diff --git a/CHANGES.md b/CHANGES.md
index 8a0a833427dd..77259ebefb55 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -5,6 +5,7 @@ Change Log
##### Additions :tada:
* Added `Scene.invertClassificationSupported` for checking if invert classification is supported.
+* Added `computeLineSegmentLineSegmentIntersection` to `Intersections2D`. [#7228](https://github.com/AnalyticalGraphicsInc/Cesium/pull/7228)
##### Fixes :wrench:
* Fixed issue causing polyline to look wavy depending on the position of the camera [#7209](https://github.com/AnalyticalGraphicsInc/cesium/pull/7209)
diff --git a/Source/Core/Intersections2D.js b/Source/Core/Intersections2D.js
index 36f88b1eb673..5c7ddbc7ccdb 100644
--- a/Source/Core/Intersections2D.js
+++ b/Source/Core/Intersections2D.js
@@ -1,9 +1,13 @@
define([
+ './Cartesian2',
'./Cartesian3',
+ './Check',
'./defined',
'./DeveloperError'
], function(
+ Cartesian2,
Cartesian3,
+ Check,
defined,
DeveloperError) {
'use strict';
@@ -278,5 +282,60 @@ define([
return new Cartesian3(l1, l2, l3);
};
+ /**
+ * Compute the intersection between 2 line segments
+ *
+ * @param {Number} x00 The x coordinate of the first line's first vertex.
+ * @param {Number} y00 The y coordinate of the first line's first vertex.
+ * @param {Number} x01 The x coordinate of the first line's second vertex.
+ * @param {Number} y01 The y coordinate of the first line's second vertex.
+ * @param {Number} x10 The x coordinate of the second line's first vertex.
+ * @param {Number} y10 The y coordinate of the second line's first vertex.
+ * @param {Number} x11 The x coordinate of the second line's second vertex.
+ * @param {Number} y11 The y coordinate of the second line's second vertex.
+ * @param {Cartesian2} [result] The instance into to which to copy the result. If this parameter
+ * is undefined, a new instance is created and returned.
+ * @returns {Cartesian2} The intersection point, undefined if there is no intersection point or lines are coincident.
+ *
+ * @example
+ * var result = Cesium.Intersections2D.computeLineSegmentLineSegmentIntersection(0.0, 0.0, 0.0, 2.0, -1, 1, 1, 1);
+ * // result === new Cesium.Cartesian2(0.0, 1.0);
+ */
+ Intersections2D.computeLineSegmentLineSegmentIntersection = function(x00, y00, x01, y01, x10, y10, x11, y11, result) {
+ //>>includeStart('debug', pragmas.debug);
+ Check.typeOf.number('x00', x00);
+ Check.typeOf.number('y00', y00);
+ Check.typeOf.number('x01', x01);
+ Check.typeOf.number('y01', y01);
+ Check.typeOf.number('x10', x10);
+ Check.typeOf.number('y10', y10);
+ Check.typeOf.number('x11', x11);
+ Check.typeOf.number('y11', y11);
+ //>>includeEnd('debug');
+
+ var numerator1A = (x11 - x10) * (y00 - y10) - (y11 - y10) * (x00 - x10);
+ var numerator1B = (x01 - x00) * (y00 - y10) - (y01 - y00) * (x00 - x10);
+ var denominator1 = (y11 - y10) * (x01 - x00) - (x11 - x10) * (y01 - y00);
+
+ // If denominator = 0, then lines are parallel. If denominator = 0 and both numerators are 0, then coincident
+ if (denominator1 === 0) {
+ return;
+ }
+
+ var ua1 = numerator1A / denominator1;
+ var ub1 = numerator1B / denominator1;
+
+ if (ua1 >= 0 && ua1 <= 1 && ub1 >= 0 && ub1 <= 1) {
+ if (!defined(result)) {
+ result = new Cartesian2();
+ }
+
