gecko-dev/gfx/2d/Matrix.cpp

124 строки
3.2 KiB
C++

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* 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