refactor: replace manual VAO draws with recursive scene graph draw function

src/main.rs

@@ -127,6 +127,21 @@ unsafe fn create_vao(vertices: &Vec<f32>, normals: &Vec<f32>, colors: &Vec<f32>,
     vao_id
 }
 
+// Scene graph drawing function
+unsafe fn draw_scene(node: &scene_graph::SceneNode, transform_loc: i32, view_projection: &glm::Mat4, transform_so_far: &glm::Mat4) {
+    // Draw this node if drawable
+    if node.index_count > 0 {
+        let model_transform = view_projection * *transform_so_far;
+        gl::UniformMatrix4fv(transform_loc, 1, gl::FALSE, model_transform.as_ptr());
+        gl::BindVertexArray(node.vao_id);
+        gl::DrawElements(gl::TRIANGLES, node.index_count, gl::UNSIGNED_INT, ptr::null());
+    }
+    // Recurse to children
+    for &child in &node.children {
+        draw_scene(&*child, transform_loc, view_projection, transform_so_far);
+    }
+}
+
 fn main() {
     // Set up the necessary objects to deal with windows and event handling
     let el = glutin::event_loop::EventLoop::new();