#include "OgreOcclusionCullingSceneTraverser.h"
#include "OgreMath.h"
#include "OgreIteratorWrappers.h"
#include "OgreCamera.h"
#include "OgreHardwareOcclusionQuery.h"
//#include "OgreWireBoundingBox.h"
#include "OgreSolidHalfBoundingBox.h"


#include <windows.h>

namespace Ogre {
	
	//-----------------------------------------------------------------------
	OcclusionCullingSceneTraverser::OcclusionCullingSceneTraverser(SceneManager *sm, RenderSystem *rsys): 
	mFrameId(1), mDistanceQueue(NULL), mVisibilityThreshold(0), mCurrentTestIdx(0),
	mQueryMode(MODE_RENDER), mNumSceneNodes(0), mCurrentAlgorithm(RENDER_COHERENT),
	mNumTraversedNodes(0), mNumQueryCulledNodes(0), mNumFrustumCulledNodes(0), 
	mNumRenderedGeometry(0), mSceneManager(sm), mRenderSystem(rsys)
	{		
		mHalfBoundingBox[0] = mHalfBoundingBox[1] = 0;
	}
	//-----------------------------------------------------------------------
	OcclusionCullingSceneTraverser::~OcclusionCullingSceneTraverser()
	{		
		if(mHalfBoundingBox[0]) delete mHalfBoundingBox[0];
		if(mHalfBoundingBox[1]) delete mHalfBoundingBox[1];

		deleteQueries();
		//SceneManager::~SceneManager();
	}
	//-----------------------------------------------------------------------
	void OcclusionCullingSceneTraverser::renderScene( Camera *cam, SceneNode *root )
	{
		mNumTraversedNodes = 0;
		mNumQueryCulledNodes = 0;
		mNumFrustumCulledNodes = 0;
		mNumRenderedGeometry = 0;
		
		mDistanceQueue = new PriorityQueue(myless<SceneNode *>(cam));
		mDistanceQueue->push(root);
		mCurrentTestIdx = 0;

		mCurrentAlgorithm = RENDER_CULL_FRUSTUM;
		switch(mCurrentAlgorithm)
		{
			case RENDER_CULL_FRUSTUM:
				renderCullFrustum(cam);
		        break;
			case RENDER_STOP_AND_WAIT:
				renderStopAndWait(cam);
				break;
			case RENDER_COHERENT:
				renderCoherentWithQueue(cam);
				break;
			default:
				renderCullFrustum(cam);
				break;
		}	
		
		delete mDistanceQueue;

		mFrameId ++;
	}
	//-----------------------------------------------------------------------
	void OcclusionCullingSceneTraverser::renderCoherentWithQueue(Camera *cam)
	{
		QueryQueue queryQueue;

		//-- PART 1: process finished occlusion queries
		while(!mDistanceQueue->empty() || !queryQueue.empty())
		{
			while(!queryQueue.empty() && 
				  ((queryQueue.front().second)->resultAvailable() || mDistanceQueue->empty()))
			{
				SceneNode *node = queryQueue.front().first;
				HardwareOcclusionQuery *query = queryQueue.front().second;

				queryQueue.pop();
			
				// wait until result available
				unsigned int visiblePixels;
				query->pullOcclusionQuery(&visiblePixels);

				if(visiblePixels > mVisibilityThreshold)
				{
					pullUpVisibility(node);
					traverseNode(cam, node);
				}
				else
				{
					mNumQueryCulledNodes ++;
				}
			}	

			//-- PART 2: hierarchical traversal
			if(!mDistanceQueue->empty())
			{
				SceneNode *node = mDistanceQueue->top();
				mDistanceQueue->pop();
	
				if(cam->isVisible(node->_getWorldAABB()))
				{
					// identify previously visible nodes
					bool wasVisible = node->isNodeVisible() && (node->lastVisited() == mFrameId - 1);
					
					// identify nodes that we cannot skip queries for
					bool leafOrWasInvisible = !wasVisible || isLeaf(node);

					// reset node's visibility classification 
					node->setNodeVisible(false);

					// update node's visited flag
					node->setLastVisited(mFrameId);
				
					// skip testing previously visible interior nodes
					if(leafOrWasInvisible)
					{
						HardwareOcclusionQuery *query = issueOcclusionQuery(node, wasVisible);
						queryQueue.push(query_pair(node, query));
					}
					
