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Graphics Programming Black Book (Special Edition)
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chapter51
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l51-4.c
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1997-06-18
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67 lines
/* Routines to perform incremental rotations around the three axes
Tested with Borland C++ 4.02 in small model by Jim Mischel 12/16/94.
*/
#include <math.h>
#include "polygon.h"
/* Concatenate a rotation by Angle around the X axis to the transformation in
XformToChange, placing result back in XformToChange. */
void AppendRotationX(double XformToChange[4][4], double Angle)
{
double Temp10, Temp11, Temp12, Temp20, Temp21, Temp22;
double CosTemp = cos(Angle), SinTemp = sin(Angle);
/* Calculate the new values of the four affected matrix entries */
Temp10 = CosTemp*XformToChange[1][0]+ -SinTemp*XformToChange[2][0];
Temp11 = CosTemp*XformToChange[1][1]+ -SinTemp*XformToChange[2][1];
Temp12 = CosTemp*XformToChange[1][2]+ -SinTemp*XformToChange[2][2];
Temp20 = SinTemp*XformToChange[1][0]+ CosTemp*XformToChange[2][0];
Temp21 = SinTemp*XformToChange[1][1]+ CosTemp*XformToChange[2][1];
Temp22 = SinTemp*XformToChange[1][2]+ CosTemp*XformToChange[2][2];
/* Put the results back into XformToChange */
XformToChange[1][0] = Temp10; XformToChange[1][1] = Temp11;
XformToChange[1][2] = Temp12; XformToChange[2][0] = Temp20;
XformToChange[2][1] = Temp21; XformToChange[2][2] = Temp22;
}
/* Concatenate a rotation by Angle around the Y axis to the transformation in
XformToChange, placing result back in XformToChange. */
void AppendRotationY(double XformToChange[4][4], double Angle)
{
double Temp00, Temp01, Temp02, Temp20, Temp21, Temp22;
double CosTemp = cos(Angle), SinTemp = sin(Angle);
/* Calculate the new values of the four affected matrix entries */
Temp00 = CosTemp*XformToChange[0][0]+ SinTemp*XformToChange[2][0];
Temp01 = CosTemp*XformToChange[0][1]+ SinTemp*XformToChange[2][1];
Temp02 = CosTemp*XformToChange[0][2]+ SinTemp*XformToChange[2][2];
Temp20 = -SinTemp*XformToChange[0][0]+ CosTemp*XformToChange[2][0];
Temp21 = -SinTemp*XformToChange[0][1]+ CosTemp*XformToChange[2][1];
Temp22 = -SinTemp*XformToChange[0][2]+ CosTemp*XformToChange[2][2];
/* Put the results back into XformToChange */
XformToChange[0][0] = Temp00; XformToChange[0][1] = Temp01;
XformToChange[0][2] = Temp02; XformToChange[2][0] = Temp20;
XformToChange[2][1] = Temp21; XformToChange[2][2] = Temp22;
}
/* Concatenate a rotation by Angle around the Z axis to the transformation in
XformToChange, placing result back in XformToChange. */
void AppendRotationZ(double XformToChange[4][4], double Angle)
{
double Temp00, Temp01, Temp02, Temp10, Temp11, Temp12;
double CosTemp = cos(Angle), SinTemp = sin(Angle);
/* Calculate the new values of the four affected matrix entries */
Temp00 = CosTemp*XformToChange[0][0]+ -SinTemp*XformToChange[1][0];
Temp01 = CosTemp*XformToChange[0][1]+ -SinTemp*XformToChange[1][1];
Temp02 = CosTemp*XformToChange[0][2]+ -SinTemp*XformToChange[1][2];
Temp10 = SinTemp*XformToChange[0][0]+ CosTemp*XformToChange[1][0];
Temp11 = SinTemp*XformToChange[0][1]+ CosTemp*XformToChange[1][1];
Temp12 = SinTemp*XformToChange[0][2]+ CosTemp*XformToChange[1][2];
/* Put the results back into XformToChange */
XformToChange[0][0] = Temp00; XformToChange[0][1] = Temp01;
XformToChange[0][2] = Temp02; XformToChange[1][0] = Temp10;
XformToChange[1][1] = Temp11; XformToChange[1][2] = Temp12;
}