Commandbuffer.Blit flips the image until switching to VR

Hi, I am using a commandbuffer for a simple grab of the camera buffer into a temp rendertexture that is used later in a material (a helmet visor). The problem is that the blit flips the Y coordinate of the uvs. I could correct for this by changing the helmet shader (1-uv.y), but when switching into VR it stops flipping the uvs, so I can't rely on a constant solution. After having switched to VR once, the uvs stop being flipped even after returning to screen mode, which is disconcerting. I am using single pass stereo (NOT instanced). Here is some of the code:

Code (CSharp):

1. RenderTextureDescriptor desc;
2.                 if (VR.VRController.Instance.VREnabled) {
3.                     desc = UnityEngine.XR.XRSettings.eyeTextureDesc;
4.                 } else {
5.                     desc = new RenderTextureDescriptor(Screen.width, Screen.height, RenderTextureFormat.DefaultHDR);
6.                 }
7.                 desc.depthBufferBits = 0;
8.                 holoRenderTex = RenderTexture.GetTemporary(desc);

Code (CSharp):

1.                 blitCommand = new CommandBuffer();
2.                 blitCommand.name = "HUDBlit";
3.                 blitCommand.Blit(BuiltinRenderTextureType.CurrentActive, holoRenderTex);
4.                 holoCamera.AddCommandBuffer(CameraEvent.AfterEverything, blitCommand);
5.                 glassMat.SetTexture("_HoloTex", holoRenderTex);

 

I found a workaround: specifying a blit material using the hidden blit shader fixes the uv flip.

Code (CSharp):

1. blitMat = new Material(Shader.Find("Hidden/BlitCopy"));
2. blitCommand.Blit(BuiltinRenderTextureType.CurrentActive, holoRenderTex, blitMat);

 

I have been trying to duplicate your answer but with succese. When I use the 2 parameter version of blitCommand.Blit(src, dest) my result is upside down. If I use the 3 parameter version blitCommand.Blit(src, dest, material) my "_MainTex" is not populated with a texture. Any idea of why this could be the case?