/******************************************************************/
/* 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
{
  // get texel
  assert(_map);
  color texel = (*_map)(textureCoord);

  // get desired local normal
  vec3d normal(texel.r, texel.g, texel.b);
  normal.normalize();

  // create coordinate system. Keep U aligned as close as possible to the X axis.
  return coordinateTransformation(normal, vec3d(1.0f, 0.0, 0.0));
}


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