Add rgb elements to V3f

src/vec/vec.h

@@ -31,9 +31,18 @@ struct f32x2 {
 
 typedef struct f32x3 V3f;
 struct f32x3 {
-  f32 x;
-  f32 y;
-  f32 z;
+  union {
+    f32 x;
+    f32 r;
+  };
+  union {
+    f32 y;
+    f32 g;
+  };
+  union {
+    f32 z;
+    f32 b;
+  };
 };
 
 typedef struct f32x4 V4f;