Workaround for PCVR depth submission (#685)

This is a partial fix for the issue discussed in #420

The issue was coming from RenderWrapper.cs, where an offscreen render texture is created so it can be reused and rescaled for performance when using the video recording tools. I'm not entirely sure why this is breaking our XR pipeline, as it appears the render texture is created properly.

As a stopgap, we keep using the normal camera, but switch to the offscreen render during recording.

This may be magically resolved when we upgrade Unity versions.

Assets/Scripts/Rendering/RenderWrapper.cs

@@ -23,6 +23,12 @@
 #pragma warning disable 649, 414
 #endif
 
+// TODO:Mikesky - For some reason, offscreen rendering to m_hdrTarget is losing depth on XR.
+// Unity's docs say this should be fine, so it may be a Unity bug.
+// Investigate if this is fixed in newer Unity versions
+// The temp fix is to no longer cull primary camera, and only display the offscreen render during
+// a recording session, which is very rare and not likely to be using depth.
+
 namespace TiltBrush
 {
 
@@ -200,9 +206,12 @@ void OnPreCull()
             // Store the clear and culling mask to restore after rendering.
             m_cameraClearFlags = srcCam.clearFlags;
             m_cameraCullingMask = srcCam.cullingMask;
-            srcCam.cullingMask = 0;
-            srcCam.clearFlags = CameraClearFlags.Nothing;
             srcCam.allowHDR = GetTargetFormat() != RenderTextureFormat.ARGB32;
+
+            // TODO:Mikesky - See top of file.
+            // srcCam.cullingMask = 0;
+            // srcCam.clearFlags = CameraClearFlags.Nothing;
+
 #endif
 
             if (ReadBackTextures != null && m_readbackTextureFrame != Time.frameCount)
@@ -456,7 +465,8 @@ public void OnRenderImage(RenderTexture source, RenderTexture destination)
                 }
                 else
                 {
-                    Graphics.Blit(m_hdrTarget, destination);
+                    // TODO:Mikesky - See top of file.
+                    Graphics.Blit(source, destination);
                     // Generate the outline mask for later use in the post fx chain
                     if (m_StencilToMaskMaterial)
                     {
@@ -469,9 +479,10 @@ public void OnRenderImage(RenderTexture source, RenderTexture destination)
                         // Only need the selection mask if the selection effect is enabled
                         if (App.Instance.SelectionEffect.RenderHighlight())
                         {
-                            Graphics.Blit(m_hdrTarget, destination);
-                            Graphics.Blit(destination, m_hdrTarget, m_StencilToMaskMaterial);
-                            Graphics.Blit(m_hdrTarget, m_MaskTarget);
+                            // TODO:Mikesky - See top of file.
+                            Graphics.Blit(source, destination);
+                            Graphics.Blit(destination, source, m_StencilToMaskMaterial);
+                            Graphics.Blit(source, m_MaskTarget);
                         }
                     }
                 }