gecko-dev/gfx/thebes/gfxQuaternion.h
Boris Chiou 8828547018 Bug 1737209 - Fix the conversion from (axis,angle) pair to the quaternion vector. r=emilio
Basically, quaternion vectors make sense only when the rotation is within
(-360deg, 360deg). If its angle is larger than or equal to 360deg, its
direction may be different, so we have to tweak the conversion.

Also, tweak the code of interpolation for rotate3D to match the spec and
put more comments there.

Differential Revision: https://phabricator.services.mozilla.com/D186998
2023-09-01 20:15:51 +00:00

96 lines
3.1 KiB
C++

/* -*- 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;
}
gfxQuaternion Slerp(const gfxQuaternion& aOther, gfxFloat aCoeff) const {
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;
}
using Super::operator*=;
// Quaternion multiplication
// Reference:
// https://en.wikipedia.org/wiki/Quaternion#Ordered_list_form
//
// (w1, x1, y1, z1)(w2, x2, y2, z2) = (w1w2 - x1x2 - y1y2 - z1z2,
// w1x2 + x1w2 + y1z2 - z1y2,
// w1y2 - x1z2 + y1w2 + z1x2,
// w1z2 + x1y2 - y1x2 + z1w2)
gfxQuaternion operator*(const gfxQuaternion& aOther) const {
return gfxQuaternion(
w * aOther.x + x * aOther.w + y * aOther.z - z * aOther.y,
w * aOther.y - x * aOther.z + y * aOther.w + z * aOther.x,
w * aOther.z + x * aOther.y - y * aOther.x + z * aOther.w,
w * aOther.w - x * aOther.x - y * aOther.y - z * aOther.z);
}
gfxQuaternion& operator*=(const gfxQuaternion& aOther) {
*this = *this * aOther;
return *this;
}
mozilla::gfx::Matrix4x4 ToMatrix() const {
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 */