fix(instancing): keep batches correct after load-time classification

rendering/opengl33renderer.h

@@ -376,7 +376,7 @@ class opengl33_renderer : public gfx_renderer {
 	// cell's buckets are merged here keyed by (TModel3d*, skins), so that
 	// Render_Instanced() runs once per unique model across the whole pass instead
 	// of once per cell -- collapsing many tiny instanced draws into a few large
-	// batches. Reused every pass; cleared at the top of Render(scene::basic_region*).
+	// batches. Reused every pass; the vectors are emptied (not freed) at the top of Render(scene::basic_region*).
 	scene::basic_cell::instance_bucket_map m_frame_instance_buckets;
   renderpass_config m_colorpass; // parametrs of most recent color pass
 	std::array<renderpass_config, 3> m_shadowpass; // parametrs of most recent shadowmap pass for each of csm stages
@@ -426,6 +426,11 @@ class opengl33_renderer : public gfx_renderer {
 	// reused across calls -- clear() retains capacity, so once it has grown to
 	// the largest batch seen, steady-state frames perform no allocation here.
 	std::vector<glm::mat4> m_instance_modelviews;
+	// further persistent scratch buffers for Render_Instanced(): culled instances paired with their
+	// squared distance, and the lod bounds of the drawn model which split them into lod bands
+	std::vector<std::pair<float, glm::mat4>> m_instance_survivors;
+	std::vector<float> m_instance_lodbounds;
+	std::vector<TSubModel const *> m_instance_lodpending;
 	gl::scene_ubs scene_ubs;
 	gl::model_ubs model_ubs;
 	gl::light_ubs light_ubs;