/*
-----------------------------------------------------------------------------
This source file is part of OGRE
    (Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2011 Torus Knot Software Ltd

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
-----------------------------------------------------------------------------
*/
// RenderSystem implementation
// Note that most of this class is abstract since
//  we cannot know how to implement the behaviour without
//  being aware of the 3D API. However there are a few
//  simple functions which can have a base implementation

#include "CmRenderSystem.h"

#include "CmViewport.h"
#include "CmException.h"
#include "CmRenderTarget.h"
#include "CmRenderWindow.h"
#include "CmHardwarePixelBuffer.h"
#include "CmHardwareOcclusionQuery.h"
#include "CmCommandQueue.h"
#include "CmDeferredRenderContext.h"
#include "boost/bind.hpp"

#if CM_DEBUG_MODE
#define THROW_IF_NOT_RENDER_THREAD throwIfNotRenderThread();
#else
#define THROW_IF_NOT_RENDER_THREAD 
#endif

namespace CamelotEngine {

    static const TexturePtr sNullTexPtr;

    //-----------------------------------------------------------------------
    RenderSystem::RenderSystem()
        : mActiveRenderTarget(0)
        , mCullingMode(CULL_CLOCKWISE)
		, mVsync(false)
		, mVSyncInterval(1)
        , mInvertVertexWinding(false)
        , mDisabledTexUnitsFrom(0)
        , mVertexProgramBound(false)
		, mGeometryProgramBound(false)
        , mFragmentProgramBound(false)
		, mClipPlanesDirty(true)
		, mCurrentCapabilities(nullptr)
		, mRenderThreadFunc(nullptr)
		, mRenderThreadShutdown(false)
		, mCommandQueue(nullptr)
		, mMaxCommandNotifyId(0)
    {
    }

    //-----------------------------------------------------------------------
    RenderSystem::~RenderSystem()
    {
        shutdown_internal();

		delete mCurrentCapabilities;
		mCurrentCapabilities = 0;
    }
	//-----------------------------------------------------------------------
	void RenderSystem::startUp()
	{
		mRenderThreadId = CM_THREAD_CURRENT_ID;
		mCommandQueue = new CommandQueue(CM_THREAD_CURRENT_ID);

		initRenderThread();

		queueCommand(boost::bind(&RenderSystem::startUp_internal, this));
	}
	//-----------------------------------------------------------------------
	void RenderSystem::startUp_internal()
	{
		THROW_IF_NOT_RENDER_THREAD;

		mVertexProgramBound = false;
		mGeometryProgramBound = false;
		mFragmentProgramBound = false;
	}
	//-----------------------------------------------------------------------
	void RenderSystem::shutdown(void)
	{
		queueCommand(boost::bind(&RenderSystem::shutdown_internal, this), true);
		// TODO - What if something gets queued between these two calls?
		shutdownRenderThread();
	}
	//-----------------------------------------------------------------------
	void RenderSystem::shutdown_internal(void)
	{
		// TODO - I should probably sync this up to make sure no other threads are doing anything while shutdown is in progress

		// Remove all the render targets.
		// (destroy primary target last since others may depend on it)
		RenderTarget* primary = 0;
		for (auto it = mRenderTargets.begin(); it != mRenderTargets.end(); ++it)
		{
			if (!primary && (*it)->isPrimary())
				primary = *it;
			else
				delete *it;
		}
		delete primary;
		mRenderTargets.clear();

		mPrioritisedRenderTargets.clear();

		if(mCommandQueue != nullptr)
		{
			delete mCommandQueue;
			mCommandQueue = nullptr;
		}
	}
    //-----------------------------------------------------------------------
    void RenderSystem::swapAllRenderTargetBuffers(bool waitForVSync)
    {
		THROW_IF_NOT_RENDER_THREAD;

