geometry Namespace Reference

Functions
void	unit_tests ()
float	squareDistanceBetweenPoints (Coordinates A, Coordinates B)
float	squareDistanceBetweenPoints (float x1, float y1, float x2, float y2)
bool	pointInCircumcircleOf (Coordinates p1, Coordinates p2, Coordinates p3, Coordinates p0)
Coordinates	circumcenterOf (Coordinates A, Coordinates B, Coordinates C)
bool	pointInTriangle (Coordinates p1, Coordinates p2, Coordinates p3, Coordinates p0)
float	squareDistanceBetweenSegmentAndPoint (float x1, float x2, float y1, float y2, float px, float py)
bool	parallelLines (Coordinates A, Coordinates B, Coordinates C, Coordinates D)
Coordinates	intersectionOfLines (Coordinates A, Coordinates B, Coordinates C, Coordinates D)
Coordinates	behindIntersectionOfLines (Coordinates A, Coordinates B, Coordinates C, Coordinates D)
bool	collisionBetweenSegmentAndLine (Coordinates O, Coordinates P, Coordinates A, Coordinates B)
bool	collisionBetweenSegmentAndSegment (Coordinates A, Coordinates B, Coordinates C, Coordinates D)
bool	collisionBetweenLineAndCircle (Coordinates A, Coordinates B, Coordinates C, float radius)
bool	pointInsideCircle (Coordinates A, Coordinates C, float radius)
bool	pointOnCircle (Coordinates A, Coordinates C, float radius)
bool	collisionBetweenSegmentAndCircle (Coordinates A, Coordinates B, Coordinates C, float radius)
Coordinates	projectionOfPointOnLine (Coordinates A, Coordinates B, Coordinates C)
unsigned int	intersectionsBetweenLineAndCircle (Coordinates A, Coordinates B, Coordinates C, float square_radius, Coordinates *S1, Coordinates *S2)
unsigned int	intersectionsBetweenSegmentAndCircle (Coordinates A, Coordinates B, Coordinates C, float square_radius, Coordinates *S1, Coordinates *S2)
bool	coeffAndOrdnOfLine (Coordinates A, Coordinates B, float *coef, float *ordn)

Detailed Description

Geometry is a namespace that define lots of useful geometry functions.

Function Documentation

Coordinates geometry::behindIntersectionOfLines	(	Coordinates	A,
		Coordinates	B,
		Coordinates	C,
		Coordinates	D
	)

Parameters

A	Coordinates of a line point
B	Coordinates of another line point
C	Coordinates of a line point
D	Coordinates of another line point

Returns

Coordinates of a point that is behind the intersection of the lines, and on (A;B)

Note

distance between returned point and intersection of lines is equal to EPSILON

returned point is nearer of A than B; difference is about EPSILON lines are not parallel

Coordinates geometry::circumcenterOf	(	Coordinates	A,
		Coordinates	B,
		Coordinates	C
	)

Parameters

A	Coordinates of a point of triangle
B	Coordinates of a point of triangle
C	Coordinates of a point of triangle

Returns

C Coordinates of triangle's circumcenter

bool geometry::coeffAndOrdnOfLine	(	Coordinates	A,
		Coordinates	B,
		float *	coef,
		float *	ordn
	)

Parameters

A	Coordinates of a point on the line
B	Coordinates of another point on the line
coef	ref of float, modified
ordn	ref of float, modified

Returns

false if line is vertical, else true

Warning

if line is vertical, ordn only is modifed and represent the offset in x axis

bool geometry::collisionBetweenLineAndCircle	(	Coordinates	A,
		Coordinates	B,
		Coordinates	C,
		float	radius
	)

Parameters

A	Coordinates of a line point
B	Coordinates of another line point
C	Coordinates of circle's center
radius	of the circle

Returns

true if circle collide with (AB) line

bool geometry::collisionBetweenSegmentAndCircle	(	Coordinates	A,
		Coordinates	B,
		Coordinates	C,
		float	radius
	)

Parameters

A	Coordinates of segment point
B	Coordinates of segment point
C	Coordinates of circle's center
radius	of the circle

Returns

true if circle collide with [AB] segment

bool geometry::collisionBetweenSegmentAndLine	(	Coordinates	O,
		Coordinates	P,
		Coordinates	A,
		Coordinates	B
	)

Parameters

O	Coordinates of a segment point
P	Coordinates of another segment point
A	Coordinates of a line point
B	Coordinates of another line point

Returns

true if [OP] segment cross with (AB) line

0 if [OP] and (AB) don't cross, 1 if ]OP[ cross (AB) or 2 if O or P are on (AB)

bool geometry::collisionBetweenSegmentAndSegment	(	Coordinates	A,
		Coordinates	B,
		Coordinates	C,
		Coordinates	D
	)

Parameters

A	Coordinates of a first segment point
B	Coordinates of another first segment point
C	Coordinates of a second segment point
D	Coordinates of another second segment point

