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/*
* Copyright (C) 1999 Antti Koivisto (koivisto@kde.org)
* Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#include "platform/transforms/Rotation.h"
#include "platform/animation/AnimationUtilities.h"
#include "platform/transforms/TransformationMatrix.h"
namespace blink {
namespace {
const double kAngleEpsilon = 1e-4;
Rotation extractFromMatrix(const TransformationMatrix& matrix,
const Rotation& fallbackValue) {
TransformationMatrix::DecomposedType decomp;
if (!matrix.decompose(decomp))
return fallbackValue;
double x = -decomp.quaternionX;
double y = -decomp.quaternionY;
double z = -decomp.quaternionZ;
double length = std::sqrt(x * x + y * y + z * z);
double angle = 0;
if (length > 0.00001) {
x /= length;
y /= length;
z /= length;
angle = rad2deg(std::acos(decomp.quaternionW) * 2);
} else {
x = 0;
y = 0;
z = 1;
}
return Rotation(FloatPoint3D(x, y, z), angle);
}
} // namespace
bool Rotation::getCommonAxis(const Rotation& a,
const Rotation& b,
FloatPoint3D& resultAxis,
double& resultAngleA,
double& resultAngleB) {
resultAxis = FloatPoint3D(0, 0, 1);
resultAngleA = 0;
resultAngleB = 0;
bool isZeroA = a.axis.isZero() || fabs(a.angle) < kAngleEpsilon;
bool isZeroB = b.axis.isZero() || fabs(b.angle) < kAngleEpsilon;
if (isZeroA && isZeroB)
return true;
if (isZeroA) {
resultAxis = b.axis;
resultAngleB = b.angle;
return true;
}
if (isZeroB) {
resultAxis = a.axis;
resultAngleA = a.angle;
return true;
}
double dot = a.axis.dot(b.axis);
if (dot < 0)
return false;
double aSquared = a.axis.lengthSquared();
double bSquared = b.axis.lengthSquared();
double error = std::abs(1 - (dot * dot) / (aSquared * bSquared));
if (error > kAngleEpsilon)
return false;
resultAxis = a.axis;
resultAngleA = a.angle;
resultAngleB = b.angle;
return true;
}
Rotation Rotation::slerp(const Rotation& from,
const Rotation& to,
double progress) {
double fromAngle;
double toAngle;
FloatPoint3D axis;
if (getCommonAxis(from, to, axis, fromAngle, toAngle))
return Rotation(axis, blink::blend(fromAngle, toAngle, progress));
TransformationMatrix fromMatrix;
TransformationMatrix toMatrix;
fromMatrix.rotate3d(from);
toMatrix.rotate3d(to);
toMatrix.blend(fromMatrix, progress);
return extractFromMatrix(toMatrix, progress < 0.5 ? from : to);
}
Rotation Rotation::add(const Rotation& a, const Rotation& b) {
double angleA;
double angleB;
FloatPoint3D axis;
if (getCommonAxis(a, b, axis, angleA, angleB))
return Rotation(axis, angleA + angleB);
TransformationMatrix matrix;
matrix.rotate3d(a);
matrix.rotate3d(b);
return extractFromMatrix(matrix, b);
}
} // namespace blink
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