ON_Triangle Class Reference

#include <opennurbs_line.h>

Public Member Functions
	ON_Triangle ()=default
	Default constructor is uninitialized. More...
	ON_Triangle (const double vertices[9])
	ON_Triangle (const ON_3dPoint &a, const ON_3dPoint &b, const ON_3dPoint &c)
	ON_Triangle (const ON_3dPoint vertices[3])
	ON_Triangle (const ON_Triangle &tri)=default
	ON_Triangle (double x)
	Allows Triangle(0.0) ZeroTriangle. More...
	~ON_Triangle ()=default
double	Area () const
ON_BoundingBox	BoundingBox () const
ON_3dPoint	Centroid () const
ON_3dPoint	ClosestPointTo (const ON_3dPoint &test_point) const
bool	ClosestPointTo (const ON_3dPoint &test_point, double *s1, double *s2) const
void	Create (const ON_3dPoint &a, const ON_3dPoint &b, const ON_3dPoint &c)
void	Create (const ON_3dPoint vertices[3])
double	DistanceTo (const ON_3dPoint &test_point) const
ON_Line	Edge (int i) const
void	Flip (unsigned char edge=0)
bool	GetBarycentricCoordinates (const ON_3dPoint &test_point, bool constrainInside, double *s1, double *s2) const
bool	GetBoundingBox (ON_BoundingBox &bbox, int bGrowBox=false) const
bool	GetTightBoundingBox (ON_BoundingBox &tight_bbox, bool bGrowBox=false, const ON_Xform *xform=nullptr) const
bool	IsDegenerate (double tol=ON_ZERO_TOLERANCE) const
bool	IsValid () const
unsigned char	LongestEdge () const
ON_3dVector	Normal () const
	operator const ON_3dPoint * () const
	operator ON_3dPoint * ()
ON_Triangle &	operator= (const ON_Triangle &tri)=default
ON_3dPoint &	operator[] (int)
	Triangle[i] = Triangle.m_V[i]. More...
const ON_3dPoint &	operator[] (int) const
ON_PlaneEquation	PlaneEquation () const
ON_3dPoint	PointAt (double s1, double s2) const
void	Reverse (int i)
bool	Rotate (double angle_in_radians, const ON_3dVector &axis_of_rotation, const ON_3dPoint &center_of_rotation)
bool	Rotate (double sin_angle, double cos_angle, const ON_3dVector &axis_of_rotation, const ON_3dPoint &center_of_rotation)
	rotate line about a point and axis More...
unsigned char	ShortestEdge () const
void	Spin (unsigned char move)
void	Split (unsigned char edge, ON_3dPoint pt, ON_Triangle &out_a, ON_Triangle &out_b) const
bool	Transform (const ON_Xform &xform)
bool	Translate (const ON_3dVector &delta)
ON_3dVector	UnitNormal () const

Public Attributes
ON_3dPoint	m_V [3]
	vertices More...

Static Public Attributes
static const ON_Triangle	NanTriangle
	{ON_3dPoint::NanPoint, ON_3dPoint::NanPoint, ON_3dPoint::NanPoint} More...
static const ON_Triangle	UnsetTriangle
	{ON_3dPoint::UnsetPoint, ON_3dPoint::UnsetPoint, ON_3dPoint::UnsetPoint} More...
static const ON_Triangle	ZeroTriangle
	{ON_3dPoint::Origin, ON_3dPoint::Origin, ON_3dPoint::Origin} More...

Constructor & Destructor Documentation

ON_Triangle() [1/6]

ON_Triangle::ON_Triangle ( )

default

Default constructor is uninitialized.

ON_Triangle() [2/6]

ON_Triangle::ON_Triangle

(

const ON_3dPoint

vertices[3]

)

ON_Triangle() [3/6]

ON_Triangle::ON_Triangle	(	const ON_3dPoint &	a,
		const ON_3dPoint &	b,
		const ON_3dPoint &	c
	)

ON_Triangle() [4/6]

ON_Triangle::ON_Triangle

(

double

x

)

Allows Triangle(0.0) ZeroTriangle.

ON_Triangle() [5/6]

ON_Triangle::ON_Triangle

(

const double

vertices[9]

)

ON_Triangle() [6/6]

ON_Triangle::ON_Triangle ( const ON_Triangle &  tri )

default

~ON_Triangle()

ON_Triangle::~ON_Triangle ( )

default

Member Function Documentation

Area()

double ON_Triangle::Area

(

)

const

Returns: Area of triangle

BoundingBox()

ON_BoundingBox ON_Triangle::BoundingBox

(

)

const

Description: Get Triangles 3d axis aligned bounding box. Returns: 3d bounding box.

