/******************************************************************/
/* 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 <cassert>
#include "normalMap.h"
#include "coordinateTransform.h"


//////////////////
// Constructors //
//////////////////
normalMap::normalMap(const std::shared_ptr<const texture_base>& map, const std::shared_ptr<const shader_base>& shader)
  : shadingFrameTransformation(shader)
{
  _map = map;
}

/////////////
// Methods //
/////////////
transformation3d normalMap::_transformation(const vec2d& textureCoord) const
{
  // HW5: Implement a normal map. This method returns a transformation that
  //      transforms the shading frame into the shading frame defined by the
  //      normals in the _map. The normals are specified in the local shading
  //      frame where N=(0,0,1). The resulting coordinate transformation should
  //      align the Z axis with the new normal, and map the X axis to remain in
  //      the plane defined by the normal and the X axis.
  // Modifies: nothing
  // Returns: transformation3d
  color normalColor = (*_map)(textureCoord);
  vec3d normal = vec3d(normalColor.r, normalColor.g, normalColor.b);
  // maintain x-axis in plane
  transformation3d normalTransform = coordinateTransformation(normal, vec3d(1, 0, 0));
  return normalTransform;
}


void normalMap::_print(std::ostream& s) const
{
  s << "normalMap (" << *_map << ") -> {" << *_shader << "}";
}