//-----------------------------------------------------------------------
void CompositorChain::_compile()
{
	clearCompiledState();

	bool compositorsEnabled = false;

	// force default scheme so materials for compositor quads will determined correctly
	MaterialManager& matMgr = MaterialManager::getSingleton();
	String prevMaterialScheme = matMgr.getActiveScheme();
	matMgr.setActiveScheme(MaterialManager::DEFAULT_SCHEME_NAME);
	
    /// Set previous CompositorInstance for each compositor in the list
    CompositorInstance *lastComposition = mOriginalScene;
	mOriginalScene->mPreviousInstance = 0;
	CompositionPass* pass = mOriginalScene->getTechnique()->getOutputTargetPass()->getPass(0);
	pass->setClearBuffers(mViewport->getClearBuffers());
	pass->setClearColour(mViewport->getBackgroundColour());
    for(Instances::iterator i=mInstances.begin(); i!=mInstances.end(); ++i)
    {
        if((*i)->getEnabled())
        {
			compositorsEnabled = true;
            (*i)->mPreviousInstance = lastComposition;
            lastComposition = (*i);
        }
    }
    

    /// Compile misc targets
    lastComposition->_compileTargetOperations(mCompiledState);
    
    /// Final target viewport (0)
	mOutputOperation.renderSystemOperations.clear();
    lastComposition->_compileOutputOperation(mOutputOperation);

	// Deal with viewport settings
	if (compositorsEnabled != mAnyCompositorsEnabled)
	{
		mAnyCompositorsEnabled = compositorsEnabled;
		if (mAnyCompositorsEnabled)
		{
			// Save old viewport clearing options
			mOldClearEveryFrameBuffers = mViewport->getClearBuffers();
			// Don't clear anything every frame since we have our own clear ops
			mViewport->setClearEveryFrame(false);
		}
		else
		{
			// Reset clearing options
			mViewport->setClearEveryFrame(mOldClearEveryFrameBuffers > 0, 
				mOldClearEveryFrameBuffers);
		}
	}

	// restore material scheme
	matMgr.setActiveScheme(prevMaterialScheme);

    
    mDirty = false;
}
//-----------------------------------------------------------------------
void CompositorChain::preViewportUpdate(const RenderTargetViewportEvent& evt)
{
	// Only set up if there is at least one compositor enabled, and it's this viewport
    if(evt.source != mViewport || !mAnyCompositorsEnabled)
        return;

	// set original scene details from viewport
	CompositionPass* pass = mOriginalScene->getTechnique()->getOutputTargetPass()->getPass(0);
	CompositionTargetPass* passParent = pass->getParent();
	if (pass->getClearBuffers() != mViewport->getClearBuffers() ||
		pass->getClearColour() != mViewport->getBackgroundColour() ||
		passParent->getVisibilityMask() != mViewport->getVisibilityMask() ||
		passParent->getMaterialScheme() != mViewport->getMaterialScheme() ||
		passParent->getShadowsEnabled() != mViewport->getShadowsEnabled())
	{
		// recompile if viewport settings are different
		pass->setClearBuffers(mViewport->getClearBuffers());
		pass->setClearColour(mViewport->getBackgroundColour());
		passParent->setVisibilityMask(mViewport->getVisibilityMask());
		passParent->setMaterialScheme(mViewport->getMaterialScheme());
		passParent->setShadowsEnabled(mViewport->getShadowsEnabled());
		_compile();
	}

	Camera *cam = mViewport->getCamera();
	if (cam)
	{
		/// Prepare for output operation
		preTargetOperation(mOutputOperation, mViewport, cam);
	}
}
void TerrainManager::fixCompositorClearColor()
{
    // hack
    // now with extensive error checking
    if (CompositorManager::getSingleton().hasCompositorChain(gEnv->mainCamera->getViewport()))
    {
        CompositorInstance* co = CompositorManager::getSingleton().getCompositorChain(gEnv->mainCamera->getViewport())->_getOriginalSceneCompositor();
        if (co)
        {
            CompositionTechnique* ct = co->getTechnique();
            if (ct)
            {
                CompositionTargetPass* ctp = ct->getOutputTargetPass();
                if (ctp)
                {
                    CompositionPass* p = ctp->getPass(0);
                    if (p)
                    {
                        p->setClearColour(Ogre::ColourValue::Black);
                    }
                }
            }
        }
    }
}