Centroid()

ON_3dPoint ON_Triangle::Centroid

(

)

const

Returns: Evaluation of PointAt(1/3.0, 1/3.0);

ClosestPointTo() [1/2]

ON_3dPoint ON_Triangle::ClosestPointTo

(

const ON_3dPoint &

test_point

)

const

Description: Find the point on the triangle that is closest to the test_point. Parameters: test_point - [in] Returns: The point on the line that is closest to test_point.

ClosestPointTo() [2/2]

bool ON_Triangle::ClosestPointTo	(	const ON_3dPoint &	test_point,
		double *	s1,
		double *	s2
	)		const

Description: Find the point on the triangle that is closest to the test_point. Parameters: test_point - [in] s1, s2 - [out] PointAt( *s1, *s2) is the point on the triangle closest to test_point. Returns: true if successful.

Create() [1/2]

void ON_Triangle::Create	(	const ON_3dPoint &	a,
		const ON_3dPoint &	b,
		const ON_3dPoint &	c
	)

Description: Create a Triangle from three points. Parameters: a,b,c - [in] vertices

Create() [2/2]

void ON_Triangle::Create

(

const ON_3dPoint

vertices[3]

)

Description: Create a Triangle from three points. Parameters: vertices - [in] vertices

DistanceTo()

double ON_Triangle::DistanceTo

(

const ON_3dPoint &

test_point

)

const

Description: Find the point on the triangle that is closest to the test_point. Parameters: test_point -[in] Returns: distance from the point on triangle that is closest to test_point. See Also: ON_3dPoint::DistanceTo ON_Line::ClosestPointTo

Edge()

ON_Line ON_Triangle::Edge

(

int

i

)

const

Returns: Edge opposite m_V[i] Specifically, ON_Line( m_V[(i+1)%3 ], m_V[(i+2)%3 ] )

Flip()

void ON_Triangle::Flip

(

unsigned char

edge = 0

)

Description: Flip the normal of the triangle, by swapping the points of an edge. Parameters: edge - [in] The edge, as defined in the Edge() method. I.e., edge 0 swaps m_V[1] and m_V[2]

GetBarycentricCoordinates()

bool ON_Triangle::GetBarycentricCoordinates	(	const ON_3dPoint &	test_point,
		bool	constrainInside,
		double *	s1,
		double *	s2
	)		const

Description: Find the point that is closest to the test_point. Parameters: test_point - [in] constrainInside[in] - if true, variable are inside triangle s1, s2 - [out] PointAt( *s1, *s2) is the point on the triangle closest to test_point.

Returns: true if successful.

GetBoundingBox()

bool ON_Triangle::GetBoundingBox	(	ON_BoundingBox &	bbox,
		int	bGrowBox = false
	)		const

Description: Get line's 3d axis aligned bounding box or the union of the input box with the object's bounding box. Parameters: bbox - [in/out] 3d axis aligned bounding box bGrowBox - [in] (default=false) If true, then the union of the input bbox and the object's bounding box is returned in bbox. If false, the object's bounding box is returned in bbox. Returns: true if object has bounding box and calculation was successful.

GetTightBoundingBox()

bool ON_Triangle::GetTightBoundingBox	(	ON_BoundingBox &	tight_bbox,
		bool	bGrowBox = false,
		const ON_Xform *	xform = nullptr
	)		const

Description: Get tight bounding box with respect to a given frame Parameters: tight_bbox - [in/out] tight bounding box bGrowBox -[in] (default=false) If true and the input tight_bbox is valid, then returned tight_bbox is the union of the input tight_bbox and the line's tight bounding box. xform -[in] (default=nullptr) If not nullptr, the tight bounding box of the transformed triangle is calculated. The triangle is not modified. Returns: True if a valid tight_bbox is returned.

IsDegenerate()

bool ON_Triangle::IsDegenerate

(

double

tol = ON_ZERO_TOLERANCE

)

const

Returns: true if Area()< tol Note: Recall Area = .5* base * height. So this degeneracy tests for a combination long enough and high enough. See Also: ON_Triangle::Area()

IsValid()

bool ON_Triangle::IsValid

(

)

const

Returns: True if m_V[i].IsValid() for all i

LongestEdge()

unsigned char ON_Triangle::LongestEdge

(

)

const

Returns: Index of edge opposite to m_V[i] that is longest. When lengths are equal, lowest index has priority.

