DtExtent Class Reference

The DtExtent represents an axis-aligned 3d bounding box. More...

Public Member Functions
	DtExtent ()
	Constructs an empty or undefined instance.
	DtExtent (const DtExtent &orig)
	DtExtent (const double minX, const double maxX, const double minY, const double maxY, const double minZ, const double maxZ)
	Set the extent explicitly.
	DtExtent (const DtPoint &p0, const DtPoint &p1)
	Construct the minimal extent that includes both p0 and p1.
	DtExtent (const DtChord &lineSeg)
	Construct the minimal extent that includes the chord.
virtual	~DtExtent ()
DtExtent &	operator= (const DtExtent &orig)
virtual bool	operator== (const DtExtent &rhs) const
virtual bool	operator!= (const DtExtent &rhs) const
virtual const DtPoint	center () const
	Compute the center point.
virtual void	setCenter (const DtPoint &p)
	Move the origin, while retaining the dimensions of the box.
virtual void	setFromCenter (const DtPoint &p, const double &xDist, const double &yDist, const double &zDist)
	Set the extents with the dimensions listed, centered around the point.
virtual DtPoint	maxPoint () const
	Return the maximum xyz coordinate of the bounding box.
virtual DtPoint	minPoint () const
	Return the minimum xyz coordinate of the bounding box.
bool	empty () const
	Returns true if the exent is undefined.
virtual void	expandToInclude (const DtExtent &otherExtent)
	Expand extent, if necessary, to include input extent.
virtual void	expandToInclude (const DtPoint &point)
	Expand extent, if necessary, to include input point.
virtual bool	contains (const DtExtent &otherExtent) const
	Determine if another extents box is entirely contained by this one.
virtual bool	contains (const DtPoint &point) const
	Determine if a point is contained in the extent.
virtual bool	contains (const DtChord &chord) const
	Determine if a chord is contained in the extent.
bool	intersects (const DtExtent &otherExtent) const
	Determine if the two extents overlap (either partially or fully).
bool	doesNotIntersect (const DtExtent &otherExtent) const
	Determine if the two extents are entirely disjoint.
bool	intersects (const DtSphere &sphere) const
	Determine if the extent of the sphere intersects with the extent.
double	minX () const
	Access and/or mutate individual values.
double	minY () const
	Access and/or mutate individual values.
double	minZ () const
	Access and/or mutate individual values.
double	maxX () const
	Access and/or mutate individual values.
double	maxY () const
	Access and/or mutate individual values.
double	maxZ () const
	Access and/or mutate individual values.
void	setMinX (double x)
	Access and/or mutate individual values.
void	setMinY (double y)
	Access and/or mutate individual values.
void	setMinZ (double z)
	Access and/or mutate individual values.
void	setMaxX (double x)
	Access and/or mutate individual values.
void	setMaxY (double y)
	Access and/or mutate individual values.
void	setMaxZ (double z)
	Access and/or mutate individual values.
double	xSize () const
	Return the size of the bounding box along the axis.
double	ySize () const
	Return the size of the bounding box along the axis.
double	zSize () const
	Return the size of the bounding box along the axis.

Static Public Member Functions
static DtExtent &	nullExtent ()
	Return an invalid or empty extent, using the default constructor.

Protected Member Functions
bool	intersectsLineOfChord (const DtChord &chord, double &distInChordLengthsFirst, double &distInChordLengthsLast) const
	Determines if the infinite line of which chord is a part intersects the extent.
bool	intersectsSoFar (const double pointVal, const double rayVal, const double side0, const double side1, double &firstTime, double &lastTime) const
	The following is an ancillary routine to update the intersection times for a chord.
void	guaranteeValidConstruction ()
	Non-virtual since called from constructors Will flip values to ensure left < right etc.

Protected Attributes
double	myMinX
double	myMaxX
double	myMinY
double	myMaxY
double	myMinZ
double	myMaxZ

Detailed Description

The DtExtent represents an axis-aligned 3d bounding box.

