Tilemaps.Components.CullBounds is a new function that calculates the cull bounds for an orthogonal map.

Author: photonstorm

src/tilemaps/components/CullBounds.js

@@ -0,0 +1,47 @@
+/**
+ * @author       Richard Davey <rich@photonstorm.com>
+ * @copyright    2020 Photon Storm Ltd.
+ * @license      {@link https://opensource.org/licenses/MIT|MIT License}
+ */
+
+var SnapCeil = require('../../math/snap/SnapCeil');
+var SnapFloor = require('../../math/snap/SnapFloor');
+
+/**
+ * Returns the bounds in the given orthogonal layer that are within the cameras viewport.
+ * This is used internally by the cull tiles function.
+ *
+ * @function Phaser.Tilemaps.Components.CullBounds
+ * @since 3.50.0
+ *
+ * @param {Phaser.Tilemaps.LayerData} layer - The Tilemap Layer to act upon.
+ * @param {Phaser.Cameras.Scene2D.Camera} camera - The Camera to run the cull check against.
+ *
+ * @return {object} An object containing the `left`, `right`, `top` and `bottom` bounds.
+ */
+var CullBounds = function (layer, camera)
+{
+    var tilemap = layer.tilemapLayer.tilemap;
+    var tilemapLayer = layer.tilemapLayer;
+
+    //  We need to use the tile sizes defined for the map as a whole, not the layer,
+    //  in order to calculate the bounds correctly. As different sized tiles may be
+    //  placed on the grid and we cannot trust layer.baseTileWidth to give us the true size.
+    var tileW = Math.floor(tilemap.tileWidth * tilemapLayer.scaleX);
+    var tileH = Math.floor(tilemap.tileHeight * tilemapLayer.scaleY);
+
+    var boundsLeft = SnapFloor(camera.worldView.x - tilemapLayer.x, tileW, 0, true) - tilemapLayer.cullPaddingX;
+    var boundsRight = SnapCeil(camera.worldView.right - tilemapLayer.x, tileW, 0, true) + tilemapLayer.cullPaddingX;
+
+    var boundsTop = SnapFloor(camera.worldView.y - tilemapLayer.y, tileH, 0, true) - tilemapLayer.cullPaddingY;
+    var boundsBottom = SnapCeil(camera.worldView.bottom - tilemapLayer.y, tileH, 0, true) + tilemapLayer.cullPaddingY;
+
+    return {
+        left: boundsLeft,
+        right: boundsRight,
+        top: boundsTop,
+        bottom: boundsBottom
+    };
+};
+
+module.exports = CullBounds;