right-handed DirectionVector

Added missing Vector3::One

include/J3ML/J3ML.hpp

@@ -84,6 +84,9 @@ namespace J3ML::Math::Constants {
     constexpr float RecipSqrt2Pi = 0.3989422804014326779399460599343818684758586311649346576659258296706579258993018385012523339073069364;
     /// pi - https://www.mathsisfun.com/numbers/pi.html
     constexpr float Pi = 3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679;
+    /// pi * 0.5.
+    constexpr float HalfPi = 1.5707963267948966192313216916397514420985846996875529104874722961539082031431044993140174126710585;
+
     /// e - https://www.mathsisfun.com/numbers/e-eulers-number.html
     constexpr float EulersNumber = 2.7182818284590452353602874713526624977572470936999595749669676277240766303535475945713821785251664274;
     /// 2pi - The ratio of a circle's circumferecne to its radius, and the number of radians in one turn.

include/J3ML/LinearAlgebra/AxisAngle.hpp

@@ -2,28 +2,23 @@
 
 #include <J3ML/LinearAlgebra/EulerAngle.hpp>
 #include <J3ML/LinearAlgebra/Quaternion.hpp>
-#include <J3ML/LinearAlgebra/AxisAngle.hpp>
 #include <J3ML/LinearAlgebra/Vector3.hpp>
 
-namespace J3ML::LinearAlgebra
-{
+namespace J3ML::LinearAlgebra {
+    class AxisAngle;
+}
 
-    /// Transitional datatype, not useful for internal representation of rotation
-    /// But has uses for conversion and manipulation.
-    class AxisAngle {
-    public:
-        Vector3 axis;
-        float angle;
-    public:
-        AxisAngle();
-        explicit AxisAngle(const Quaternion& q);
-        explicit AxisAngle(const EulerAngle& e);
+/// Transitional datatype, not useful for internal representation of rotation
+/// But has uses for conversion and manipulation.
+class J3ML::LinearAlgebra::AxisAngle {
+public:
+    Vector3 axis;
+    // Radians.
+    float angle;
+public:
+    AxisAngle();
+    explicit AxisAngle(const Quaternion& q);
+    explicit AxisAngle(const EulerAngleXYZ& e);
+    AxisAngle(const Vector3& axis, float angle);
 
-        AxisAngle(const Vector3 &axis, float angle);
-
-        EulerAngle ToEulerAngleXYZ() const;
-
-        Quaternion ToQuaternion() const;
-        static AxisAngle FromEulerAngleXYZ(const EulerAngle&);
-    };
-}
+};

include/J3ML/LinearAlgebra/DirectionVector.hpp

@@ -0,0 +1,20 @@
+#pragma once
+#include <J3ML/LinearAlgebra/Vector3.hpp>
+
+namespace J3ML::LinearAlgebra {
+    class DirectionVectorRH;
+}
+
+/// Direction vector of a given Matrix3x3 RotationMatrix in a Right-handed coordinate space.
+class J3ML::LinearAlgebra::DirectionVectorRH : public Vector3 {
+private:
+    // This is purposefully not exposed because these types aren't usually convertable.
+    explicit DirectionVectorRH(const Vector3& rhs);
+public:
+    static DirectionVectorRH Forward(const Matrix3x3& rhs);
+    static DirectionVectorRH Backward(const Matrix3x3& rhs);
+    static DirectionVectorRH Left(const Matrix3x3& rhs);
+    static DirectionVectorRH Right(const Matrix3x3& rhs);
+    static DirectionVectorRH Up(const Matrix3x3& rhs);
+    static DirectionVectorRH Down(const Matrix3x3& rhs);
+};

include/J3ML/LinearAlgebra/EulerAngle.hpp

@@ -5,48 +5,19 @@
 #include <J3ML/LinearAlgebra/AxisAngle.hpp>
 
 namespace J3ML::LinearAlgebra {
+    class EulerAngleXYZ;
+}
 
-    class AxisAngle;
-
-// Essential Reading:
-// http://www.essentialmath.com/GDC2012/GDC2012_JMV_Rotations.pdf
-class EulerAngle {
+class J3ML::LinearAlgebra::EulerAngleXYZ {
 public:
-    EulerAngle();
-    EulerAngle(float pitch, float yaw, float roll);
-    EulerAngle(const Vector3& vec) : pitch(vec.x), yaw(vec.y), roll(vec.z) {}
-
-    AxisAngle ToAxisAngle() const;
-
-    [[nodiscard]] Quaternion ToQuaternion() const;
-
-
-    explicit EulerAngle(const Quaternion& rhs);
-    explicit EulerAngle(const AxisAngle& rhs);
-
-    /// TODO: Implement separate upper and lower bounds
-    /// Preserves internal value of euler angles, normalizes and clamps the output.
-    /// This does not solve gimbal lock!!!
-    float GetPitch(float pitch_limit) const;
-    float GetYaw(float yaw_limit)     const;
-    float GetRoll(float roll_limit)   const;
-
-    bool operator==(const EulerAngle& a) const;
-    void clamp();
-
-    // TODO: Euler Angles do not represent a vector, length doesn't apply, nor is this information meaningful for this data type.
-    // If you need a meaningful representation of length in 3d space, use a vector!!
-    [[nodiscard]] float length() const {
-        return 0;
-    }
-    // TODO: Implement
-    Vector3 unitVector() const;
-
-    EulerAngle movementAngle() const;
 public:
-    float pitch;
-    float yaw;
-    float roll;
+    float roll = 0; // X
+    float pitch = 0; // Y
+    float yaw = 0; // Z
+public:
+    EulerAngleXYZ(float roll, float pitch, float yaw);
+public:
+    explicit EulerAngleXYZ(const Quaternion& rhs);
+    explicit EulerAngleXYZ(const AxisAngle& rhs);
+    explicit EulerAngleXYZ(const Matrix3x3& rhs);
 };
-
-}

include/J3ML/LinearAlgebra/Forward.hpp

@@ -7,7 +7,7 @@ namespace J3ML::LinearAlgebra
     class Vector3; // A type representing a position in a 3-dimensional coordinate space.
     class Vector4; // A type representing a position in a 4-dimensional coordinate space.
     class Angle2D; // Uses x,y components to represent a 2D rotation.
-    class EulerAngle; // Uses pitch,yaw,roll components to represent a 3D orientation.
+    class EulerAngleXYZ; // Uses pitch,yaw,roll components to represent a 3D orientation.
     class AxisAngle; //
     class CoordinateFrame; //
     class Matrix2x2;
@@ -15,6 +15,7 @@ namespace J3ML::LinearAlgebra
     class Matrix4x4;
     class Transform2D;
     class Transform3D;
+    class DirectionVectorRH; // A type representing a direction in 3D space.
     class Quaternion;
 
 

include/J3ML/LinearAlgebra/Matrix3x3.hpp

@@ -63,7 +63,10 @@ namespace J3ML::LinearAlgebra {
         /// Constructs this matrix3x3 from the given quaternion.
         explicit Matrix3x3(const Quaternion& orientation);
         /// Constructs this matrix3x3 from the given euler angle.
-        explicit Matrix3x3(const EulerAngle& orientation);
+
+        explicit Matrix3x3(const EulerAngleXYZ& orientation);
+
+        explicit Matrix3x3(const AxisAngle& orientation);
 
         /// Constructs this Matrix3x3 from a pointer to an array of floats.
         explicit Matrix3x3(const float *data);
@@ -153,6 +156,7 @@ namespace J3ML::LinearAlgebra {
 
         /// Sets this matrix to perform a rotation about the given axis and angle.
         void SetRotatePart(const Vector3& a, float angle);
+
         void SetRotatePart(const AxisAngle& axisAngle);
         /// Sets this matrix to perform the rotation expressed by the given quaternion.
         void SetRotatePart(const Quaternion& quat);
@@ -239,17 +243,10 @@ namespace J3ML::LinearAlgebra {
         inline float* ptr() { return &elems[0][0];}
         [[nodiscard]] inline const float* ptr() const {return &elems[0][0];}
 
-
-        /// Convers this rotation matrix to a quaternion.
-        /// This function assumes that the matrix is orthonormal (no shear or scaling) and does not perform any mirroring (determinant > 0)
-        [[nodiscard]] Quaternion ToQuat() const;
         /// Attempts to convert this matrix to a quaternion. Returns false if the conversion cannot succeed (this matrix was not a rotation
         /// matrix, and there is scaling ,shearing, or mirroring in this matrix)
         bool TryConvertToQuat(Quaternion& q) const;
 
-        /// Converts this rotation matrix to an Euler Angle.
-        [[nodiscard]] EulerAngle ToEulerAngle() const;
-
         /// Returns the main diagonal.
         /// The main diagonal consists of the elements at m[0][0], m[1][1], m[2][2]
         [[nodiscard]] Vector3 Diagonal() const;

include/J3ML/LinearAlgebra/Matrix4x4.hpp

@@ -71,8 +71,7 @@ namespace J3ML::LinearAlgebra {
 
         /// Constructs this Matrix4x4 from the given quaternion.
         explicit Matrix4x4(const Quaternion& orientation);
-        /// Constructs this Matrix4x4 from the given Euler Angle.
-        explicit Matrix4x4(const EulerAngle& orientation);
+
 
         /// Constructs this float4x4 from the given quaternion and translation.
         /// Logically, the translation occurs after the rotation has been performed.
@@ -567,8 +566,6 @@ namespace J3ML::LinearAlgebra {
 
         [[nodiscard]] Quaternion ToQuat() const;
 