Extents are often used to identify terrain. They are very similar to bounding volumes (just a box offset from an origin), but they are used differently, hence the separate class with a different internal representation.

Extents are not guaranteed to be consistent (xMin <= xMax etc.), for historical reasons. The main reason is to use this inconsistent state to indicate that the extent is undefined. There are several ways to create an inconsistent, or empty extent:

1. Call the default constructor
2. Call the constructor which takes 6 doubles.
3. Set an individual value erroneously.

Note, degenerate extents (where min == max) are not considered empty. Note, constructors that take pairs of points or a chord etc. will ensure that the extent is valid.

Constructor & Destructor Documentation

DtExtent::DtExtent

(

)

Constructs an empty or undefined instance.

Min > Max, predominantly for historical reasons. empty() will return true when the extent is in this state.

DtExtent::DtExtent

(

const DtExtent &

orig

)

DtExtent::DtExtent	(	const double	minX,
		const double	maxX,
		const double	minY,
		const double	maxY,
		const double	minZ,
		const double	maxZ
	)

Set the extent explicitly.

The extent may be valid or inconsistent depending on the argument values.

DtExtent::DtExtent	(	const DtPoint &	p0,
		const DtPoint &	p1
	)

Construct the minimal extent that includes both p0 and p1.

When the line segment (p0,p1) is parallel to any of the axes, a degenerate extent results.

DtExtent::DtExtent

(

const DtChord &

lineSeg

)

Construct the minimal extent that includes the chord.

If the chord is parallel to any of the axes, a degenerate extent results.

virtual DtExtent::~DtExtent ( )

virtual

Member Function Documentation

DtExtent& DtExtent::operator=

(

const DtExtent &

orig

)

virtual bool DtExtent::operator== ( const DtExtent &  rhs ) const

virtual

virtual bool DtExtent::operator!= ( const DtExtent &  rhs ) const

virtual

double DtExtent::minX

(

)

const

Access and/or mutate individual values.

Referenced by DtOctreeNode< DtVrfObject >::addMemberToChild(), and DtOctreeNode< DtVrfObject >::intersectionMask().

double DtExtent::minY

(

)

const

Access and/or mutate individual values.

Referenced by DtOctreeNode< DtVrfObject >::addMemberToChild(), and DtOctreeNode< DtVrfObject >::intersectionMask().

double DtExtent::minZ

(

)

const

Access and/or mutate individual values.

Referenced by DtOctreeNode< DtVrfObject >::addMemberToChild(), DtOctreeNode< DtVrfObject >::intersectionMask(), DtBaseTriangle::minZ(), and DtBasePolygon::minZ().

double DtExtent::maxX

(

)

const

Access and/or mutate individual values.

Referenced by DtOctreeNode< DtVrfObject >::addMemberToChild(), and DtOctreeNode< DtVrfObject >::intersectionMask().

double DtExtent::maxY

(

)

const

Access and/or mutate individual values.

Referenced by DtOctreeNode< DtVrfObject >::addMemberToChild(), and DtOctreeNode< DtVrfObject >::intersectionMask().

double DtExtent::maxZ

(

)

const

Access and/or mutate individual values.

Referenced by DtOctreeNode< DtVrfObject >::addMemberToChild(), DtOctreeNode< DtVrfObject >::intersectionMask(), DtBaseTriangle::maxZ(), and DtBasePolygon::maxZ().

void DtExtent::setMinX

(

double

x

)

Access and/or mutate individual values.

void DtExtent::setMinY

(

double

y

)

Access and/or mutate individual values.

void DtExtent::setMinZ

(

double

z

)

Access and/or mutate individual values.

void DtExtent::setMaxX

(

double

x

)

Access and/or mutate individual values.

void DtExtent::setMaxY

(

double

y

)

Access and/or mutate individual values.

void DtExtent::setMaxZ

(

double

z

)

Access and/or mutate individual values.

virtual const DtPoint DtExtent::center ( ) const

virtual

Compute the center point.