+ result.x = x00 + ua1 * (x01 - x00);
+ result.y = y00 + ua1 * (y01 - y00);
+
+ return result;
+ }
+ };
+
return Intersections2D;
});
diff --git a/Specs/Core/Intersections2DSpec.js b/Specs/Core/Intersections2DSpec.js
index 5b4b34dc452c..0dd49009d51d 100644
--- a/Specs/Core/Intersections2DSpec.js
+++ b/Specs/Core/Intersections2DSpec.js
@@ -288,4 +288,58 @@ defineSuite([
expect(result3.z).toBeGreaterThan(0.0);
});
});
+
+ describe('computeLineSegmentLineSegmentIntersection', function() {
+ it('returns the correct result for intersection point', function() {
+ var intersection0 = Intersections2D.computeLineSegmentLineSegmentIntersection(0.0, 0.0, 0.0, 2.0, -1.0, 1.0, 1.0, 1.0);
+ expect(intersection0.x).toEqualEpsilon(0.0, 1e-15);
+ expect(intersection0.y).toEqualEpsilon(1.0, 1e-15);
+
+ var intersection1 = Intersections2D.computeLineSegmentLineSegmentIntersection(0.0, 0.0, 10.0, 5.0, 0.0, 5.0, 10.0, 0.0);
+ expect(intersection1.x).toEqualEpsilon(5.0, 1e-15);
+ expect(intersection1.y).toEqualEpsilon(2.5, 1e-15);
+
+ var intersection2 = Intersections2D.computeLineSegmentLineSegmentIntersection(0.0, -5.0, 4.0, 3.0, -2.0, 1.0, 4.0, -2.0);
+ expect(intersection2.x).toEqualEpsilon(2.0, 1e-15);
+ expect(intersection2.y).toEqualEpsilon(-1.0, 1e-15);
+ });
+
+ it('returns the correct result for intersection point on a vertex', function() {
+ var intersection0 = Intersections2D.computeLineSegmentLineSegmentIntersection(0.0, 0.0, 0.0, 2.0, -1.0, 0.0, 1.0, 0.0);
+ expect(intersection0.x).toEqualEpsilon(0.0, 1e-15);
+ expect(intersection0.y).toEqualEpsilon(0.0, 1e-15);
+
+ var intersection1 = Intersections2D.computeLineSegmentLineSegmentIntersection(0.0, 0.0, 1.0, 1.0, 1.0, 1.0, 2.0, 0.0);
+ expect(intersection1.x).toEqualEpsilon(1.0, 1e-15);
+ expect(intersection1.y).toEqualEpsilon(1.0, 1e-15);
+
+ var intersection2 = Intersections2D.computeLineSegmentLineSegmentIntersection(0.0, 0.0, 4.0, 3.0, 5.0, 0.0, 4.0, 3.0);
+ expect(intersection2.x).toEqualEpsilon(4.0, 1e-15);
+ expect(intersection2.y).toEqualEpsilon(3.0, 1e-15);
+ });
+
+ it('returns undefined for non-intersecting lines', function() {
+ var intersection0 = Intersections2D.computeLineSegmentLineSegmentIntersection(0.0, 0.0, 0.0, 5.0, 0.1, 4.8, 5.0, 0.0);
+ expect(intersection0).toBeUndefined();
+
+ var intersection1 = Intersections2D.computeLineSegmentLineSegmentIntersection(10.0, 0.0, 0.0, -10.0, 0.0, 0.0, -8.0, -8.0);
+ expect(intersection1).toBeUndefined();
+ });
+
+ it('returns undefined for parallel lines', function() {
+ var intersection0 = Intersections2D.computeLineSegmentLineSegmentIntersection(0.0, 0.0, 0.0, 2.0, 1.0, 1.0, 1.0, 4.0);
+ expect(intersection0).toBeUndefined();
+
+ var intersection1 = Intersections2D.computeLineSegmentLineSegmentIntersection(1.0, 1.0, 4.0, 4.0, 0.0, 0.0, 3.0, 3.0);
+ expect(intersection1).toBeUndefined();
+ });
+
+ it('returns undefined for coincident lines', function() {
+ var intersection0 = Intersections2D.computeLineSegmentLineSegmentIntersection(0.0, 0.0, 0.0, 2.0, 0.0, 1.0, 0.0, 4.0);
+ expect(intersection0).toBeUndefined();
+
+ var intersection1 = Intersections2D.computeLineSegmentLineSegmentIntersection(0.0, 0.0, 0.0, 2.0, 0.0, 0.0, 0.0, 2.0);
+ expect(intersection1).toBeUndefined();
+ });
+ });
});