runevision · October 22, 2017 11:09 · Oct 22, 2017
diff --git a/CameraTrackingRefraction.cs b/CameraTrackingRefraction.cs
@@ -0,0 +1,50 @@
+using UnityEngine;
+using UnityEngine.Rendering;
+
+// This script is added to cameras automatically at runtime by the ObjectNeedingRefraction scripts.
+public class CameraTrackingRefraction : MonoBehaviour {
+
+	[System.NonSerialized]
+	public int lastRenderedFrame = -1;
+
+	Camera cam;
+	CommandBuffer buffer;
+
+	void Awake () {
+		cam = Camera.current;
+		cam.depthTextureMode = DepthTextureMode.Depth;
+	}
+
+	public void SetIsNeededThisFrame () {
+		lastRenderedFrame = Time.frameCount;
+		if (buffer == null)
+			CreateCommandBuffer ();
+		enabled = true;
+	}
+
+	void Update () {
+		if (lastRenderedFrame < Time.frameCount - 1) {
+			DestroyCommandBuffer ();
+			enabled = false;
+		}
+	}
+
+	void DestroyCommandBuffer () {
+		cam.RemoveCommandBuffer (CameraEvent.AfterSkybox, buffer);
+		buffer = null;
+	}
+
+	void CreateCommandBuffer ()
+	{
+		buffer = new CommandBuffer();
+		buffer.name = "Grab screen";
+
+		int screenCopyID = Shader.PropertyToID("_RefractionGrabTexture");
+		buffer.GetTemporaryRT (screenCopyID, -1, -1, 0, FilterMode.Bilinear);
+		buffer.Blit (BuiltinRenderTextureType.CurrentActive, screenCopyID);
+
+		buffer.SetGlobalTexture("_RefractionGrabTexture", screenCopyID);
+
+		cam.AddCommandBuffer (CameraEvent.AfterSkybox, buffer);
+	}
+}
diff --git a/ObjectNeedingRefraction.cs b/ObjectNeedingRefraction.cs
@@ -0,0 +1,27 @@
+using System.Collections.Generic;
+using UnityEngine;
+
+// Place this script on all GameObject with renderers with materials
+// that use shaders that need the _RefractionGrabTexture "grab texture".
+// The GrabPass in the shader can then be removed and the rest should ideally work as-is.
+public class ObjectNeedingRefraction : MonoBehaviour {
+
+	static Dictionary<Camera, CameraTrackingRefraction> m_Trackers =
+		new Dictionary<Camera, CameraTrackingRefraction>();
+
+	public void OnWillRenderObject () {
+		var cam = Camera.current;
+		if (!cam)
+			return;
+
+		CameraTrackingRefraction tracker;
+		if (!m_Trackers.TryGetValue (cam, out tracker)) {
+			tracker = cam.GetComponent<CameraTrackingRefraction> ();
+			if (!tracker)
+				tracker = cam.gameObject.AddComponent<CameraTrackingRefraction> ();
+			m_Trackers[cam] = tracker;
+		}
+
+		tracker.SetIsNeededThisFrame ();
+	}
+}