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