Math.ToXY is a new mini function that will take a given index and return a Vector2 containing the x and y coordinates of that index within a grid.

Author: photonstorm

CHANGELOG.md

@@ -14,6 +14,7 @@
 * `TextureManager.addGLTexture` is a new method that allows you to add a WebGLTexture directly into the Texture Manager, saved under the given key.
 * `TextureSource.isGLTexture` is a new boolean property that reflects if the data backing the underlying Texture Source is a WebGLTexture or not.
 * `TextureTintPipeline.batchSprite` will now flip the UV if the TextureSource comes from a GLTexture.
+* `Math.ToXY` is a new mini function that will take a given index and return a Vector2 containing the x and y coordinates of that index within a grid.
 
 ### Updates
 

src/math/ToXY.js

@@ -0,0 +1,52 @@
+/**
+ * @author       Richard Davey <rich@photonstorm.com>
+ * @copyright    2019 Photon Storm Ltd.
+ * @license      {@link https://opensource.org/licenses/MIT|MIT License}
+ */
+
+var Vector2 = require('./Vector2');
+
+/**
+ * Returns a Vec2 containing the x and y position of the given index in a `width` x `height` sized grid.
+ * 
+ * For example, in a 6 x 4 grid, index 16 would equal x: 4 y: 2.
+ * 
+ * If the given index is out of range an empty Vec2 is returned.
+ *
+ * @function Phaser.Math.ToXY
+ * @since 3.19.0
+ *
+ * @param {integer} index - The position within the grid to get the x/y value for.
+ * @param {integer} width - The width of the grid.
+ * @param {integer} height - The height of the grid.
+ * @param {Phaser.Math.Vector2} [out] - An optional Vector2 to store the result in. If not given, a new Vector2 instance will be created.
+ *
+ * @return {Phaser.Math.Vector2} A Vector2 where the x and y properties contain the given grid index.
+ */
+var ToXY = function (index, width, height, out)
+{
+    if (out === undefined) { out = new Vector2(); }
+
+    var x = 0;
+    var y = 0;
+    var total = width * height;
+
+    if (index > 0 && index <= total)
+    {
+        if (index > width - 1)
+        {
+            y = Math.floor(index / width);
+            x = index - (y * width);
+        }
+        else
+        {
+            x = index;
+        }
+
+        out.set(x, y);
+    }
+
+    return out;
+};
+
+module.exports = ToXY;

src/math/index.js

@@ -57,6 +57,7 @@ var PhaserMath = {
     SinCosTableGenerator: require('./SinCosTableGenerator'),
     SmootherStep: require('./SmootherStep'),
     SmoothStep: require('./SmoothStep'),
+    ToXY: require('./ToXY'),
     TransformXY: require('./TransformXY'),
     Within: require('./Within'),
     Wrap: require('./Wrap'),