Switch to using tangent normals

src/main.c

@@ -33,14 +33,14 @@ int main(void) {
   }
 
   Model obj = load_obj_file(arena, RESOURCE("head.obj"), RESOURCE("head.pnm"),
-                            RESOURCE("head_nm.pnm"));
+                            RESOURCE("head_nm_tangent.pnm"));
   if (IS_INVALID_MODEL(obj)) {
     return TINY_EXIT_MODEL_LOAD_FAILED;
   }
 
   PhongMaterial material = {
-      .ambient = 0.1f,
-      .diffuse = 1.2f,
+      .ambient = 0.3f,
+      .diffuse = 1.0f,
       .specular = 0.1f,
       .shininess = 0.8f,
   };