80 lines
2.2 KiB
C++
80 lines
2.2 KiB
C++
// Copyright 2016 Citra Emulator Project
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// Licensed under GPLv2 or any later version
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// Refer to the license.txt file included.
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#pragma once
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#include "common/vector_math.h"
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namespace Common {
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template <typename T>
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class Quaternion {
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public:
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Vec3<T> xyz;
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T w{};
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[[nodiscard]] Quaternion<decltype(-T{})> Inverse() const {
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return {-xyz, w};
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}
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[[nodiscard]] Quaternion<decltype(T{} + T{})> operator+(const Quaternion& other) const {
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return {xyz + other.xyz, w + other.w};
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}
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[[nodiscard]] Quaternion<decltype(T{} - T{})> operator-(const Quaternion& other) const {
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return {xyz - other.xyz, w - other.w};
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}
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[[nodiscard]] Quaternion<decltype(T{} * T{} - T{} * T{})> operator*(
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const Quaternion& other) const {
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return {xyz * other.w + other.xyz * w + Cross(xyz, other.xyz),
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w * other.w - Dot(xyz, other.xyz)};
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}
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[[nodiscard]] Quaternion<T> Normalized() const {
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T length = std::sqrt(xyz.Length2() + w * w);
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return {xyz / length, w / length};
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}
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[[nodiscard]] std::array<decltype(-T{}), 16> ToMatrix() const {
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const T x2 = xyz[0] * xyz[0];
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const T y2 = xyz[1] * xyz[1];
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const T z2 = xyz[2] * xyz[2];
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const T xy = xyz[0] * xyz[1];
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const T wz = w * xyz[2];
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const T xz = xyz[0] * xyz[2];
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const T wy = w * xyz[1];
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const T yz = xyz[1] * xyz[2];
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const T wx = w * xyz[0];
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return {1.0f - 2.0f * (y2 + z2),
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2.0f * (xy + wz),
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2.0f * (xz - wy),
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0.0f,
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2.0f * (xy - wz),
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1.0f - 2.0f * (x2 + z2),
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2.0f * (yz + wx),
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0.0f,
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2.0f * (xz + wy),
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2.0f * (yz - wx),
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1.0f - 2.0f * (x2 + y2),
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0.0f,
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0.0f,
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0.0f,
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0.0f,
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1.0f};
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}
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};
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template <typename T>
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[[nodiscard]] auto QuaternionRotate(const Quaternion<T>& q, const Vec3<T>& v) {
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return v + 2 * Cross(q.xyz, Cross(q.xyz, v) + v * q.w);
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}
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[[nodiscard]] inline Quaternion<float> MakeQuaternion(const Vec3<float>& axis, float angle) {
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return {axis * std::sin(angle / 2), std::cos(angle / 2)};
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}
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} // namespace Common
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