Add Rectangle.equalsEpsilon

CHANGES.md

@@ -16,6 +16,7 @@ Change Log
    * Added `PostProcessStage` which takes a fragment shader that processes the color and depth texture from the stage run before it.
    * Added `PostProcessStageComposite` for multi-stage post-processes like depth of field.
    * Added a new Sandcastle label `Post Processing` to showcase the different built-in post-process stages.
+ * Added `Rectangle.equalsEpsilon` for comparing the equality of two rectangles [#6533](https://github.com/AnalyticalGraphicsInc/cesium/pull/6533)
 
 ##### Fixes :wrench:
 * Fixed a bug causing custom TilingScheme classes to not be able to use a GeographicProjection. [#6524](https://github.com/AnalyticalGraphicsInc/cesium/pull/6524)

Source/Core/Rectangle.js

@@ -365,6 +365,30 @@ define([
         return result;
     };
 
+    /**
+     * Compares the provided Rectangles componentwise and returns
+     * <code>true</code> if they pass an absolute or relative tolerance test,
+     * <code>false</code> otherwise.
+     *
+     * @param {Rectangle} [left] The first Rectangle.
+     * @param {Rectangle} [right] The second Rectangle.
+     * @param {Number} absoluteEpsilon The absolute epsilon tolerance to use for equality testing.
+     * @returns {Boolean} <code>true</code> if left and right are within the provided epsilon, <code>false</code> otherwise.
+     */
+    Rectangle.equalsEpsilon = function(left, right, absoluteEpsilon) {
+        //>>includeStart('debug', pragmas.debug);
+        Check.typeOf.number('absoluteEpsilon', absoluteEpsilon);
+        //>>includeEnd('debug');
+
+        return (left === right) ||
+               (defined(left) &&
+                defined(right) &&
+                (Math.abs(left.west - right.west) <= absoluteEpsilon) &&
+                (Math.abs(left.south - right.south) <= absoluteEpsilon) &&
+                (Math.abs(left.east - right.east) <= absoluteEpsilon) &&
+                (Math.abs(left.north - right.north) <= absoluteEpsilon));
+    };
+
     /**
      * Duplicates this Rectangle.
      *
@@ -418,11 +442,7 @@ define([
         Check.typeOf.number('epsilon', epsilon);
         //>>includeEnd('debug');
 
-        return defined(other) &&
-               (Math.abs(this.west - other.west) <= epsilon) &&
-               (Math.abs(this.south - other.south) <= epsilon) &&
-               (Math.abs(this.east - other.east) <= epsilon) &&
-               (Math.abs(this.north - other.north) <= epsilon);
+        return Rectangle.equalsEpsilon(this, other, epsilon);
     };
 
     /**

Specs/Core/RectangleSpec.js

@@ -248,6 +248,22 @@ defineSuite([
         expect(Rectangle.equals(rectangle, undefined)).toEqual(false);
     });
 
+    it('Static equals epsilon works in all cases', function() {
+        var rectangle1 = new Rectangle(0.1, 0.2, 0.3, 0.4);
+        expect(Rectangle.equalsEpsilon(rectangle1, new Rectangle(0.1, 0.2, 0.3, 0.4), 0.0)).toEqual(true);
+        expect(Rectangle.equalsEpsilon(rectangle1, new Rectangle(0.5, 0.2, 0.3, 0.4), 0.0)).toEqual(false);
+        expect(Rectangle.equalsEpsilon(rectangle1, new Rectangle(0.1, 0.5, 0.3, 0.4), 0.0)).toEqual(false);
+        expect(Rectangle.equalsEpsilon(rectangle1, new Rectangle(0.1, 0.2, 0.5, 0.4), 0.0)).toEqual(false);
+        expect(Rectangle.equalsEpsilon(rectangle1, new Rectangle(0.1, 0.2, 0.3, 0.5), 0.0)).toEqual(false);
+        expect(Rectangle.equalsEpsilon(rectangle1, new Rectangle(0.5, 0.2, 0.3, 0.4), 0.4)).toEqual(true);
+        expect(Rectangle.equalsEpsilon(rectangle1, new Rectangle(0.1, 0.5, 0.3, 0.4), 0.3)).toEqual(true);
+        expect(Rectangle.equalsEpsilon(rectangle1, new Rectangle(0.1, 0.2, 0.5, 0.4), 0.2)).toEqual(true);
+        expect(Rectangle.equalsEpsilon(rectangle1, new Rectangle(0.1, 0.2, 0.3, 0.5), 0.1)).toEqual(true);
+        expect(Rectangle.equalsEpsilon(rectangle1, undefined, 0.0)).toEqual(false);
+        expect(Rectangle.equalsEpsilon(undefined, rectangle1, 0.0)).toEqual(false);
+        expect(Rectangle.equalsEpsilon(rectangle1, rectangle1, 0.0)).toEqual(true);
+    });
+
     it('Equals epsilon works in all cases', function() {
         var rectangle = new Rectangle(0.1, 0.2, 0.3, 0.4);
         expect(rectangle.equalsEpsilon(new Rectangle(0.1, 0.2, 0.3, 0.4), 0.0)).toEqual(true);