 Cartesian3 First point of the triangle
p1 Cartesian3 Second point of the triangle
p2 Cartesian3 Third point of the triangle
plane Plane Intersection plane
Returns:
An object with properties positions and indices, which are arrays that represent three triangles that do not cross the plane. (Undefined if no intersection exists)
Example:
var origin = Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883);
var normal = ellipsoid.geodeticSurfaceNormal(origin);
var plane = Cesium.Plane.fromPointNormal(origin, normal);

var p0 = new Cesium.Cartesian3(...);
var p1 = new Cesium.Cartesian3(...);
var p2 = new Cesium.Cartesian3(...);

// convert the triangle composed of points (p0, p1, p2) to three triangles that don't cross the plane
var triangles = Cesium.IntersectionTests.trianglePlaneIntersection(p0, p1, p2, plane);