source: code/archive/Presentation_FS17/src/libraries/tools/bsp/OgreGpuCommandBufferFlush.cpp @ 12373

#include "OgreGpuCommandBufferFlush.h"
#include "OgreRoot.h"
#include "OgreRenderSystem.h"
#include "OgreHardwareOcclusionQuery.h"

namespace Ogre
{
        //---------------------------------------------------------------------
        GpuCommandBufferFlush::GpuCommandBufferFlush()
                : mUseOcclusionQuery(true)
                , mMaxQueuedFrames(2)
                , mCurrentFrame(0)
                , mStartPull(false)
                , mStarted(false)
        {

        }
        //---------------------------------------------------------------------
        GpuCommandBufferFlush::~GpuCommandBufferFlush()
        {
                stop();
        }
        //---------------------------------------------------------------------
        void GpuCommandBufferFlush::start(size_t maxQueuedFrames)
        {
                if (!Root::getSingletonPtr() || !Root::getSingletonPtr()->getRenderSystem())
                        return;

                stop();
                mMaxQueuedFrames = maxQueuedFrames;
                RenderSystem* rsys = Root::getSingleton().getRenderSystem();
                mUseOcclusionQuery = rsys->getCapabilities()->hasCapability(RSC_HWOCCLUSION);

                if (mUseOcclusionQuery)
                {
                        for (size_t i = 0; i < mMaxQueuedFrames; ++i)
                        {
                                HardwareOcclusionQuery* hoq = rsys->createHardwareOcclusionQuery();
                                mHOQList.push_back(hoq);
                        }
                }

                mCurrentFrame = 0;
                mStartPull = false;

                Root::getSingleton().addFrameListener(this);

                mStarted = true;

        }
        //---------------------------------------------------------------------
        void GpuCommandBufferFlush::stop()
        {
                if (!mStarted || !Root::getSingletonPtr() || !Root::getSingletonPtr()->getRenderSystem())
                        return;

                RenderSystem* rsys = Root::getSingleton().getRenderSystem();
                for (HOQList::iterator i = mHOQList.begin(); i != mHOQList.end(); ++i)
                {
                        rsys->destroyHardwareOcclusionQuery(*i);
                }
                mHOQList.clear();

                Root::getSingleton().removeFrameListener(this);

                mStarted = false;

        }
        //---------------------------------------------------------------------
        bool GpuCommandBufferFlush::frameStarted(const FrameEvent& evt)
        {
                if (mUseOcclusionQuery)
                {

                        mHOQList[mCurrentFrame]->beginOcclusionQuery();

                }

                return true;
        }
        //---------------------------------------------------------------------
        bool GpuCommandBufferFlush::frameEnded(const FrameEvent& evt)
        {
                if (mUseOcclusionQuery)
                {
                        mHOQList[mCurrentFrame]->endOcclusionQuery();
                }
                mCurrentFrame = (mCurrentFrame + 1) % mMaxQueuedFrames;
                // If we've wrapped around, time to start pulling
                if (mCurrentFrame == 0)
                        mStartPull = true;

                if (mStartPull)
                {
                        unsigned int dummy;
                        mHOQList[mCurrentFrame]->pullOcclusionQuery(&dummy);
                }

                return true;
        }
        //---------------------------------------------------------------------


}