去掉obi，使用自写绳索

Assets/Obi/Scripts/Common/Backends/Burst/Solver/FindFluidParticlesJob.cs

@@ -1,33 +0,0 @@
-#if (OBI_BURST && OBI_MATHEMATICS && OBI_COLLECTIONS)
-using UnityEngine;
-using Unity.Jobs;
-using Unity.Collections;
-using Unity.Mathematics;
-using Unity.Burst;
-using System;
-using System.Collections;
-
-namespace Obi
-{
-    [BurstCompile]
-    struct FindFluidParticlesJob : IJob
-    {
-        [ReadOnly] public NativeArray<int> activeParticles;
-        [ReadOnly] public NativeArray<int> phases;
-
-        public NativeList<int> fluidParticles;
-
-        public void Execute()
-        {
-            fluidParticles.Clear();
-
-            for (int i = 0; i < activeParticles.Length; ++i)
-            {
-                int p = activeParticles[i];
-                if ((phases[p] & (int)ObiUtils.ParticleFlags.Fluid) != 0)
-                    fluidParticles.Add(p);
-            }
-        }
-    }
-}
-#endif