math: implement rotate() for mat3 in addition to mat4.

src/lol/math/vector.h

@@ -1561,15 +1561,27 @@ template <typename T> struct Mat4
     /* Helpers for transformation matrices */
     static Mat4<T> translate(T x, T y, T z);
     static Mat4<T> translate(Vec3<T> v);
-    static Mat4<T> rotate(T angle, T x, T y, T z);
-    static Mat4<T> rotate(T angle, Vec3<T> v);
-    static Mat4<T> rotate(Quat<T> q);
 
     static inline Mat4<T> translate(Mat4<T> const &mat, Vec3<T> v)
     {
         return translate(v) * mat;
     }
 
+    static inline Mat4<T> rotate(T angle, T x, T y, T z)
+    {
+        return Mat4<T>(Mat3<T>::rotate(angle, x, y, z), (T)1);
+    }
+
+    static inline Mat4<T> rotate(T angle, Vec3<T> v)
+    {
+        return Mat4<T>(Mat3<T>::rotate(angle, v), (T)1);
+    }
+
+    static inline Mat4<T> rotate(Quat<T> q)
+    {
+        return Mat4<T>(Mat3<T>::rotate(q), (T)1);
+    }
+
     static inline Mat4<T> rotate(Mat4<T> &mat, T angle, Vec3<T> v)
     {
         return rotate(angle, v) * mat;

src/math/vector.cpp

@@ -320,7 +320,25 @@ template<> mat4 mat4::translate(vec3 v)
     return translate(v.x, v.y, v.z);
 }
 
-template<> mat4 mat4::rotate(float angle, float x, float y, float z)
+template<> mat2 mat2::rotate(float angle)
+{
+    angle *= (M_PI / 180.0f);
+
+    float st = sinf(angle);
+    float ct = cosf(angle);
+
+    mat2 ret;
+
+    ret[0][0] = ct;
+    ret[0][1] = st;
+
+    ret[1][0] = -st;
+    ret[1][1] = ct;
+
+    return ret;
+}
+
+template<> mat3 mat3::rotate(float angle, float x, float y, float z)
 {
     angle *= (M_PI / 180.0f);
 
@@ -337,7 +355,7 @@ template<> mat4 mat4::rotate(float angle, float x, float y, float z)
     float mty = (1.0f - ct) * y;
     float mtz = (1.0f - ct) * z;
 
-    mat4 ret(1.0f);
+    mat3 ret;
 
     ret[0][0] = x * mtx + ct;
     ret[0][1] = x * mty + st * z;
@@ -354,19 +372,19 @@ template<> mat4 mat4::rotate(float angle, float x, float y, float z)
     return ret;
 }
 
-template<> mat4 mat4::rotate(float angle, vec3 v)
+template<> mat3 mat3::rotate(float angle, vec3 v)
 {
     return rotate(angle, v.x, v.y, v.z);
 }
 
-template<> mat4 mat4::rotate(quat q)
+template<> mat3 mat3::rotate(quat q)
 {
-    mat4 ret(1.0f);
     float n = norm(q);
 
     if (!n)
-        return ret;
+        return mat3(1.0f);
 
+    mat3 ret;
     float s = 2.0f / n;
 
     ret[0][0] = 1.0f - s * (q.y * q.y + q.z * q.z);