From 09e867eb07c35fc7d2acb807a33b6123b52eda6e Mon Sep 17 00:00:00 2001
From: Kelsi <kelsihates2fa@gmail.com>
Date: Tue, 5 May 2026 23:53:52 -0700
Subject: [PATCH] fix(editor): move rebuildObjects AFTER beginFrame (instance
 SSBO fix)

ROOT CAUSE of NPCs not rendering: rebuildObjects() called createInstance()
BEFORE beginFrame(), causing instance SSBO writes to use the wrong frame
index. The M2 renderer writes instance transforms to a per-frame buffer
indexed by getCurrentFrame(), but the frame index isn't valid until after
beginFrame() returns.

This is the same bug documented in the project memory:
"M2 models not rendering (draws=0): update() was called before
beginFrame(), causing frame index mismatch in instance SSBO"

Models loaded correctly (log confirmed 2192v 7926i 8b) but instances
were invisible because their transform data was written to the wrong
frame buffer.

Fix: move the rebuild block after beginFrame(), alongside update().
---
 tools/editor/editor_app.cpp | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/tools/editor/editor_app.cpp b/tools/editor/editor_app.cpp
index 1c90d3ec..4e388bd8 100644
--- a/tools/editor/editor_app.cpp
+++ b/tools/editor/editor_app.cpp
@@ -125,17 +125,6 @@ void EditorApp::run() {
             lastNpcCount_ = npcCount;
         }
 
-        if (objChanged || objectsDirty_) {
-            // Full M2 rebuild only when placed objects change
-            objectsDirty_ = false;
-            lastObjCount_ = objCount;
-            if (objCount > 0 || npcCount > 0) {
-                vkDeviceWaitIdle(vkCtx->getDevice());
-                viewport_.rebuildObjects(objectPlacer_.getObjects(), npcSpawner_.getSpawns());
-            }
-            lastNpcCount_ = npcCount; // sync after rebuild
-        }
-
         // Show gizmo arrows on selected object
         auto& gizmo = viewport_.getGizmo();
         if (auto* sel = objectPlacer_.getSelected()) {
@@ -148,6 +137,17 @@ void EditorApp::run() {
         VkCommandBuffer cmd = vkCtx->beginFrame(imageIndex);
         if (cmd == VK_NULL_HANDLE) continue;
 
+        // Rebuild objects AFTER beginFrame so instance SSBO uses correct frame index
+        if (objChanged || objectsDirty_) {
+            objectsDirty_ = false;
+            lastObjCount_ = objCount;
+            if (objCount > 0 || npcCount > 0) {
+                vkDeviceWaitIdle(vkCtx->getDevice());
+                viewport_.rebuildObjects(objectPlacer_.getObjects(), npcSpawner_.getSpawns());
+            }
+            lastNpcCount_ = npcCount;
+        }
+
         // Update M2 animations AFTER beginFrame (so getCurrentFrame is correct)
         viewport_.update(dt);