From c9c687fc7382f0f50cc36174332142805ee87a03 Mon Sep 17 00:00:00 2001
From: Kawe Mazidjatari <48657826+Mauler125@users.noreply.github.com>
Date: Sun, 13 Oct 2024 14:39:52 +0200
Subject: [PATCH] Recast: add bounds check for sweepscan indices

Only happens on extremely large and complex geometry.
---
 .../recast/Recast/Source/RecastRegion.cpp      | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/thirdparty/recast/Recast/Source/RecastRegion.cpp b/src/thirdparty/recast/Recast/Source/RecastRegion.cpp
index 5b28b806..331041d7 100644
--- a/src/thirdparty/recast/Recast/Source/RecastRegion.cpp
+++ b/src/thirdparty/recast/Recast/Source/RecastRegion.cpp
@@ -1425,6 +1425,15 @@ bool rcBuildRegionsMonotone(rcContext* ctx, rcCompactHeightfield& chf,
 				if (!previd)
 				{
 					previd = rid++;
+
+					// todo(amos): figure out why this happens on very complex and large
+					// input geometry.
+					if (previd >= nsweeps)
+					{
+						ctx->log(RC_LOG_ERROR, "rcBuildLayerRegions: Sweep index out of bounds: previd (%d), nsweeps (%d).", previd, nsweeps);
+						return false;
+					}
+
 					sweeps[previd].rid = previd;
 					sweeps[previd].ns = 0;
 					sweeps[previd].nei = 0;
@@ -1734,6 +1743,15 @@ bool rcBuildLayerRegions(rcContext* ctx, rcCompactHeightfield& chf,
 				if (!previd)
 				{
 					previd = rid++;
+
+					// todo(amos): figure out why this happens on very complex and large
+					// input geometry.
+					if (previd >= nsweeps)
+					{
+						ctx->log(RC_LOG_ERROR, "rcBuildLayerRegions: Sweep index out of bounds: previd (%d), nsweeps (%d).", previd, nsweeps);
+						return false;
+					}
+
 					sweeps[previd].rid = previd;
 					sweeps[previd].ns = 0;
 					sweeps[previd].nei = 0;