Windows2003-3790/windows/advcore/gdiplus/test/simpsons/vecmath.cpp

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2001-01-01 00:00:00 +01:00
// File: VecMath.cpp
// Author: Michael Marr (mikemarr)
//
// History:
// -@- 8/1/95 (mikemarr) added FloatEquals
#include "StdAfx.h"
#include "VecMath.h"
// Function: FloatEquals
// Peform a "fuzzy" compare of two floating point numbers. This relies
// on the IEEE bit representation of floating point numbers.
int
FloatEquals(float x1, float x2)
{
#define EXPMASK 0x7f800000
#define BITSOFPRECISION 19
#define MANTBITS 23
#define EXPOFFSET (BITSOFPRECISION<<MANTBITS)
#define ZEROEPS 3.8e-6F
#define TINYEPS 1.E-35F
if (x1 == x2) return 1; // quick out on exact match
float flEps;
if ((x1 == 0.0f) || (x2 == 0.0f)) {
flEps = ZEROEPS;
} else {
float maxX;
if (x1 > x2)
maxX = x1;
else
maxX = x2;
// grab the exponent of the larger number
unsigned int uExp = (*((unsigned int *) &maxX) & EXPMASK);
if (uExp < EXPOFFSET)
flEps = TINYEPS;
else {
uExp -= EXPOFFSET;
flEps = *((float *) &uExp);
}
}
return (((x1 + flEps) >= x2) && ((x1 - flEps) <= x2));
}
#include <math.h>
float
Vector2::Norm() const
{
return (float) sqrt(NormSquared());
}
float
CoVector2::Norm() const
{
return (float) sqrt(NormSquared());
}
float
Vector3::Norm() const
{
return (float) sqrt(NormSquared());
}
float
CoVector3::Norm() const
{
return (float) sqrt(NormSquared());
}
// Function: Rotate
// rotate the vector counterclockwise around the given axis by theta radians
// Preconditions:
// axis must be UNIT LENGTH
void Vector3::Rotate(const Vector3 &vAxis, float fTheta)
{
float fCosTheta = float(cos(fTheta)), fSinTheta = float(sin(fTheta));
*this *= fCosTheta;
*this += (vAxis * (Dot(*this, vAxis) * (1.f - fCosTheta)));
*this += (Cross(*this, vAxis) * fSinTheta);
}