swizzle support

include/cglm/vec3.h

@@ -44,6 +44,7 @@
    CGLM_INLINE void  glm_vec_maxv(vec3 v1, vec3 v2, vec3 dest);
    CGLM_INLINE void  glm_vec_minv(vec3 v1, vec3 v2, vec3 dest);
    CGLM_INLINE void  glm_vec_ortho(vec3 v, vec3 dest);
+   CGLM_INLINE void  glm_vec_swizzle(vec3 v, int mask, vec3 dest);
 
  Convenient:
    CGLM_INLINE void  glm_cross(vec3 a, vec3 b, vec3 d);
@@ -69,6 +70,11 @@
 #define GLM_ZUP  (vec3){0.0f, 0.0f, 1.0f}
 #define GLM_XUP  (vec3){1.0f, 0.0f, 0.0f}
 
+#define GLM_XXX GLM_SHUFFLE3(0, 0, 0)
+#define GLM_YYY GLM_SHUFFLE3(1, 1, 1)
+#define GLM_ZZZ GLM_SHUFFLE3(2, 2, 2)
+#define GLM_ZYX GLM_SHUFFLE3(0, 1, 2)
+
 /*!
  * @brief init vec3 using vec4
  *
@@ -528,4 +534,25 @@ glm_normalize_to(vec3 v, vec3 dest) {
   glm_vec_normalize_to(v, dest);
 }
 
+/*!
+ * @brief swizzle vector components
+ *
+ * you can use existin masks e.g. GLM_XXX, GLM_ZYX
+ *
+ * @param[in]  v    source
+ * @param[in]  mask mask
+ * @param[out] dest destination
+ */
+CGLM_INLINE
+void
+glm_vec_swizzle(vec3 v, int mask, vec3 dest) {
+  vec3 t;
+
+  t[0] = v[(mask & (3 << 0))];
+  t[1] = v[(mask & (3 << 2)) >> 2];
+  t[2] = v[(mask & (3 << 4)) >> 4];
+
+  glm_vec_copy(t, dest);
+}
+
 #endif /* cglm_vec3_h */