					// always traverse a node if it was visible
					if(wasVisible)
					{
						traverseNode(cam, node);
					}
				}
				else
				{
					mNumFrustumCulledNodes ++;
				}
			}
		}
	}
	//-----------------------------------------------------------------------
	void OcclusionCullingSceneTraverser::renderCullFrustum(Camera *cam)
	{
		while(!mDistanceQueue->empty())
		{
			SceneNode *node = mDistanceQueue->top();
			mDistanceQueue->pop();
	
			// interesting for visualization purpose
			node->setNodeVisible(false);
				
			if(!cam->isVisible(node->_getWorldAABB()))
			{
				// update node's visited flag 
				node->setLastVisited(mFrameId);
				node->setNodeVisible(true);
				traverseNode(cam, node);
			}
			//else
				if(cam->isVisible(node->_getWorldAABB()))
				{
					mNumQueryCulledNodes ++;
				}else
			{			
				mNumFrustumCulledNodes ++;
			}
		}
	}	
	//-----------------------------------------------------------------------
	void OcclusionCullingSceneTraverser::renderStopAndWait(Camera *cam)
	{
		while(!mDistanceQueue->empty())
		{
			SceneNode *node = mDistanceQueue->top();
			mDistanceQueue->pop();
		
			// interesting for the visualization
			node->setNodeVisible(false);
			node->setLastVisited(mFrameId);

			if(cam->isVisible(node->_getWorldAABB()))
			{
				HardwareOcclusionQuery *query = issueOcclusionQuery(node, false);
				
				unsigned int visiblePixels;
				// wait if result not available
				query->pullOcclusionQuery(&visiblePixels);
				
				// node visible
				if(visiblePixels > mVisibilityThreshold)
				{
					traverseNode(cam, node);
				}
				else
				{
					mNumQueryCulledNodes ++;
				}
			}
			else
			{
				mNumFrustumCulledNodes ++;
			}
		}
	}
	//-----------------------------------------------------------------------
	HardwareOcclusionQuery *OcclusionCullingSceneTraverser::issueOcclusionQuery( SceneNode *node, bool wasVisible )
	{
		// change state so the bounding box gets not actually rendered on the screen
		setRenderingMode(MODE_QUERY);

		// get next available test id
		HardwareOcclusionQuery *query = mOcclusionQueries[mCurrentTestIdx++];
		
		query->beginOcclusionQuery();
				
		renderBoundingBox(node);

		query->endOcclusionQuery();

		return query;
	}
	//-----------------------------------------------------------------------
	void OcclusionCullingSceneTraverser::setRenderingMode( int mode )
	{	
		// avoid unnecessary state changes
		if(mode != mQueryMode)
		{
			bool enabled = (mode == MODE_RENDER);
			
			mRenderSystem->_setColourBufferWriteEnabled(enabled, 
				enabled, enabled, enabled);
			mRenderSystem->_setDepthBufferWriteEnabled(enabled);
			mRenderSystem->setLightingEnabled(enabled);

			mQueryMode = mode;
		}
	}
	//-----------------------------------------------------------------------
	void OcclusionCullingSceneTraverser::traverseNode( Camera *cam, SceneNode *node )
	{
		mNumTraversedNodes ++;
		
		if(node->numAttachedObjects() > 0)
		{
			renderSceneNode(cam, node);
		}

		// internal node: add children to priority queue for further processing
		Node::ChildNodeIterator it = node->getChildIterator();
					
		while (it.hasMoreElements())			
		{ 
			SceneNode* sceneChild = static_cast<SceneNode*>(it.getNext());
			mDistanceQueue->push(sceneChild);
		}
	}
	//-----------------------------------------------------------------------
	void OcclusionCullingSceneTraverser::renderSceneNode( Camera *cam, SceneNode *node )
	{
		setRenderingMode(MODE_RENDER);
		
		//HACK (too slow)
		mSceneManager->_renderSceneNode(cam, node);
		//MessageBox( NULL, "myplugin registered", "this is my plugin", MB_OK | MB_ICONERROR | MB_TASKMODAL);
	}
	//-----------------------------------------------------------------------
	void OcclusionCullingSceneTraverser::preprocess( void )
	{
		//-- initialise occlusion queries.
		deleteQueries();
		
		for(unsigned int i=0; i < mNumSceneNodes; i++)
		{
			mOcclusionQueries.push_back(mRenderSystem->createHardwareOcclusionQuery());
		}	
	}
	//-----------------------------------------------------------------------
	void OcclusionCullingSceneTraverser::setSceneManager( SceneManager *sm )
	{
		mSceneManager = sm;
	}
	//-----------------------------------------------------------------------
	void OcclusionCullingSceneTraverser::setRenderSystem( RenderSystem *rsys )
	{
		mRenderSystem = rsys;
	}
	//-----------------------------------------------------------------------
	/*unsigned int OcclusionCullingSceneManager::countSceneNodes(SceneNode *node)
	{
		unsigned int result = 1;
		
