phaser/src/math/TransformXY.js
2020-01-15 12:07:09 +00:00

49 lines
1.7 KiB
JavaScript

/**
* @author Richard Davey <rich@photonstorm.com>
* @copyright 2020 Photon Storm Ltd.
* @license {@link https://opensource.org/licenses/MIT|MIT License}
*/
var Vector2 = require('./Vector2');
/**
* Takes the `x` and `y` coordinates and transforms them into the same space as
* defined by the position, rotation and scale values.
*
* @function Phaser.Math.TransformXY
* @since 3.0.0
*
* @param {number} x - The x coordinate to be transformed.
* @param {number} y - The y coordinate to be transformed.
* @param {number} positionX - Horizontal position of the transform point.
* @param {number} positionY - Vertical position of the transform point.
* @param {number} rotation - Rotation of the transform point, in radians.
* @param {number} scaleX - Horizontal scale of the transform point.
* @param {number} scaleY - Vertical scale of the transform point.
* @param {(Phaser.Math.Vector2|Phaser.Geom.Point|object)} [output] - The output vector, point or object for the translated coordinates.
*
* @return {(Phaser.Math.Vector2|Phaser.Geom.Point|object)} The translated point.
*/
var TransformXY = function (x, y, positionX, positionY, rotation, scaleX, scaleY, output)
{
if (output === undefined) { output = new Vector2(); }
var radianSin = Math.sin(rotation);
var radianCos = Math.cos(rotation);
// Rotate and Scale
var a = radianCos * scaleX;
var b = radianSin * scaleX;
var c = -radianSin * scaleY;
var d = radianCos * scaleY;
// Invert
var id = 1 / ((a * d) + (c * -b));
output.x = (d * id * x) + (-c * id * y) + (((positionY * c) - (positionX * d)) * id);
output.y = (a * id * y) + (-b * id * x) + (((-positionY * a) + (positionX * b)) * id);
return output;
};
module.exports = TransformXY;