ON_SubDHash Class Reference

ON_SubDHash provides a simple way to save a SubD's vertex, edge, and face SHA1 hashes. Typically it is used when a calculation needs to know if the current SubD has is geometrically identical to a previous SubD. When speed is not important, comparing the current value of ON_SubD::GeometryHash() to a previously save value of ON_SubD::GeometryHash() is functionally identical but typically much slower when the SubDs are different. More...

#include <opennurbs_subd.h>

Public Member Functions
	ON_SubDHash ()=default
	ON_SubDHash (const ON_SubDHash &)=default
	~ON_SubDHash ()=default
void	Dump (ON_TextLog &) const
unsigned int	EdgeCount () const
	Copied from the SubD when the hash is created. More...
const ON_SHA1_Hash	EdgeHash () const
	If two SubDs have identical EdgeHash() values, then the SubD edge information associated with HashType() is identical. More...
unsigned int	FaceCount () const
	Copied from the SubD when the hash is created. More...
const ON_SHA1_Hash	FaceHash () const
	If two SubDs have identical FaceHash() values, then the SubD face information associated with HashType() is identical. More...
ON_SubDHashType	HashType () const
bool	IsEmpty () const
bool	IsNotEmpty () const
ON_SubDHash &	operator= (const ON_SubDHash &)=default
bool	Read (class ON_BinaryArchive &)
ON__UINT64	SubDGeometryContentSerialNumber () const
	The geometry content serial number can be used to quickly determine if a SubD is exactly the instance used to create this ON_SubDHash. If the geometry content serial numbers are equal, then the SubD is identical to the one use to create the hash. If the geometry content serial numbers differ, the current SubD hashes need to be checked against this to see what, if anything, changed. For example, moving a vertex will not change a topology hash. More...
const ON_SHA1_Hash	SubDHash () const
	If two SubDs have identical SubDHash() values, then the SubD vertex, edge, and face information associated with HashType() is identical. More...
ON__UINT64	SubDRuntimeSerialNumber () const
	The runtime serial number can be used to identify the SubD that was hashed to created this ON_SubDHash. More...
unsigned int	VertexCount () const
	Copied from the SubD when the hash is created. More...
const ON_SHA1_Hash	VertexHash () const
	If two SubDs have identical VertexHash() values, then the SubD vertex information associated with HashType() is identical. More...
bool	Write (class ON_BinaryArchive &) const

Static Public Member Functions
static int	Compare (const ON_SubDHash &lhs, const ON_SubDHash &rhs)
	Dictionary compare of VertexCount(), EdgeCount(), FaceCount(), VertexHash(), EdgeHash(), and FaceHash() in that order. More...
static const ON_SubDHash	Create (ON_SubDHashType hash_type, const class ON_SubD &subd)
	Saves the counts and hashes of the specified type. More...
static const ON_SubDHash	Create (ON_SubDHashType hash_type, const class ON_SubDimple *subdimple)

Static Public Attributes
static const ON_SubDHash	Empty
	All counts are zero and all hashes are ON_SHA1::EmptyContentHash. More...

Friends
class	ON_SubDimple

Detailed Description

ON_SubDHash provides a simple way to save a SubD's vertex, edge, and face SHA1 hashes. Typically it is used when a calculation needs to know if the current SubD has is geometrically identical to a previous SubD. When speed is not important, comparing the current value of ON_SubD::GeometryHash() to a previously save value of ON_SubD::GeometryHash() is functionally identical but typically much slower when the SubDs are different.

Constructor & Destructor Documentation

ON_SubDHash() [1/2]

ON_SubDHash::ON_SubDHash ( )

default

~ON_SubDHash()

ON_SubDHash::~ON_SubDHash ( )

default

ON_SubDHash() [2/2]

ON_SubDHash::ON_SubDHash ( const ON_SubDHash &  )

default

Member Function Documentation

Compare()

static int ON_SubDHash::Compare ( const ON_SubDHash &  lhs, const ON_SubDHash &  rhs  )

static

Dictionary compare of VertexCount(), EdgeCount(), FaceCount(), VertexHash(), EdgeHash(), and FaceHash() in that order.

NOTE WELL: SubDRuntimeSerialNumber() and SubdGeometryContentSerialNumber() are not compared because the reason this class exists is for it to be used to see if two different SubDs have identical content.

