third_party/WebKit/Source/platform/transforms/Rotation.h

// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef Rotation_h
#define Rotation_h

#include "platform/geometry/FloatPoint3D.h"

namespace blink {

struct PLATFORM_EXPORT Rotation {
  Rotation() : axis(0, 0, 0), angle(0) {}

  Rotation(const FloatPoint3D& axis, double angle) : axis(axis), angle(angle) {}

  // If either rotation is effectively "zero" or both rotations share the same
  // normalized axes this function returns true and the "non-zero" axis is
  // returned as resultAxis and the effective angles are returned as
  // resultAngleA and resultAngleB.  Otherwise false is returned.
  static bool getCommonAxis(const Rotation& /*a*/,
                            const Rotation& /*b*/,
                            FloatPoint3D& resultAxis,
                            double& resultAngleA,
                            double& resultAngleB);

  // A progress of 0 corresponds to "from" and a progress of 1 corresponds to
  // "to".
  static Rotation slerp(const Rotation& from,
                        const Rotation& to,
                        double progress);

  // Returns a rotation whose effect is equivalent to applying a followed by b.
  static Rotation add(const Rotation& /*a*/, const Rotation& /*b*/);

  // No restrictions on the axis vector.
  FloatPoint3D axis;

  // Measured in degrees.
  double angle;
};

}  // namespace blink

#endif  // Rotation_h