Tried extrapolating collision data forward in time. Worked but not su…

…per stable and error is small. Parking for now.
wave-harmonic · May 21, 2018 · 8146864 · 8146864
1 parent e8e65bf
commit 8146864
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Showing 2 changed files with 32 additions and 3 deletions.
diff --git a/src/unity/Assets/Crest-Examples/Scripts/Collision/OceanHeightDemo.cs b/src/unity/Assets/Crest-Examples/Scripts/Collision/OceanHeightDemo.cs
@@ -8,6 +8,11 @@
 /// </summary>
 public class OceanHeightDemo : MonoBehaviour
 {
+    public bool _extrapolateForwards = true;
+
+    float _lastTime = -1f;
+    float _lastHeight;
+
 	void Update ()
     {
         float scale = transform.lossyScale.x;
@@ -17,9 +22,24 @@ void Update ()
 
         if (lod > -1)
         {
+            var wdc = OceanRenderer.Instance.Builder._shapeWDCs[lod];
+
             var pos = transform.position;
-            var height = OceanRenderer.Instance.Builder._shapeWDCs[lod].GetHeightExpensive(ref pos);
-            transform.position += Vector3.up * (height - pos.y);
+            var height = wdc.GetHeightExpensive(ref pos);
+            var time = wdc.GetCollisionTime();
+
+            var targetHeight = height;
+
+            if (_extrapolateForwards && _lastTime != -1f && (time - _lastTime) > Mathf.Epsilon)
+            {
+                float vel = (height - _lastHeight) / (time - _lastTime);
+                targetHeight += (OceanRenderer.Instance.ElapsedTime - time) * vel;
+            }
+
+            transform.position += Vector3.up * (targetHeight - pos.y);
+
+            _lastHeight = height;
+            _lastTime = time;
         }
     }
 }
diff --git a/src/unity/Assets/Crest/Scripts/WaveDataCam.cs b/src/unity/Assets/Crest/Scripts/WaveDataCam.cs
@@ -30,13 +30,15 @@ struct CollisionRequest
         {
             public AsyncGPUReadbackRequest _request;
             public RenderData _renderData;
+            public float _time;
         }
         Queue<CollisionRequest> _requests = new Queue<CollisionRequest>();
         const int MAX_REQUESTS = 8;
 
         // collision data
         NativeArray<ushort> _collDataNative;
         RenderData _collRenderData;
+        float _collTime;
 
         Material _matOceanDepth;
         RenderTexture _rtOceanDepth;
@@ -147,6 +149,7 @@ void UpdateShapeReadback()
                     var data = request._request.GetData<ushort>();
                     data.CopyTo(_collDataNative);
                     _collRenderData = request._renderData;
+                    _collTime = request._time;
 
                     Profiler.EndSample();
                 }
@@ -229,6 +232,11 @@ public float GetHeightExpensive(ref Vector3 worldPos)
             return posFlatland.y + disp.y;
         }
 
+        public float GetCollisionTime()
+        {
+            return _collTime;
+        }
+
         public void EnqueueReadbackRequest(RenderTexture target)
         {
             if (_requests.Count < MAX_REQUESTS)
@@ -237,7 +245,8 @@ public void EnqueueReadbackRequest(RenderTexture target)
                     new CollisionRequest
                     {
                         _request = AsyncGPUReadback.Request(cam.targetTexture),
-                        _renderData = _renderData
+                        _renderData = _renderData,
+                        _time = OceanRenderer.Instance.ElapsedTime,
                     }
                 );
             }