virtual void DtExtent::setCenter ( const DtPoint &  p )

virtual

Move the origin, while retaining the dimensions of the box.

virtual void DtExtent::setFromCenter ( const DtPoint &  p, const double &  xDist, const double &  yDist, const double &  zDist  )

virtual

Set the extents with the dimensions listed, centered around the point.

double DtExtent::xSize

(

)

const

Return the size of the bounding box along the axis.

double DtExtent::ySize

(

)

const

Return the size of the bounding box along the axis.

double DtExtent::zSize

(

)

const

Return the size of the bounding box along the axis.

virtual DtPoint DtExtent::maxPoint ( ) const

virtual

Return the maximum xyz coordinate of the bounding box.

virtual DtPoint DtExtent::minPoint ( ) const

virtual

Return the minimum xyz coordinate of the bounding box.

bool DtExtent::empty

(

)

const

Returns true if the exent is undefined.

This can happen if the default constructor was called, or if min/max values were explicitly set inconsistently.

virtual void DtExtent::expandToInclude ( const DtExtent &  otherExtent )

virtual

Expand extent, if necessary, to include input extent.

Referenced by DtChordBundle::addToEnd(), and DtTriangleIndirect::extent().

virtual void DtExtent::expandToInclude ( const DtPoint &  point )

virtual

Expand extent, if necessary, to include input point.

virtual bool DtExtent::contains ( const DtExtent &  otherExtent ) const

virtual

Determine if another extents box is entirely contained by this one.

On the border counts as "contained".

Referenced by DtOctreeNode< DtVrfObject >::addMember().

virtual bool DtExtent::contains ( const DtPoint &  point ) const

virtual

Determine if a point is contained in the extent.

On the border counts as "contained".

virtual bool DtExtent::contains ( const DtChord &  chord ) const

virtual

Determine if a chord is contained in the extent.

On the border counts as "contained".

bool DtExtent::intersects

(

const DtExtent &

otherExtent

)

const

Determine if the two extents overlap (either partially or fully).

A shared "wall" counts as intersecting.

bool DtExtent::doesNotIntersect

(

const DtExtent &

otherExtent

)

const

Determine if the two extents are entirely disjoint.

i.e. they do not intersect at all.

bool DtExtent::intersects

(

const DtSphere &

sphere

)

const

Determine if the extent of the sphere intersects with the extent.

bool DtExtent::intersectsLineOfChord ( const DtChord &  chord, double &  distInChordLengthsFirst, double &  distInChordLengthsLast  ) const

protected

Determines if the infinite line of which chord is a part intersects the extent.

Returns the t-values corresponding to the intersection points in distInChordLengthsFirst, and distInChordLengthsLast, such that distInChordLengthsFirst <= distInChordLengthsLast.

bool DtExtent::intersectsSoFar ( const double  pointVal, const double  rayVal, const double  side0, const double  side1, double &  firstTime, double &  lastTime  ) const

protected

The following is an ancillary routine to update the intersection times for a chord.

What is passed in are single-axis coordinates of a point and a ray (x, y, or z coordinates), and the corresponding values for opposite faces of the extent–side0 and side1. Must have side1>side0, always. The distance in chord lengths to the first and last encounter with the bounding volume so far are passed in as scalars firstTime and lastTime. If there is no intersection, the routine returns false. Otherwise (there is an intersection), the routine returns true and returns the updated distance in chord lengths to the first and last encounter with the bounding volume so far.

void DtExtent::guaranteeValidConstruction ( )

protected

Non-virtual since called from constructors Will flip values to ensure left < right etc.

static DtExtent& DtExtent::nullExtent ( )

static

Return an invalid or empty extent, using the default constructor.

Member Data Documentation

double DtExtent::myMinX

protected

double DtExtent::myMaxX

protected

double DtExtent::myMinY

protected

double DtExtent::myMaxY

protected

double DtExtent::myMinZ

protected

double DtExtent::myMaxZ

protected

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

• include/geometry/tdbextent.h