-        [[nodiscard]] EulerAngle ToEulerAngle() const;
-
         /// Returns true if this Matrix4x4 is equal to the given Matrix4x4, up to given per-element epsilon.
         bool Equals(const Matrix4x4& other, float epsilon = 1e-3f) const;
 

include/J3ML/LinearAlgebra/Quaternion.hpp

@@ -4,258 +4,237 @@
 #include <J3ML/Algorithm/RNG.hpp>
 #include <cmath>
 
-namespace J3ML::LinearAlgebra
-{
-    class Quaternion {
-    public:
-        /// The identity quaternion performs no rotation when applied to a vector.
-        static const Quaternion Identity;
-        /// A compile-time constant Quaternion with the value (NAN, NAN, NAN, NAN).
-        /// For this constant, each element has the value of quiet NAN, or Not-A-Number.
-        /// @note Never compare a Quaternion to this value! Due to how IEEE floats work, "nan == nan" returns false!
-        /// That is, nothing is equal to NaN, not even NaN itself!
-        static const Quaternion NaN;
-    public:
-        /// The default constructor does not initialize any member values.
-        Quaternion();
-        /// Copy constructor
-        Quaternion(const Quaternion &rhs) = default;
-        /// Constructs a quaternion from the given data buffer.
-        /// @param data An array of four floats to use for the quaternion, in the order 'x,y,z,w.' (== 'i,j,k,w')
-        explicit Quaternion(const float *data);
+namespace J3ML::LinearAlgebra {
+    class Quaternion;
+}
 
-        explicit Quaternion(const Matrix3x3 &rotationMtrx);
-        explicit Quaternion(const Matrix4x4 &rotationMtrx);
+class J3ML::LinearAlgebra::Quaternion {
+public:
+    float x;
+    float y;
+    float z;
+    float w;
+public:
+    /// The identity quaternion performs no rotation when applied to a vector.
+    static const Quaternion Identity;
+    /// A compile-time constant Quaternion with the value (NAN, NAN, NAN, NAN).
+    /// For this constant, each element has the value of quiet NAN, or Not-A-Number.
+    /// @note Never compare a Quaternion to this value! Due to how IEEE floats work, "nan == nan" returns false!
+    /// That is, nothing is equal to NaN, not even NaN itself!
+    static const Quaternion NaN;
+public:
+    /// The default constructor does not initialize any member values.
+    Quaternion() = default;
+    /// Copy constructor
+    Quaternion(const Quaternion &rhs);
+    /// Quaternion from Matrix3x3
+    explicit Quaternion(const Matrix3x3& ro_mat);
+    /// Quaternion from Matrix4x4 RotatePart.
+    explicit Quaternion(const Matrix4x4& ro_mat);
+    /// Quaternion from EulerAngleXYZ.
+    explicit Quaternion(const EulerAngleXYZ& rhs);
+    /// Quaternion from AxisAngle.
+    explicit Quaternion(const AxisAngle& angle);
+    /// Quaternion from Vector4 (no conversion).
+    explicit Quaternion(const Vector4& vector4);
 
-        /// @param x The factor of i.
-        /// @param y The factor of j.
-        /// @param z The factor of k.
-        /// @param w The scalar factor (or 'w').
-        /// @note The input data is not normalized after construction, this has to be done manually.
-        Quaternion(float X, float Y, float Z, float W);
+    /// @param x The factor of i.
+    /// @param y The factor of j.
+    /// @param z The factor of k.
+    /// @param w The scalar factor (or 'w').
+    /// @note The input data is not normalized after construction, this has to be done manually.
+    Quaternion(float X, float Y, float Z, float W);
 
-        /// Constructs this quaternion by specifying a rotation axis and the amount of rotation to be performed about that axis
-        /// @param rotationAxis The normalized rotation axis to rotate about. If using Vector4 version of the constructor, the w component of this vector must be 0.
-        /// @param rotationAngleRadians The angle to rotate by, in radians. For example, Pi/4.f equals to 45 degrees, Pi/2.f is 90 degrees, etc.
-        /// @see DegToRad()
-        Quaternion(const Vector3 &rotationAxis, float rotationAngleRadians);
-        Quaternion(const Vector4 &rotationAxis, float rotationAngleRadians);
+    /// Creates a LookAt quaternion.
+    /** A LookAt quaternion is a quaternion that orients an object to face towards a specified target direction.
+    @param localForward Specifies the forward direction in the local space of the object. This is the direction
+    the model is facing at in its own local/object space, often +X(1,0,0), +Y(0,1,0), or +Z(0,0,1).
+    The vector to pass in here depends on the conventions you or your modeling software is using, and it is best
+    to pick one convention for all your objects, and be consistent.
+    This input parameter must be a normalized vector.
+    @param targetDirection Specifies the desired world space direction the object should look at. This function
+    will compute a quaternion which will rotate the localForward vector to orient towards this targetDirection
+    vector. This input parameter must be a normalized vector.
+    @param localUp Specifies the up direction in the local space of the object. This is the up direction the model
+    was authored in, often +Y (0,1,0) or +Z (0,0,1). The vector to pass in here depends on the conventions you
+    or your modeling software is using, and it is best to pick one convention for all your objects, and be
+    consistent. This input parameter must be a normalized vector. This vector must be perpendicular to the
+    vector localForward, i.e. localForward.Dot(localUp) == 0.
+    @param worldUp Specifies the global up direction of the scene in world space. Simply rotating one vector to
+    coincide with another (localForward->targetDirection) would cause the up direction of the resulting
+    orientation to drift (e.g. the model could be looking at its target its head slanted sideways). To keep
+    the up direction straight, this function orients the localUp direction of the model to point towards
+    the specified worldUp direction (as closely as possible). The worldUp and targetDirection vectors cannot be
+    collinear, but they do not need to be perpendicular either.
+    @return A quaternion that maps the given local space forward direction vector to point towards the given target
+    direction, and the given local up direction towards the given target world up direction. For the returned
+    quaternion Q it holds that M * localForward = targetDirection, and M * localUp lies in the plane spanned
+    by the vectors targetDirection and worldUp.
+    @see RotateFromTo() */
+    static Quaternion LookAt(const Vector3& localForward, const Vector3& targetDirection, const Vector3& localUp, const Vector3& worldUp);
 
-        explicit Quaternion(const Vector4& vector4);
-        explicit Quaternion(const EulerAngle& angle);
-        explicit Quaternion(const AxisAngle& angle);
+     /// Creates a new quaternion that rotates about the positive X axis by the given rotation.
+     static Quaternion RotateX(float rad);
+     /// Creates a new quaternion that rotates about the positive Y axis by the given rotation.
+     static Quaternion RotateY(float rad);
+     /// Creates a new quaternion that rotates about the positive Z axis by the given rotation.
+     static Quaternion RotateZ(float rad);
 
-        /// Creates a LookAt quaternion.
-        /** A LookAt quaternion is a quaternion that orients an object to face towards a specified target direction.
-            @param localForward Specifies the forward direction in the local space of the object. This is the direction
-                the model is facing at in its own local/object space, often +X(1,0,0), +Y(0,1,0), or +Z(0,0,1).
-                The vector to pass in here depends on the conventions you or your modeling software is using, and it is best
-                to pick one convention for all your objects, and be consistent.
-                This input parameter must be a normalized vector.
-            @param targetDirection Specifies the desired world space direction the object should look at. This function
-                will compute a quaternion which will rotate the localForward vector to orient towards this targetDirection
-                vector. This input parameter must be a normalized vector.
-            @param localUp Specifies the up direction in the local space of the object. This is the up direction the model
-                was authored in, often +Y (0,1,0) or +Z (0,0,1). The vector to pass in here depends on the conventions you
-                or your modeling software is using, and it is best to pick one convention for all your objects, and be
-                consistent. This input parameter must be a normalized vector. This vector must be perpendicular to the
-                vector localForward, i.e. localForward.Dot(localUp) == 0.
-            @param worldUp Specifies the global up direction of the scene in world space. Simply rotating one vector to
-                coincide with another (localForward->targetDirection) would cause the up direction of the resulting
-                orientation to drift (e.g. the model could be looking at its target its head slanted sideways). To keep
-                the up direction straight, this function orients the localUp direction of the model to point towards
-                the specified worldUp direction (as closely as possible). The worldUp and targetDirection vectors cannot be
-                collinear, but they do not need to be perpendicular either.
-            @return A quaternion that maps the given local space forward direction vector to point towards the given target
-                direction, and the given local up direction towards the given target world up direction. For the returned
-                quaternion Q it holds that M * localForward = targetDirection, and M * localUp lies in the plane spanned
-                by the vectors targetDirection and worldUp.
-            @see RotateFromTo() */
-        static Quaternion LookAt(const Vector3& localForward, const Vector3& targetDirection, const Vector3& localUp, const Vector3& worldUp);
+     /// Creates a new quaternion that rotates sourceDirection vector (in world space) to coincide with the
+     /// targetDirection vector (in world space).
+     /// Rotation is performed about the origin.
+     /// The vectors sourceDirection and targetDirection are assumed to be normalized.
+     /// @note There are multiple such rotations - this function returns the rotation that has the shortest angle
+     /// (when decomposed to axis-angle notation).
+     static Quaternion RotateFromTo(const Vector3& sourceDirection, const Vector3& targetDirection);
+     static Quaternion RotateFromTo(const Vector4& sourceDirection, const Vector4& targetDirection);
 
