From ed9cd80034e8b69347b3c6d9f70bddcc79fc7d09 Mon Sep 17 00:00:00 2001
From: Kawe Mazidjatari <48657826+Mauler125@users.noreply.github.com>
Date: Fri, 25 Oct 2024 01:12:51 +0200
Subject: [PATCH] Recast: fix generation of concave polygons

These changes seem to yield better results for the larger maps. The improvements are minimal however. This change is probably more noticable on tile cache.
---
 .../Source/DetourTileCacheBuilder.cpp         | 20 +++++++++----------
 .../recast/Recast/Source/RecastMesh.cpp       | 20 +++++++++----------
 2 files changed, 18 insertions(+), 22 deletions(-)

diff --git a/src/thirdparty/recast/DetourTileCache/Source/DetourTileCacheBuilder.cpp b/src/thirdparty/recast/DetourTileCache/Source/DetourTileCacheBuilder.cpp
index 390d0c37..cd7af04e 100644
--- a/src/thirdparty/recast/DetourTileCache/Source/DetourTileCacheBuilder.cpp
+++ b/src/thirdparty/recast/DetourTileCache/Source/DetourTileCacheBuilder.cpp
@@ -1284,18 +1284,16 @@ static int triangulate(int n, const unsigned char* verts, unsigned short* indice
 		for (int k = i1; k < n; k++)
 			indices[k] = indices[k+1];
 		
-		if (i1 >= n) i1 = 0;
-		i = REV_STEP_DIR(i1,n);
 		// Update diagonal flags.
-		if (diagonal(REV_STEP_DIR(i, n), i1, n, verts, indices))
-			indices[i] |= 0x8000;
-		else
-			indices[i] &= 0x7fff;
-		
-		if (diagonal(i, STEP_DIR(i1, n), n, verts, indices))
-			indices[i1] |= 0x8000;
-		else
-			indices[i1] &= 0x7fff;
+		for (int k = 0; k < n; k++) // See https://github.com/recastnavigation/recastnavigation/pull/734
+		{
+			const int k1 = STEP_DIR(k, n);
+			const int k2 = STEP_DIR(k1, n);
+			if (diagonal(k, k2, n, verts, indices))
+				indices[k1] |= 0x8000;
+			else
+				indices[k1] &= 0x7fff;
+		}
 	}
 	
 	// Append the remaining triangle.
diff --git a/src/thirdparty/recast/Recast/Source/RecastMesh.cpp b/src/thirdparty/recast/Recast/Source/RecastMesh.cpp
index 913983c6..ee114c7c 100644
--- a/src/thirdparty/recast/Recast/Source/RecastMesh.cpp
+++ b/src/thirdparty/recast/Recast/Source/RecastMesh.cpp
@@ -457,18 +457,16 @@ static int triangulate(int n, const int* verts, int* indices, int* tris)
 		for (int k = i1; k < n; k++)
 			indices[k] = indices[k+1];
 		
-		if (i1 >= n) i1 = 0;
-		i = REV_STEP_DIR(i1,n);
 		// Update diagonal flags.
-		if (diagonal(REV_STEP_DIR(i, n), i1, n, verts, indices))
-			indices[i] |= 0x80000000;
-		else
-			indices[i] &= 0x0fffffff;
-		
-		if (diagonal(i, STEP_DIR(i1, n), n, verts, indices))
-			indices[i1] |= 0x80000000;
-		else
-			indices[i1] &= 0x0fffffff;
+		for (int k = 0; k < n; k++) // See https://github.com/recastnavigation/recastnavigation/pull/734
+		{
+			const int k1 = STEP_DIR(k, n);
+			const int k2 = STEP_DIR(k1, n);
+			if (diagonal(k, k2, n, verts, indices))
+				indices[k1] |= 0x80000000;
+			else
+				indices[k1] &= 0x0fffffff;
+		}
 	}
 	
 	// Append the remaining triangle.