Command Buffer Blit not working on VR Singlepass Instanced?

Hello, I've been working on updating some assets to work with VR SPI but I don't seem to have any luck with command buffers.

For regular VR and non VR I've been using the typical CommandBuffer.Blit() but this doesnt seem to work with SPI? It seems that only the left eye gets rendered.

Code (CSharp):

1. RtDownsampler.vrUsage = UnityEngine.XR.XRSettings.eyeTextureDesc.vrUsage;
2. RtDownsampler.Create();
3. ...
4. RenderTargetIdentifier ssaaCommandBufferTargetId = new RenderTargetIdentifier(RtDownsampler);
5. ...
6. CbDownsampler.Blit(BuiltinRenderTextureType.CameraTarget, ssaaCommandBufferTargetId);
7. CbDownsampler.Blit(ssaaCommandBufferTargetId, BuiltinRenderTextureType.CameraTarget, MaterialCurrent, 0);

I am using a test shader currently that should render 1 different color to each eye and is setup to support SPI as per unity docs.

Code (CSharp):

1. Shader "Hidden/SPI_Def"
2. {
3.     Properties
4.     {
5.         _MainTex ("Texture", 2D) = "" {}
6.     }
7.     SubShader {
8.         Tags{ "RenderType" = "Opaque"  "Queue" = "Geometry+0" }
9.         Blend [_SrcBlend] [_DstBlend]
10.         Pass {
11.              ZTest Always Cull Off ZWrite On
12.             CGPROGRAM
13.             #include "UnityCG.cginc"
14.             //#include "Include/_SSAA_Utils.cginc"
15.             #pragma vertex vert//_img
16.             #pragma fragment frag
17.             UNITY_DECLARE_SCREENSPACE_TEXTURE(_MainTex); //Insert
18.             struct Input
19.             {
20.                 float4 vertex : POSITION;
21.                 float2 uv : TEXCOORD0;
22.  
23.                 UNITY_VERTEX_INPUT_INSTANCE_ID //Insert
24.             };
25.             struct Varying
26.             {
27.                 float2 uv : TEXCOORD0;
28.                 float4 vertex : SV_POSITION;
29.  
30.                 UNITY_VERTEX_OUTPUT_STEREO //Insert
31.             };
32.             Varying vert(Input input)
33.             {
34.                 Varying o;
35.                 UNITY_SETUP_INSTANCE_ID(input); //Insert
36.                 UNITY_INITIALIZE_OUTPUT(Varying, o); //Insert
37.                 UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o); //Insert
38.  
39.                 o.vertex = UnityObjectToClipPos(input.vertex);
40.                 o.uv = input.uv;
41.                 return o;
42.             }
43.             fixed4 frag(Varying i) : SV_Target
44.             {
45.                 UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(i);
46.                 return lerp(float4(1,0,0,1), float4(0,1,0,1), unity_StereoEyeIndex);
47.                 //return UNITY_SAMPLE_SCREENSPACE_TEXTURE(_MainTex, i.texcoord);
48.             }
49.             ENDCG
50.         }
51.     }
52.     Fallback Off
53. }
54.  

So, what is the best way to handle post processing with command buffers on VR single-pass instanced? Or am I missing something in my shader or command buffer?

 

bump

 

no one can tell?

 

Thanks for the info. Seems that there is more to it than just setting up the shaders as in that doc links. However by digging more through postprocessing stack v2 source and with the help of a fellow asset store publisher I managed to get it running.

This is how the command buffer code looks now.

Code (CSharp):

1. CbDownsampler.GetTemporaryRT(Shader.PropertyToID("_SSAAVRSamplerTexture"), UnityEngine.XR.XRSettings.eyeTextureDesc);
2. RenderTargetIdentifier ssaaCommandBufferTargetId = new RenderTargetIdentifier(Shader.PropertyToID("_SSAAVRSamplerTexture"));
3.                
4. CbDownsampler.Blit(BuiltinRenderTextureType.CameraTarget, ssaaCommandBufferTargetId);
5. CbDownsampler.Blit(ssaaCommandBufferTargetId, BuiltinRenderTextureType.CameraTarget, MaterialDefault);

The important bit seems to be using the xr eye texture descriptor (which I wasn't using before because on multi pass and singlepass the rendering worked as is) when generating the render texture, and I've also switched from manually constructed render textures in original post to cb.GetTemporaryRT(..) for ease of use

Using render textures constructed by code also seem to work, however the render target identifier has to be constructed like this for some reason (important bits are the extra parameters) so I stick with the cb.GetTemporaryRT implementation as its more cleaner and easier to understand code wise.

Code (CSharp):

1. RenderTargetIdentifier ssaaCommandBufferTargetId = new RenderTargetIdentifier(RtDownsampler, 0, CubemapFace.Unknown, -1);

Maybe it would be good to include some of this information regarding construction of the RTs to be used with vr rendering in the unity docs, so the next person running into this issue wouldn't have to dig through source code of other assets and ask around other developers for 1 week to get it running

 

Hi everyone,
i was trying to achieve the same thing, but unfortunately i am a complete newbie, especially to the SRP.
When I was trying your code @Raul_MadGoat i had the following 2 errors:

Attempting to get Camera relative temporary RenderTexture (width || height <= 0) via a CommandBuffer Unlit in a Sriptable Render Pipeline.

Trying to get RenderBuffer with invalid antiAliasing (must be at least 1)

Would anyone maybe know how to port a Shader to VR (preferably SPI) or has any propper tutorial showing how (including the C# part), i would be very thankful! As i am slowly turning mad.

 

Yes. For future people searching for this. This fixed the problem I was having with SPI and command buffers.
Here's my distilled code:

commandBuffer.GetTemporaryRT(_shaderPropertyID, UnityEngine.XR.XRSettings.eyeTextureDesc);

commandBuffer.SetRenderTarget(_shaderPropertyID, 0, CubemapFace.Unknown, -1);