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rdMath Class Reference

This class provides basic math functions and constants. More...

#include <rdMath.h>

List of all members.

Static Public Member Functions
double	CopySign (double aMag, double aSign)
	Return the magnitude of aMag with the sign of aSign.
bool	IsZero (double aValue)
	Return wheter or not an argument is closer to zero than the constant rdMath::ZERO.
double	SigmaUp (double tau, double to, double t)
	A smooth step-up function using exponentials.
double	SigmaDn (double tau, double to, double t)
	A smooth step-down function using exponentials.
int	FitParabola (double aX1, double aY1, double aX2, double aY2, double aX3, double aY3, double *rC0, double *rC1, double *rC2)
	Fit a parabola of the form y = c0 + c1*x + c2*x^2 to three points (x1,y1), (x2,y2), (x3,y3).
int	ComputeIntersection (const rdLine *aLine, const rdPlane *aPlane, double rPoint[3])
	Compute the intersection of a line with a plane.
void	ComputeNormal (double aP1X, double aP1Y, double aP1Z, double aP2X, double aP2Y, double aP2Z, double aP3X, double aP3Y, double aP3Z, double rNormal[3])
	Compute a normal to the plane described by three points (P1, P2, P3).
Static Public Attributes
const double	PI = acos(-1.0)
const double	RTD = 180.0/PI
const double	DTR = PI/180.0
const double	SMALL = 1.0e-8
const double	ZERO = 1.0e-14
const double	NAN = 1.357931415e-29
const double	INFINITY = 1.0e30
const double	MINUS_INFINITY = -INFINITY
const double	PLUS_INFINITY = INFINITY

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Detailed Description

This class provides basic math functions and constants.

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Member Function Documentation

int rdMath::ComputeIntersection (  const rdLine *  aLine, const rdPlane *  aPlane, double  rPoint[3] )  [static]

Compute the intersection of a line with a plane. The line and plane can either intersect at a point, not intersect at all, or be coincident. Parameters: aLine  Line. aPlane  Plane. rPoint  Point of intersection. rPoint is set to the "zero" point of the line in the event that line and plane are coincident; it is unchanged if the line and plane do not intersect. Returns: -1 if the line and plane do not intersect; 0 if the line and plane intersect at a point; 1 if the line is coincident with the plane.

void rdMath::ComputeNormal (  double  aP1X, double  aP1Y, double  aP1Z, double  aP2X, double  aP2Y, double  aP2Z, double  aP3X, double  aP3Y, double  aP3Z, double  rNormal[3] )  [static]

Compute a normal to the plane described by three points (P1, P2, P3). The normal is computed by taking the cross product: n = (p2-p1) x (p3-p2) / | (p2-p1) x (p3-p2) | The three points should be distinct. Parameters: aP1X  X component of point 1.. aP1Y  Y component of point 1. aP1Z  Z component of point 1. aP2X  X component of point 2. aP2Y  Y component of point 2. aP2Z  Z component of point 2. aP3X  X component of point 3. aP3Y  Y component of point 3. aP3Z  Z component of point 3. rNormal  Unit vector normal to the plane defined by P1, P2, and P3.

double rdMath::CopySign (  double  aMag, double  aSign )  [static]

Return the magnitude of aMag with the sign of aSign. Note that if aSign has a value of 0.0, or aMag has a value of 0.0, the sign of aMag is not changed. Parameters: aMag  Magnitude aSign  Sign Returns: Value with size of aMag and sign of aSign.

int rdMath::FitParabola (  double  aX1, double  aY1, double  aX2, double  aY2, double  aX3, double  aY3, double *  rC0, double *  rC1, double *  rC2 )  [static]

Fit a parabola of the form y = c0 + c1*x + c2*x^2 to three points (x1,y1), (x2,y2), (x3,y3). It is required that x3 > x2 > x1. If this condition is not met, -1 is returned. Otherwise, 0 is returned. To imporove numerical accuracy, the independent variables are mapped to a new set of variables such that x1 -> 1.0, x3 -> 2.0, and x2 is mapped to some number in between.

bool rdMath::IsZero (  double  aValue  )  [static]

Return wheter or not an argument is closer to zero than the constant rdMath::ZERO. Parameters: aMag  Magnitude aSign  Sign Returns: Value with size of aMag and sign of aSign.

double rdMath::SigmaDn (  double  tau, double  to, double  t )  [static]

A smooth step-down function using exponentials. Parameters: tau  Rise and fall time constant. to  Location of the midpoint of the step. t  Independent variable

double rdMath::SigmaUp (  double  tau, double  to, double  t )  [static]

A smooth step-up function using exponentials. Parameters: tau  Rise and fall time constant. to  Location of the midpoint of the step. t  Independent variable

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

• rdMath.h
• rdMath.cpp

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