        // Update all in order of priority
        // This ensures render-to-texture targets get updated before render windows
		RenderTargetPriorityMap::iterator itarg, itargend;
		itargend = mPrioritisedRenderTargets.end();
		for( itarg = mPrioritisedRenderTargets.begin(); itarg != itargend; ++itarg )
		{
			if( itarg->second->isActive())
				itarg->second->swapBuffers(waitForVSync);
		}
    }
	//---------------------------------------------------------------------------------------------
	RenderWindow* RenderSystem::createRenderWindow(const String &name, unsigned int width, unsigned int height, 
		bool fullScreen, const NameValuePairList *miscParams)
	{
		AsyncOp op;

		if(miscParams != nullptr)
			op = queueReturnCommand(boost::bind(&RenderSystem::createRenderWindow_internal, this, name, width, height, fullScreen, *miscParams, _1), true);
		else
			op = queueReturnCommand(boost::bind(&RenderSystem::createRenderWindow_internal, this, name, width, height, fullScreen, NameValuePairList(), _1), true);

		return op.getReturnValue<RenderWindow*>();
	}
    //---------------------------------------------------------------------------------------------
    void RenderSystem::destroyRenderWindow(RenderWindow* renderWindow)
    {
		THROW_IF_NOT_RENDER_THREAD;

        destroyRenderTarget(renderWindow);
    }
    //---------------------------------------------------------------------------------------------
    void RenderSystem::destroyRenderTexture(RenderTexture* renderTexture)
    {
		THROW_IF_NOT_RENDER_THREAD;

        destroyRenderTarget(renderTexture);
    }
    //---------------------------------------------------------------------------------------------
    void RenderSystem::destroyRenderTarget(RenderTarget* renderTarget)
    {
		THROW_IF_NOT_RENDER_THREAD;

        detachRenderTarget(*renderTarget);
        delete renderTarget;
    }
    //---------------------------------------------------------------------------------------------
    void RenderSystem::attachRenderTarget( RenderTarget &target )
    {
		THROW_IF_NOT_RENDER_THREAD;

		assert( target.getPriority() < CM_NUM_RENDERTARGET_GROUPS );

        mRenderTargets.push_back(&target);
        mPrioritisedRenderTargets.insert(
            RenderTargetPriorityMap::value_type(target.getPriority(), &target ));
    }
	//---------------------------------------------------------------------------------------------
	void RenderSystem::detachRenderTarget(RenderTarget& renderTarget)
	{
		THROW_IF_NOT_RENDER_THREAD;

		auto it = std::find(mRenderTargets.begin(), mRenderTargets.end(), &renderTarget);
		RenderTarget* foundRT = nullptr;

		if( it != mRenderTargets.end() )
		{
			foundRT = *it;

			/* Remove the render target from the priority groups. */
			RenderTargetPriorityMap::iterator itarg, itargend;
			itargend = mPrioritisedRenderTargets.end();
			for( itarg = mPrioritisedRenderTargets.begin(); itarg != itargend; ++itarg )
			{
				if( itarg->second == *it ) {
					mPrioritisedRenderTargets.erase( itarg );
					break;
				}
			}

			mRenderTargets.erase( it );
		}
		/// If detached render target is the active render target, reset active render target
		if(foundRT == mActiveRenderTarget)
			mActiveRenderTarget = 0;
	}
	//---------------------------------------------------------------------------------------------
	const RenderSystemCapabilities* RenderSystem::getCapabilities(void) const 
	{ 
		THROW_IF_NOT_RENDER_THREAD;

		return mCurrentCapabilities; 
	}
	//---------------------------------------------------------------------------------------------
	const DriverVersion& RenderSystem::getDriverVersion(void) const 
	{ 
		THROW_IF_NOT_RENDER_THREAD;

		return mDriverVersion; 
	}
    //-----------------------------------------------------------------------
    Viewport RenderSystem::getViewport(void)
    {
		THROW_IF_NOT_RENDER_THREAD;

        return mActiveViewport;
    }
	//-----------------------------------------------------------------------
    void RenderSystem::setSamplerState(UINT16 texUnit, const SamplerState& tl)
    {
		THROW_IF_NOT_RENDER_THREAD;

        // This method is only ever called to set a texture unit to valid details
        // The method _disableTextureUnit is called to turn a unit off

