package {

	import flash.display.Shader;
	import flash.display.Sprite;
	import flash.events.Event;
	import flash.events.KeyboardEvent;
	import flash.filters.ShaderFilter;
	import flash.media.Camera;
	import flash.media.Video;
	import flash.ui.Keyboard;

	[SWF(width=640, height=480, backgroundColor=0x666666, frameRate=12)]

	/**
	* Demonstrates using user webcam input. In addition, this class uses a custom shader that distorts an
	* image like a funhouse mirror. Through the use of the keyboard, the user can alter
	* the parameters of the distortion applied.
	*/
	public class graphic_flex_image_effects_12_Flex_FunhouseMirror extends Sprite {

		// the width/height of the webcam image
		private static const MIRROR_WIDTH:uint = 640;
		private static const MIRROR_HEIGHT:uint = 480;

		private var _shaderProxy:graphic_flex_image_effects_12_Flex_ShaderProxy;
		private var _video:Video;

		/**
		* Constructor. This instantiates a ShaderProxy and passes a path to a shader file to load.
		*/
		public function graphic_flex_image_effects_12_Flex_FunhouseMirror() {
			// if you are using the Flex framework, you can embed the shader bytecode and pass
			// the class from the embed tag to this constructor
			_shaderProxy = new graphic_flex_image_effects_12_Flex_ShaderProxy("graphic-flex-image-effects-12-assets-funhouseMirror.pbj");
			// if (default) you are passing a path to a .pbj file, wait for COMPLETE
			if (_shaderProxy.shader == null) {
				_shaderProxy.addEventListener(Event.COMPLETE, onShaderLoaded);
			// if bytecode was embedded, we can proceed immediately
			} else {
				createMirror();
			}
		}

		/**
		* Grabs webcam input, if allowed, and sets up a Video instance to display its data.
		* The custom shader is applied as a filter to the video.
		*/
		private function createMirror():void {
			var camera:Camera = Camera.getCamera();
			// does NOT handle messaging the user if no camera is available or allowed
			if (camera != null) {
				camera.setMode(MIRROR_WIDTH, MIRROR_HEIGHT, stage.frameRate);
				_video = new Video(MIRROR_WIDTH, MIRROR_HEIGHT);
				_video.attachCamera(camera);
				_video.filters = [new ShaderFilter(_shaderProxy.shader)];
				addChild(_video);
				// keyboard event listener so shader parameters can be altered
				stage.addEventListener(KeyboardEvent.KEY_DOWN, onStageKeyDown);
			}
		}

		/**
		* Handler for when a key is pressed. This allows for altering the shader parameters.
		*
		* @param event Event dispatched by stage.
		*/
		private function onStageKeyDown(event:KeyboardEvent):void {
			// amount by which values should be changed
			var rate:Number = .05;
			// grab current values
			var rX:Number = _shaderProxy.warpRatioX;
			var rY:Number = _shaderProxy.warpRatioY;
			var dX:Number = _shaderProxy.distortionX;
			var dY:Number = _shaderProxy.distortionY;
			switch (event.keyCode) {
				case Keyboard.UP:
					// SHIFT is pressed, alter distortion
					if (event.shiftKey) {
						_shaderProxy.distortionY = Math.min(1, dY + rate);
					// else alter ratio position
					} else {
						_shaderProxy.warpRatioY = Math.max(0, rY - rate);
					}
					break;
				case Keyboard.DOWN:
					// SHIFT is pressed, alter distortion
					if (event.shiftKey) {
						_shaderProxy.distortionY = Math.max(0, dY - rate);
					// else alter ratio position
					} else {
						_shaderProxy.warpRatioY = Math.min(1, rY + rate);
					}
					break;
				case Keyboard.RIGHT:
					// SHIFT is pressed, alter distortion
					if (event.shiftKey) {
						_shaderProxy.distortionX = Math.min(1, dX + rate);
					// else alter ratio position
					} else {
						_shaderProxy.warpRatioX = Math.min(1, rX + rate);
					}
					break;
				case Keyboard.LEFT:
					// SHIFT is pressed, alter distortion
					if (event.shiftKey) {
						_shaderProxy.distortionX = Math.max(0, dX - rate);
					// else alter ratio position
					} else {
						_shaderProxy.warpRatioX = Math.max(0, rX - rate);
					}
					break;
				// if arrow keys were not pressed, don't update shader
				default:
					return;
			}
			// reapply shader with changes
			_video.filters = [new ShaderFilter(_shaderProxy.shader)];
		}

		/**
		* Handler for when shader completes loading.
		*
		* @param event Event dispatched by ShaderProxy.
		*/
		private function onShaderLoaded(event:Event):void {
			_shaderProxy.removeEventListener(Event.COMPLETE, onShaderLoaded);
			// set end positions of warp based on mirror size
			_shaderProxy.warpEndX = MIRROR_WIDTH;
			_shaderProxy.warpEndY = MIRROR_HEIGHT;
			createMirror();
		}

	}

}