basic qua ext rotation functions

headers/vmath.hpp/vmath_ext.hpp

@@ -662,3 +662,57 @@ namespace vmath_hpp
         return dot(v, normal) / length2(normal) * normal;
     }
 }
+
+//
+// Quaternion Transform
+//
+
+namespace vmath_hpp
+{
+    // qrotate
+
+    template < typename T >
+    [[nodiscard]] qua<T> qrotate(T angle, const vec<T, 3>& axis) {
+        const auto [s, c] = sincos(angle * T(0.5));
+        const auto [x, y, z] = normalize(axis);
+        return {vec{x,y,z} * s, c};
+    }
+
+    template < typename T >
+    [[nodiscard]] qua<T> qrotate(const qua<T>& q, T angle, const vec<T, 3>& axis) {
+        return q * qrotate(angle, axis);
+    }
+
+    template < typename T >
+    [[nodiscard]] qua<T> qrotate_x(T angle) {
+        const auto [s, c] = sincos(angle * T(0.5));
+        return {s, T(0), T(0), c};
+    }
+
+    template < typename T >
+    [[nodiscard]] qua<T> qrotate_x(const qua<T>& q, T angle) {
+        return qrotate(q, angle, unit3_x<T>);
+    }
+
+    template < typename T >
+    [[nodiscard]] qua<T> qrotate_y(T angle) {
+        const auto [s, c] = sincos(angle * T(0.5));
+        return {T(0), s, T(0), c};
+    }
+
+    template < typename T >
+    [[nodiscard]] qua<T> qrotate_y(const qua<T>& q, T angle) {
+        return qrotate(q, angle, unit3_y<T>);
+    }
+
+    template < typename T >
+    [[nodiscard]] qua<T> qrotate_z(T angle) {
+        const auto [s, c] = sincos(angle * T(0.5));
+        return {T(0), T(0), s, c};
+    }
+
+    template < typename T >
+    [[nodiscard]] qua<T> qrotate_z(const qua<T>& q, T angle) {
+        return qrotate(q, angle, unit3_z<T>);
+    }
+}

headers/vmath.hpp/vmath_qua_fun.hpp

@@ -226,3 +226,24 @@ namespace vmath_hpp
         return not_equal_to(vec{xs}, vec{ys});
     }
 }
+
+//
+// Quaternion Functions
+//
+
+namespace vmath_hpp
+{
+    // conjugate
+
+    template < typename T >
+    [[nodiscard]] constexpr qua<T> conjugate(const qua<T>& q) {
+        return {-q.v, q.s};
+    }
+
+    // inverse
+
+    template < typename T >
+    [[nodiscard]] constexpr qua<T> inverse(const qua<T>& q) {
+        return conjugate(q) * rcp(dot(q, q));
+    }
+}