Normal()

ON_3dVector ON_Triangle::Normal

(

)

const

Returns: N = ( b-a) X ( c-a) where a,b,c are the vertices See Also: ON_Triangle UnitNormal()

operator const ON_3dPoint *()

ON_Triangle::operator const ON_3dPoint *

(

)

const

operator ON_3dPoint *()

ON_Triangle::operator ON_3dPoint *

(

)

operator=()

ON_Triangle& ON_Triangle::operator= ( const ON_Triangle &  tri )

default

operator[]() [1/2]

ON_3dPoint& ON_Triangle::operator[]

(

int

)

Triangle[i] = Triangle.m_V[i].

operator[]() [2/2]

const ON_3dPoint& ON_Triangle::operator[]

(

int

)

const

PlaneEquation()

ON_PlaneEquation ON_Triangle::PlaneEquation

(

)

const

Returns: Plane containing Triangle with normal given by UnitNormal(). Notes: Ensure !IsDegenerate() to guarantee meaningful result

PointAt()

ON_3dPoint ON_Triangle::PointAt	(	double	s1,
		double	s2
	)		const

Description: Evaluate point on triangle. Parameters: s1, s2 - [in] evaluation parameter. Returns: (1-s1-s2)* m_V[0] + s1*m_V[1] + s2*m_V[2] Notes: Point is in the triangle iff s1>=0, s2>=0 and s1 + s2<=1. Other values produce points on the plane of the triangle.

Reverse()

void ON_Triangle::Reverse

(

int

i

)

Description: Reverse endpoints of Edge[i].

Rotate() [1/2]

bool ON_Triangle::Rotate	(	double	angle_in_radians,
		const ON_3dVector &	axis_of_rotation,
		const ON_3dPoint &	center_of_rotation
	)

Rotate() [2/2]

bool ON_Triangle::Rotate	(	double	sin_angle,
		double	cos_angle,
		const ON_3dVector &	axis_of_rotation,
		const ON_3dPoint &	center_of_rotation
	)

rotate line about a point and axis

ShortestEdge()

unsigned char ON_Triangle::ShortestEdge

(

)

const

Returns: Index of edge opposite to m_V[i] that is shortest. When lengths are equal, lowest index has priority.

Spin()

void ON_Triangle::Spin

(

unsigned char

move

)

Description: Circle the order of points in the triangle, without any influence to any geometric property. Parameters: move - [in] Amounts of rotations in the order of the three points. By means of examples, "move" of 1 will move m_V[0] to m_V[1], m_V[1] to m_V[2] and m_V[2] to m_V[0].

Split()

void ON_Triangle::Split	(	unsigned char	edge,
		ON_3dPoint	pt,
		ON_Triangle &	out_a,
		ON_Triangle &	out_b
	)		const

Description: Split the triangles into two, by choosing an edge and a new point that will appear along the edge. Parameters: edge - [in] Edge index as defined in Edge() pt - [in] Point to add as splitter along edge out_a - [out] First triangle out_b - [out] Second triangle

Transform()

bool ON_Triangle::Transform

(

const ON_Xform &

xform

)

Translate()

bool ON_Triangle::Translate

(

const ON_3dVector &

delta

)

UnitNormal()

ON_3dVector ON_Triangle::UnitNormal

(

)

const

Returns: Normal().Unitize() Notes: Ensure !IsDegenerate() to guarantee that UnitNormal().Length()==1 and the result is not just a bunch of noise. Can return zero vector in some degenerate cases.

Member Data Documentation

m_V

ON_3dPoint ON_Triangle::m_V[3]

vertices

NanTriangle

const ON_Triangle ON_Triangle::NanTriangle

static

{ON_3dPoint::NanPoint, ON_3dPoint::NanPoint, ON_3dPoint::NanPoint}

UnsetTriangle

const ON_Triangle ON_Triangle::UnsetTriangle

static

{ON_3dPoint::UnsetPoint, ON_3dPoint::UnsetPoint, ON_3dPoint::UnsetPoint}

ZeroTriangle

const ON_Triangle ON_Triangle::ZeroTriangle

static

{ON_3dPoint::Origin, ON_3dPoint::Origin, ON_3dPoint::Origin}