From d6ae135fd67551a82363b88331c39f3006f1a338 Mon Sep 17 00:00:00 2001
From: Kawe Mazidjatari <48657826+Mauler125@users.noreply.github.com>
Date: Wed, 14 Aug 2024 01:28:16 +0200
Subject: [PATCH] Recast: draw height point offset in traverse links

Show the actual kink from raycast point to actual link point.
---
 src/naveditor/Editor.cpp                      |  5 +++-
 .../DebugUtils/Include/DetourDebugDraw.h      |  7 ++++-
 .../DebugUtils/Source/DetourDebugDraw.cpp     | 28 +++++++++++++++++--
 3 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/src/naveditor/Editor.cpp b/src/naveditor/Editor.cpp
index 091ecafe..7c3fb5c3 100644
--- a/src/naveditor/Editor.cpp
+++ b/src/naveditor/Editor.cpp
@@ -175,6 +175,7 @@ void Editor::resetCommonSettings()
 
 	m_cellSize = 16.0f;
 	m_cellHeight = 5.85f;
+	m_traverseLinkParams.cellHeight = m_cellHeight;
 
 	// todo(amos): check if this applies for all hulls, and check if this is the
 	// actual value used by the game. This seems to generate slopes very close
@@ -213,7 +214,9 @@ void Editor::handleCommonSettings()
 	ImGui::Text("Rasterization");
 
 	ImGui::SliderFloat("Cell Size", &m_cellSize, 12.1f, 100.0f);
-	ImGui::SliderFloat("Cell Height", &m_cellHeight, 0.4f, 100.0f);
+	
+	if (ImGui::SliderFloat("Cell Height", &m_cellHeight, 0.4f, 100.0f))
+		m_traverseLinkParams.cellHeight = m_cellHeight;
 	
 	if (m_geom)
 	{
diff --git a/src/thirdparty/recast/DebugUtils/Include/DetourDebugDraw.h b/src/thirdparty/recast/DebugUtils/Include/DetourDebugDraw.h
index 184cc4ed..1927b33a 100644
--- a/src/thirdparty/recast/DebugUtils/Include/DetourDebugDraw.h
+++ b/src/thirdparty/recast/DebugUtils/Include/DetourDebugDraw.h
@@ -49,7 +49,8 @@ struct duDrawTraverseLinkParams
 	duDrawTraverseLinkParams() :
 		traverseLinkType(-1),
 		traverseLinkDistance(-1),
-		traverseAnimType(-2)
+		traverseAnimType(-2),
+		cellHeight(0.0f)
 	{}
 
 	int traverseLinkType;
@@ -58,6 +59,10 @@ struct duDrawTraverseLinkParams
 	// -2 means all, -1 means disjoint poly groups only, anything above
 	// refers to an actual anim type and indexes into the traverse tables.
 	int traverseAnimType;
+
+	// Used to determine the max LOS angle, this information is lost after
+	// the mesh tile has been build so we have to cache it from the editor.
+	float cellHeight;
 };
 
 void duDebugDrawNavMesh(struct duDebugDraw* dd, const dtNavMesh& mesh, const float* offset, unsigned int flags, const duDrawTraverseLinkParams& traverseLinkParams);
diff --git a/src/thirdparty/recast/DebugUtils/Source/DetourDebugDraw.cpp b/src/thirdparty/recast/DebugUtils/Source/DetourDebugDraw.cpp
index 90fcce58..f07ff553 100644
--- a/src/thirdparty/recast/DebugUtils/Source/DetourDebugDraw.cpp
+++ b/src/thirdparty/recast/DebugUtils/Source/DetourDebugDraw.cpp
@@ -212,13 +212,37 @@ static void drawTraverseLinks(duDebugDraw* dd, const dtNavMesh& mesh, const dtNa
 			query->getEdgeMidPoint(basePolyRef, link->ref, startPos);
 			query->getEdgeMidPoint(link->ref, basePolyRef, endPos);
 
+			const float slopeAngle = rdMathFabsf(rdCalcSlopeAngle(startPos, endPos));
+			const float offsetAmount = rdCalcLedgeSpanOffsetAmount(tile->header->walkableRadius, 
+				slopeAngle, rdCalcMaxLOSAngle(tile->header->walkableRadius, traverseLinkParams.cellHeight));
+
+			const bool startPointHighest = startPos[2] > endPos[2];
+			float* highestPos = startPointHighest ? startPos : endPos;
+
+			const dtPolyRef lowPolyRef = startPointHighest ? link->ref : basePolyRef;
+			const dtPolyRef highPolyRef = startPointHighest ? basePolyRef : link->ref;
+
+			float normal[3];
+			query->getEdgeNormal(highPolyRef, lowPolyRef, normal);
+
+			// The offset between the height point and the ray point
+			// used to account for the ledge span.
+			const float offsetEndPos[3] = {
+				highestPos[0] + normal[0] * offsetAmount,
+				highestPos[1] + normal[1] * offsetAmount,
+				highestPos[2]
+			};
+
 			// Unique color for each type.
 			const int col = duIntToCol(link->traverseType, 128);
 
 			dd->begin(DU_DRAW_LINES, 2.0f, offset);
 
-			dd->vertex(startPos, col);
-			dd->vertex(endPos, col);
+			const float* targetStartPos = startPointHighest ? offsetEndPos : startPos;
+			const float* targetEndPos = startPointHighest ? startPos : offsetEndPos;
+
+			dd->vertex(targetStartPos, col);
+			dd->vertex(targetEndPos, col);
 
 			const bool hasReverseLink = link->reverseLink != DT_NULL_TRAVERSE_REVERSE_LINK;