        // Set texture layer filtering
        setTextureFiltering(texUnit, 
            tl.getTextureFiltering(FT_MIN), 
            tl.getTextureFiltering(FT_MAG), 
            tl.getTextureFiltering(FT_MIP));

        // Set texture layer filtering
        setTextureAnisotropy(texUnit, tl.getTextureAnisotropy());

		// Set mipmap biasing
		setTextureMipmapBias(texUnit, tl.getTextureMipmapBias());

        // Texture addressing mode
        const UVWAddressingMode& uvw = tl.getTextureAddressingMode();
        setTextureAddressingMode(texUnit, uvw);
    }
    //-----------------------------------------------------------------------
    void RenderSystem::disableTextureUnit(UINT16 texUnit)
    {
		THROW_IF_NOT_RENDER_THREAD;

        setTexture(texUnit, false, sNullTexPtr);
    }
    //---------------------------------------------------------------------
    void RenderSystem::disableTextureUnitsFrom(UINT16 texUnit)
    {
		THROW_IF_NOT_RENDER_THREAD;

        UINT16 disableTo = CM_MAX_TEXTURE_LAYERS;
        if (disableTo > mDisabledTexUnitsFrom)
            disableTo = mDisabledTexUnitsFrom;
        mDisabledTexUnitsFrom = texUnit;
        for (UINT16 i = texUnit; i < disableTo; ++i)
        {
            disableTextureUnit(i);
        }
    }
    //-----------------------------------------------------------------------
    void RenderSystem::setTextureFiltering(UINT16 unit, FilterOptions minFilter,
            FilterOptions magFilter, FilterOptions mipFilter)
    {
		THROW_IF_NOT_RENDER_THREAD;

        setTextureFiltering(unit, FT_MIN, minFilter);
        setTextureFiltering(unit, FT_MAG, magFilter);
        setTextureFiltering(unit, FT_MIP, mipFilter);
    }
	//-----------------------------------------------------------------------
	bool RenderSystem::getWaitForVerticalBlank(void) const
	{
		THROW_IF_NOT_RENDER_THREAD;

		return mVsync;
	}
	//-----------------------------------------------------------------------
	void RenderSystem::setWaitForVerticalBlank(bool enabled)
	{
		THROW_IF_NOT_RENDER_THREAD;

		mVsync = enabled;
	}
	//-----------------------------------------------------------------------
	void RenderSystem::setInvertVertexWinding_(bool invert)
	{
		THROW_IF_NOT_RENDER_THREAD;

		mInvertVertexWinding = invert;
	}
	//-----------------------------------------------------------------------
	bool RenderSystem::getInvertVertexWinding(void) const
	{
		THROW_IF_NOT_RENDER_THREAD;

		return mInvertVertexWinding;
	}
	//-----------------------------------------------------------------------
	CullingMode RenderSystem::getCullingMode(void) const
	{
		THROW_IF_NOT_RENDER_THREAD;
		return mCullingMode;
	}
	//---------------------------------------------------------------------
	void RenderSystem::addClipPlane (const Plane &p)
	{
		THROW_IF_NOT_RENDER_THREAD;

		mClipPlanes.push_back(p);
		mClipPlanesDirty = true;
	}
	//---------------------------------------------------------------------
	void RenderSystem::addClipPlane (float A, float B, float C, float D)
	{
		THROW_IF_NOT_RENDER_THREAD;

		addClipPlane(Plane(A, B, C, D));
	}
	//---------------------------------------------------------------------
	void RenderSystem::setClipPlanes(const PlaneList& clipPlanes)
	{
		THROW_IF_NOT_RENDER_THREAD;

		if (clipPlanes != mClipPlanes)
		{
			mClipPlanes = clipPlanes;
			mClipPlanesDirty = true;
		}
	}
	//---------------------------------------------------------------------
	void RenderSystem::resetClipPlanes()
	{
		THROW_IF_NOT_RENDER_THREAD;

