NLMISC::CPolygon2D Class Reference

A 2d convex polygon. More...

#include <polygon.h>

Public Types
typedef std::vector< CVector2f >	TVec2fVect
typedef std::pair< sint, sint >	TRaster
typedef std::vector< TRaster >	TRasterVect
Public Member Functions
	CPolygon2D ()
	default ctor
void	swap (CPolygon2D &other)
	CPolygon2D (const CPolygon &src, const CMatrix &projMat=CMatrix::Identity)
	Build a 2D polygon from this 3D polygon, by using the given projection matrix The x and y components of projected vertices are used to create the 2D polygon.
void	fromPolygon (const CPolygon &src, const CMatrix &projMat=CMatrix::Identity)
	Reinit a 2D polygon from this 3D polygon, by using the given projection matrix The x and y components of projected vertices are used to create the 2D polygon.
	CPolygon2D (const CTriangle &tri, const CMatrix &projMat=CMatrix::Identity)
	Build a 2D polygon from the given triangle, by using the given projection matrix The x and y components of projected vertices are used to create the 2D polygon.
bool	isConvex ()
	Check whether this polygon is convex;.
void	buildConvexHull (CPolygon2D &dest) const
	Build a convex hull from this polygon.
void	getBestTriplet (uint &index0, uint &index1, uint &index2)
	get the best triplet of vector. e.g the triplet that has the best surface
void	serial (NLMISC::IStream &f) throw (NLMISC::EStream)
	Serial this polygon.
void	computeBorders (TRasterVect &borders, sint &minimumY) const
	Compute the borders of this poly with sub-pixel accuracy.
void	computeOuterBorders (TRasterVect &borders, sint &minimumY) const
	The same as compute borders, but pixel are seen as surfaces and not as points.
void	computeInnerBorders (TRasterVect &borders, sint &minimumY) const
	The same as compute borders, but pixel are seen as surfaces and not as points In this version, only pixels that are entirely INSIDE the poly are kept IMPORTANT: coordinates must be in the -32000, 32000 range.
bool	intersect (const CPolygon2D &other) const
	Test whether this polygon intersect another convex polygon. Currently not optimized.
bool	contains (const CVector2f &p, bool hintIsConvex=true) const
	Check whether a point is contained by this poly.
bool	getNonNullSeg (uint &seg) const
	Get the index of a segment of this poly that is a non null segment.
void	getLineEquation (uint index, float &a, float &b, float &c) const
	Get a line equation of the seg starting at the given index.
bool	isCCWOriented () const
void	getBoundingRect (CVector2f &minCorner, CVector2f &maxCorner) const
bool	selfIntersect () const
Public Attributes
TVec2fVect	Vertices
Private Member Functions
float	sumDPAgainstLine (float a, float b, float c) const
	Sum the dot product of this poly vertices against a line equation ax + by + c.
const CVector2f &	getSegRef0 (uint index) const
	Get ref to the first vertex that start at index.
const CVector2f &	getSegRef1 (uint index) const
void	checkValidBorders () const

Detailed Description

A 2d convex polygon.

Definition at line 125 of file polygon.h.

Member Typedef Documentation

typedef std::pair<sint, sint> NLMISC::CPolygon2D::TRaster

Definition at line 167 of file polygon.h.

typedef std::vector<TRaster> NLMISC::CPolygon2D::TRasterVect

Definition at line 168 of file polygon.h.

typedef std::vector<CVector2f> NLMISC::CPolygon2D::TVec2fVect

Definition at line 128 of file polygon.h.

Constructor & Destructor Documentation

NLMISC::CPolygon2D::CPolygon2D ( ) [inline]

default ctor

Definition at line 132 of file polygon.h.

NLMISC::CPolygon2D::CPolygon2D	(	const CPolygon &	src,
		const CMatrix &	projMat = `CMatrix::Identity`
	)

Build a 2D polygon from this 3D polygon, by using the given projection matrix The x and y components of projected vertices are used to create the 2D polygon.

Definition at line 839 of file polygon.cpp.

References fromPolygon().

NLMISC::CPolygon2D::CPolygon2D	(	const CTriangle &	tri,
		const CMatrix &	projMat = `CMatrix::Identity`
	)

Build a 2D polygon from the given triangle, by using the given projection matrix The x and y components of projected vertices are used to create the 2D polygon.

