// Rotation /* Matrix to quaternion */ glm::quat q_from_matrix3x3{ glm::mat3{1} }; // cast operator will handle this glm::quat q_from_matrix4x4{ glm::mat4{1} }; // cast operator will handle this /* Matrix to Euler rotation */ float x, y, z; // radians glm::extractEulerAngleXYZ(glm::mat4{ 1 }, x, y, z); glm::extractEulerAngleZYX(glm::mat4{ 1 }, z, y, x); // pay attention to the parameter order, z->y->x /* Quaternion to matrix */ glm::mat3 matrix3x3_from_quaternion{ glm::quat{1.0f, 0, 0, 0} }; // cast operator will handle this glm::mat4 matrix4x4_from_quaternion{ glm::quat{1.0f, 0, 0, 0} }; // cast operator will handle this /* Quaternion to Euler rotation */ glm::vec3 euler_angles_zyx = glm::eulerAngles(glm::quat{ 1.0f, 0, 0, 0 }); // rotation matrices do not commute in multiplication, and the rotation around x->y->z order means z->y->x matrices order /* Euler rotation to matrix */ glm::mat3 matrix3x3_from_euler = glm::eulerAngleXYZ(0.0f, 0.0f, 0.0f); // rotation order is z axis -> y axis -> x axis, the equal matirces multiplication order is x->y->z glm::mat3 matrix4x4_from_euler = glm::eulerAngleZYX(0.0f, 0.0f, 0.0f); // rotation order is x axis -> y axis -> z axis, the equal matirces multiplication order is z->y->x /* Euler rotation to quaternion */ float euler_x, euler_y, euler_z; // radians euler_x = euler_y = euler_z = 0.0f; glm::quat quaternion_from_euler{ glm::vec3{euler_x, euler_y, euler_z} }; // the original rotation order is x axis -> y axis -> z axis, matrices multip