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/* -*- Mode: C++; tab-width: 2; 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/. */
#ifndef GFX_QUATERNION_H
#define GFX_QUATERNION_H
#include "mozilla/gfx/BasePoint4D.h"
#include "mozilla/gfx/Matrix.h"
#include "nsAlgorithm.h"
#include <algorithm>
struct gfxQuaternion : public mozilla::gfx::BasePoint4D<gfxFloat, gfxQuaternion> {
typedef mozilla::gfx::BasePoint4D<gfxFloat, gfxQuaternion> Super;
gfxQuaternion() : Super() {}
gfxQuaternion(gfxFloat aX, gfxFloat aY, gfxFloat aZ, gfxFloat aW) : Super(aX, aY, aZ, aW) {}
explicit gfxQuaternion(const mozilla::gfx::Matrix4x4& aMatrix) {
w = 0.5 * sqrt(std::max(1 + aMatrix[0][0] + aMatrix[1][1] + aMatrix[2][2], 0.0f));
x = 0.5 * sqrt(std::max(1 + aMatrix[0][0] - aMatrix[1][1] - aMatrix[2][2], 0.0f));
y = 0.5 * sqrt(std::max(1 - aMatrix[0][0] + aMatrix[1][1] - aMatrix[2][2], 0.0f));
z = 0.5 * sqrt(std::max(1 - aMatrix[0][0] - aMatrix[1][1] + aMatrix[2][2], 0.0f));
if(aMatrix[2][1] > aMatrix[1][2])
x = -x;
if(aMatrix[0][2] > aMatrix[2][0])
y = -y;
if(aMatrix[1][0] > aMatrix[0][1])
z = -z;
}
// Convert from |direction axis, angle| pair to gfxQuaternion.
//
// Reference:
// https://en.wikipedia.org/wiki/Quaternions_and_spatial_rotation
//
// if the direction axis is (x, y, z) = xi + yj + zk,
// and the angle is |theta|, this formula can be done using
// an extension of Euler's formula:
// q = cos(theta/2) + (xi + yj + zk)(sin(theta/2))
// = cos(theta/2) +
// x*sin(theta/2)i + y*sin(theta/2)j + z*sin(theta/2)k
// Note: aDirection should be an unit vector and
// the unit of aAngle should be Radian.
gfxQuaternion(const mozilla::gfx::Point3D &aDirection, gfxFloat aAngle) {
MOZ_ASSERT(mozilla::gfx::FuzzyEqual(aDirection.Length(), 1.0f),
"aDirection should be an unit vector");
x = aDirection.x * sin(aAngle/2.0);
y = aDirection.y * sin(aAngle/2.0);
z = aDirection.z * sin(aAngle/2.0);
w = cos(aAngle/2.0);
}
gfxQuaternion Slerp(const gfxQuaternion &aOther, gfxFloat aCoeff) {
gfxFloat dot = mozilla::clamped(DotProduct(aOther), -1.0, 1.0);
if (dot == 1.0) {
return *this;
}
gfxFloat theta = acos(dot);
gfxFloat rsintheta = 1/sqrt(1 - dot*dot);
gfxFloat rightWeight = sin(aCoeff*theta)*rsintheta;
gfxQuaternion left = *this;
gfxQuaternion right = aOther;
left *= cos(aCoeff*theta) - dot*rightWeight;
right *= rightWeight;
return left + right;
}
mozilla::gfx::Matrix4x4 ToMatrix() {
mozilla::gfx::Matrix4x4 temp;
temp[0][0] = 1 - 2 * (y * y + z * z);
temp[0][1] = 2 * (x * y + w * z);
temp[0][2] = 2 * (x * z - w * y);
temp[1][0] = 2 * (x * y - w * z);
temp[1][1] = 1 - 2 * (x * x + z * z);
temp[1][2] = 2 * (y * z + w * x);
temp[2][0] = 2 * (x * z + w * y);
temp[2][1] = 2 * (y * z - w * x);
temp[2][2] = 1 - 2 * (x * x + y * y);
return temp;
}
};
#endif /* GFX_QUATERNION_H */
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