Add complex scene rendering example

README.md

@@ -7,3 +7,4 @@ C implementation of the [*Ray tracing in one week-end*](https://raytracing.githu
 ![Ray tracing in one week-end book cover](examples/book-cover.png)
 ![Earth](examples/earth.png)
 ![Cornell box](examples/cornell.png)
+![Complex scene](examples/complex-scene.png)

scenes.c

@@ -349,5 +349,7 @@ const Hittable *complex_scene(Arena *arena) {
           (Vec3){-100, 270, 395}, arena),
       arena);
 
-  return objects;
+  Hittable *bvh_root = hittable_create_bvh_node(
+      objects->list.objects, 0, objects->list.size, 0.0, 1.0, arena);
+  return bvh_root;
 }