Returns

true if [AB] segment cross with [CD] segment

Coordinates geometry::intersectionOfLines	(	Coordinates	A,
		Coordinates	B,
		Coordinates	C,
		Coordinates	D
	)

Parameters

A	Coordinates of a line point
B	Coordinates of another line point
C	Coordinates of a line point
D	Coordinates of another line point

Returns

Coordinates of intersection of the lines lines are not parallel

unsigned int geometry::intersectionsBetweenLineAndCircle	(	Coordinates	A,
		Coordinates	B,
		Coordinates	C,
		float	square_radius,
		Coordinates *	S1,
		Coordinates *	S2
	)

Parameters

A	Coordinates of a point on the line
B	Coordinates of another point on the line
C	Coordinates of center of circle
square_radius	of the circle
S1	reference to Coordinates of the first find point of intersection between cricle and line
S2	reference to Coordinates of the second find point

Returns

number of solution, 0, 1 or 2

Note

if return 0, S1 and S2 are not modified, if 1, S1 only is modifed, else, both modified

unsigned int geometry::intersectionsBetweenSegmentAndCircle	(	Coordinates	A,
		Coordinates	B,
		Coordinates	C,
		float	square_radius,
		Coordinates *	S1,
		Coordinates *	S2
	)

Parameters

A	Coordinates of extremity of [AB]
B	Coordinates of extremity of [AB]
C	Coordinates of center of circle
square_radius	of the circle
S1	reference to Coordinates of the first find point of intersection between cricle and [AB]
S2	reference to Coordinates of the second find point

Returns

number of solution, 0, 1 or 2

Note

if return 2, S1 and S2 are modified, if 1, S1 is modified and maybe S2, else both can be modified

bool geometry::parallelLines	(	Coordinates	A,
		Coordinates	B,
		Coordinates	C,
		Coordinates	D
	)

Parameters

A	Coordinates of a line point
B	Coordinates of another line point
C	Coordinates of a line point
D	Coordinates of another line point

Returns

true if lines are parallels

Warning

if A == B or C == D, lines are parallel

bool geometry::pointInCircumcircleOf	(	Coordinates	p1,
		Coordinates	p2,
		Coordinates	p3,
		Coordinates	p0
	)

Parameters

p1	Coordinates of a point of triangle
p2	Coordinates of a point of triangle
p3	Coordinates of a point of triangle
p0	Coordinates of tested point

Returns

true iff tested point is in circumcircle of triangle composed by p1, p2 and p3.

bool geometry::pointInsideCircle	(	Coordinates	A,
		Coordinates	C,
		float	radius
	)

Parameters

A	Coordinates of tested point
C	Coordinates of circle's center
radius	of the circle

Returns

true if tested point is inside circle

Note

return false if point is exactly on circle

bool geometry::pointInTriangle	(	Coordinates	p1,
		Coordinates	p2,
		Coordinates	p3,
		Coordinates	p0
	)

Parameters

p1	Coordinates of a point of triangle
p2	Coordinates of a point of triangle
p3	Coordinates of a point of triangle
p0	Coordinates of tested point

Returns

true iff tested point is in triangle composed by p1, p2 and p3.

bool geometry::pointOnCircle	(	Coordinates	A,
		Coordinates	C,
		float	radius
	)

Parameters

A	Coordinates of tested point
C	Coordinates of circle's center
radius	of the circle

Returns

true if tested point is on circle, false if tested point is inside or outside the circle

Coordinates geometry::projectionOfPointOnLine	(	Coordinates	A,
		Coordinates	B,
		Coordinates	C
	)

Parameters

A	a point on the line
B	another point on the line
C	the evaluated point

Returns

the projection of evaluated point on the line

float geometry::squareDistanceBetweenPoints	(	Coordinates	A,
		Coordinates	B
	)

Parameters

A	Coordinates of a point of triangle
B	Coordinates of a point of triangle

Returns

square distance between the two points

Warning

return value is square of distance, not real distance

float geometry::squareDistanceBetweenPoints	(	float	x1,
		float	y1,
		float	x2,
		float	y2
	)

Parameters

x1	coordinate in x for first point
y1	coordinate in y for first point
x2	coordinate in x for second point
y2	coordinate in y for second point

Returns

square distance between the two points

Warning

return value is square of distance, not real distance

float geometry::squareDistanceBetweenSegmentAndPoint	(	float	x1,
		float	y1,
		float	x2,
		float	y2,
		float	px,
		float	py
	)

Parameters

x1	coordinate in x for first point of segment
y1	coordinate in y for first point of segment
x2	coordinate in x for second point of segment
y2	coordinate in y for second point of segment
px	coordinate in x of tested point
py	coordinate in y of tested point

Returns

shorter square distance between segment and point

Warning

return value is square of distance, not real distance

void geometry::unit_tests

(

)

call that once for verify integrity of geometry fonctions

Warning

: assertion fail if detected problem