-        /// Creates a new Quaternion that rotates about the given axis by the given angle.
-        static Quaternion RotateAxisAngle(const AxisAngle& axisAngle);
-
-        /// Creates a new quaternion that rotates about the positive X axis by the given rotation.
-        static Quaternion RotateX(float angleRadians);
-        /// Creates a new quaternion that rotates about the positive Y axis by the given rotation.
-        static Quaternion RotateY(float angleRadians);
-        /// Creates a new quaternion that rotates about the positive Z axis by the given rotation.
-        static Quaternion RotateZ(float angleRadians);
-
-        /// Creates a new quaternion that rotates sourceDirection vector (in world space) to coincide with the
-        /// targetDirection vector (in world space).
-        /// Rotation is performed about the origin.
-        /// The vectors sourceDirection and targetDirection are assumed to be normalized.
-        /// @note There are multiple such rotations - this function returns the rotation that has the shortest angle
-        /// (when decomposed to axis-angle notation).
-        static Quaternion RotateFromTo(const Vector3& sourceDirection, const Vector3& targetDirection);
-        static Quaternion RotateFromTo(const Vector4& sourceDirection, const Vector4& targetDirection);
-
-        /// Creates a new quaternion that
-        /// 1. rotates sourceDirection vector to coincide with the targetDirection vector, and then
-        /// 2. rotates sourceDirection2 (which was transformed by 1.) to targetDirection2, but keeping the constraint that
-        /// sourceDirection must look at targetDirection
-        static Quaternion RotateFromTo(const Vector3& sourceDirection, const Vector3& targetDirection, const Vector3& sourceDirection2, const Vector3& targetDirection2);
+     /// Creates a new quaternion that
+     /// 1. rotates sourceDirection vector to coincide with the targetDirection vector, and then
+     /// 2. rotates sourceDirection2 (which was transformed by 1.) to targetDirection2, but keeping the constraint that
+     /// sourceDirection must look at targetDirection
+     static Quaternion RotateFromTo(const Vector3& sourceDirection, const Vector3& targetDirection, const Vector3& sourceDirection2, const Vector3& targetDirection2);
 
 
-        /// Returns a uniformly random unitary quaternion.
-        static Quaternion RandomRotation(RNG &rng);
-    public:
-        void SetFromAxisAngle(const Vector3 &vector3, float between);
+     /// Returns a uniformly random unitary quaternion.
+     static Quaternion RandomRotation(RNG &rng);
+public:
+    /// Inverses this quaternion in-place.
+    /// @note For optimization purposes, this function assumes that the quaternion is unitary, in which
+    /// case the inverse of the quaternion is simply just the same as its conjugate.
+    /// This function does not detect whether the operation succeeded or failed.
+    void Inverse();
 
-        void SetFromAxisAngle(const Vector4 &vector4, float between);
-        void SetFrom(const AxisAngle& angle);
+    /// Returns an inverted copy of this quaternion.
+    [[nodiscard]] Quaternion Inverted() const;
+    /// Computes the conjugate of this quaternion in-place.
+    void Conjugate();
+    /// Returns a conjugated copy of this quaternion.
+    [[nodiscard]] Quaternion Conjugated() const;
 
-        /// Inverses this quaternion in-place.
-        /// @note For optimization purposes, this function assumes that the quaternion is unitary, in which
-        /// case the inverse of the quaternion is simply just the same as its conjugate.
-        /// This function does not detect whether the operation succeeded or failed.
-        void Inverse();
+    /// Inverses this quaternion in-place.
+    /// Call this function when the quaternion is not known beforehand to be normalized.
+    /// This function computes the inverse proper, and normalizes the result.
+    /// @note Because of the normalization, it does not necessarily hold that q * q.InverseAndNormalize() == id.
+    /// @return Returns the old length of this quaternion (not the old length of the inverse quaternion).
+    float InverseAndNormalize();
 
-        /// Returns an inverted copy of this quaternion.
-        [[nodiscard]] Quaternion Inverted() const;
-        /// Computes the conjugate of this quaternion in-place.
-        void Conjugate();
-        /// Returns a conjugated copy of this quaternion.
-        [[nodiscard]] Quaternion Conjugated() const;
+    /// Returns the local +X axis in the post-transformed coordinate space. This is the same as transforming the vector (1,0,0) by this quaternion.
+    [[nodiscard]] Vector3 WorldX() const;
+    /// Returns the local +Y axis in the post-transformed coordinate space. This is the same as transforming the vector (0,1,0) by this quaternion.
+    [[nodiscard]] Vector3 WorldY() const;
+    /// Returns the local +Z axis in the post-transformed coordinate space. This is the same as transforming the vector (0,0,1) by this quaternion.
+    [[nodiscard]] Vector3 WorldZ() const;
+    /// Returns the axis of rotation for this quaternion.
+    [[nodiscard]] Vector3 Axis() const;
 
-        /// Inverses this quaternion in-place.
-        /// Call this function when the quaternion is not known beforehand to be normalized.
-        /// This function computes the inverse proper, and normalizes the result.
-        /// @note Because of the normalization, it does not necessarily hold that q * q.InverseAndNormalize() == id.
-        /// @return Returns the old length of this quaternion (not the old length of the inverse quaternion).
-        float InverseAndNormalize();
+    /// Returns the angle of rotation for this quaternion, in radians.
+    [[nodiscard]] float Angle() const;
 
-        /// Returns the local +X axis in the post-transformed coordinate space. This is the same as transforming the vector (1,0,0) by this quaternion.
-        [[nodiscard]] Vector3 WorldX() const;
-        /// Returns the local +Y axis in the post-transformed coordinate space. This is the same as transforming the vector (0,1,0) by this quaternion.
-        [[nodiscard]] Vector3 WorldY() const;
-        /// Returns the local +Z axis in the post-transformed coordinate space. This is the same as transforming the vector (0,0,1) by this quaternion.
-        [[nodiscard]] Vector3 WorldZ() const;
+    [[nodiscard]] float LengthSquared() const;
+    [[nodiscard]] float Length() const;
 
-        /// Returns the axis of rotation for this quaternion.
-        [[nodiscard]] Vector3 Axis() const;
+    [[nodiscard]] Matrix3x3 ToMatrix3x3() const;
+    [[nodiscard]] Matrix4x4 ToMatrix4x4() const;
 
-        /// Returns the angle of rotation for this quaternion, in radians.
-        [[nodiscard]] float Angle() const;
+    [[nodiscard]] Matrix4x4 ToMatrix4x4(const Vector3 &translation) const;
 
-        [[nodiscard]] float LengthSquared() const;
-        [[nodiscard]] float Length() const;
+    [[nodiscard]] Vector3 Transform(const Vector3& vec) const;
+    [[nodiscard]] Vector3 Transform(float X, float Y, float Z) const;
+    // Note: We only transform the x,y,z components of 4D vectors, w is left untouched
+    [[nodiscard]] Vector4 Transform(const Vector4& vec) const;
+    [[nodiscard]] Vector4 Transform(float X, float Y, float Z, float W) const;
 
-        [[nodiscard]] EulerAngle ToEulerAngle() const;
+    [[nodiscard]] Quaternion Lerp(const Quaternion& b, float t) const;
+    static Quaternion Lerp(const Quaternion &source, const Quaternion& target, float t);
+    [[nodiscard]] Quaternion Slerp(const Quaternion& q2, float t) const;
+    static Quaternion Slerp(const Quaternion &source, const Quaternion& target, float t);
+
+    /// Returns the 'from' vector rotated towards the 'to' vector by the given normalized time parameter.
+    /** This function slerps the given 'form' vector toward the 'to' vector.
+    @param from A normalized direction vector specifying the direction of rotation at t=0
+    @param to A normalized direction vector specifying the direction of rotation at t=1
+    @param t The interpolation time parameter, in the range [0, 1]. Input values outside this range are
+    silently clamped to the [0, 1] interval.
+    @return A spherical linear interpolation of the vector 'from' towards the vector 'to'. */
+    static Vector3 SlerpVector(const Vector3& from, const Vector3& to, float t);
+
+    /// Returns the 'from' vector rotated towards the 'to' vector by the given absolute angle, in radians.
+    /** This function slerps the given 'from' vector towards the 'to' vector.
+    @param from A normalized direction vector specifying the direction of rotation at angleRadians=0.
+    @param to A normalized direction vector specifying the target direction to rotate towards.
+    @param angleRadians The maximum angle to rotate the 'from' vector by, in the range [0, pi]. If the
+    angle between 'from' and 'to' is smaller than this angle, then the vector 'to' is returned.
+    Input values outside this range are silently clamped to the [0, pi] interval.
+    @return A spherical linear interpolation of the vector 'from' towards the vector 'to'. */
+    static Vector3 SlerpVectorAbs(const Vector3 &from, const Vector3& to, float angleRadians);
+
+    /// Normalizes this quaternion in-place.
+    /// @returns false if failure, true if success.
+    [[nodiscard]] bool Normalize();
+    /// Returns a normalized copy of this quaternion.
+    [[nodiscard]] Quaternion Normalized() const;
+
+    /// Returns true if the length of this quaternion is one.
+    [[nodiscard]] bool IsNormalized(float epsilon = 1e-5f) const;
+    [[nodiscard]] bool IsInvertible(float epsilon = 1e-3f) const;
+
+    /// Returns true if the entries of this quaternion are all finite.
+    [[nodiscard]] bool IsFinite() const;
+
+    /// Returns true if this quaternion equals rhs, up to the given epsilon.
+    [[nodiscard]] bool Equals(const Quaternion& rhs, float epsilon = 1e-3f) const;
+
+    /// Compares whether this Quaternion and the given Quaternion are identical bit-by-bit in the underlying representation.
+    /// @note Prefer using this over e.g. memcmp, since there can be SSE-related padding in the structures.
+    bool BitEquals(const Quaternion& rhs) const;
+
+    /// @return A pointer to the first element (x). The data is contiguous in memory.
+    /// ptr[0] gives x, ptr[1] gives y, ptr[2] gives z, ptr[3] gives w.
+    inline float *ptr() { return &x; }
+    [[nodiscard]] inline const float *ptr() const { return &x; }
 
 
-        [[nodiscard]] Matrix3x3 ToMatrix3x3() const;
-        [[nodiscard]] Matrix4x4 ToMatrix4x4() const;
+    // Multiplies two quaternions together.
+    // The product q1 * q2 returns a quaternion that concatenates the two orientation rotations.
+    // The rotation q2 is applied first before q1.
+    Quaternion operator * (const Quaternion& rhs) const;
 