		if (!mClipPlanes.empty())
		{
			mClipPlanes.clear();
			mClipPlanesDirty = true;
		}
	}
	//-----------------------------------------------------------------------
	void RenderSystem::bindGpuProgram(GpuProgramHandle prg)
	{
		THROW_IF_NOT_RENDER_THREAD;

		switch(prg->getBindingDelegate_internal()->getType())
		{
		case GPT_VERTEX_PROGRAM:
			// mark clip planes dirty if changed (programmable can change space)
			if (!mVertexProgramBound && !mClipPlanes.empty())
				mClipPlanesDirty = true;

			mVertexProgramBound = true;
			break;
		case GPT_GEOMETRY_PROGRAM:
			mGeometryProgramBound = true;
			break;
		case GPT_FRAGMENT_PROGRAM:
			mFragmentProgramBound = true;
			break;
		}
	}
	//-----------------------------------------------------------------------
	void RenderSystem::unbindGpuProgram(GpuProgramType gptype)
	{
		THROW_IF_NOT_RENDER_THREAD;

		switch(gptype)
		{
		case GPT_VERTEX_PROGRAM:
			// mark clip planes dirty if changed (programmable can change space)
			if (mVertexProgramBound && !mClipPlanes.empty())
				mClipPlanesDirty = true;
			mVertexProgramBound = false;
			break;
		case GPT_GEOMETRY_PROGRAM:
			mGeometryProgramBound = false;
			break;
		case GPT_FRAGMENT_PROGRAM:
			mFragmentProgramBound = false;
			break;
		}
	}
	//-----------------------------------------------------------------------
	bool RenderSystem::isGpuProgramBound(GpuProgramType gptype)
	{
		THROW_IF_NOT_RENDER_THREAD;

	    switch(gptype)
	    {
        case GPT_VERTEX_PROGRAM:
            return mVertexProgramBound;
        case GPT_GEOMETRY_PROGRAM:
            return mGeometryProgramBound;
        case GPT_FRAGMENT_PROGRAM:
            return mFragmentProgramBound;
	    }
        // Make compiler happy
        return false;
	}
	//-----------------------------------------------------------------------
	void RenderSystem::render(const RenderOperation& op)
	{
		THROW_IF_NOT_RENDER_THREAD;

		// sort out clip planes
		// have to do it here in case of matrix issues
		if (mClipPlanesDirty)
		{
			setClipPlanesImpl(mClipPlanes);
			mClipPlanesDirty = false;
		}
	}

	/************************************************************************/
	/* 								PRIVATE		                     		*/
	/************************************************************************/

	void RenderSystem::initRenderThread()
	{
		mRenderThreadFunc = new RenderWorkerFunc(this);

#if CM_THREAD_SUPPORT
		CM_THREAD_CREATE(t, *mRenderThreadFunc);
		mRenderThread = t;

		CM_LOCK_MUTEX_NAMED(mRenderThreadStartMutex, lock)
		CM_THREAD_WAIT(mRenderThreadStartCondition, mRenderThreadStartMutex, lock)

#else
		CM_EXCEPT(InternalErrorException, "Attempting to start a render thread but Camelot isn't compiled with thread support.");
#endif
	}

	void RenderSystem::runRenderThread()
	{
		mRenderThreadId = CM_THREAD_CURRENT_ID;

		CM_THREAD_NOTIFY_ALL(mRenderThreadStartCondition)

		while(true)
		{
			if(mRenderThreadShutdown)
				return;

			// Wait until we get some ready commands
			vector<CommandQueue::Command>::type* commands = nullptr;
			{
				CM_LOCK_MUTEX_NAMED(mCommandQueueMutex, lock)

				while(mCommandQueue->isEmpty())
					CM_THREAD_WAIT(mCommandReadyCondition, mCommandQueueMutex, lock)

				commands = mCommandQueue->flush();
			}

			// Play commands
			mCommandQueue->playback(commands, boost::bind(&RenderSystem::commandCompletedNotify, this, _1)); 
		}

	}

	void RenderSystem::shutdownRenderThread()
	{
		mRenderThreadShutdown = true;

