package {

	import flash.display.Bitmap;
	import flash.display.BitmapData;
	import flash.display.Loader;
	import flash.display.LoaderInfo;
	import flash.display.Sprite;
	import flash.events.Event;
	import flash.events.MouseEvent;
	import flash.net.URLRequest;
	import flash.text.TextField;

	[SWF(width=550, height=400, backgroundColor=0xFFFFFF)]

	/**
	* Draws a bitmap into a rectangle using drawTriangles, allowing for points on the rectangle to be moved
	* in order to distort the bitmap.
	*/
	public class graphic_flex_image_effects_01_Flex_RenderingTriangles extends Sprite {

		private var _anchors:Vector.<Sprite>;
		private var _anchor:Sprite;
		private var _anchorIndex:uint;
		private var _vertices:Vector.<Number>;
		private var _indices:Vector.<int>;
		private var _uvtData:Vector.<Number>;
		private var _image:BitmapData;

		/**
		* Constructor.
		*/
		public function graphic_flex_image_effects_01_Flex_RenderingTriangles() {
			loadImage();
		}

		/**
		* Loads the image to distort.
		*/
		private function loadImage():void {
			var loader:Loader = new Loader();
			loader.contentLoaderInfo.addEventListener(Event.COMPLETE, onImageLoaded);
			loader.load(new URLRequest("../../assets/footprints.jpg"));
		}

		/**
		* Defines the vertices, indicies and uvtData for the four triangles.
		* For the vertices, adds visual anchor points so that the vertices can be moved by dragging the anchors.
		*/
		private function defineTriangles():void {
			// the padding between the image and the sides of the stage
			var border:Number = 50;
			var width:Number = stage.stageWidth;
			var height:Number = stage.stageHeight;

			// holds the five anchor points
			_anchors = new Vector.<Sprite>();
			addAnchor(border, border);
			addAnchor(width-border, border);
			addAnchor(width/2, height/2);
			addAnchor(border, height-border);
			addAnchor(width-border, height-border);

			_vertices = new Vector.<Number>();
			for each (var anchor:Sprite in _anchors) {
				_vertices.push(anchor.x, anchor.y);
			}

			_indices = new Vector.<int>();
			_indices.push(1, 0, 2);
			_indices.push(0, 2, 3);
			_indices.push(1, 2, 4);
			_indices.push(2, 3, 4);

			_uvtData = new Vector.<Number>();
			_uvtData.push(0, 0);
			_uvtData.push(1, 0);
			_uvtData.push(.5, .5);
			_uvtData.push(0, 1);
			_uvtData.push(1, 1);
		}

		/**
		* Adds a visual anchor point at the specified x/y position.
		*
		* @param x The x position of the anchor.
		* @param y The y position of the anchor.
		*/
		private function addAnchor(x:Number, y:Number):void {
			var anchor:Sprite = new Sprite();
			// creates a circle of thick radius by setting a thick linestyle and drawing a line of 1 pixel
			anchor.graphics.lineStyle(20);
			anchor.graphics.lineTo(1, 0);
			anchor.addEventListener(MouseEvent.MOUSE_DOWN, onAnchorDown);
			anchor.addEventListener(MouseEvent.MOUSE_UP, onAnchorUp);
			anchor.x = x;
			anchor.y = y;
			// places a label in the anchor that shows its index in the _anchors vector
			var label:TextField = new TextField();
			label.x = -4;
			label.y = -9;
			label.mouseEnabled = false;
			label.textColor = 0xFFFFFF;
			label.text = String(_anchors.length);
			anchor.addChild(label);
			addChild(anchor);
			_anchors.push(anchor);
		}

		/**
		* Redraws the bitmap based on the current vertex positions.
		*/
		private function draw():void {
			graphics.clear();
			graphics.beginBitmapFill(_image);
			graphics.drawTriangles(_vertices, _indices, _uvtData);
			graphics.endFill();
		}

		/**
		* Handler for when an anchor gets clicked. This begins drag of the anchor.
		*
		* @param event Event dispatched by anchor sprite.
		*/
		private function onAnchorDown(event:MouseEvent):void {
			_anchor = event.target as Sprite;
			_anchor.startDrag();
			_anchorIndex = _anchors.indexOf(_anchor);
			stage.addEventListener(MouseEvent.MOUSE_MOVE, onAnchorMove);
		}

		/**
		* Handler for when an anchor is dragged. This updates the associated vertex position and redraws the bitmap.
		*
		* @param event Event dispatched by anchor sprite.
		*/
		private function onAnchorMove(event:MouseEvent):void {
			_vertices[_anchorIndex*2] = _anchor.x;
			_vertices[_anchorIndex*2+1] = _anchor.y;
			draw();
			event.updateAfterEvent();
		}

		/**
		* Handler for when an anchor is released after dragging. This stops the dragging.
		*
		* @param event Event dispatched by anchor sprite.
		*/
		private function onAnchorUp(event:MouseEvent):void {
			if (_anchor) {
				_anchor.stopDrag();
				stage.removeEventListener(MouseEvent.MOUSE_MOVE, onAnchorMove);
			}
		}

		/**
		* Handler for when the image loads in. This saves the image in memory and draws the bitmap into the triangles.
		*
		* @param event Event dispatched by loader info.
		*/
		private function onImageLoaded(event:Event):void {
			var loaderInfo:LoaderInfo = event.target as LoaderInfo;
			var bitmap:Bitmap = loaderInfo.content as Bitmap;
			_image = bitmap.bitmapData;
			defineTriangles();
			draw();
		}

	}

}