-        [[nodiscard]] Matrix4x4 ToMatrix4x4(const Vector3 &translation) const;
+    // Unsafe
+    Quaternion operator * (float scalar) const;
 
-        [[nodiscard]] Vector3 Transform(const Vector3& vec) const;
-        [[nodiscard]] Vector3 Transform(float X, float Y, float Z) const;
-        // Note: We only transform the x,y,z components of 4D vectors, w is left untouched
-        [[nodiscard]] Vector4 Transform(const Vector4& vec) const;
-        [[nodiscard]] Vector4 Transform(float X, float Y, float Z, float W) const;
+    // Unsafe
+    Quaternion operator / (float scalar) const;
 
-        [[nodiscard]] Quaternion Lerp(const Quaternion& b, float t) const;
-        static Quaternion Lerp(const Quaternion &source, const Quaternion& target, float t);
-        [[nodiscard]] Quaternion Slerp(const Quaternion& q2, float t) const;
-        static Quaternion Slerp(const Quaternion &source, const Quaternion& target, float t);
+    // Transforms the given vector by this Quaternion.
+    Vector3 operator * (const Vector3& rhs) const;
 
-        /// Returns the 'from' vector rotated towards the 'to' vector by the given normalized time parameter.
-        /** This function slerps the given 'form' vector toward the 'to' vector.
-            @param from A normalized direction vector specifying the direction of rotation at t=0
-            @param to A normalized direction vector specifying the direction of rotation at t=1
-            @param t The interpolation time parameter, in the range [0, 1]. Input values outside this range are
-            silently clamped to the [0, 1] interval.
-            @return A spherical linear interpolation of the vector 'from' towards the vector 'to'. */
-        static Vector3 SlerpVector(const Vector3& from, const Vector3& to, float t);
+    Vector4 operator * (const Vector4& rhs) const;
 
-        /// Returns the 'from' vector rotated towards the 'to' vector by the given absolute angle, in radians.
-        /** This function slerps the given 'from' vector towards the 'to' vector.
-            @param from A normalized direction vector specifying the direction of rotation at angleRadians=0.
-            @param to A normalized direction vector specifying the target direction to rotate towards.
-            @param angleRadians The maximum angle to rotate the 'from' vector by, in the range [0, pi]. If the
-                angle between 'from' and 'to' is smaller than this angle, then the vector 'to' is returned.
-                Input values outside this range are silently clamped to the [0, pi] interval.
-            @return A spherical linear interpolation of the vector 'from' towards the vector 'to'. */
-        static Vector3 SlerpVectorAbs(const Vector3 &from, const Vector3& to, float angleRadians);
-
-        /// Normalizes this quaternion in-place.
-        /// Returns the old length of this quaternion, or 0 if normalization failed.
-        float Normalize();
-        /// Returns a normalized copy of this quaternion.
-        [[nodiscard]] Quaternion Normalized() const;
-
-        /// Returns true if the length of this quaternion is one.
-        [[nodiscard]] bool IsNormalized(float epsilon = 1e-5f) const;
-        [[nodiscard]] bool IsInvertible(float epsilon = 1e-3f) const;
-
-        /// Returns true if the entries of this quaternion are all finite.
-        [[nodiscard]] bool IsFinite() const;
-
-        /// Returns true if this quaternion equals rhs, up to the given epsilon.
-        [[nodiscard]] bool Equals(const Quaternion& rhs, float epsilon = 1e-3f) const;
-
-        /// Compares whether this Quaternion and the given Quaternion are identical bit-by-bit in the underlying representation.
-        /// @note Prefer using this over e.g. memcmp, since there can be SSE-related padding in the structures.
-        bool BitEquals(const Quaternion& rhs) const;
-
-        /// @return A pointer to the first element (x). The data is contiguous in memory.
-        /// ptr[0] gives x, ptr[1] gives y, ptr[2] gives z, ptr[3] gives w.
-        inline float *ptr() { return &x; }
-        [[nodiscard]] inline const float *ptr() const { return &x; }
-
-
-        // Multiplies two quaternions together.
-        // The product q1 * q2 returns a quaternion that concatenates the two orientation rotations.
-        // The rotation q2 is applied first before q1.
-        Quaternion operator * (const Quaternion& rhs) const;
-
-        // Unsafe
-        Quaternion operator * (float scalar) const;
-
-        // Unsafe
-        Quaternion operator / (float scalar) const;
-
-        // Transforms the given vector by this Quaternion.
-        Vector3 operator * (const Vector3& rhs) const;
-
-        Vector4 operator * (const Vector4& rhs) const;
-
-        // Divides a quaternion by another. Divison "a / b" results in a quaternion that rotates the orientation b to coincide with orientation of
-        Quaternion operator / (const Quaternion& rhs) const;
-        Quaternion operator + (const Quaternion& rhs) const;
+    // Divides a quaternion by another. Divison "a / b" results in a quaternion that rotates the orientation b to coincide with orientation of
+    Quaternion operator / (const Quaternion& rhs) const;
+    Quaternion operator + (const Quaternion& rhs) const;
 
 
 
-        Quaternion operator + () const;
-        Quaternion operator - () const;
+    Quaternion operator + () const;
+    Quaternion operator - () const;
 
-        /// Computes the dot product of this and the given quaternion.
-        /// Dot product is commutative.
-        [[nodiscard]] float Dot(const Quaternion &quaternion) const;
+    /// Computes the dot product of this and the given quaternion.
+    /// Dot product is commutative.
+    [[nodiscard]] float Dot(const Quaternion &quaternion) const;
 
-        /// Returns the angle between this and the target orientation (the shortest route) in radians.
-        [[nodiscard]] float AngleBetween(const Quaternion& target) const;
-        /// Returns the axis of rotation to get from this orientation to target orientation (the shortest route).
-        [[nodiscard]] Vector3 AxisFromTo(const Quaternion& target) const;
+    /// Returns the angle between this and the target orientation (the shortest route) in radians.
+    [[nodiscard]] float AngleBetween(const Quaternion& target) const;
+    /// Returns the axis of rotation to get from this orientation to target orientation (the shortest route).
+    [[nodiscard]] Vector3 AxisFromTo(const Quaternion& target) const;
 
 
-        [[nodiscard]] AxisAngle ToAxisAngle() const;
-        void SetFromAxisAngle(const AxisAngle& axisAngle);
+    /// Sets this quaternion to represent the same rotation as the given matrix.
+    void Set(const Matrix3x3& matrix);
+    void Set(const Matrix4x4& matrix);
+    void Set(float x, float y, float z, float w);
+    void Set(const Quaternion& q);
+    void Set(const Vector4& v);
 
-        /// Sets this quaternion to represent the same rotation as the given matrix.
-        void Set(const Matrix3x3& matrix);
-        void Set(const Matrix4x4& matrix);
-        void Set(float x, float y, float z, float w);
-        void Set(const Quaternion& q);
-        void Set(const Vector4& v);
-
-    public:
-        float x;
-        float y;
-        float z;
-        float w;
-    };
-}
+};

include/J3ML/LinearAlgebra/Vector3.hpp

@@ -68,15 +68,15 @@ public:
     /** @note Due to static data initialization order being undefined in C++, do NOT use this
         member to initialize other static data in other compilation units! */
     static const Vector3 NegativeInfinity;
-    /// Specifies a compile-time constant Vector3 with value (1,1,1).
+    /// Specifies a compile-time constant Vector3 with value (1,0,0).
     /** @note Due to static data initialization order being undefined in C++, do NOT use this
         member to initialize other static data in other compilation units! */
     static const Vector3 UnitX;
-    /// Specifies a compile-time constant Vector3 with value (1,1,1).
+    /// Specifies a compile-time constant Vector3 with value (0,1,0).
     /** @note Due to static data initialization order being undefined in C++, do NOT use this
         member to initialize other static data in other compilation units! */
     static const Vector3 UnitY;
-    /// Specifies a compile-time constant Vector3 with value (1,1,1).
+    /// Specifies a compile-time constant Vector3 with value (0,0,1).
     /** @note Due to static data initialization order being undefined in C++, do NOT use this
         member to initialize other static data in other compilation units! */
     static const Vector3 UnitZ;

src/J3ML/LinearAlgebra/AxisAngle.cpp

@@ -2,60 +2,22 @@
 #include <J3ML/LinearAlgebra/Quaternion.hpp>
 namespace J3ML::LinearAlgebra {
 
-    AxisAngle::AxisAngle() : axis(Vector3::Zero) {}
+    AxisAngle::AxisAngle() : axis(Vector3::Zero), angle(0) {}
 
-    AxisAngle::AxisAngle(const Vector3 &axis, float angle) : axis(axis), angle(angle) {}
+    AxisAngle::AxisAngle(const Vector3& axis, float angle) : axis(axis), angle(angle) {}
 
-    Quaternion AxisAngle::ToQuaternion() const {
-        return {
-                axis.x * std::sin(angle/2),
-                axis.y * std::sin(angle/2),
-                axis.z * std::sin(angle/2),
-                std::cos(angle/2)
-        };
+
+    AxisAngle::AxisAngle(const Quaternion& rhs) {
+        float halfAngle = std::acos(rhs.w);
+        angle = halfAngle * 2.f;
+        float reciprocalSinAngle = 1.f / std::sqrt(1.f - rhs.w*rhs.w);
+
+        axis = { rhs.x*reciprocalSinAngle, rhs.y*reciprocalSinAngle, rhs.z*reciprocalSinAngle };
     }
 
