Queries

Functions
XN_C_API XnStatus XN_C_DECL	xnNodeQueryAllocate (XnNodeQuery **ppQuery)
XN_C_API void XN_C_DECL	xnNodeQueryFree (XnNodeQuery *pQuery)
XN_C_API XnStatus XN_C_DECL	xnNodeQuerySetVendor (XnNodeQuery *pQuery, const XnChar *strVendor)
XN_C_API XnStatus XN_C_DECL	xnNodeQuerySetName (XnNodeQuery *pQuery, const XnChar *strName)
XN_C_API XnStatus XN_C_DECL	xnNodeQuerySetMinVersion (XnNodeQuery *pQuery, const XnVersion *pMinVersion)
XN_C_API XnStatus XN_C_DECL	xnNodeQuerySetMaxVersion (XnNodeQuery *pQuery, const XnVersion *pMaxVersion)
XN_C_API XnStatus XN_C_DECL	xnNodeQueryAddSupportedCapability (XnNodeQuery *pQuery, const XnChar *strNeededCapability)
XN_C_API XnStatus XN_C_DECL	xnNodeQueryAddSupportedMapOutputMode (XnNodeQuery *pQuery, const XnMapOutputMode *pMapOutputMode)
XN_C_API XnStatus XN_C_DECL	xnNodeQuerySetSupportedMinUserPositions (XnNodeQuery *pQuery, const XnUInt32 nCount)
XN_C_API XnStatus XN_C_DECL	xnNodeQuerySetExistingNodeOnly (XnNodeQuery *pQuery, XnBool bExistingNode)
XN_C_API XnStatus XN_C_DECL	xnNodeQuerySetNonExistingNodeOnly (XnNodeQuery *pQuery, XnBool bNonExistingNode)
XN_C_API XnStatus XN_C_DECL	xnNodeQueryAddNeededNode (XnNodeQuery *pQuery, const XnChar *strInstanceName)
XN_C_API XnStatus XN_C_DECL	xnNodeQuerySetCreationInfo (XnNodeQuery *pQuery, const XnChar *strCreationInfo)
XN_C_API XnStatus XN_C_DECL	xnNodeQueryFilterList (XnContext *pContext, const XnNodeQuery *pQuery, XnNodeInfoList *pList)

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Detailed Description

This page details functions for building queries. Queries can be used during enumeration, and provide an easy way for filtering results before they return to user.

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Function Documentation

XN_C_API XnStatus XN_C_DECL xnNodeQueryAddNeededNode	(	XnNodeQuery *	pQuery,
		const XnChar *	strInstanceName
	)

Adds a needed node.

Parameters:

pQuery	[in] Query object.
strInstanceName	[in] The name of the needed instance.

XN_C_API XnStatus XN_C_DECL xnNodeQueryAddSupportedCapability	(	XnNodeQuery *	pQuery,
		const XnChar *	strNeededCapability
	)

Adds a capability that the node must support. Note that for checking if a capability is supported, the node must be created (if it's not an existing one). This operation might take a bit longer...

Parameters:

pQuery	[in] Query object.
strNeededCapability	[in] A needed capability name.

XN_C_API XnStatus XN_C_DECL xnNodeQueryAddSupportedMapOutputMode	(	XnNodeQuery *	pQuery,
		const XnMapOutputMode *	pMapOutputMode
	)

Adds a MapOutputMode that the node must support. Note that for checking if a capability is supported, the node must be created (if it's not an existing one). This operation might take a bit longer...

Parameters:

pQuery	[in] Query object.
pMapOutputMode	[in] A map output mode. Each field of the mode can be set to (-1), meaning results will not be filtered by this field.

XN_C_API XnStatus XN_C_DECL xnNodeQueryAllocate

(

XnNodeQuery **

ppQuery

)

Allocates a new query object. This object must be freed using xnNodeQueryFree().

Parameters:

ppQuery

[out] Created query object.

XN_C_API XnStatus XN_C_DECL xnNodeQueryFilterList	(	XnContext *	pContext,
		const XnNodeQuery *	pQuery,
		XnNodeInfoList *	pList
	)

Filters a list of nodes according to query. The list will contain only nodes that match all query terms. Note that some query terms might require creation of a node, and thus may take longer.

Parameters:

pContext	[in] OpenNI Context object.
pQuery	[in] Query object.
pList	[in] The list to be filtered.

XN_C_API void XN_C_DECL xnNodeQueryFree

(

XnNodeQuery *

pQuery

)

Frees a query object previously created using xnNodeQueryAllocate().

Parameters:

pQuery

[in] Query object.

XN_C_API XnStatus XN_C_DECL xnNodeQuerySetCreationInfo	(	XnNodeQuery *	pQuery,
		const XnChar *	strCreationInfo
	)

Sets the creation info field of a query object.

Parameters:

pQuery	[in] Query object.
strCreationInfo	[in] The creation info to set in the query.

XN_C_API XnStatus XN_C_DECL xnNodeQuerySetExistingNodeOnly	(	XnNodeQuery *	pQuery,
		XnBool	bExistingNode
	)

Filter results so that only existing nodes will be returned.

Parameters:

pQuery	[in] Query object.
bExistingNode	[in] TRUE to return only existing ones, FALSE otherwise.

XN_C_API XnStatus XN_C_DECL xnNodeQuerySetMaxVersion	(	XnNodeQuery *	pQuery,
		const XnVersion *	pMaxVersion
	)

Sets the maximum required version.

Parameters:

pQuery	[in] Query object.
pMaxVersion	[in] Max Version.

XN_C_API XnStatus XN_C_DECL xnNodeQuerySetMinVersion	(	XnNodeQuery *	pQuery,
		const XnVersion *	pMinVersion
	)

Sets the minimum required version.

Parameters:

pQuery	[in] Query object.
pMinVersion	[in] Min Version.

XN_C_API XnStatus XN_C_DECL xnNodeQuerySetName	(	XnNodeQuery *	pQuery,
		const XnChar *	strName
	)

Sets the requested name.

Parameters:

pQuery	[in] Query object.
strName	[in] Product Name.

XN_C_API XnStatus XN_C_DECL xnNodeQuerySetNonExistingNodeOnly	(	XnNodeQuery *	pQuery,
		XnBool	bNonExistingNode
	)

Filter results so that only non-existing nodes will be returned.

Parameters:

pQuery	[in] Query object.
bNonExistingNode	[in] TRUE to return only non-existing ones, FALSE otherwise.

XN_C_API XnStatus XN_C_DECL xnNodeQuerySetSupportedMinUserPositions	(	XnNodeQuery *	pQuery,
		const XnUInt32	nCount
	)

Sets the minimum required user positions this node supports. Note that for checking if a capability is supported, the node must be created (if it's not an existing one). This operation might take a bit longer...

Parameters:

pQuery	[in] Query object.
nCount	[in] The number of required positions.

XN_C_API XnStatus XN_C_DECL xnNodeQuerySetVendor	(	XnNodeQuery *	pQuery,
		const XnChar *	strVendor
	)

Sets the requested vendor.

Parameters:

pQuery	[in] Query object.
strVendor	[in] Vendor Name.