Definition at line 2159 of file polygon.cpp.

References NLMISC::CTriangle::V0, NLMISC::CTriangle::V1, NLMISC::CTriangle::V2, and Vertices.

Member Function Documentation

void NLMISC::CPolygon2D::buildConvexHull ( CPolygon2D & dest ) const

Build a convex hull from this polygon.

The result poly is ordered, so it can also be used to order a convex poly given its set of vertices. NB: require this != &dest

Definition at line 895 of file polygon.cpp.

References NLMISC::n, nlassert, Vertices, and NLMISC::CVector2f::y.

void NLMISC::CPolygon2D::checkValidBorders ( ) const [private]

Definition at line 1978 of file polygon.cpp.

References nlassert, and Vertices.

Referenced by computeBorders(), computeInnerBorders(), and computeOuterBorders().

void NLMISC::CPolygon2D::computeBorders	(	TRasterVect &	borders,
		sint &	minimumY
	)			const

Compute the borders of this poly with sub-pixel accuracy.

No clipping is performed. Only points exactly inside or exactly on the left border of the polygon are kept. This means that pixels are seen as points, not as surfaces. The output is in a vector of sint pairs. minimumY is filled with the minimum y value of the poly. Each pairs gives [xmin, xmax] for the current segment. if xmin > xmax, then no point is valid for this segment. Otherwise, all points from x = xmin (included) to x = xmax (included) are valid. IMPORTANT: coordinates must be in the -32000, 32000 range. This is checked in debug

check poly height, and discard null height

Definition at line 1201 of file polygon.cpp.

References checkValidBorders(), NLMISC::Next(), NLMISC::Prev(), NLMISC::ScanEdge(), swap(), and Vertices.

Referenced by NL3D::CLodCharacterShapeBuild::compile(), and RenderTriangle().

void NLMISC::CPolygon2D::computeInnerBorders	(	TRasterVect &	borders,
		sint &	minimumY
	)			const

The same as compute borders, but pixel are seen as surfaces and not as points In this version, only pixels that are entirely INSIDE the poly are kept IMPORTANT: coordinates must be in the -32000, 32000 range.

This is checked in debug

Definition at line 1792 of file polygon.cpp.

References checkValidBorders(), min, NLMISC::ScanInnerEdge(), swap(), Vertices, NLMISC::CVector2f::x, and NLMISC::CVector2f::y.

Referenced by NL3D::CWaterModel::getNumWantedVertices().

void NLMISC::CPolygon2D::computeOuterBorders	(	TRasterVect &	borders,
		sint &	minimumY
	)			const

The same as compute borders, but pixel are seen as surfaces and not as points.

Any pixel that is touched by the poly will be selected IMPORTANT: coordinates must be in the -32000, 32000 range. This is checked in debug

Definition at line 1501 of file polygon.cpp.

References checkValidBorders(), min, nlassert, NLMISC::ScanOuterEdgeLeft(), NLMISC::ScanOuterEdgeRight(), swap(), Vertices, NLMISC::CVector2f::x, and NLMISC::CVector2f::y.

Referenced by NL3D::addQuadToSilhouette(), NL3D::CPackedZone32::addTri(), NL3D::CPackedZone32::appendSelection(), NL3D::CPackedZone16::appendSelection(), NL3D::CQuadGrid< T >::buildSelectionShape(), NL3D::CWaterModel::getNumWantedVertices(), and NL3D::CPackedWorld::select().

bool NLMISC::CPolygon2D::contains	(	const CVector2f &	p,
		bool	hintIsConvex = `true`
	)			const

Check whether a point is contained by this poly.

contains the seg 2d equation

Definition at line 2090 of file polygon.cpp.

References getLineEquation(), getSegRef0(), getSegRef1(), nlassert, Vertices, NLMISC::CVector2f::x, and NLMISC::CVector2f::y.

Referenced by intersect().

void NLMISC::CPolygon2D::fromPolygon	(	const CPolygon &	src,
		const CMatrix &	projMat = `CMatrix::Identity`
	)

Reinit a 2D polygon from this 3D polygon, by using the given projection matrix The x and y components of projected vertices are used to create the 2D polygon.

Definition at line 845 of file polygon.cpp.

References Vertices, NLMISC::CPolygon::Vertices, NLMISC::CVector::x, and NLMISC::CVector::y.

Referenced by CPolygon2D().