citra-mk7/src/common/quaternion.h

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2016-12-11 22:32:01 +01:00
// Copyright 2016 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#pragma once
#include "common/vector_math.h"
namespace Math {
template <typename T>
class Quaternion {
public:
Math::Vec3<T> xyz;
T w;
Quaternion<decltype(-T{})> Inverse() const {
return {-xyz, w};
}
Quaternion<decltype(T{} + T{})> operator+(const Quaternion& other) const {
return {xyz + other.xyz, w + other.w};
}
Quaternion<decltype(T{} - T{})> operator-(const Quaternion& other) const {
return {xyz - other.xyz, w - other.w};
}
Quaternion<decltype(T{} * T{} - T{} * T{})> operator*(const Quaternion& other) const {
return {xyz * other.w + other.xyz * w + Cross(xyz, other.xyz),
w * other.w - Dot(xyz, other.xyz)};
}
Quaternion<T> Normalized() const {
T length = std::sqrt(xyz.Length2() + w * w);
return {xyz / length, w / length};
}
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};
template <typename T>
auto QuaternionRotate(const Quaternion<T>& q, const Math::Vec3<T>& v) {
return v + 2 * Cross(q.xyz, Cross(q.xyz, v) + v * q.w);
}
inline Quaternion<float> MakeQuaternion(const Math::Vec3<float>& axis, float angle) {
return {axis * std::sin(angle / 2), std::cos(angle / 2)};
}
} // namspace Math