geom2d Namespace Reference

Simple 2D geometry. More...

Classes
class	Point
class	Rect
class	PolarPoint
class	Line
Functions
bool	circleCircleIntersection (double a1, double b1, double r1, double a2, double b2, double r2, double &px, double &py, double &qx, double &qy)
double	dist (const Line &l, const Point &p)
	perpendicular distance from a point to an (infinite) line
Point	closestPointOnLine (const Line &line, const Point &point)
	Returns the closest point to 'point' that lies on 'line'.
bool	lineLineIntersection (const Line &l1, const Line &l2, Point &p)
void	convertToRhoAlpha (const Line &line, double &rho, double &alpha)
double	rho (const Line &line)
double	alpha (const Line &line)
double	dist (const Point &p1, const Point &p2)
	Distance between points.
double	dist (const PolarPoint &p1, const PolarPoint &p2)
	Distance between points.
double	distSq (const Point &p1, const Point &p2)
	Squared distance between points.
double	distSq (const PolarPoint &p1, const PolarPoint &p2)
	Squared distance between points.
bool	operator== (const Point &p1, const Point &p2)
	equality
bool	operator!= (const Point &p1, const Point &p2)
	equality
void	rotate (Point &p, double theta)
	Rotate points about the origin.
void	rotate (const Point &p, double theta, Point &q)
	Rotate points about the origin.
void	addTransform (Point &p, double x, double y, double theta)
void	addTransform (const Point &p, double x, double y, double theta, Point &tp)
void	subtractTransform (Point &p, double x, double y, double theta)
void	subtractTransform (const Point &p, double x, double y, double theta, Point &tp)
bool	circleCircleIntersection (const Point &c1, double r1, const Point &c2, double r2, Point &p, Point &q)
	Convenience function. Circle centres are c1 and c2.
double	dotProduct (double v1[2], double v2[2])
	Dot-product of two 2D vectors.
Point	closestPointToOrigin (const Line &l)
	Returns the point on the line that's closest to the origin.

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Detailed Description

Simple 2D geometry.

This is a small library for simple 2D geometry.

See also:

libHydroGeom2d

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Function Documentation

void geom2d::addTransform	(	const Point &	p,
		double	x,
		double	y,
		double	theta,
		Point &	tp
	)			[inline]

add a transformation (x,y,theta) to a point (rotate then translate)

References rotate().

void geom2d::addTransform	(	Point &	p,
		double	x,
		double	y,
		double	theta
	)			[inline]

add a transformation (x,y,theta) to a point (rotate then translate)

References rotate().

SOEXPORT double geom2d::alpha

(

const Line &

line

)

Polar coords: (rho,alpha) is the length and angle of a perpendicular bisector from the origin.

SOEXPORT bool geom2d::circleCircleIntersection	(	double	a1,
		double	b1,
		double	r1,
		double	a2,
		double	b2,
		double	r2,
		double &	px,
		double &	py,
		double &	qx,
		double &	qy
	)

Find the intersection points of two circles. Returns false if they don't meet. Returns true if they do (and possibly a repeated intersection point if they meet at one point).

Circle equation for centre=(a,b), radius=r is: (x-a)^2 + (y-b)^2 = r^2

Throws exceptions (std::string) for problems such as negative radius or co-incident circles.

Referenced by circleCircleIntersection().

SOEXPORT void geom2d::convertToRhoAlpha	(	const Line &	line,
		double &	rho,
		double &	alpha
	)

Polar coords: (rho,alpha) is the length and angle of a perpendicular bisector from the origin.

SOEXPORT bool geom2d::lineLineIntersection	(	const Line &	l1,
		const Line &	l2,
		Point &	p
	)

Intersection between two lines. Returns false if the lines don't intersect.

SOEXPORT double geom2d::rho

(

const Line &

line

)

Polar coords: (rho,alpha) is the length and angle of a perpendicular bisector from the origin.

void geom2d::subtractTransform	(	const Point &	p,
		double	x,
		double	y,
		double	theta,
		Point &	tp
	)			[inline]

subtract a transformation (x,y,theta) from a point (translate then rotate)

References rotate().

void geom2d::subtractTransform	(	Point &	p,
		double	x,
		double	y,
		double	theta
	)			[inline]

subtract a transformation (x,y,theta) from a point (translate then rotate)

References rotate().