From 50bee3da41a9d4e30f1a65915d958590729e3bd5 Mon Sep 17 00:00:00 2001
From: Regalis <regalis@undertowgames.com>
Date: Wed, 1 Jun 2016 20:58:03 +0300
Subject: [PATCH] Wall convexhulls are split every 5 sections, convexhull edges
 that overlap with another convexhull are ignored (i.e. unneccessarys shadows
 aren't drawn where two walls meet)

---
 Subsurface/Source/Map/Lights/ConvexHull.cs | 40 ++++++++++++++++++++--
 Subsurface/Source/Map/Structure.cs         |  7 ++++
 2 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/Subsurface/Source/Map/Lights/ConvexHull.cs b/Subsurface/Source/Map/Lights/ConvexHull.cs
index be5443e8e..7453f2246 100644
--- a/Subsurface/Source/Map/Lights/ConvexHull.cs
+++ b/Subsurface/Source/Map/Lights/ConvexHull.cs
@@ -55,6 +55,7 @@ namespace Barotrauma.Lights
         private int primitiveCount;
 
         private bool[] backFacing;
+        private bool[] ignoreEdge;
 
         private VertexPositionColor[] shadowVertices;
         private VertexPositionTexture[] penumbraVertices;
@@ -111,10 +112,37 @@ namespace Barotrauma.Lights
             //CalculateDimensions();
             
             backFacing = new bool[primitiveCount];
-            
+            ignoreEdge = new bool[primitiveCount];
+                        
             Enabled = true;
 
+            foreach (ConvexHull ch in list)
+            {
+                UpdateIgnoredEdges(ch);
+                ch.UpdateIgnoredEdges(this);
+            }
+
+
             list.Add(this);
+
+        }
+
+        private void UpdateIgnoredEdges(ConvexHull ch)
+        {
+            for (int i = 0; i < vertices.Length; i++)
+            {
+                if (vertices[i].X >= ch.boundingBox.X && vertices[i].X <= ch.boundingBox.Right && 
+                    vertices[i].Y >= ch.boundingBox.Y && vertices[i].Y <= ch.boundingBox.Bottom)
+                {
+                    Vector2 p = vertices[(i + 1) % vertices.Length];
+
+                    if (p.X >= ch.boundingBox.X && p.X <= ch.boundingBox.Right && 
+                        p.Y >= ch.boundingBox.Y && p.Y <= ch.boundingBox.Bottom)
+                    {
+                        ignoreEdge[i] = true;
+                    }
+                }                    
+            }            
         }
         
         private void CalculateDimensions()
@@ -199,8 +227,8 @@ namespace Barotrauma.Lights
 
         public bool Intersects(Rectangle rect)
         {
-            if (!Enabled)
-                return false;
+            if (!Enabled) return false;
+
             Rectangle transformedBounds = boundingBox;
             if (parentEntity != null && parentEntity.Submarine != null)
             {
@@ -219,6 +247,12 @@ namespace Barotrauma.Lights
             //compute facing of each edge, using N*L
             for (int i = 0; i < primitiveCount; i++)
             {
+                if (ignoreEdge[i])
+                {
+                    backFacing[i] = false;
+                    continue;
+                }
+
                 Vector2 firstVertex = new Vector2(vertices[i].X, vertices[i].Y);
                 int secondIndex = (i + 1) % primitiveCount;
                 Vector2 secondVertex = new Vector2(vertices[secondIndex].X, vertices[secondIndex].Y);
diff --git a/Subsurface/Source/Map/Structure.cs b/Subsurface/Source/Map/Structure.cs
index af87f2973..6298baf60 100644
--- a/Subsurface/Source/Map/Structure.cs
+++ b/Subsurface/Source/Map/Structure.cs
@@ -257,6 +257,13 @@ namespace Barotrauma
             var mergedSections = new List<WallSection>();
             foreach (var section in sections)
             {
+                if (mergedSections.Count > 5)
+                {
+                    mergedSections.Add(section);
+                    GenerateMergedHull(mergedSections);
+                    continue;
+                }
+
                 // if there is a gap and we have sections to merge, do it.
                 if (section.gap != null)
                 {