mirror of
https://github.com/ptitSeb/Serious-Engine
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82 lines
2.1 KiB
C++
82 lines
2.1 KiB
C++
/* Copyright (c) 2002-2012 Croteam Ltd. All rights reserved. */
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#include "stdh.h"
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#include <Engine/Math/Functions.h>
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/////////////////////////////////////////////////////////////////////
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// Snapping functions
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// does "snap to grid" for given coordinate
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void Snap( FLOAT &fDest, FLOAT fStep)
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{
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// this must use floor() to get proper snapping of negative values.
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FLOAT fDiv = fDest/fStep;
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FLOAT fRound = fDiv + 0.5f;
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FLOAT fSnap = FLOAT(floor(fRound));
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FLOAT fRes = fSnap * fStep;
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fDest = fRes;
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}
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// does "snap to grid" for given coordinate
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void Snap( DOUBLE &fDest, DOUBLE fStep)
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{
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// this must use floor() to get proper snapping of negative values.
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DOUBLE fDiv = fDest/fStep;
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DOUBLE fRound = fDiv + 0.5f;
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DOUBLE fSnap = DOUBLE(floor(fRound));
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DOUBLE fRes = fSnap * fStep;
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fDest = fRes;
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}
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#if 0
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// does "snap to grid" for given angle
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void Snap( ANGLE &angDest, ANGLE angStep)
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{
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/* Watch out for unsigned-signed mixing!
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All sub-expressions and arguments must be unsigned for this to work correctly!
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Unfortunately, ANGLE is not an unsigned type by default, so we must cast it.
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Also, angStep must be a divisor of ANGLE_180!
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*/
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ASSERT(ANGLE_180%angStep == 0); // don't test with ANGLE_360 ,since it is 0!
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angDest = ANGLE( ((UWORD(angDest)+UWORD(angStep)/2U)/UWORD(angStep))*UWORD(angStep) );
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}
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#endif
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double adSinQuadrants[4][2] =
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{
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{1.0, 0.0},
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{-1.0, -90.0},
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{-1.0, 0.0},
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{1.0, -90.0},
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};
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double adCosQuadrants[4][2] =
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{
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{-1.0, -90.0},
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{-1.0, 0.0},
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{1.0, -90.0},
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{1.0, 0.0},
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};
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FLOAT Sin(ANGLE a)
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{
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double aWrapped = WrapAngle(a);
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double aIn90 = fmod(aWrapped, 90.0);
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int iQuadrant = int(aWrapped/90.0);
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double fSin = adSinQuadrants[iQuadrant][0]*
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sin((aIn90+adSinQuadrants[iQuadrant][1])*PI/ANGLE_180);
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return FLOAT (fSin);
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}
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FLOAT Cos(ANGLE a)
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{
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double aWrapped = WrapAngle(a);
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double aIn90 = fmod(aWrapped, 90.0);
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int iQuadrant = int(aWrapped/90.0);
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double fCos = adCosQuadrants[iQuadrant][0]*
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sin((aIn90+adCosQuadrants[iQuadrant][1])*PI/ANGLE_180);
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return FLOAT (fCos);
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}
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FLOAT Tan(ANGLE a)
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{
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return Sin(a)/Cos(a);
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}
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