Simplify barycentric coordinates function

src/model/render.c

@@ -193,15 +193,10 @@ internal TriangleBBox get_triangle_bbox(const Image *img,
 }
 
 internal V3f get_barycentric_coords(V3f a, V3f b, V3f c, V3f p) {
-  V3f s[2];
+  V3f x_vec = V3(V3f, f32, c.x, b.x, a.x, a.x, a.x, p.x);
+  V3f y_vec = V3(V3f, f32, c.y, b.y, a.y, a.y, a.y, p.y);
 
-  for (u64 i = 0; i < 2; ++i) {
-    s[i].x = c.elements[i] - a.elements[i];
-    s[i].y = b.elements[i] - a.elements[i];
-    s[i].z = a.elements[i] - p.elements[i];
-  }
-
-  V3f u = cross_product(s[0], s[1]);
+  V3f u = cross_product(x_vec, y_vec);
   if (fabsf(u.z) < 1e-2) {
     return (V3f){-1.0f, 1.0f, 1.0f};
   }