Unity Physics creating collider from mesh

PhysicsUtility.cs

using System;
using System.Runtime.CompilerServices;
using Unity.Burst;
using Unity.Collections;
using Unity.Entities;
using Unity.Jobs;
using Unity.Mathematics;
using Unity.Physics;
using UnityEngine;
using UnityEngine.Rendering;
using Collider = Unity.Physics.Collider;
using Material = Unity.Physics.Material;


namespace GallantGames
{
	public struct ConvertMeshToNativeBuffersJob : IJob
	{
		[ReadOnly] public Mesh.MeshData MeshData;
		[WriteOnly] public NativeArray<float3> MeshVertices;
		[WriteOnly] public NativeArray<int3> MeshTriangles;


		public void Execute()
		{
			MeshData.GetVertices( MeshVertices.Reinterpret<Vector3>() );

			if (MeshData.indexFormat == IndexFormat.UInt16)
			{
				var indexData16 = MeshData.GetIndexData<ushort>();
				var index16 = 0;
				for (var sm = 0; sm < MeshData.subMeshCount; ++sm)
				{
					var subMesh = MeshData.GetSubMesh( sm );
					for (int i = subMesh.indexStart, count = 0; count < subMesh.indexCount; i += 3, count += 3)
					{
						MeshTriangles[index16++] = (int3) new uint3( indexData16[i], indexData16[i + 1], indexData16[i + 2] );
					}
				}
			}
			else
			{
				var indexData32 = MeshData.GetIndexData<uint>();
				var index32 = 0;
				for (var sm = 0; sm < MeshData.subMeshCount; ++sm)
				{
					var subMesh = MeshData.GetSubMesh( sm );
					for (int i = subMesh.indexStart, count = 0; count < subMesh.indexCount; i += 3, count += 3)
					{
						MeshTriangles[index32++] = (int3) new uint3( indexData32[i], indexData32[i + 1], indexData32[i + 2] );
					}
				}
			}
		}
	}


	public struct CreatePhysicsMeshColliderJob : IJob
	{
		[ReadOnly] public NativeArray<float3> MeshVertices;
		[ReadOnly] public NativeArray<int3> MeshTriangles;
		[ReadOnly] public CollisionFilter CollisionFilter;
		[ReadOnly] public Material Material;
		[WriteOnly] public NativeReference<BlobAssetReference<Collider>> Collider;


		public void Execute()
		{
			Collider.Value = Unity.Physics.MeshCollider.Create( MeshVertices, MeshTriangles, CollisionFilter, Material );
		}
	}


	public static class PhysicsUtility
	{
		public static BlobAssetReference<Collider> CreateColliderForMesh( Mesh mesh, CollisionFilter collisionFilter )
		{
			var material = new Material
			{
				FrictionCombinePolicy = Material.CombinePolicy.Maximum,
				RestitutionCombinePolicy = Material.CombinePolicy.Maximum,
				Friction = 0.5f,
				Restitution = 0.5f
			};

			using var meshDataArray = Mesh.AcquireReadOnlyMeshData( mesh );
			var meshData = meshDataArray[0];
			var vertices = new NativeArray<float3>( meshData.vertexCount, Allocator.TempJob );
			var triangles = new NativeArray<int3>( meshData.GetTriangleCount(), Allocator.TempJob );

			var convertMeshToNativeBuffersJob = new ConvertMeshToNativeBuffersJob
			{
				MeshData = meshData,
				MeshVertices = vertices,
				MeshTriangles = triangles
			};
			convertMeshToNativeBuffersJob.Run();

			var createPhysicsMeshColliderJob = new CreatePhysicsMeshColliderJob
			{
				MeshVertices = vertices,
				MeshTriangles = triangles,
				CollisionFilter = collisionFilter,
				Material = material,
				Collider = new NativeReference<BlobAssetReference<Collider>>( Allocator.TempJob )
			};
			createPhysicsMeshColliderJob.Run();

			var collider = createPhysicsMeshColliderJob.Collider.Value;

			createPhysicsMeshColliderJob.MeshVertices.Dispose();
			createPhysicsMeshColliderJob.MeshTriangles.Dispose();
			createPhysicsMeshColliderJob.Collider.Dispose();

			return collider;
		}


		public static void AddComponentsForMesh( Entity entity, EntityManager entityManager, BlobAssetReference<Collider> collider, PhysicsBodyMotionType bodyMotionType = PhysicsBodyMotionType.Static )
		{
			entityManager.AddComponentData( entity, new PhysicsCollider { Value = collider } );

			switch (bodyMotionType)
			{
				case PhysicsBodyMotionType.Dynamic:
					entityManager.AddComponentData( entity, new PhysicsVelocity() );
					entityManager.AddComponentData( entity, PhysicsMass.CreateDynamic( collider.Value.MassProperties, 1.0f ) );
					break;
				case PhysicsBodyMotionType.Kinematic:
					entityManager.AddComponentData( entity, new PhysicsVelocity() );
					entityManager.AddComponentData( entity, PhysicsMass.CreateKinematic( collider.Value.MassProperties ) );
					break;
				case PhysicsBodyMotionType.Static:
					break;
				default:
					throw new ArgumentOutOfRangeException( nameof(bodyMotionType), bodyMotionType, null );
			}

			entityManager.AddSharedComponentManaged( entity, new PhysicsWorldIndex { Value = 0 } );
		}


		public static void AddComponentsForMesh( Entity entity, EntityManager entityManager, Mesh mesh, CollisionFilter collisionFilter, PhysicsBodyMotionType bodyMotionType = PhysicsBodyMotionType.Static )
		{
			var collider = CreateColliderForMesh( mesh, collisionFilter );
			AddComponentsForMesh( entity, entityManager, collider, bodyMotionType );
		}


		public static void AddComponentsForMesh( Entity entity, EntityCommandBuffer entityCommandBuffer, BlobAssetReference<Collider> collider, PhysicsBodyMotionType bodyMotionType = PhysicsBodyMotionType.Static )
		{
			entityCommandBuffer.AddComponent( entity, new PhysicsCollider { Value = collider } );

			switch (bodyMotionType)
			{
				case PhysicsBodyMotionType.Dynamic:
					entityCommandBuffer.AddComponent( entity, new PhysicsVelocity() );
					entityCommandBuffer.AddComponent( entity, PhysicsMass.CreateDynamic( collider.Value.MassProperties, 1.0f ) );
					break;
				case PhysicsBodyMotionType.Kinematic:
					entityCommandBuffer.AddComponent( entity, new PhysicsVelocity() );
					entityCommandBuffer.AddComponent( entity, PhysicsMass.CreateKinematic( collider.Value.MassProperties ) );
					break;
				case PhysicsBodyMotionType.Static:
					break;
				default:
					throw new ArgumentOutOfRangeException( nameof(bodyMotionType), bodyMotionType, null );
			}

			entityCommandBuffer.AddSharedComponent( entity, new PhysicsWorldIndex { Value = 0 } );
		}


		public static void AddComponentsForMesh( Entity entity, EntityCommandBuffer entityCommandBuffer, Mesh mesh, CollisionFilter collisionFilter, PhysicsBodyMotionType bodyMotionType = PhysicsBodyMotionType.Static )
		{
			var collider = CreateColliderForMesh( mesh, collisionFilter );
			AddComponentsForMesh( entity, entityCommandBuffer, collider, bodyMotionType );
		}
	}
}