From fc8c07a949270381d6b089527b0b28c72c868142 Mon Sep 17 00:00:00 2001
From: rdb <git@rdb.name>
Date: Tue, 25 Oct 2022 13:19:53 +0200
Subject: [PATCH] pgraph: Remove unused vertices during premunge phase

Disable with premunge-remove-unused-vertices config var - let me know if causes issues for you, performance or otherwise, though!
---
 panda/src/pgraph/config_pgraph.cxx   | 5 +++++
 panda/src/pgraph/config_pgraph.h     | 1 +
 panda/src/pgraph/geomNode.cxx        | 3 +++
 panda/src/pgraph/sceneGraphReducer.I | 1 +
 4 files changed, 10 insertions(+)

diff --git a/panda/src/pgraph/config_pgraph.cxx b/panda/src/pgraph/config_pgraph.cxx
index 406f8fa41a..7b175f15d0 100644
--- a/panda/src/pgraph/config_pgraph.cxx
+++ b/panda/src/pgraph/config_pgraph.cxx
@@ -290,6 +290,11 @@ ConfigVariableBool premunge_data
           "encoding requirements, as appropriate.  When this is false, the "
           "data will be munged at render time instead."));
 
+ConfigVariableBool premunge_remove_unused_vertices
+("premunge-remove-unused-vertices", true,
+ PRC_DESC("Set this true to remove unused vertices as part of the premunge "
+          "which occurs when models are loaded from disk."));
+
 ConfigVariableBool preserve_geom_nodes
 ("preserve-geom-nodes", false,
  PRC_DESC("This specifies the default value for the \"preserved\" flag on "
diff --git a/panda/src/pgraph/config_pgraph.h b/panda/src/pgraph/config_pgraph.h
index 59551133aa..0cba3cf971 100644
--- a/panda/src/pgraph/config_pgraph.h
+++ b/panda/src/pgraph/config_pgraph.h
@@ -55,6 +55,7 @@ extern ConfigVariableBool depth_offset_decals;
 extern ConfigVariableInt max_collect_vertices;
 extern ConfigVariableInt max_collect_indices;
 extern EXPCL_PANDA_PGRAPH ConfigVariableBool premunge_data;
+extern ConfigVariableBool premunge_remove_unused_vertices;
 extern ConfigVariableBool preserve_geom_nodes;
 extern ConfigVariableBool flatten_geoms;
 extern EXPCL_PANDA_PGRAPH ConfigVariableInt max_lenses;
diff --git a/panda/src/pgraph/geomNode.cxx b/panda/src/pgraph/geomNode.cxx
index c92d27d5f0..bd10178594 100644
--- a/panda/src/pgraph/geomNode.cxx
+++ b/panda/src/pgraph/geomNode.cxx
@@ -892,6 +892,9 @@ do_premunge(GraphicsStateGuardianBase *gsg,
       CPT(Geom) geom = entry._geom.get_read_pointer();
       PT(GeomMunger) munger = gsg->get_geom_munger(geom_state, current_thread);
       entry._geom = transformer.premunge_geom(geom, munger);
+      if (premunge_remove_unused_vertices) {
+        transformer.register_vertices(entry._geom.get_write_pointer(), true);
+      }
     }
   }
   CLOSE_ITERATE_CURRENT_AND_UPSTREAM(_cycler);
diff --git a/panda/src/pgraph/sceneGraphReducer.I b/panda/src/pgraph/sceneGraphReducer.I
index 2db336c546..4e0f6e6585 100644
--- a/panda/src/pgraph/sceneGraphReducer.I
+++ b/panda/src/pgraph/sceneGraphReducer.I
@@ -176,5 +176,6 @@ premunge(PandaNode *root, const RenderState *initial_state) {
   if (_gsg != nullptr) {
     PStatTimer timer(_premunge_collector);
     r_premunge(root, initial_state);
+    _transformer.finish_apply();
   }
 }