From 706d2b6d9d2b130338f8de8e6bb1de847e15d9a9 Mon Sep 17 00:00:00 2001
From: in0finite <leshow816@gmail.com>
Date: Sun, 27 Feb 2022 00:44:14 +0100
Subject: [PATCH] generate box colliders for water mesh

---
 Assets/Prefabs/WaterCollision.prefab     | 13 ++++----
 Assets/Scripts/Behaviours/World/Water.cs | 42 +++++++++++-------------
 Assets/Scripts/Utilities/MathUtils.cs    | 10 ++++++
 3 files changed, 35 insertions(+), 30 deletions(-)

diff --git a/Assets/Prefabs/WaterCollision.prefab b/Assets/Prefabs/WaterCollision.prefab
index d266c695..1e4d2dce 100644
--- a/Assets/Prefabs/WaterCollision.prefab
+++ b/Assets/Prefabs/WaterCollision.prefab
@@ -9,7 +9,7 @@ GameObject:
   serializedVersion: 6
   m_Component:
   - component: {fileID: 7995634715881356742}
-  - component: {fileID: 8546980230320474744}
+  - component: {fileID: 4513590737340015457}
   m_Layer: 4
   m_Name: WaterCollision
   m_TagString: Untagged
@@ -31,8 +31,8 @@ Transform:
   m_Father: {fileID: 0}
   m_RootOrder: 0
   m_LocalEulerAnglesHint: {x: 0, y: 0, z: 0}
---- !u!64 &8546980230320474744
-MeshCollider:
+--- !u!65 &4513590737340015457
+BoxCollider:
   m_ObjectHideFlags: 0
   m_CorrespondingSourceObject: {fileID: 0}
   m_PrefabInstance: {fileID: 0}
@@ -41,7 +41,6 @@ MeshCollider:
   m_Material: {fileID: 0}
   m_IsTrigger: 1
   m_Enabled: 1
-  serializedVersion: 4
-  m_Convex: 1
-  m_CookingOptions: 30
-  m_Mesh: {fileID: 0}
+  serializedVersion: 2
+  m_Size: {x: 1, y: 1, z: 1}
+  m_Center: {x: 0, y: 0, z: 0}
diff --git a/Assets/Scripts/Behaviours/World/Water.cs b/Assets/Scripts/Behaviours/World/Water.cs
index 57e1d450..8387f636 100644
--- a/Assets/Scripts/Behaviours/World/Water.cs
+++ b/Assets/Scripts/Behaviours/World/Water.cs
@@ -13,6 +13,7 @@ namespace SanAndreasUnity.Behaviours.World
         [SerializeField] private GameObject m_waterCollisionPrefab;
 
         [SerializeField] private bool m_createCollisionObjects = false;
+        [SerializeField] private float m_collisionHeight = 20f;
 
         [HideInInspector] [SerializeField] private List<Transform> m_renderingObjects = new List<Transform>();
         [HideInInspector] [SerializeField] private List<Transform> m_collisionObjects = new List<Transform>();
@@ -167,42 +168,37 @@ namespace SanAndreasUnity.Behaviours.World
             int i = 0;
             foreach (var face in faces)
             {
-                Vector3[] vertices = new Vector3[face.Vertices.Length];
-                Vector3[] normals = new Vector3[face.Vertices.Length];
-                int numIndices = (face.Vertices.Length - 2) * 3;
-                int[] indices = new int[numIndices];
-
-                int verticesIndex = 0;
-                int indicesIndex = 0;
-
-                ProcessFace(face, vertices, normals, ref verticesIndex, indices, ref indicesIndex);
-
                 Vector3 center = Vector3.zero;
-                vertices.ForEach(v => center += v / vertices.Length);
-                for (int v = 0; v < vertices.Length; v++)
-                    vertices[v] = vertices[v] - center;
+                face.Vertices.ForEach(v => center += v.Position / face.Vertices.Length);
 
-                var mesh = new Mesh();
+                // create box collider based on vertices
+                Vector3 min = Vector3.positiveInfinity;
+                Vector3 max = Vector3.negativeInfinity;
+                for (int v = 0; v < face.Vertices.Length; v++)
+                {
+                    min = MathUtils.MinComponents(min, face.Vertices[v].Position);
+                    max = MathUtils.MaxComponents(max, face.Vertices[v].Position);
+                }
 
-                mesh.vertices = vertices;
-                mesh.normals = normals;
-                mesh.SetIndices(indices, MeshTopology.Triangles, 0);
-
-                mesh.name = $"Water collision mesh {i}";
+                Vector3 size = max - min;
+                size.y = m_collisionHeight;
 
                 GameObject go = availableObjects.Count > 0
                     ? availableObjects.Dequeue().gameObject
                     : Instantiate(m_waterCollisionPrefab, this.transform);
 
-                go.name = mesh.name;
+                go.name = $"Water collision {i}";
 
-                go.transform.localPosition = center;
+                go.transform.localPosition = center.WithY(center.y - size.y * 0.5f);
                 go.transform.localRotation = Quaternion.identity;
 
-                var meshCollider = go.GetComponentOrThrow<MeshCollider>();
+                var boxCollider = go.GetComponentOrThrow<BoxCollider>();
+                boxCollider.size = size;
+
+                /*var meshCollider = go.GetComponentOrThrow<MeshCollider>();
                 if (meshCollider.sharedMesh != null && !EditorUtilityEx.IsAsset(meshCollider.sharedMesh))
                     F.DestroyEvenInEditMode(meshCollider.sharedMesh);
-                meshCollider.sharedMesh = mesh;
+                meshCollider.sharedMesh = mesh;*/
 
                 m_collisionObjects.Add(go.transform);
 
diff --git a/Assets/Scripts/Utilities/MathUtils.cs b/Assets/Scripts/Utilities/MathUtils.cs
index d57695c3..c040a557 100644
--- a/Assets/Scripts/Utilities/MathUtils.cs
+++ b/Assets/Scripts/Utilities/MathUtils.cs
@@ -17,5 +17,15 @@ namespace SanAndreasUnity.Utilities
             Vector3 projection = v + t * (w - v);  // Projection falls on the segment
             return Vector3.Distance(p, projection);
         }
+
+        public static Vector3 MinComponents(Vector3 a, Vector3 b)
+        {
+            return new Vector3(Mathf.Min(a.x, b.x), Mathf.Min(a.y, b.y), Mathf.Min(a.z, b.z));
+        }
+
+        public static Vector3 MaxComponents(Vector3 a, Vector3 b)
+        {
+            return new Vector3(Mathf.Max(a.x, b.x), Mathf.Max(a.y, b.y), Mathf.Max(a.z, b.z));
+        }
     }
 }