is uniform scaled func for mat4

include/cglm-affine.h

@@ -295,6 +295,23 @@ glm_decompose_scalev(mat4 m, vec3 s) {
   s[2] = glm_vec_norm(m[2]);
 }
 
+/*!
+ * @brief returns true if matrix is uniform scaled. This is helpful for 
+ *        creating normal matrix.
+ *
+ * @param m[in] m
+ *
+ * @return boolean
+ */
+CGLM_INLINE
+bool
+glm_uniscaled(mat4 m) {
+  vec3 s;
+  glm_decompose_scalev(m, s);
+
+  return glm_vec_eq_all(s);
+}
+
 /*!
  * @brief decompose rotation matrix (mat4) and scale vector [Sx, Sy, Sz]
  *

include/cglm-vec-ext.h

@@ -73,10 +73,22 @@ glm_vec_eq(vec3 v, float val) {
   return v[0] == val && v[0] == v[1] && v[0] == v[2];
 }
 
+CGLM_INLINE
+bool
+glm_vec_eq_all(vec3 v) {
+  return v[0] == v[1] && v[0] == v[2];
+}
+
 CGLM_INLINE
 bool
 glm_vec4_eq(vec4 v, float val) {
   return v[0] == val && v[0] == v[1] && v[0] == v[2] && v[0] == v[3];
 }
 
+CGLM_INLINE
+bool
+glm_vec4_eq_all(vec4 v) {
+  return v[0] == v[1] && v[0] == v[2] && v[0] == v[3];
+}
+
 #endif /* cglm_vec_ext_h */