phaser/src/tilemaps/components/WorldToTileX.js
2018-04-16 15:25:22 +01:00

46 lines
1.5 KiB
JavaScript

/**
* @author Richard Davey <rich@photonstorm.com>
* @copyright 2018 Photon Storm Ltd.
* @license {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
*/
/**
* Converts from world X coordinates (pixels) to tile X coordinates (tile units), factoring in the
* layer's position, scale and scroll.
*
* @function Phaser.Tilemaps.Components.WorldToTileX
* @private
* @since 3.0.0
*
* @param {number} worldX - [description]
* @param {boolean} [snapToFloor=true] - Whether or not to round the tile coordinate down to the
* nearest integer.
* @param {Phaser.Cameras.Scene2D.Camera} [camera=main camera] - [description]
* @param {Phaser.Tilemaps.LayerData} layer - The Tilemap Layer to act upon.
*
* @return {number} The X location in tile units.
*/
var WorldToTileX = function (worldX, snapToFloor, camera, layer)
{
if (snapToFloor === undefined) { snapToFloor = true; }
var tileWidth = layer.baseTileWidth;
var tilemapLayer = layer.tilemapLayer;
if (tilemapLayer)
{
if (camera === undefined) { camera = tilemapLayer.scene.cameras.main; }
// Find the world position relative to the static or dynamic layer's top left origin,
// factoring in the camera's horizontal scroll
worldX = worldX - (tilemapLayer.x + camera.scrollX * (1 - tilemapLayer.scrollFactorX));
tileWidth *= tilemapLayer.scaleX;
}
return snapToFloor
? Math.floor(worldX / tileWidth)
: worldX / tileWidth;
};
module.exports = WorldToTileX;