phaser/src/tilemaps/components/WorldToTileY.js
2020-11-26 12:55:40 +00:00

42 lines
1.5 KiB
JavaScript

/**
* @author Richard Davey <rich@photonstorm.com>
* @copyright 2020 Photon Storm Ltd.
* @license {@link https://opensource.org/licenses/MIT|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 - The y coordinate to be converted, in pixels, not tiles.
* @param {boolean} snapToFloor - Whether or not to round the tile coordinate down to the nearest integer.
* @param {?Phaser.Cameras.Scene2D.Camera} camera - The Camera to use when calculating the tile index from the world values.
* @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) { 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;