/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "Matrix.h"

#include "Quaternion.h"

#include "Tools.h"

#include <algorithm>

#include <ostream>

#include <math.h>

#include <float.h>  // for FLT_EPSILON

#include "mozilla/FloatingPoint.h" // for UnspecifiedNaN

using namespace std;

namespace mozilla {

namespace gfx {

/* Force small values to zero.  We do this to avoid having sin(360deg)

 * evaluate to a tiny but nonzero value.

 */

double

FlushToZero(double aVal)

{

  // XXX Is double precision really necessary here

  if (-FLT_EPSILON < aVal && aVal < FLT_EPSILON) {

    return 0.0f;

  } else {

    return aVal;

  }

}

/* Computes tan(aTheta).  For values of aTheta such that tan(aTheta) is

 * undefined or very large, SafeTangent returns a manageably large value

 * of the correct sign.

 */

double

SafeTangent(double aTheta)

{

  // XXX Is double precision really necessary here

  const double kEpsilon = 0.0001;

  /* tan(theta) = sin(theta)/cos(theta); problems arise when

   * cos(theta) is too close to zero.  Limit cos(theta) to the

   * range [-1, -epsilon] U [epsilon, 1].

   */

  double sinTheta = sin(aTheta);

  double cosTheta = cos(aTheta);

  if (cosTheta >= 0 && cosTheta < kEpsilon) {

    cosTheta = kEpsilon;

  } else if (cosTheta < 0 && cosTheta >= -kEpsilon) {

    cosTheta = -kEpsilon;

  }

  return FlushToZero(sinTheta / cosTheta);

}

template<> Matrix

Matrix::Rotation(Float aAngle)

{

  Matrix newMatrix;

  Float s = sinf(aAngle);

  Float c = cosf(aAngle);

  newMatrix._11 = c;

  newMatrix._12 = s;

  newMatrix._21 = -s;

  newMatrix._22 = c;

  return newMatrix;

}

template<> MatrixDouble

MatrixDouble::Rotation(Double aAngle)

{

  MatrixDouble newMatrix;

  Double s = sin(aAngle);

  Double c = cos(aAngle);

  newMatrix._11 = c;

  newMatrix._12 = s;

  newMatrix._21 = -s;

  newMatrix._22 = c;

  return newMatrix;

}

template<> Matrix4x4

MatrixDouble::operator*(const Matrix4x4& aMatrix) const

{

  Matrix4x4 resultMatrix;

  resultMatrix._11 = this->_11 * aMatrix._11 + this->_12 * aMatrix._21;

  resultMatrix._12 = this->_11 * aMatrix._12 + this->_12 * aMatrix._22;

  resultMatrix._13 = this->_11 * aMatrix._13 + this->_12 * aMatrix._23;

  resultMatrix._14 = this->_11 * aMatrix._14 + this->_12 * aMatrix._24;

  resultMatrix._21 = this->_21 * aMatrix._11 + this->_22 * aMatrix._21;

  resultMatrix._22 = this->_21 * aMatrix._12 + this->_22 * aMatrix._22;

  resultMatrix._23 = this->_21 * aMatrix._13 + this->_22 * aMatrix._23;

  resultMatrix._24 = this->_21 * aMatrix._14 + this->_22 * aMatrix._24;

  resultMatrix._31 = aMatrix._31;

  resultMatrix._32 = aMatrix._32;

  resultMatrix._33 = aMatrix._33;

  resultMatrix._34 = aMatrix._34;

  resultMatrix._41 = this->_31 * aMatrix._11 + this->_32 * aMatrix._21 + aMatrix._41;

  resultMatrix._42 = this->_31 * aMatrix._12 + this->_32 * aMatrix._22 + aMatrix._42;

  resultMatrix._43 = this->_31 * aMatrix._13 + this->_32 * aMatrix._23 + aMatrix._43;

  resultMatrix._44 = this->_31 * aMatrix._14 + this->_32 * aMatrix._24 + aMatrix._44;

  return resultMatrix;

}

} // namespace gfx

} // namespace mozilla