source: GTP/trunk/App/Demos/Vis/FriendlyCulling/src/OcclusionQuery.cpp @ 2800

#include <iostream>
#include "OcclusionQuery.h"
#include "glInterface.h"

using namespace std;


namespace CHCDemoEngine
{

OcclusionQuery::OcclusionQuery()
{
        glGenQueriesARB(1, &mQueryId);

        // reverse for multiqueries with 20 nodes
        mNodes.reserve(32);
}


OcclusionQuery::~OcclusionQuery()
{
        glDeleteQueriesARB(1, &mQueryId);
}


void OcclusionQuery::BeginQuery() const
{
        glBeginQueryARB(GL_SAMPLES_PASSED_ARB, mQueryId);
}


void OcclusionQuery::EndQuery() const
{
        glEndQueryARB(GL_SAMPLES_PASSED_ARB);
}


unsigned int OcclusionQuery::GetQueryId() const
{
        return mQueryId;
}


bool OcclusionQuery::ResultAvailable() const
{
        GLuint available = GL_FALSE;

        glGetQueryObjectuivARB(mQueryId, GL_QUERY_RESULT_AVAILABLE_ARB, &available);

        return available == GL_TRUE;
}


unsigned int OcclusionQuery::GetQueryResult() const
{
        GLuint sampleCount = 1;

        glGetQueryObjectuivARB(mQueryId, GL_QUERY_RESULT_ARB, &sampleCount);
        
        return sampleCount;
}



QueryHandler::QueryHandler(): mCurrentQueryIdx(0) 
{
        Allocate(500);
}


OcclusionQuery *QueryHandler::RequestQuery()
{
        OcclusionQuery *query;

        if (mCurrentQueryIdx == mOcclusionQueries.size())
        {
                query = new OcclusionQuery();
                mOcclusionQueries.push_back(query);
        }
        else
        {
                query = mOcclusionQueries[mCurrentQueryIdx];
                query->Reset();
        }

        ++ mCurrentQueryIdx;

        return query;
}


void QueryHandler::ResetQueries()
{
        mCurrentQueryIdx = 0;
}


void QueryHandler::DestroyQueries()
{
        CLEAR_CONTAINER(mOcclusionQueries);
        
        mCurrentQueryIdx = 0;
        mOcclusionQueries.clear();
}


void QueryHandler::Allocate(int n)
{
        unsigned int *ids = new unsigned int[n]; 
        glGenQueriesARB(n, ids);

        for (int i = 0; i < n; ++ i) 
        {
                OcclusionQuery *q = new OcclusionQuery(ids[i]);
                mOcclusionQueries.push_back(q);
        }

        mCurrentQueryIdx = n;
        delete [] ids;
}


} // namespace