-    AxisAngle::AxisAngle(const Quaternion &q) {
-        auto theta = std::acos(q.w) * 2.f;
-        auto ax = q.x / std::sin(std::acos(theta));
-        auto ay = q.y / std::sin(std::acos(theta));
-        auto az = q.z / std::sin(std::acos(theta));
-    }
-
-    AxisAngle::AxisAngle(const EulerAngle &e) {
-
-        // Assuming the angles are in radians
-
-        float heading = e.pitch;
-        float attitude = e.yaw;
-        float bank = e.roll;
-
-        float c1 = std::cos(heading / 2.f);
-        float s1 = std::sin(heading / 2.f);
-        float c2 = std::cos(attitude / 2.f);
-        float s2 = std::sin(attitude / 2.f);
-        float c3 = std::cos(bank / 2.f);
-        float s3 = std::sin(bank / 2.f);
-
-        float w = c1*c2*c3 - s1*s2*s3;
-        float x = c1*c2*c3 + s1*s2*s3;
-        float y = s1*c2*c3 + c1*s2*s3;
-        float z = c1*s2*c3 - s1*c2*s3;
-
-        angle = 2.f * std::acos(w);
-
-        double norm = x*x + y*y + z*z;
-        if (norm < 0.001) { // when all euler angles are zero angle=0, so
-            // we can set axis to anything to avoid divide by zero
-            x = 1;
-            y = z = 0;
-        } else {
-            norm = std::sqrt(norm);
-            x /= norm;
-            y /= norm;
-            z /= norm;
-        }
-
-        axis = {x, y, z};
+    AxisAngle::AxisAngle(const EulerAngleXYZ& e) {
+        auto a = AxisAngle(Quaternion(e));
+        axis = a.axis;
+        angle = a.angle;
     }
 }

src/J3ML/LinearAlgebra/DirectionVector.cpp

@@ -0,0 +1,38 @@
+#include <J3ML/LinearAlgebra/DirectionVector.hpp>
+#include <J3ML/LinearAlgebra/Matrix3x3.hpp>
+
+DirectionVectorRH::DirectionVectorRH(const Vector3& rhs) {
+    x = rhs.x;
+    y = rhs.y;
+    z = rhs.z;
+}
+
+DirectionVectorRH DirectionVectorRH::Forward(const Matrix3x3& rhs) {
+    return DirectionVectorRH(rhs.Col(2));
+}
+
+DirectionVectorRH DirectionVectorRH::Backward(const Matrix3x3& rhs) {
+    return DirectionVectorRH(-rhs.Col(2));
+}
+
+DirectionVectorRH DirectionVectorRH::Left(const Matrix3x3& rhs) {
+    return DirectionVectorRH(-rhs.Col(0));
+}
+
+DirectionVectorRH DirectionVectorRH::Right(const Matrix3x3& rhs) {
+    return DirectionVectorRH(rhs.Col(0));
+}
+
+DirectionVectorRH DirectionVectorRH::Up(const Matrix3x3 &rhs) {
+    return DirectionVectorRH(rhs.Col(1));
+}
+
+DirectionVectorRH DirectionVectorRH::Down(const Matrix3x3& rhs) {
+    return DirectionVectorRH(-rhs.Col(1));
+}
+
+
+
+
+
+

src/J3ML/LinearAlgebra/EulerAngle.cpp

@@ -1,147 +1,45 @@
 #include <J3ML/LinearAlgebra/EulerAngle.hpp>
+#include <J3ML/LinearAlgebra/Matrix3x3.hpp>
 #include <cmath>
 #include <algorithm>
 
 
 namespace J3ML::LinearAlgebra {
-    EulerAngle::EulerAngle(float pitch, float yaw, float roll): pitch(pitch), yaw(yaw), roll(roll)
-    {}
 
-    float EulerAngle::GetPitch(float pitch_limit) const
-    { return std::clamp( std::remainderf(pitch,360.f), -pitch_limit, pitch_limit); }
-
-    float EulerAngle::GetYaw(float yaw_limit) const
-    { return std::clamp(std::remainderf(yaw, 360.f), -yaw_limit, yaw_limit);   }
-
-    float EulerAngle::GetRoll(float pitch_limit) const
-    { return std::clamp( std::remainderf(pitch,360.f), -pitch_limit, pitch_limit); }
-
-    bool EulerAngle::operator==(const EulerAngle& a) const
-    {
-        return (pitch == a.pitch) && (yaw == a.yaw) && (roll == a.roll);
+    EulerAngleXYZ::EulerAngleXYZ(float roll, float pitch, float yaw) {
+        this->roll = roll;
+        this->pitch = pitch;
+        this->yaw = yaw;
     }
 
-    void EulerAngle::clamp()
-    {
-        if (this->pitch > 89.0f)
-            this->pitch = 89.0f;
-        if (this->pitch <= -89.0f)
-            this->pitch = -89.0f;
-        //TODO: Make this entirely seamless by getting the amount they rotated passed -180 and +180 by.
-        if (this->yaw <= -180.0f)
-            this->yaw = 180.0f;
-        if (this->yaw >= 180.01f)
-            this->yaw = -179.9f;
-        if (this->roll >= 360.0f)
-            this->roll = 0.0;
-        if (this->roll <= -360.0f)
-            this->roll = 0.0;
+    EulerAngleXYZ::EulerAngleXYZ(const AxisAngle& rhs) {
+        *this = EulerAngleXYZ(Quaternion(rhs));
     }
 
-    EulerAngle EulerAngle::movementAngle() const
-    {
-        EulerAngle a;
-        a.pitch = (cos(Math::Radians(yaw)) * cos(Math::Radians(pitch)));
-        a.yaw = -sin(Math::Radians(pitch));
-        a.roll = (sin(Math::Radians(yaw)) * cos(Math::Radians(pitch)));
-        return a;
+    EulerAngleXYZ::EulerAngleXYZ(const Quaternion& q) {
+        float sy = 2 * q.x * q.z + 2 * q.y * q.w;
+        bool gimbal_lock = std::abs(sy) > 0.99999f;
+
+        if (!gimbal_lock)
+            roll = Math::Degrees(std::atan2(-(2 * q.y * q.z - 2 * q.x * q.w),2 * q.w * q.w + 2 * q.z * q.z - 1));
+        else
+            roll = Math::Degrees(std::atan2(2 * q.y * q.z + 2 * q.x * q.w,2 * q.w * q.w + 2 * q.y * q.y - 1));
+
+        pitch = Math::Degrees(std::asin(sy));
+
+        if (!gimbal_lock)
+            yaw = Math::Degrees(std::atan2(-(2 * q.x * q.y - 2 * q.z * q.w),2 * q.w * q.w + 2 * q.x * q.x - 1));
+        else
+            yaw = 0;
     }
 
-    EulerAngle::EulerAngle() : pitch(0), yaw(0), roll(0) {}
+    EulerAngleXYZ::EulerAngleXYZ(const Matrix3x3& rhs) {
+        auto m = rhs.Transposed();
+        auto sy = m.At(0, 2);
+        auto unlocked = std::abs(sy) < 0.99999f;
 
-    EulerAngle::EulerAngle(const AxisAngle &rhs) {
-
-        float x = rhs.axis.x;
-        float y = rhs.axis.y;
-        float z = rhs.axis.z;
-        float angle = rhs.angle;
-
-        double s = std::sin(rhs.angle);
-
-        double c = std::cos(rhs.angle);
-
-        double t = 1-c;
-
-        // if axis is not already normalized then uncomment this
-
-        // double magnitude = std::sqrt(x*x + y*y + z*z);
-        // if (magnitude == 0) throw error;
-        // x /= magnitude;
-        // y /= magnitude;
-        // z /= magnitude;
-
-        if ((x*y*t + z*s) > 0.998) { // North pole singularity detected
-            pitch = 2 * std::atan2(x * std::sin(angle/2.f), std::cos(angle/2.f));
-            yaw = Math::Pi / 2.f;
-            roll = 0;
-            return;
-        }
-
-        if ((x*y*t + z*s) < -0.998) { // South pole singularity detected
-            pitch = -2 * std::atan2(x * std::sin(angle/2.f), std::cos(angle/2.f));
-            yaw = -Math::Pi / 2.f;
-            roll = 0;
-            return;
-        }
-
-        pitch = std::atan2(y * s-x * z * t, 1 - (y*y + z*z) * t);
-        yaw = std::asin(x * y * t + z * s);
-        roll = std::atan2(x * s - y * z * t, 1 - (x*x + z*z) * t);
-    }
-
-    AxisAngle EulerAngle::ToAxisAngle() const {
-        auto c1 = std::cos(yaw / 2);
-        auto c2 = std::cos(pitch / 2);
-        auto c3 = std::cos(roll / 2);
-        auto s1 = std::sin(yaw / 2);
-        auto s2 = std::sin(pitch / 2);
-        auto s3 = std::sin(roll / 2);
-
-        auto angle = 2 * std::acos(c1*c2*c3 - s1*s2*s3);
-
-        auto x = s1*s2*c3 + c1*c2*s3;
-        auto y = s1*c2*c3 + c1*s2*s3;
-        auto z = c1*s2*c3 - s1*c2*s3;
-
-        // todo: normalize?
-        // sqrt(x^2 + y^2 + z^2) = sqrt((s1 s2 c3 +c1 c2 s3)^2+(s1 c2 c3 + c1 s2 s3)^2+(c1 s2 c3 - s1 c2 s3)^2)
-
-        return {{x,y,z}, angle};
-    }
-
-    Quaternion EulerAngle::ToQuaternion() const {
-        auto c1 = std::cos(yaw / 2);
-        auto c2 = std::cos(pitch / 2);
-        auto c3 = std::cos(roll / 2);
-        auto s1 = std::sin(yaw / 2);
-        auto s2 = std::sin(pitch / 2);
-        auto s3 = std::sin(roll / 2);
-
-        auto w = c1*c2*c3 - s1*s2*s3;
-        auto x = s1*s2*c3 + c1*c2*s3;
-        auto y = s1*c2*c3 + c1*s2*s3;
-        auto z = c1*s2*c3 - s1*c2*s3;
-
-        return {w,x,y,z};
-    }
-
-    EulerAngle::EulerAngle(const Quaternion &rhs) {
-        double test = rhs.x * rhs.y + rhs.z * rhs.w;
-        if (test > 0.499) { // Singularity at north pole
-            pitch = 2 * std::atan2(rhs.x, rhs.w);
-            yaw = Math::Pi / 2.f;
-            roll = 0;
-            return;
-        }
-
-        if (test < -0.499) { // Singularity at south pole
-            pitch = -2 * std::atan2(rhs.x, rhs.y);
-            yaw = - Math::Pi / 2.f;
-            roll = 0;
-            return;
-        }
-        float sqx = rhs.x * rhs.x;
-        float sqy = rhs.y * rhs.y;
-        float sqz = rhs.z * rhs.z;
+        roll = Math::Degrees(unlocked ? std::atan2(-m.At(1, 2), m.At(2, 2)) : std::atan2(m.At(2, 1), m.At(1, 1)));
+        pitch = Math::Degrees(std::asin(sy));
+        yaw = Math::Degrees(unlocked ? std::atan2(-m.At(0, 1), m.At(0, 0)) : 0);
     }
 }