Parameters

lhs
rhs

Returns

-1: lhs < rhs 0: lhs == rsh 1: lhs > rhs

Create() [1/2]

static const ON_SubDHash ON_SubDHash::Create ( ON_SubDHashType  hash_type, const class ON_SubD &  subd  )

static

Saves the counts and hashes of the specified type.

Saves the counts and hashes of the specified type.

Parameters

hash_type
subd

Returns

Create() [2/2]

static const ON_SubDHash ON_SubDHash::Create ( ON_SubDHashType  hash_type, const class ON_SubDimple *  subdimple  )

static

Dump()

void ON_SubDHash::Dump

(

ON_TextLog &

)

const

EdgeCount()

unsigned int ON_SubDHash::EdgeCount

(

)

const

Copied from the SubD when the hash is created.

Returns

Number of hashed edges.

EdgeHash()

const ON_SHA1_Hash ON_SubDHash::EdgeHash

(

)

const

If two SubDs have identical EdgeHash() values, then the SubD edge information associated with HashType() is identical.

Returns

A SHA1 hash of the SubD's edge information associated with HashType().

FaceCount()

unsigned int ON_SubDHash::FaceCount

(

)

const

Copied from the SubD when the hash is created.

Returns

Number of hashed faces.

FaceHash()

const ON_SHA1_Hash ON_SubDHash::FaceHash

(

)

const

If two SubDs have identical FaceHash() values, then the SubD face information associated with HashType() is identical.

Returns

A SHA1 hash of the SubD's face information associated with HashType().

HashType()

ON_SubDHashType ON_SubDHash::HashType

(

)

const

IsEmpty()

bool ON_SubDHash::IsEmpty

(

)

const

Returns: True if vertex count is 0 or HashType is unset.

IsNotEmpty()

bool ON_SubDHash::IsNotEmpty

(

)

const

Returns: True if vertex count is > 0 and HashType is geometry or toplology.

operator=()

ON_SubDHash& ON_SubDHash::operator= ( const ON_SubDHash &  )

default

Read()

bool ON_SubDHash::Read

(

class ON_BinaryArchive &

)

SubDGeometryContentSerialNumber()

ON__UINT64 ON_SubDHash::SubDGeometryContentSerialNumber

(

)

const

The geometry content serial number can be used to quickly determine if a SubD is exactly the instance used to create this ON_SubDHash. If the geometry content serial numbers are equal, then the SubD is identical to the one use to create the hash. If the geometry content serial numbers differ, the current SubD hashes need to be checked against this to see what, if anything, changed. For example, moving a vertex will not change a topology hash.

Returns

Returns: If this hash was created from an ON_SubD, then the value of subd.GeometryContentSerialNumber() at the at the instant this hash was created is returned. Otherwise, 0 is returned.

SubDHash()

const ON_SHA1_Hash ON_SubDHash::SubDHash

(

)

const

If two SubDs have identical SubDHash() values, then the SubD vertex, edge, and face information associated with HashType() is identical.

Returns

A SHA1 hash of the SubD's vertex, edge, and face information associated with HashType().

SubDRuntimeSerialNumber()

ON__UINT64 ON_SubDHash::SubDRuntimeSerialNumber

(

)

const

The runtime serial number can be used to identify the SubD that was hashed to created this ON_SubDHash.

Returns

If this hash was created from an ON_SubD, then the value of subd.RuntimeSerialNumber() is returned. Otherwise, 0 is returned.

VertexCount()

unsigned int ON_SubDHash::VertexCount

(

)

const

Copied from the SubD when the hash is created.

Returns

Number of hashed vertices.

VertexHash()

const ON_SHA1_Hash ON_SubDHash::VertexHash

(

)

const

If two SubDs have identical VertexHash() values, then the SubD vertex information associated with HashType() is identical.

Returns

A SHA1 hash of the SubD's vertex information associated with HashType().

Write()

bool ON_SubDHash::Write

(

class ON_BinaryArchive &

)

const

Friends And Related Function Documentation

ON_SubDimple

friend class ON_SubDimple

friend

Member Data Documentation

Empty

const ON_SubDHash ON_SubDHash::Empty

static

All counts are zero and all hashes are ON_SHA1::EmptyContentHash.