# Source: gameobjects/Graphics.js

    /**
    * @author       Richard Davey <rich@photonstorm.com>
    * @copyright    2014 Photon Storm Ltd.
    * @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
    */

    /**
    * Creates a new `Graphics` object.
    *
    * @class Phaser.Graphics
    * @constructor
    *
    * @param {Phaser.Game} game Current game instance.
    * @param {number} x - X position of the new graphics object.
    * @param {number} y - Y position of the new graphics object.
    */
    Phaser.Graphics = function (game, x, y) {

        x = x || 0;
        y = y || 0;

        /**
        * @property {Phaser.Game} game - A reference to the currently running Game.
        */
        this.game = game;

        /**
        * @property {boolean} exists - If exists = false then the Text isn't updated by the core game loop.
        * @default
        */
        this.exists = true;

        /**
        * @property {string} name - The user defined name given to this object.
        * @default
        */
        this.name = '';

        /**
        * @property {number} type - The const type of this object.
        * @default
        */
        this.type = Phaser.GRAPHICS;

        /**
        * @property {number} z - The z-depth value of this object within its Group (remember the World is a Group as well). No two objects in a Group can have the same z value.
        */
        this.z = 0;

        /**
        * @property {Phaser.Point} world - The world coordinates of this Sprite. This differs from the x/y coordinates which are relative to the Sprites container.
        */
        this.world = new Phaser.Point(x, y);

        /**
        * @property {Phaser.Point} cameraOffset - If this object is fixedToCamera then this stores the x/y offset that its drawn at, from the top-left of the camera view.
        */
        this.cameraOffset = new Phaser.Point();

        PIXI.Graphics.call(this);

        this.position.set(x, y);

        /**
        * A small internal cache:
        * 0 = previous position.x
        * 1 = previous position.y
        * 2 = previous rotation
        * 3 = renderID
        * 4 = fresh? (0 = no, 1 = yes)
        * 5 = outOfBoundsFired (0 = no, 1 = yes)
        * 6 = exists (0 = no, 1 = yes)
        * 7 = fixed to camera (0 = no, 1 = yes)
        * 8 = destroy phase? (0 = no, 1 = yes)
        * @property {Array} _cache
        * @private
        */
        this._cache = [ 0, 0, 0, 0, 1, 0, 1, 0, 0 ];

    };

    Phaser.Graphics.prototype = Object.create(PIXI.Graphics.prototype);
    Phaser.Graphics.prototype.constructor = Phaser.Graphics;

    /**
    * Automatically called by World.preUpdate.
    * @method Phaser.Graphics.prototype.preUpdate
    */
    Phaser.Graphics.prototype.preUpdate = function () {

        this._cache[0] = this.world.x;
        this._cache[1] = this.world.y;
        this._cache[2] = this.rotation;

        if (!this.exists || !this.parent.exists)
        {
            this.renderOrderID = -1;
            return false;
        }

        if (this.autoCull)
        {
            //  Won't get rendered but will still get its transform updated
            this.renderable = this.game.world.camera.screenView.intersects(this.getBounds());
        }

        this.world.setTo(this.game.camera.x + this.worldTransform[2], this.game.camera.y + this.worldTransform[5]);

        if (this.visible)
        {
            this._cache[3] = this.game.stage.currentRenderOrderID++;
        }

        return true;

    };

    /**
    * Override and use this function in your own custom objects to handle any update requirements you may have.
    *
    * @method Phaser.Graphics#update
    * @memberof Phaser.Graphics
    */
    Phaser.Graphics.prototype.update = function() {

    };

    /**
    * Automatically called by World.postUpdate.
    * @method Phaser.Graphics.prototype.postUpdate
    */
    Phaser.Graphics.prototype.postUpdate = function () {

        //  Fixed to Camera?
        if (this._cache[7] === 1)
        {
            this.position.x = (this.game.camera.view.x + this.cameraOffset.x) / this.game.camera.scale.x;
            this.position.y = (this.game.camera.view.y + this.cameraOffset.y) / this.game.camera.scale.y;
        }

    };

    /**
    * Destroy this Graphics instance.
    *
    * @method Phaser.Graphics.prototype.destroy
    * @param {boolean} [destroyChildren=true] - Should every child of this object have its destroy method called?
    */
    Phaser.Graphics.prototype.destroy = function(destroyChildren) {

        if (this.game === null || this.destroyPhase) { return; }

        if (typeof destroyChildren === 'undefined') { destroyChildren = true; }

        this._cache[8] = 1;

        this.clear();

        if (this.parent)
        {
            if (this.parent instanceof Phaser.Group)
            {
                this.parent.remove(this);
            }
            else
            {
                this.parent.removeChild(this);
            }
        }

        var i = this.children.length;

        if (destroyChildren)
        {
            while (i--)
            {
                this.children[i].destroy(destroyChildren);
            }
        }
        else
        {
            while (i--)
            {
                this.removeChild(this.children[i]);
            }
        }

        this.exists = false;
        this.visible = false;

        this.game = null;

        this._cache[8] = 0;

    };

    /*
    * Draws a {Phaser.Polygon} or a {PIXI.Polygon} filled
    *
    * @method Phaser.Graphics.prototype.drawPolygon
    */
    Phaser.Graphics.prototype.drawPolygon = function (poly) {

        this.moveTo(poly.points[0].x, poly.points[0].y);

        for (var i = 1; i < poly.points.length; i += 1)
        {
            this.lineTo(poly.points[i].x, poly.points[i].y);
        }

        this.lineTo(poly.points[0].x, poly.points[0].y);