		Node::ChildNodeIterator it = node->getChildIterator();
		
		while (it.hasMoreElements())
		{ 
			SceneNode* sceneChild = static_cast<SceneNode*>(it.getNext());
			result += countSceneNodes(sceneChild);
        }

		return result;
	}*/
	//-----------------------------------------------------------------------
	bool OcclusionCullingSceneTraverser::isLeaf( SceneNode *node )
	{
		return (node->numChildren() == 0);
	}
	//-----------------------------------------------------------------------
	void OcclusionCullingSceneTraverser::pullUpVisibility( SceneNode *node )
	{
		while(node && !node->isNodeVisible())
		{
			node->setNodeVisible(true);
			node = static_cast<SceneNode *>(node->getParent());
		}
	}
	//-----------------------------------------------------------------------
	void OcclusionCullingSceneTraverser::deleteQueries( void )
	{
		for(unsigned int i=0; i < mNumSceneNodes; i++)
			delete mOcclusionQueries[i];

		mOcclusionQueries.clear();
	}
	//-----------------------------------------------------------------------
	void OcclusionCullingSceneTraverser::renderBoundingBox( SceneNode *node )
	{
		// Render two halfes of the bounding box (using triangle fans)
		for(int half = 0; half < 2; half ++)
		{
			SolidHalfBoundingBox *box = getSolidHalfBoundingBox(half);
			
			box->setupBoundingBox(node->_getWorldAABB());

			static RenderOperation ro;
			mSceneManager->useRenderableViewProjMode(box);
			box->getRenderOperation(ro);
			ro.srcRenderable = box; 
			mRenderSystem->_render(ro);

			//mSceneManager->renderSingleObject(getSolidHalfBoundingBox(half), 
			//	getSolidHalfBoundingBox(half)->getTechnique()->getPass(0), false);
		}
	}
	//-----------------------------------------------------------------------
	SolidHalfBoundingBox *OcclusionCullingSceneTraverser::getSolidHalfBoundingBox( int half )
	{
		if(!mHalfBoundingBox[half])
			mHalfBoundingBox[half] = new SolidHalfBoundingBox(half == 1);

		return mHalfBoundingBox[half];	
	}
	//-----------------------------------------------------------------------
	bool OcclusionCullingSceneTraverser::setOption( const String & key, const void * val )
	{
		if ( key == "Algorithm" )
		{
			mCurrentAlgorithm = * static_cast < const int * > ( val );
			return true;
		}
		if ( key == "Threshold" )
		{
			mVisibilityThreshold = * static_cast < const int * > ( val );
			return true;
		}

		return false;
	}
	//-----------------------------------------------------------------------
	bool OcclusionCullingSceneTraverser::getOption( const String & key, void *val )
	{
		if ( key == "Algorithm" )
		{
			* static_cast < int * > ( val ) = mCurrentAlgorithm;
			return true;
		}
		if ( key == "Threshold" )
		{
			* static_cast < unsigned int * > ( val ) = mVisibilityThreshold;
			return true;
		}
		if ( key == "NumSceneNodes" )
		{
			* static_cast < unsigned int * > ( val ) = mNumSceneNodes;
			return true;
		}
		if ( key == "NumTraversedNodes" )
		{
			* static_cast < unsigned int * > ( val ) = mNumTraversedNodes;
			return true;
		}
		if ( key == "NumQueryCulledNodes" )
		{
			* static_cast < unsigned int * > ( val ) = mNumQueryCulledNodes;
			return true;
		}
		if ( key == "NumFrustumCulledNodes" )
		{
			* static_cast < unsigned int * > ( val ) = mNumFrustumCulledNodes;
			return true;
		}
		return false;
	}
	//-----------------------------------------------------------------------
	bool OcclusionCullingSceneTraverser::getOptionKeys( StringVector & refKeys )
	{
		refKeys.push_back( "Algorithm" );
		refKeys.push_back( "Threshold" );
		refKeys.push_back( "NumSceneNodes" );
		refKeys.push_back( "NumTraversedNodes" );
		refKeys.push_back( "NumQueryCulledNodes" );
		refKeys.push_back( "NumFrustumCulledNodes" );
		//refKeys.push_back( "mNumRenderedGeometry" );

		return true;
	}
	//-----------------------------------------------------------------------
	void OcclusionCullingSceneTraverser::setNumSceneNodes(int num)
	{
		mNumSceneNodes = num;
	}
}