src/J3ML/LinearAlgebra/Matrix3x3.cpp

@@ -109,27 +109,8 @@ namespace J3ML::LinearAlgebra {
         //this->elems[2][2] = r3.z;
     }
 
-    Matrix3x3::Matrix3x3(const Quaternion &orientation) {
-        SetRotatePart(orientation);
-    }
-
-    Matrix3x3::Matrix3x3(const EulerAngle &orientation) {
-        auto sa = std::sin(orientation.pitch);
-        auto ca = std::cos(orientation.pitch);
-        auto sb = std::sin(orientation.roll);
-        auto cb = std::cos(orientation.roll);
-        auto sh = std::sin(orientation.yaw);
-        auto ch = std::cos(orientation.yaw);
-
-        At(0, 0) = ch*ca;
-        At(0, 1) = -ch*sa*cb + sh*sh;
-        At(0, 2) = ch*sa*sb + sh*cb;
-        At(1, 0) = sa;
-        At(1, 1) = ca*cb;
-        At(1, 2) = -ca*cb;
-        At(2, 0) = -sh*ca;
-        At(2, 1) = sh*sa*cb + ch*sb;
-        At(2, 2) = -sh*sa*sb + ch*cb;
+    Matrix3x3::Matrix3x3(const Quaternion& orientation) {
+        *this = Matrix3x3(EulerAngleXYZ(orientation));
     }
 
     float Matrix3x3::Determinant() const {
@@ -207,28 +188,7 @@ namespace J3ML::LinearAlgebra {
         };
     }
 
-    Quaternion Matrix3x3::ToQuat() const {
-        auto m00 = At(0,0);
-        auto m01 = At(0, 1);
-        auto m02 = At(0, 2);
-        auto m10 = At(1,0);
-        auto m11 = At(1, 1);
-        auto m12 = At(1, 2);
-        auto m20 = At(2,0);
-        auto m21 = At(2, 1);
-        auto m22 = At(2, 2);
-
-        auto w = std::sqrt(1.f + m00 + m11 + m22) / 2.f;
-        float w4 = (4.f * w);
-        return {
-                (m21 - m12) / w4,
-                (m02 - m20) / w4,
-                (m10 - m01) / w4,
-                w
-        };
-    }
-
-    void Matrix3x3::SetRotatePart(const Vector3 &a, float angle) {
+    void Matrix3x3::SetRotatePart(const Vector3& a, float angle) {
         float s = std::sin(angle);
         float c = std::cos(angle);
 
@@ -371,9 +331,9 @@ namespace J3ML::LinearAlgebra {
         return m;
     }
 
-    Matrix3x3 Matrix3x3::FromScale(float sx, float sy, float sz) {
+    Matrix3x3 Matrix3x3::FromScale(float sin_roll, float sy, float sz) {
         Matrix3x3 m;
-        m.At(0,0) = sx;
+        m.At(0,0) = sin_roll;
         m.At(1,1) = sy;
         m.At(2,2) = sz;
         return m;
@@ -992,25 +952,12 @@ namespace J3ML::LinearAlgebra {
 
     bool Matrix3x3::TryConvertToQuat(Quaternion &q) const {
         if (IsColOrthogonal() && HasUnitaryScale() && !HasNegativeScale()) {
-            q = ToQuat();
+            q = Quaternion(*this);
             return true;
         }
         return false;
     }
 
-    EulerAngle Matrix3x3::ToEulerAngle() const {
-        auto heading = std::atan2(-At(2, 0), At(0, 0));
-        auto attitude = std::asin(At(1, 0));
-        auto bank = std::atan2(-At(1,2), At(1,1));
-        if (At(1, 0) == 1 || At(1, 0) == -1) // North Pole || South Pole
-        {
-            heading = std::atan2(At(0, 2), At(2,2));
-            bank = 0;
-        }
-
-        return {attitude, heading, bank};
-    }
-
     void Matrix3x3::BatchTransform(Vector3 *pointArray, int numPoints, int stride) const {
         assert(pointArray || numPoints == 0);
         assert(stride >= (int)sizeof(Vector3));
@@ -1119,6 +1066,25 @@ namespace J3ML::LinearAlgebra {
         return m;
     }
 
+    Matrix3x3::Matrix3x3(const EulerAngleXYZ& e) {
+        float cos_roll = std::cos(Math::Radians(e.roll));
+        float sin_roll = std::sin(Math::Radians(e.roll));
+        float cos_pitch = std::cos(Math::Radians(e.pitch));
+        float sin_pitch = std::sin(Math::Radians(e.pitch));
+        float cos_yaw = std::cos(Math::Radians(e.yaw));
+        float sin_yaw = std::sin(Math::Radians(e.yaw));
+
+        Matrix3x3 m;
+        m.SetRow(0, Vector3(cos_pitch * cos_yaw, sin_roll * sin_pitch *cos_yaw + cos_roll * sin_yaw, -cos_roll * sin_pitch *cos_yaw + sin_roll * sin_yaw));
+        m.SetRow(1, Vector3(-cos_pitch * sin_yaw, -sin_roll * sin_pitch * sin_yaw + cos_roll *cos_yaw, cos_roll * sin_pitch * sin_yaw + sin_roll *cos_yaw));
+        m.SetRow(2, Vector3(sin_pitch, -sin_roll * cos_pitch, cos_roll * cos_pitch));
+        *this = m;
+    }
+
+    Matrix3x3::Matrix3x3(const AxisAngle& orientation) {
+        *this = Matrix3x3(Quaternion(orientation));
+    }
+
 
 }
 

src/J3ML/LinearAlgebra/Matrix4x4.cpp

@@ -86,10 +86,6 @@ namespace J3ML::LinearAlgebra {
         Set3x3Part(Matrix3x3(orientation));
     }
 
-    Matrix4x4::Matrix4x4(const EulerAngle &orientation) {
-        Set3x3Part(Matrix3x3(orientation));
-    }
-
     void Matrix4x4::SetTranslatePart(float translateX, float translateY, float translateZ) {
         elems[0][3] = translateX;
         elems[1][3] = translateY;
@@ -777,19 +773,6 @@ namespace J3ML::LinearAlgebra {
         };
     }
 
-    EulerAngle Matrix4x4::ToEulerAngle() const {
-        auto heading = std::atan2(-At(2, 0), At(0, 0));
-        auto attitude = std::asin(At(1, 0));
-        auto bank = std::atan2(-At(1,2), At(1,1));
-        if (At(1, 0) == 1 || At(1, 0) == -1) // North Pole || South Pole
-        {
-            heading = std::atan2(At(0, 2), At(2,2));
-            bank = 0;
-        }
-
-        return {attitude, heading, bank};
-    }
-
     bool Matrix4x4::InverseOrthogonalUniformScale() {
         assert(!ContainsProjection());
         assert(IsColOrthogonal(1e-3f));

src/J3ML/LinearAlgebra/Quaternion.cpp

@@ -1,23 +1,46 @@
-#include <J3ML/LinearAlgebra/Vector3.hpp>
-#include <J3ML/LinearAlgebra/Vector4.hpp>
 #include <J3ML/LinearAlgebra/Matrix3x3.hpp>
 #include <J3ML/LinearAlgebra/Matrix4x4.hpp>
 #include <J3ML/LinearAlgebra/Quaternion.hpp>
 #include <J3ML/LinearAlgebra/AxisAngle.hpp>
+#include <J3ML/LinearAlgebra/EulerAngle.hpp>
+#include <J3ML/LinearAlgebra/Vector4.hpp>
+#include <J3ML/LinearAlgebra/Vector3.hpp>
 
 namespace J3ML::LinearAlgebra {
 
     const Quaternion Quaternion::Identity = Quaternion(0.f, 0.f, 0.f, 1.f);
     const Quaternion Quaternion::NaN      = Quaternion(NAN, NAN, NAN, NAN);
 
-    Quaternion Quaternion::operator-() const
-    {
+    Quaternion Quaternion::operator-() const {
         return {-x, -y, -z, -w};
     }
 
-    Quaternion::Quaternion(const Matrix3x3 &rotationMtrx) {}
+    Quaternion::Quaternion(const Matrix3x3& ro_mat) {
+        auto m = ro_mat.Transposed();
+        auto m00 = m.At(0,0);
+        auto m01 = m.At(0, 1);
+        auto m02 = m.At(0, 2);
+        auto m10 = m.At(1,0);
+        auto m11 = m.At(1, 1);
+        auto m12 = m.At(1, 2);
+        auto m20 = m.At(2,0);
+        auto m21 = m.At(2, 1);
+        auto m22 = m.At(2, 2);
 
