OcclusionQueryBank.h

#pragma once

#include <vector>
namespace ParaEngine
{
    // Little struct used to store queries and their outstanding state
    struct LatentQueryElement
    {
        LPDIRECT3DQUERY9 query;
        enum 
        {
            UNUSED = 0,
            ISSUEDBEGIN = 1,
            ISSUEDEND = 2,
        } state;

        void* pUserData;
        LatentQueryElement():query(NULL), state(UNUSED), pUserData(NULL){};
    };

    typedef std::vector<LatentQueryElement> QueryVector;

    class LatentOcclusionQueryBank
    {
    public:
        LatentOcclusionQueryBank( IDirect3DDevice9 *  pD3DDev);
        ~LatentOcclusionQueryBank();
        HRESULT GetLatestResults(DWORD *count);
        HRESULT BeginNextQuery();
        HRESULT EndNextQuery();
        uint32 GetNumActiveQueries();

        
        HRESULT BeginNewQuery(void* pUserData = NULL);
        HRESULT EndNewQuery();
        HRESULT WaitForFirstResult(DWORD *count, void** pUserData=NULL);
        HRESULT CheckForFirstResult(DWORD *count, void** pUserData=NULL);
        bool HasUnusedQuery();


        void Cleanup();
        bool IsValid();
        
    protected:
        bool m_bIsValid;
        QueryVector m_Queries;
        int m_head;

        int m_nFirstUnusedIndex;
        int m_nFirstQueryIndex;
    };
}