phaser/src/actions/ShiftPosition.js

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/**
* @author Richard Davey <rich@photonstorm.com>
* @copyright 2018 Photon Storm Ltd.
* @license {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
*/
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var Vector2 = require('../math/Vector2');
// Iterate through items changing the position of each element to
// be that of the element that came before it in the array (or after it if direction = 1)
// The first items position is set to x/y.
// The final x/y coords are returned
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/**
* [description]
*
* @function Phaser.Actions.ShiftPosition
* @since 3.0.0
*
* @param {array} items - An array of Game Objects. The contents of this array are updated by this Action.
* @param {number} x - [description]
* @param {number} y - [description]
* @param {integer} [direction=0] - [description]
* @param {Phaser.Math.Vector2|object} [output] - [description]
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*
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* @return {array} The array of Game Objects that was passed to this Action.
*/
var ShiftPosition = function (items, x, y, direction, output)
{
if (direction === undefined) { direction = 0; }
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if (output === undefined) { output = new Vector2(); }
var px;
var py;
if (items.length > 1)
{
var i;
var cx;
var cy;
var cur;
if (direction === 0)
{
// Bottom to Top
var len = items.length - 1;
px = items[len].x;
py = items[len].y;
for (i = len - 1; i >= 0; i--)
{
// Current item
cur = items[i];
// Get current item x/y, to be passed to the next item in the list
cx = cur.x;
cy = cur.y;
// Set current item to the previous items x/y
cur.x = px;
cur.y = py;
// Set current as previous
px = cx;
py = cy;
}
// Update the head item to the new x/y coordinates
items[len].x = x;
items[len].y = y;
}
else
{
// Top to Bottom
px = items[0].x;
py = items[0].y;
for (i = 1; i < items.length; i++)
{
// Current item
cur = items[i];
// Get current item x/y, to be passed to the next item in the list
cx = cur.x;
cy = cur.y;
// Set current item to the previous items x/y
cur.x = px;
cur.y = py;
// Set current as previous
px = cx;
py = cy;
}
// Update the head item to the new x/y coordinates
items[0].x = x;
items[0].y = y;
}
}
else
{
px = items[0].x;
py = items[0].y;
items[0].x = x;
items[0].y = y;
}
// Return the final set of coordinates as they're effectively lost from the shift and may be needed
output.x = px;
output.y = py;
return output;
};
module.exports = ShiftPosition;