-    Quaternion::Quaternion(const Matrix4x4 &rotationMtrx) {}
+        auto field_w = std::sqrt(1.f + m00 + m11 + m22) / 2.f;
+        float w4 = (4.f * field_w);
+
+        x = (m21 - m12) / w4;
+        y = (m02 - m20) / w4;
+        z = (m10 - m01) / w4;
+        w = field_w;
+        Normalize();
+    }
+
+    Quaternion::Quaternion(const Matrix4x4& ro_mat) {
+        auto q = Quaternion(ro_mat.GetRotatePart());
+        x = q.x; y = q.y; z = q.z; w = q.w;
+    }
 
     Vector3 Quaternion::WorldX() const { return Transform(1.f, 0.f, 0.f); }
 
@@ -50,22 +73,6 @@ namespace J3ML::LinearAlgebra {
             return (*this * (t - 1.f) + b * t).Normalized();
     }
 
-    void Quaternion::SetFromAxisAngle(const Vector3 &axis, float angle) {
-        float sinz, cosz;
-        sinz = std::sin(angle*0.5f);
-        cosz = std::cos(angle*0.5f);
-
-        x = axis.x * sinz;
-        y = axis.y * sinz;
-        z = axis.z * sinz;
-        w = cosz;
-    }
-
-    void Quaternion::SetFromAxisAngle(const Vector4 &axis, float angle)
-    {
-        SetFromAxisAngle(Vector3(axis.x, axis.y, axis.z), angle);
-    }
-
     Quaternion Quaternion::operator*(float scalar) const {
         return Quaternion(x * scalar, y * scalar, z * scalar, w * scalar);
     }
@@ -82,8 +89,6 @@ namespace J3ML::LinearAlgebra {
 
     Quaternion Quaternion::operator+() const { return *this; }
 
-    Quaternion::Quaternion() {}
-
     Quaternion::Quaternion(float X, float Y, float Z, float W) : x(X), y(Y), z(Z), w(W) {}
 
     // TODO: implement
@@ -148,20 +153,6 @@ namespace J3ML::LinearAlgebra {
         return (*this * (a * sign) + q2 * b).Normalized();
     }
 
-    AxisAngle Quaternion::ToAxisAngle() const {
-        float halfAngle = std::acos(w);
-        float angle = halfAngle * 2.f;
-        // TODO: Can Implement Fast Inverted Sqrt Here
-        float reciprocalSinAngle = 1.f / std::sqrt(1.f - w*w);
-
-        Vector3 axis = {
-                x*reciprocalSinAngle,
-                y*reciprocalSinAngle,
-                z*reciprocalSinAngle
-        };
-        return AxisAngle(axis, angle);
-    }
-
     float Quaternion::AngleBetween(const Quaternion &target) const {
         Quaternion delta = target / *this;
         return delta.Normalized().Angle();
@@ -212,47 +203,13 @@ namespace J3ML::LinearAlgebra {
         return Vector3(x, y, z) * rcpSinAngle;
     }
 
-    Quaternion::Quaternion(const Vector3 &rotationAxis, float rotationAngleRadians) {
-        SetFromAxisAngle(rotationAxis, rotationAngleRadians);
-    }
-
-    Quaternion::Quaternion(const Vector4 &rotationAxis, float rotationAngleRadians) {
-        SetFromAxisAngle(rotationAxis, rotationAngleRadians);
-    }
-
-    Quaternion::Quaternion(const AxisAngle &angle) {
+    Quaternion::Quaternion(const AxisAngle& angle) {
         double s = std::sin(angle.angle / 2);
         x = angle.axis.x * s;
         y = angle.axis.y * s;
         z = angle.axis.z * s;
         w = std::cos(angle.angle / 2);
-    }
-
-    Quaternion::Quaternion(const EulerAngle &angle) {
-        // Abbreviations for the various angular functions
-        double cr = std::cos(angle.roll * 0.5);
-        double sr = std::sin(angle.roll * 0.5);
-        double cp = std::cos(angle.pitch * 0.5);
-        double sp = std::sin(angle.pitch * 0.5);
-        double cy = std::cos(angle.yaw * 0.5);
-        double sy = std::sin(angle.yaw * 0.5);
-
-        w = cr * cp * cy + sr * sp * sy;
-        x = sr * cp * cy - cr * sp * sy;
-        y = cr * sp * cy + sr * cp * sy;
-        z = cr * cp * sy - sr * sp * cy;
-    }
-
-    void Quaternion::SetFrom(const AxisAngle &angle) {
-        double s = std::sin(angle.angle / 2);
-        x = angle.axis.x * s;
-        y = angle.axis.y * s;
-        z = angle.axis.z * s;
-        w = std::cos(angle.angle / 2);
-    }
-
-    EulerAngle Quaternion::ToEulerAngle() const {
-        return EulerAngle(*this);
+        Normalize();
     }
 
     Quaternion Quaternion::RandomRotation(RNG &rng) {
@@ -271,16 +228,16 @@ namespace J3ML::LinearAlgebra {
         return Quaternion::Identity;
     }
 
-    float Quaternion::Normalize() {
+    bool Quaternion::Normalize() {
         float length = Length();
         if (length < 1e-4f)
-            return 0.f;
+            return false;
         float rcpLength = 1.f / length;
         x *= rcpLength;
         y *= rcpLength;
         z *= rcpLength;
         w *= rcpLength;
-        return length;
+        return true;
     }
 
     bool Quaternion::IsNormalized(float epsilon) const {
@@ -325,9 +282,10 @@ namespace J3ML::LinearAlgebra {
 
     Quaternion Quaternion::LookAt(const Vector3 &localForward, const Vector3 &targetDirection, const Vector3 &localUp,
                                   const Vector3 &worldUp) {
-        return Matrix3x3::LookAt(localForward, targetDirection, localUp, worldUp).ToQuat();
+        return Quaternion(Matrix3x3::LookAt(localForward, targetDirection, localUp, worldUp));
     }
 
+    /*
     Quaternion Quaternion::RotateX(float angleRadians) {
         return {{1,0,0}, angleRadians};
     }
@@ -343,6 +301,7 @@ namespace J3ML::LinearAlgebra {
     Quaternion Quaternion::RotateAxisAngle(const AxisAngle &axisAngle) {
         return {axisAngle.axis, axisAngle.angle};
     }
+    */
 
     Quaternion Quaternion::RotateFromTo(const Vector3 &sourceDirection, const Vector3 &targetDirection) {
         assert(sourceDirection.IsNormalized());
@@ -369,14 +328,6 @@ namespace J3ML::LinearAlgebra {
         return Quaternion::RotateFromTo(sourceDirection.XYZ(), targetDirection.XYZ());
     }
 
-    Quaternion::Quaternion(const float *data) {
-        assert(data);
-        x = data[0];
-        y = data[1];
-        z = data[2];
-        w = data[3];
-    }
-
     Quaternion Quaternion::Lerp(const Quaternion &source, const Quaternion &target, float t) { return source.Lerp(target, t);}
 
     Quaternion Quaternion::Slerp(const Quaternion &source, const Quaternion &target, float t) { return source.Slerp(target, t);}
@@ -401,4 +352,28 @@ namespace J3ML::LinearAlgebra {
     float Quaternion::LengthSquared() const { return x*x + y*y + z*z + w*w;}
 
     float Quaternion::Length() const { return std::sqrt(LengthSquared()); }
+
+    Quaternion::Quaternion(const EulerAngleXYZ& rhs) {
+        float cos_roll = Math::Cos(0.5f * Math::Radians(rhs.roll));
+        float sin_roll = Math::Sin(0.5f * Math::Radians(rhs.roll));
+
+        float cos_pitch = Math::Cos(0.5f * Math::Radians(rhs.pitch));
+        float sin_pitch = Math::Sin(0.5f * Math::Radians(rhs.pitch));
+
+        float cos_yaw = Math::Cos(0.5f * Math::Radians(rhs.yaw));
+        float sin_yaw = Math::Sin(0.5f * Math::Radians(rhs.yaw));
+
+        x = cos_roll * sin_pitch * sin_yaw + sin_roll * cos_pitch * cos_yaw;
+        y = -sin_roll * cos_pitch * sin_yaw + cos_roll * sin_pitch * cos_yaw;
+        z = cos_roll * cos_pitch * sin_yaw + sin_roll * sin_pitch * cos_yaw;
+        w = -sin_roll * sin_pitch * sin_yaw + cos_roll * cos_pitch * cos_yaw;
+        Normalize();
+    }
+
+    Quaternion::Quaternion(const Quaternion& rhs) {
+        x = rhs.x;
+        y = rhs.y;
+        z = rhs.z;
+        w = rhs.w;
+    }
 }

src/J3ML/LinearAlgebra/Vector3.cpp

@@ -10,6 +10,7 @@
 namespace J3ML::LinearAlgebra {
 
     const Vector3 Vector3::Zero     = {0,0,0};
+    const Vector3 Vector3::One      = {1, 1, 1};
     const Vector3 Vector3::Up       = {0, -1, 0};
     const Vector3 Vector3::Down     = {0, 1, 0};
     const Vector3 Vector3::Left     = {-1, 0, 0};

tests/LinearAlgebra/AxisAngleTests.hpp

@@ -0,0 +1,25 @@
+#include <jtest/jtest.hpp>
+#include <jtest/Unit.hpp>
+
+jtest::Unit AxisAngleUnit {"AxisAngle"};
+
+namespace AxisAngleTests {
+    inline void Define() {
+        using namespace jtest;
+
+        AxisAngleUnit += Test("From_Quaternion", [] {
+            AxisAngle expected_result({0.3860166, 0.4380138, 0.8118714}, 0.6742209);
+            Quaternion q(0.1276794, 0.1448781, 0.2685358, 0.9437144);
+
+            AxisAngle from_quaternion(q);
+
+            jtest::check(Math::EqualAbs(expected_result.axis.x, from_quaternion.axis.x, 1e-6f));
+            jtest::check(Math::EqualAbs(expected_result.axis.y, from_quaternion.axis.y, 1e-6f));
+            jtest::check(Math::EqualAbs(expected_result.axis.z, from_quaternion.axis.z, 1e-6f));
+            jtest::check(Math::EqualAbs(expected_result.angle, from_quaternion.angle, 1e-6f));
+        });
+    }
+    inline void Run() {
+        AxisAngleUnit.RunAll();
+    }
+}

tests/LinearAlgebra/EulerAngleTests.hpp

@@ -5,14 +5,21 @@
 #include <jtest/jtest.hpp>
 #include <jtest/Unit.hpp>
 
-jtest::Unit EulerAngleUnit {"EulerAngle"};
+jtest::Unit EulerAngleUnit {"EulerAngle_XYZ"};
 
 namespace EulerAngleTests {
     inline void Define() {
         using namespace jtest;
 
