package away3d.lights.shadowmaps
{
	import away3d.arcane;
	import away3d.cameras.Camera3D;
	import away3d.containers.Scene3D;
	import away3d.core.managers.Stage3DProxy;
	import away3d.core.render.DepthRenderer;
	import away3d.core.traverse.EntityCollector;
	import away3d.core.traverse.ShadowCasterCollector;
	import away3d.errors.AbstractMethodError;
	import away3d.lights.LightBase;
	import away3d.textures.RenderTexture;
	import away3d.textures.TextureProxyBase;
	
	import flash.display3D.textures.TextureBase;
	
	use namespace arcane;
	
	public class ShadowMapperBase
	{
		protected var _casterCollector:ShadowCasterCollector;
		
		private var _depthMap:TextureProxyBase;
		protected var _depthMapSize:uint = 2048;
		protected var _light:LightBase;
		private var _explicitDepthMap:Boolean;
		private var _autoUpdateShadows:Boolean = true;
		arcane var _shadowsInvalid:Boolean;
		
		public function ShadowMapperBase()
		{
			_casterCollector = createCasterCollector();
		}
		
		protected function createCasterCollector():ShadowCasterCollector
		{
			return new ShadowCasterCollector();
		}
		
		public function get autoUpdateShadows():Boolean
		{
			return _autoUpdateShadows;
		}
		
		public function set autoUpdateShadows(value:Boolean):void
		{
			_autoUpdateShadows = value;
		}
		
		public function updateShadows():void
		{
			_shadowsInvalid = true;
		}
		
		/**
		 * This is used by renderers that can support depth maps to be shared across instances
		 * @param depthMap
		 */
		arcane function setDepthMap(depthMap:TextureProxyBase):void
		{
			if (_depthMap == depthMap)
				return;
			if (_depthMap && !_explicitDepthMap)
				_depthMap.dispose();
			_depthMap = depthMap;
			if (_depthMap) {
				_explicitDepthMap = true;
				_depthMapSize = _depthMap.width;
			} else
				_explicitDepthMap = false;
		}
		
		public function get light():LightBase
		{
			return _light;
		}
		
		public function set light(value:LightBase):void
		{
			_light = value;
		}
		
		public function get depthMap():TextureProxyBase
		{
			return _depthMap ||= createDepthTexture();
		}
		
		public function get depthMapSize():uint
		{
			return _depthMapSize;
		}
		
		public function set depthMapSize(value:uint):void
		{
			if (value == _depthMapSize)
				return;
			_depthMapSize = value;
			
			if (_explicitDepthMap)
				throw Error("Cannot set depth map size for the current renderer.");
			else if (_depthMap) {
				_depthMap.dispose();
				_depthMap = null;
			}
		}
		
		public function dispose():void
		{
			_casterCollector = null;
			if (_depthMap && !_explicitDepthMap)
				_depthMap.dispose();
			_depthMap = null;
		}
		
		protected function createDepthTexture():TextureProxyBase
		{
			return new RenderTexture(_depthMapSize, _depthMapSize);
		}
		
		/**
		 * Renders the depth map for this light.
		 * @param entityCollector The EntityCollector that contains the original scene data.
		 * @param renderer The DepthRenderer to render the depth map.
		 */
		arcane function renderDepthMap(stage3DProxy:Stage3DProxy, entityCollector:EntityCollector, renderer:DepthRenderer):void
		{
			_shadowsInvalid = false;
			updateDepthProjection(entityCollector.camera);
			_depthMap ||= createDepthTexture();
			drawDepthMap(_depthMap.getTextureForStage3D(stage3DProxy), entityCollector.scene, renderer);
		}
		
		protected function updateDepthProjection(viewCamera:Camera3D):void
		{
			throw new AbstractMethodError();
		}
		
		protected function drawDepthMap(target:TextureBase, scene:Scene3D, renderer:DepthRenderer):void
		{
			throw new AbstractMethodError();
		}
	}
}