ParaEngine::LatentOcclusionQueryBank Class Reference

This is a bank of occlusion queries. More...

#include <OcclusionQueryBank.h>

Public Member Functions
	LatentOcclusionQueryBank (IDirect3DDevice9 *pD3DDev)
HRESULT	GetLatestResults (DWORD *count)
HRESULT	BeginNextQuery ()
HRESULT	EndNextQuery ()
uint32	GetNumActiveQueries ()
HRESULT	BeginNewQuery (void *pUserData=NULL)
	start a new query
HRESULT	EndNewQuery ()
	end a new query
HRESULT	WaitForFirstResult (DWORD *count, void **pUserData=NULL)
	wait until the first query result is available. More...
HRESULT	CheckForFirstResult (DWORD *count, void **pUserData=NULL)
	check the first query result is available. More...
bool	HasUnusedQuery ()
	return true if there is unused query in the bank
void	Cleanup ()
bool	IsValid ()

Protected Attributes
bool	m_bIsValid
QueryVector	m_Queries
int	m_head
int	m_nFirstUnusedIndex
	the index of the first unused query in the bank
int	m_nFirstQueryIndex
	the index of the oldest query in the bank

Detailed Description

This is a bank of occlusion queries.

It is meant to allow multiple occlusion queries to be used in conjunction with a rendering strategy that culls based on the results. All calls into this class return immediately, so, it is possible for the call to GetLatestResults to return S_FALSE, indicating that there are no new results.

(Background: An occlusion query returns the number of pixels that pass z-testing; if greater than zero, you know an object is visible. For more information, look up D3DQUERYTYPE or D3DQUERYTYPE_OCCLUSION in MSDN.)

Usage:

Use just like a regular D3DQuery, replacing the following calls:

LPDIRECT3DQUERY9 -> LatentOcclusionQueryBank GetData() -> GetLatestResults() Issue(D3DISSUE_BEGIN) -> BeginNextQuery() Issue(D3DISSUE_BEGIN) -> EndNextQuery() Release() -> Free()

Remember to call Free()!

Member Function Documentation

CheckForFirstResult()

HRESULT LatentOcclusionQueryBank::CheckForFirstResult	(	DWORD *	count,
		void **	pUserData = NULL
	)

check the first query result is available.

and return immediately.

Parameters

pUserData

[out] user data when the query is issued.

WaitForFirstResult()

HRESULT LatentOcclusionQueryBank::WaitForFirstResult	(	DWORD *	count,
		void **	pUserData = NULL
	)

wait until the first query result is available.

and return the pixel count in count

Parameters

pUserData

[out] user data when the query is issued.

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The documentation for this class was generated from the following files:

• Client/trunk/ParaEngineClient/Engine/OcclusionQueryBank.h
• Client/trunk/ParaEngineClient/Engine/OcclusionQueryBank.cpp