resume lookat what to change in furture

src/Math/Matrix4f.cpp

@@ -102,4 +102,33 @@ namespace hgl
           0.0f
         );
     }
+
+    Matrix4f lookat(const Vector3f &eye,const Vector3f &target,const Vector3f &up)
+    {
+        Vector3f forward=normalize(target-eye);
+        Vector3f right=normalize(cross(forward,up));
+
+        Vector3f nup=cross(right,forward);
+
+        return Matrix4f(   right.x,
+                             nup.x,
+                        -forward.x,
+                              0.0f,
+
+                           right.y,
+                             nup.y,
+                        -forward.y,
+                              0.0f,
+
+                           right.z,
+                             nup.z,
+                   -forward.z/2.0f,
+                              0.0f,
+
+                 -dot(eye,right  ),
+                 -dot(eye,nup    ),
+                  dot(eye,forward),
+                              1.0f
+        );
+    }
 }//namespace hgl