phaser/src/tilemaps/components/WorldToTileY.js
2018-02-12 16:01:21 +00:00

45 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 Y coordinates (pixels) to tile Y coordinates (tile units), factoring in the
* layer's position, scale and scroll.
*
* @function Phaser.Tilemaps.Components.WorldToTileY
* @since 3.0.0
*
* @param {number} worldY - [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 Y location in tile units.
*/
var WorldToTileY = function (worldY, snapToFloor, camera, layer)
{
if (snapToFloor === undefined) { snapToFloor = true; }
var tileHeight = layer.baseTileHeight;
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 vertical scroll
worldY = worldY - (tilemapLayer.y + camera.scrollY * (1 - tilemapLayer.scrollFactorY));
tileHeight *= tilemapLayer.scaleY;
}
return snapToFloor
? Math.floor(worldY / tileHeight)
: worldY / tileHeight;
};
module.exports = WorldToTileY;