From ac4cd6b979df78a8139e7ded64fec82a5c465af9 Mon Sep 17 00:00:00 2001
From: Christian Semmler <mail@csemmler.com>
Date: Fri, 3 Apr 2026 20:42:41 -0700
Subject: [PATCH] Fix crash when performer's child ROIs are left dangling in
 ScenePlayer

NotifyROIDestroyed now walks the parent chain to also invalidate child
ROIs of the destroyed performer (head, limbs, etc.) that were placed
into the roiMap by BuildROIMap. The ancestor walk happens once; all
other fields are cleaned with simple pointer equality.
---
 .../src/multiplayer/animation/sceneplayer.cpp | 56 ++++++++++++++-----
 1 file changed, 42 insertions(+), 14 deletions(-)

diff --git a/extensions/src/multiplayer/animation/sceneplayer.cpp b/extensions/src/multiplayer/animation/sceneplayer.cpp
index 952f469f..c22e200b 100644
--- a/extensions/src/multiplayer/animation/sceneplayer.cpp
+++ b/extensions/src/multiplayer/animation/sceneplayer.cpp
@@ -594,38 +594,66 @@ void ScenePlayer::NotifyROIDestroyed(LegoROI* p_roi)
 		return;
 	}
 
-	for (auto& p : m_participants) {
-		if (p.roi == p_roi) {
-			p.roi = nullptr;
-		}
-		if (p.vehicleROI == p_roi) {
-			p.vehicleROI = nullptr;
-		}
-	}
+	// Walk the m_roiMap once to find p_roi and all its descendants (child ROIs
+	// are destroyed together with their parent). Collect them so every other
+	// field can be cleaned with simple pointer equality — the ancestor walk
+	// happens in exactly one place.
+	std::vector<LegoROI*> destroyed;
+	destroyed.push_back(p_roi);
 
 	if (m_roiMap) {
 		for (MxU32 i = 0; i < m_roiMapSize; i++) {
-			if (m_roiMap[i] == p_roi) {
-				m_roiMap[i] = nullptr;
+			if (!m_roiMap[i]) {
+				continue;
+			}
+
+			for (OrientableROI* cur = m_roiMap[i]; cur != nullptr; cur = cur->GetParentROI()) {
+				if (cur == p_roi) {
+					if (m_roiMap[i] != p_roi) {
+						destroyed.push_back(m_roiMap[i]);
+					}
+					m_roiMap[i] = nullptr;
+					break;
+				}
 			}
 		}
 	}
 
+	auto isDestroyed = [&destroyed](LegoROI* roi) {
+		for (LegoROI* d : destroyed) {
+			if (roi == d) {
+				return true;
+			}
+		}
+		return false;
+	};
+
+	for (auto& p : m_participants) {
+		if (p.roi && isDestroyed(p.roi)) {
+			p.roi = nullptr;
+		}
+		if (p.vehicleROI && isDestroyed(p.vehicleROI)) {
+			p.vehicleROI = nullptr;
+		}
+	}
+
 	for (auto& roi : m_ptAtCamROIs) {
-		if (roi == p_roi) {
+		if (roi && isDestroyed(roi)) {
 			roi = nullptr;
 		}
 	}
 
-	if (m_animRootROI == p_roi) {
+	if (m_animRootROI && isDestroyed(m_animRootROI)) {
 		m_animRootROI = nullptr;
 	}
 
-	if (m_vehicleROI == p_roi) {
+	if (m_vehicleROI && isDestroyed(m_vehicleROI)) {
 		m_vehicleROI = nullptr;
 	}
 
-	m_phonemePlayer.NotifyROIDestroyed(p_roi);
+	for (LegoROI* d : destroyed) {
+		m_phonemePlayer.NotifyROIDestroyed(d);
+	}
 }
 
 void ScenePlayer::CleanupProps()