    };

    /*
    * Draws a single {Phaser.Polygon} triangle from a {Phaser.Point} array
    *
    * @method Phaser.Graphics.prototype.drawTriangle
    * @param {Array<Phaser.Point>} points - An array of Phaser.Points that make up the three vertices of this triangle
    * @param {boolean} [cull=false] - Should we check if the triangle is back-facing
    */
    Phaser.Graphics.prototype.drawTriangle = function(points, cull) {

        if (typeof cull === 'undefined') { cull = false; }

        var triangle = new Phaser.Polygon(points);

        if (cull)
        {
            var cameraToFace = new Phaser.Point(this.game.camera.x - points[0].x, this.game.camera.y - points[0].y);
            var ab = new Phaser.Point(points[1].x - points[0].x, points[1].y - points[0].y);
            var cb = new Phaser.Point(points[1].x - points[2].x, points[1].y - points[2].y);
            var faceNormal = cb.cross(ab);

            if (cameraToFace.dot(faceNormal) > 0)
            {
                this.drawPolygon(triangle);
            }
        }
        else
        {
            this.drawPolygon(triangle);
        }

    };

    /*
    * Draws {Phaser.Polygon} triangles
    *
    * @method Phaser.Graphics.prototype.drawTriangles
    * @param {Array<Phaser.Point>|Array<number>} vertices - An array of Phaser.Points or numbers that make up the vertices of the triangles
    * @param {Array<number>} {indices=null} - An array of numbers that describe what order to draw the vertices in
    * @param {boolean} [cull=false] - Should we check if the triangle is back-facing
    */
    Phaser.Graphics.prototype.drawTriangles = function(vertices, indices, cull) {

        if (typeof cull === 'undefined') { cull = false; }

        var point1 = new Phaser.Point();
        var point2 = new Phaser.Point();
        var point3 = new Phaser.Point();
        var points = [];
        var i;

        if (!indices)
        {
            if (vertices[0] instanceof Phaser.Point)
            {
                for (i = 0; i < vertices.length / 3; i++)
                {
                    this.drawTriangle([vertices[i * 3], vertices[i * 3 + 1], vertices[i * 3 + 2]], cull);
                }
            }
            else
            {
                for (i = 0; i < vertices.length / 6; i++)
                {
                    point1.x = vertices[i * 6 + 0];
                    point1.y = vertices[i * 6 + 1];
                    point2.x = vertices[i * 6 + 2];
                    point2.y = vertices[i * 6 + 3];
                    point3.x = vertices[i * 6 + 4];
                    point3.y = vertices[i * 6 + 5];
                    this.drawTriangle([point1, point2, point3], cull);
                }
            }
        }
        else
        {
            if (vertices[0] instanceof Phaser.Point)
            {
                for (i = 0; i < indices.length /3; i++)
                {
                    points.push(vertices[indices[i * 3 ]]);
                    points.push(vertices[indices[i * 3 + 1]]);
                    points.push(vertices[indices[i * 3 + 2]]);

                    if (points.length === 3)
                    {
                        this.drawTriangle(points, cull);
                        points = [];
                    }
                }
            }
            else
            {
                for (i = 0; i < indices.length; i++)
                {
                    point1.x = vertices[indices[i] * 2];
                    point1.y = vertices[indices[i] * 2 + 1];
                    points.push(point1.copyTo({}));

                    if (points.length === 3)
                    {
                        this.drawTriangle(points, cull);
                        points = [];
                    }
                }
            }
        }
    };

    /**
    * Indicates the rotation of the Graphics, in degrees, from its original orientation. Values from 0 to 180 represent clockwise rotation; values from 0 to -180 represent counterclockwise rotation.
    * Values outside this range are added to or subtracted from 360 to obtain a value within the range. For example, the statement player.angle = 450 is the same as player.angle = 90.
    * If you wish to work in radians instead of degrees use the property Sprite.rotation instead.
    *
    * @name Phaser.Graphics#angle
    * @property {number} angle - Gets or sets the angle of rotation in degrees.
    */
    Object.defineProperty(Phaser.Graphics.prototype, 'angle', {

        get: function() {
            return Phaser.Math.radToDeg(this.rotation);
        },

        set: function(value) {
            this.rotation = Phaser.Math.degToRad(value);
        }

    });

    /**
    * An Graphics that is fixed to the camera uses its x/y coordinates as offsets from the top left of the camera. These are stored in Graphics.cameraOffset.
    * Note that the cameraOffset values are in addition to any parent in the display list.
    * So if this Graphics was in a Group that has x: 200, then this will be added to the cameraOffset.x
    *
    * @name Phaser.Graphics#fixedToCamera
    * @property {boolean} fixedToCamera - Set to true to fix this Graphics to the Camera at its current world coordinates.
    */
    Object.defineProperty(Phaser.Graphics.prototype, "fixedToCamera", {

        get: function () {

            return !!this._cache[7];

        },

        set: function (value) {

            if (value)
            {
                this._cache[7] = 1;
                this.cameraOffset.set(this.x, this.y);
            }
            else
            {
                this._cache[7] = 0;
            }
        }

    });

    /**
    * @name Phaser.Graphics#destroyPhase
    * @property {boolean} destroyPhase - True if this object is currently being destroyed.
    */
    Object.defineProperty(Phaser.Graphics.prototype, "destroyPhase", {

        get: function () {

            return !!this._cache[8];

        }

    });