From dd46ce1d98275f582e13c9875bedbc2e45bd4b04 Mon Sep 17 00:00:00 2001
From: Regalis <regalis@undertowgames.com>
Date: Tue, 20 Dec 2016 16:11:47 +0200
Subject: [PATCH] Adjusting submarine spawnposition if the sub (or any docked
 subs) intersect with walls

---
 Subsurface/Source/GameSession/GameSession.cs |  2 +-
 Subsurface/Source/Map/Submarine.cs           | 62 ++++++++++++++++++++
 Subsurface/Source/Utils/MathUtils.cs         | 31 ++++++++++
 3 files changed, 94 insertions(+), 1 deletion(-)

diff --git a/Subsurface/Source/GameSession/GameSession.cs b/Subsurface/Source/GameSession/GameSession.cs
index eb707dfbe..362e0f5e0 100644
--- a/Subsurface/Source/GameSession/GameSession.cs
+++ b/Subsurface/Source/GameSession/GameSession.cs
@@ -200,7 +200,7 @@ namespace Barotrauma
             {
                 level.Generate();
 
-                submarine.SetPosition(level.StartPosition - new Vector2(0.0f, 2000.0f));
+                submarine.SetPosition(submarine.FindSpawnPos(level.StartPosition - new Vector2(0.0f, 2000.0f)));
 
                 //secondSub.SetPosition(level.EndPosition - new Vector2(0.0f, 2000.0f));
 
diff --git a/Subsurface/Source/Map/Submarine.cs b/Subsurface/Source/Map/Submarine.cs
index beeb06bd7..b94c8f70f 100644
--- a/Subsurface/Source/Map/Submarine.cs
+++ b/Subsurface/Source/Map/Submarine.cs
@@ -11,6 +11,7 @@ using System.IO;
 using System.Linq;
 using System.Reflection;
 using System.Xml.Linq;
+using Voronoi2;
 
 namespace Barotrauma
 {
@@ -311,6 +312,67 @@ namespace Barotrauma
             dockedBorders.Y += dockedBorders.Height;
             return dockedBorders;
         }
+
+        public Vector2 FindSpawnPos(Vector2 spawnPos)
+        {
+            Rectangle dockedBorders = GetDockedBorders();
+            
+            int iterations = 0;
+            bool wallTooClose = false;
+            do
+            {
+                Rectangle worldBorders = new Rectangle(
+                    dockedBorders.X + (int)spawnPos.X,
+                    dockedBorders.Y + (int)spawnPos.Y, 
+                    dockedBorders.Width, 
+                    dockedBorders.Height);
+
+                wallTooClose = false;
+
+                var nearbyCells = Level.Loaded.GetCells(
+                    spawnPos, (int)Math.Ceiling(Math.Max(dockedBorders.Width, dockedBorders.Height) / (float)Level.GridCellSize));
+
+                foreach (VoronoiCell cell in nearbyCells)
+                {
+                    if (cell.CellType == CellType.Empty) continue;
+
+                    foreach (GraphEdge e in cell.edges)
+                    {
+                        List<Vector2> intersections = MathUtils.GetLineRectangleIntersections(e.point1, e.point2, worldBorders);
+                        foreach (Vector2 intersection in intersections)
+                        {
+                            wallTooClose = true;
+
+                            if (intersection.X < spawnPos.X)
+                            {
+                                spawnPos.X += intersection.X - worldBorders.X;
+                            }
+                            else
+                            {
+                                spawnPos.X += intersection.X - worldBorders.Right;
+                            }
+
+                            if (intersection.Y < spawnPos.Y)
+                            {
+                                spawnPos.Y += intersection.Y - (worldBorders.Y - worldBorders.Height);
+                            }
+                            else
+                            {
+                                spawnPos.Y += intersection.Y - worldBorders.Y;
+                            }
+
+                            spawnPos.Y = Math.Min(spawnPos.Y, Level.Loaded.Size.Y - dockedBorders.Height / 2);
+                        }
+                    }
+                }
+
+                iterations++;
+            } while (wallTooClose && iterations < 10);
+
+            return spawnPos;
+
+        
+        }
         
         //drawing ----------------------------------------------------
 
diff --git a/Subsurface/Source/Utils/MathUtils.cs b/Subsurface/Source/Utils/MathUtils.cs
index f194bbc09..ccdf61cc5 100644
--- a/Subsurface/Source/Utils/MathUtils.cs
+++ b/Subsurface/Source/Utils/MathUtils.cs
@@ -233,6 +233,37 @@ namespace Barotrauma
                 new Vector2(rect.Right, rect.Y - rect.Height));
         }
 
+        public static List<Vector2> GetLineRectangleIntersections(Vector2 a1, Vector2 a2, Rectangle rect)
+        {
+            List<Vector2> intersections = new List<Vector2>();
+
+            Vector2? intersection = GetLineIntersection(a1, a2,
+                new Vector2(rect.X, rect.Y),
+                new Vector2(rect.Right, rect.Y));
+
+            if (intersection != null) intersections.Add((Vector2)intersection);
+
+            intersection = GetLineIntersection(a1, a2,
+                new Vector2(rect.X, rect.Y - rect.Height),
+                new Vector2(rect.Right, rect.Y - rect.Height));
+
+            if (intersection != null) intersections.Add((Vector2)intersection);
+
+            intersection = GetLineIntersection(a1, a2,
+                new Vector2(rect.X, rect.Y),
+                new Vector2(rect.X, rect.Y - rect.Height));
+
+            if (intersection != null) intersections.Add((Vector2)intersection);
+
+            intersection = GetLineIntersection(a1, a2,
+                new Vector2(rect.Right, rect.Y),
+                new Vector2(rect.Right, rect.Y - rect.Height));
+
+            if (intersection != null) intersections.Add((Vector2)intersection);
+
+            return intersections;
+        }
+
         public static float LineToPointDistance(Vector2 lineA, Vector2 lineB, Vector2 point)
         {
             float xDiff = lineB.X - lineA.X;