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Clarified the documentation for Point.rotate and fixed all the examples.

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photonstorm 2015-06-13 05:02:07 +01:00
parent 9e78cd1d7a
commit 5f9bff0e8b
1 changed files with 16 additions and 8 deletions
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24
src/geom/Point.js
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@ -785,36 +785,44 @@ Phaser.Point.normalize = function (a, out) {
};
/**
* Rotates a Point around the x/y coordinates given to the desired angle.
* Rotates a Point object, or any object with exposed x/y properties, around the given coordinates by
* the angle specified. If the angle between the point and coordinates was 45 deg and the angle argument
* is 45 deg then the resulting angle will be 90 deg, as the angle argument is added to the current angle.
*
* The distance allows you to specify a distance constraint for the rotation between the point and the
* coordinates. If none is given the distance between the two is calculated and used.
*
* @method Phaser.Point.rotate
* @param {Phaser.Point} a - The Point object to rotate.
* @param {number} x - The x coordinate of the anchor point
* @param {number} y - The y coordinate of the anchor point
* @param {number} angle - The angle in radians (unless asDegrees is true) to rotate the Point to.
* @param {boolean} [asDegrees=false] - Is the given rotation in radians (false) or degrees (true)?
* @param {number} angle - The angle in radians (unless asDegrees is true) to rotate the Point by.
* @param {boolean} [asDegrees=false] - Is the given angle to rotate by in radians (false) or degrees (true)?
* @param {number} [distance] - An optional distance constraint between the Point and the anchor.
* @return {Phaser.Point} The modified point object.
*/
Phaser.Point.rotate = function (a, x, y, angle, asDegrees, distance) {
asDegrees = asDegrees || false;
distance = distance || null;
if (typeof asDegrees === 'undefined') { asDegrees = false; }
if (typeof distance === 'undefined') { distance = null; }
if (asDegrees)
{
angle = Phaser.Math.degToRad(angle);
}
// Get distance from origin (cx/cy) to this point
if (distance === null)
{
// Get distance from origin (cx/cy) to this point
distance = Math.sqrt(((x - a.x) * (x - a.x)) + ((y - a.y) * (y - a.y)));
}
var requiredAngle = angle + Math.atan2(a.y - y, a.x - x);
var t = angle + Math.atan2(a.y - y, a.x - x);
return a.setTo(x + distance * Math.cos(requiredAngle), y + distance * Math.sin(requiredAngle));
a.x = x + distance * Math.cos(t);
a.y = y + distance * Math.sin(t);
return a;
};