hw6/src/rotation3d.cpp


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/******************************************************************/
/* This file is part of the homework assignments for CSCI-427/527 */
/* at The College of William & Mary and authored by Pieter Peers. */
/* No part of this file, whether altered or in original form, can */
/* be distributed or used outside the context of CSCI-427/527     */
/* without consent of either the College of William & Mary or     */
/* Pieter Peers.                                                  */
/******************************************************************/
#include "constants.h"
#include "rotation3d.h"

//////////////////
// Constructors //
//////////////////
rotation3d::rotation3d(void) 
  : transformation3d()
{
  // Do Nothing
}


rotation3d::rotation3d(float angle, const vec3d& axis) 
  : transformation3d()
{
  vec3d norm_axis = normalize(axis);
  float s = sin(angle * PI / 180.0f);
  float c = cos(angle * PI / 180.0f);

  _transformation(0,0) = c + ((norm_axis.x * norm_axis.x) * (1.0f - c));
  _transformation(0,1) = -(norm_axis.z * s) + ((norm_axis.x * norm_axis.y) * (1.0f - c));
  _transformation(0,2) = (norm_axis.y * s) + ((norm_axis.x * norm_axis.z) * (1.0f - c));
  _transformation(1,0) = (norm_axis.z * s) + ((norm_axis.x * norm_axis.y) * (1.0f - c));
  _transformation(1,1) = c + ((norm_axis.y * norm_axis.y) * (1.0f - c));
  _transformation(1,2) = -(norm_axis.x * s) + ((norm_axis.y * norm_axis.z) * (1.0f - c));
  _transformation(2,0) = -(norm_axis.y * s) + ((norm_axis.x * norm_axis.z) * (1.0f - c));
  _transformation(2,1) = (norm_axis.x * s) + ((norm_axis.y * norm_axis.z) * (1.0f - c));
  _transformation(2,2) = c + ((norm_axis.z * norm_axis.z) * (1.0f - c));

  _inverseTransformation = transpose(_transformation);
}


rotation3d::rotation3d(const rotation3d& r) 
  : transformation3d(r)
{
  // Do Nothing
}