		// Wake all threads. They will quit after they see the shutdown flag
		CM_THREAD_NOTIFY_ALL(mCommandReadyCondition)

		mRenderThread->join();
		CM_THREAD_DESTROY(mRenderThread);

		mRenderThread = nullptr;
		mRenderThreadId = CM_THREAD_CURRENT_ID;
	}

	DeferredRenderContextPtr RenderSystem::createDeferredContext()
	{
		return DeferredRenderContextPtr(new DeferredRenderContext(this, CM_THREAD_CURRENT_ID));
	}
	
	AsyncOp RenderSystem::queueReturnCommand(boost::function<void(AsyncOp&)> commandCallback, bool blockUntilComplete)
	{
#ifdef CM_DEBUG_MODE
		if(CM_THREAD_CURRENT_ID == getRenderThreadId())
			CM_EXCEPT(InternalErrorException, "You are not allowed to call this method on the render thread!");
#endif

		AsyncOp op;
		UINT32 commandId = -1;
		{
			CM_LOCK_MUTEX(mCommandQueueMutex);

			if(blockUntilComplete)
			{
				commandId = mMaxCommandNotifyId++;
				op = mCommandQueue->queueReturn(commandCallback, true, commandId);
			}
			else
				op = mCommandQueue->queueReturn(commandCallback);
		}

		CM_THREAD_NOTIFY_ALL(mCommandReadyCondition);

		if(blockUntilComplete)
			blockUntilCommandCompleted(commandId);

		return op;
	}

	void RenderSystem::queueCommand(boost::function<void()> commandCallback, bool blockUntilComplete)
	{
#ifdef CM_DEBUG_MODE
		if(CM_THREAD_CURRENT_ID == getRenderThreadId())
			CM_EXCEPT(InternalErrorException, "You are not allowed to call this method on the render thread!");
#endif

		UINT32 commandId = -1;
		{
			CM_LOCK_MUTEX(mCommandQueueMutex);

			if(blockUntilComplete)
			{
				commandId = mMaxCommandNotifyId++;
				mCommandQueue->queue(commandCallback, true, commandId);
			}
			else
				mCommandQueue->queue(commandCallback);
		}

		CM_THREAD_NOTIFY_ALL(mCommandReadyCondition);

		if(blockUntilComplete)
			blockUntilCommandCompleted(commandId);
	}

	void RenderSystem::blockUntilCommandCompleted(UINT32 commandId)
	{
		CM_LOCK_MUTEX_NAMED(mCommandNotifyMutex, lock);

		while(true)
		{
			// Check if our command id is in the completed list
			auto iter = mCommandsCompleted.begin();
			for(; iter != mCommandsCompleted.end(); ++iter)
			{
				if(*iter == commandId)
					break;
			}

			if(iter != mCommandsCompleted.end())
			{
				mCommandsCompleted.erase(iter);
				break;
			}

			CM_THREAD_WAIT(mCommandCompleteCondition, mCommandNotifyMutex, lock);
		}
	}

	void RenderSystem::commandCompletedNotify(UINT32 commandId)
	{
		{
			CM_LOCK_MUTEX(mCommandNotifyMutex);

			mCommandsCompleted.push_back(commandId);
		}

		CM_THREAD_NOTIFY_ALL(mCommandCompleteCondition);
	}

	void RenderSystem::throwIfNotRenderThread() const
	{
		if(CM_THREAD_CURRENT_ID != getRenderThreadId())
			CM_EXCEPT(InternalErrorException, "Calling the render system from a non-render thread!");
	}

	/************************************************************************/
	/* 								THREAD WORKER                      		*/
	/************************************************************************/

	RenderSystem::RenderWorkerFunc::RenderWorkerFunc(RenderSystem* rs)
		:mRS(rs)
	{
		assert(mRS != nullptr);
	}

	void RenderSystem::RenderWorkerFunc::operator()()
	{
		mRS->runRenderThread();
	}
}

#undef THROW_IF_NOT_RENDER_THREAD