-        EulerAngleUnit += Test("Not Implemented", [] {
-            throw("Not Implemented");
+        EulerAngleUnit += Test("From_Quaternion", [] {
+            EulerAngleXYZ expected_result(-170, 88, -160);
+            Quaternion q(0.1840604, 0.6952024, 0.1819093, 0.6706149);
+
+            EulerAngleXYZ from_quaternion(q);
+
+            jtest::check(Math::EqualAbs(Math::Radians(expected_result.roll), Math::Radians(from_quaternion.roll), 1e-5f));
+            jtest::check(Math::EqualAbs(Math::Radians(expected_result.pitch), Math::Radians(from_quaternion.pitch), 1e-5f));
+            jtest::check(Math::EqualAbs(Math::Radians(expected_result.yaw), Math::Radians(from_quaternion.yaw), 1e-5f));
         });
     }
     inline void Run() {

tests/LinearAlgebra/Matrix3x3Tests.hpp

@@ -11,6 +11,42 @@ namespace Matrix3x3Tests
         using namespace jtest;
         using namespace J3ML::LinearAlgebra;
 
+        Matrix3x3Unit += Test("AngleTypeRound-TripConversion", [] {
+            EulerAngleXYZ expected_result(8, 60, -27);
+
+            Matrix3x3 m(expected_result);
+            AxisAngle a(expected_result);
+            Quaternion q(a);
+            Matrix3x3 m2(q);
+            Quaternion q2(m2);
+            AxisAngle a2(q2);
+            EulerAngleXYZ round_trip(a2);
+
+            jtest::check(Math::EqualAbs(Math::Radians(expected_result.roll), Math::Radians(round_trip.roll), 1e-6f));
+            jtest::check(Math::EqualAbs(Math::Radians(expected_result.pitch), Math::Radians(round_trip.pitch), 1e-6f));
+            jtest::check(Math::EqualAbs(Math::Radians(expected_result.yaw), Math::Radians(round_trip.yaw), 1e-6f));
+        });
+
+        Matrix3x3Unit += Test("From_EulerAngleXYZ", []{
+            Matrix3x3 expected_result(Vector3(0.4455033, 0.2269952, 0.8660254),
+                                      Vector3(-0.3421816, 0.9370536,  -0.0695866),
+                                      Vector3(-0.8273081, -0.2653369, 0.4951340)
+                                      );
+
+            EulerAngleXYZ e(8, 60, -27);
+            Matrix3x3 from_euler(e);
+
+            jtest::check(Math::EqualAbs(expected_result.At(0, 0), from_euler.At(0, 0), 1e-6f));
+            jtest::check(Math::EqualAbs(expected_result.At(0, 1), from_euler.At(0, 1), 1e-6f));
+            jtest::check(Math::EqualAbs(expected_result.At(0, 2), from_euler.At(0, 2), 1e-6f));
+            jtest::check(Math::EqualAbs(expected_result.At(1, 0), from_euler.At(1, 0), 1e-6f));
+            jtest::check(Math::EqualAbs(expected_result.At(1, 1), from_euler.At(1, 1), 1e-6f));
+            jtest::check(Math::EqualAbs(expected_result.At(1, 2), from_euler.At(1, 2), 1e-6f));
+            jtest::check(Math::EqualAbs(expected_result.At(2, 0), from_euler.At(2, 0), 1e-6f));
+            jtest::check(Math::EqualAbs(expected_result.At(2, 1), from_euler.At(2, 1), 1e-6f));
+            jtest::check(Math::EqualAbs(expected_result.At(2, 2), from_euler.At(2, 2), 1e-6f));
+        });
+
         Matrix3x3Unit += Test("Add_Unary", []
         {
             Matrix3x3 m(1,2,3, 4,5,6, 7,8,9);

tests/LinearAlgebra/Matrix4x4Tests.hpp

@@ -111,20 +111,6 @@ namespace Matrix4x4Tests {
         Matrix4x4Unit += Test("InverseOrthonormal", [] {});
         Matrix4x4Unit += Test("DeterminantCorrectness", [] { });
         Matrix4x4Unit += Test("MulMat3x3", [] {});
-
-
-        Matrix4x4Unit += Test("AngleTypeRoundtripConversion", [] {
-            Matrix4x4 matrix;
-            EulerAngle a(Math::Radians(45), Math::Radians(45), Math::Radians(45));
-            Quaternion q(a);
-            matrix.SetRotatePart(q);
-            //matrix.SetRotatePartX(a.pitch);
-            //matrix.SetRotatePartY(a.yaw);
-            //matrix.SetRotatePartZ(a.roll);
-            EulerAngle fromMatrix = matrix.GetRotatePart().ToQuat().ToEulerAngle();
-            jtest::check(a == fromMatrix);
-        });
-
     }
 
     inline void Run() {

tests/LinearAlgebra/QuaternionTests.hpp

@@ -4,10 +4,14 @@
 #include <jtest/jtest.hpp>
 #include <jtest/Unit.hpp>
 #include <J3ML/LinearAlgebra/Quaternion.hpp>
+#include <J3ML/LinearAlgebra/EulerAngle.hpp>
 #include <J3ML/Algorithm/RNG.hpp>
 
 jtest::Unit QuaternionUnit {"Quaternion"};
 namespace QuaternionTests {
+
+    // This is here to check the accuracy of the Slerp inside the Quaternion class.
+    // Although you don't jtest::check anything :shrug: - Redacted.
     Quaternion PreciseSlerp(const Quaternion &a, const Quaternion& b, float t)
     {
         double angle = a.x * b.x + a.y * b.y + a.z * b.z + a.w * b.w;
@@ -69,6 +73,28 @@ namespace QuaternionTests {
                 Quaternion lerp = q.Lerp(q2, t);
             }
         });
+        QuaternionUnit += Test("From_EulerAngleXYZ", [] {
+            Quaternion expected_result(0.1819093, 0.6706149, 0.1840604, 0.6952024);
+            EulerAngleXYZ e(10, 88, 20);
+            Quaternion from_euler(e);
+
+            jtest::check(Math::EqualAbs(expected_result.x, from_euler.x, 1e-6f));
+            jtest::check(Math::EqualAbs(expected_result.y, from_euler.y, 1e-6f));
+            jtest::check(Math::EqualAbs(expected_result.z, from_euler.z, 1e-6f));
+            jtest::check(Math::EqualAbs(expected_result.w, from_euler.w, 1e-6f));
+        });
+
+        QuaternionUnit += Test("From_AxisAngle", [] {
+            Quaternion expected_result(0.0579133, 0.0782044, 0.1765667, 0.9794664);
+            AxisAngle a({0.2872573, 0.3879036, 0.8757934}, 0.4059981);
+            Quaternion from_axis(a);
+
+            jtest::check(Math::EqualAbs(expected_result.x, from_axis.x, 1e-6f));
+            jtest::check(Math::EqualAbs(expected_result.y, from_axis.y, 1e-6f));
+            jtest::check(Math::EqualAbs(expected_result.z, from_axis.z, 1e-6f));
+            jtest::check(Math::EqualAbs(expected_result.w, from_axis.w, 1e-6f));
+        });
+
         QuaternionUnit += Test("Mat4x4Conversion", [] { throw("Not Implemented"); });
         QuaternionUnit += Test("MulOpQuat", [] { throw("Not Implemented"); });
         QuaternionUnit += Test("DivOpQuat", [] { throw("Not Implemented"); });

tests/tests.cpp

@@ -16,6 +16,7 @@
 #include "Geometry/FrustumTests.hpp"
 
 #include "LinearAlgebra/EulerAngleTests.hpp"
+#include "LinearAlgebra/AxisAngleTests.hpp"
 #include "LinearAlgebra/Matrix2x2Tests.hpp"
 #include "LinearAlgebra/Matrix3x3Tests.hpp"
 #include "LinearAlgebra/Matrix4x4Tests.hpp"
@@ -64,10 +65,11 @@ namespace LinearAlgebraTests
 {
     void Define()
     {
-        EulerAngleTests::Define();
         Vector2Tests::Define();
         Vector3Tests::Define();
         Vector4Tests::Define();
+        AxisAngleTests::Define();
+        EulerAngleTests::Define();
         QuaternionTests::Define();
         Matrix2x2Tests::Define();
         Matrix3x3Tests::Define();
@@ -76,10 +78,11 @@ namespace LinearAlgebraTests
     }
     void Run()
     {
-        EulerAngleTests::Run();
         Vector2Tests::Run();
         Vector3Tests::Run();
         Vector4Tests::Run();
+        AxisAngleTests::Run();
+        EulerAngleTests::Run();
         QuaternionTests::Run();
         Matrix2x2Tests::Run();
         Matrix3x3Tests::Run();