Add Math.Distance methods

- BetweenPoints()
- BetweenPointsSquared()
- Chebyshev()
- Snake()

Author: samme

src/math/distance/DistanceBetweenPoints.js

@@ -0,0 +1,26 @@
+/**
+ * @author       samme
+ * @copyright    2019 Photon Storm Ltd.
+ * @license      {@link https://opensource.org/licenses/MIT|MIT License}
+ */
+
+/**
+ * Calculate the distance between two points.
+ *
+ * @function Phaser.Math.Distance.BetweenPoints
+ * @since 3.22.0
+ *
+ * @param {Phaser.Types.Math.Vector2Like} a - The first point.
+ * @param {Phaser.Types.Math.Vector2Like} b - The second point.
+ *
+ * @return {number} The distance between the points.
+ */
+var DistanceBetweenPoints = function (a, b)
+{
+    var dx = a.x - b.x;
+    var dy = a.y - b.y;
+
+    return Math.sqrt(dx * dx + dy * dy);
+};
+
+module.exports = DistanceBetweenPoints;

src/math/distance/DistanceBetweenPointsSquared.js

@@ -0,0 +1,26 @@
+/**
+ * @author       samme
+ * @copyright    2019 Photon Storm Ltd.
+ * @license      {@link https://opensource.org/licenses/MIT|MIT License}
+ */
+
+/**
+ * Calculate the squared distance between two points.
+ *
+ * @function Phaser.Math.Distance.BetweenPointsSquared
+ * @since 3.22.0
+ *
+ * @param {Phaser.Types.Math.Vector2Like} a - The first point.
+ * @param {Phaser.Types.Math.Vector2Like} b - The second point.
+ *
+ * @return {number} The squared distance between the points.
+ */
+var DistanceBetweenPointsSquared = function (a, b)
+{
+    var dx = a.x - b.x;
+    var dy = a.y - b.y;
+
+    return dx * dx + dy * dy;
+};
+
+module.exports = DistanceBetweenPointsSquared;

src/math/distance/DistanceChebyshev.js

@@ -0,0 +1,28 @@
+/**
+ * @author       samme
+ * @copyright    2019 Photon Storm Ltd.
+ * @license      {@link https://opensource.org/licenses/MIT|MIT License}
+ */
+
+/**
+ * Calculate the Chebyshev distance between two sets of coordinates (points).
+ *
+ * Chebyshev distance (or chessboard distance) is the maximum of the horizontal and vertical distances.
+ * It's the effective distance when movement can be horizontal, vertical, or diagonal.
+ *
+ * @function Phaser.Math.Distance.Chebyshev
+ * @since 3.22.0
+ *
+ * @param {number} x1 - The x coordinate of the first point.
+ * @param {number} y1 - The y coordinate of the first point.
+ * @param {number} x2 - The x coordinate of the second point.
+ * @param {number} y2 - The y coordinate of the second point.
+ *
+ * @return {number} The distance between each point.
+ */
+var ChebyshevDistance = function (x1, y1, x2, y2)
+{
+    return Math.max(Math.abs(x1 - x2), Math.abs(y1 - y2));
+};
+
+module.exports = ChebyshevDistance;

src/math/distance/DistanceSnake.js

@@ -0,0 +1,28 @@
+/**
+ * @author       samme
+ * @copyright    2019 Photon Storm Ltd.
+ * @license      {@link https://opensource.org/licenses/MIT|MIT License}
+ */
+
+/**
+ * Calculate the snake distance between two sets of coordinates (points).
+ *
+ * Snake distance (rectilinear distance, Manhattan distance) is the sum of the horizontal and vertical distances.
+ * It's the effective distance when movement is allowed only horizontally or vertically (but not both).
+ *
+ * @function Phaser.Math.Distance.Snake
+ * @since 3.22.0
+ *
+ * @param {number} x1 - The x coordinate of the first point.
+ * @param {number} y1 - The y coordinate of the first point.
+ * @param {number} x2 - The x coordinate of the second point.
+ * @param {number} y2 - The y coordinate of the second point.
+ *
+ * @return {number} The distance between each point.
+ */
+var SnakeDistance = function (x1, y1, x2, y2)
+{
+    return Math.abs(x1 - x2) + Math.abs(y1 - y2);
+};
+
+module.exports = SnakeDistance;

src/math/distance/index.js

@@ -11,7 +11,11 @@
 module.exports = {
 
     Between: require('./DistanceBetween'),
+    BetweenPoints: require('./DistanceBetweenPoints'),
+    BetweenPointsSquared: require('./DistanceBetweenPointsSquared'),
+    Chebyshev: require('./DistanceChebyshev'),
     Power: require('./DistancePower'),
+    Snake: require('./DistanceSnake'),
     Squared: require('./DistanceSquared')
 
 };