HDRP: How to render anything custom

Hi,

I'm using HD render pipeline. When I use provided stuff (hd-lit shader, Shader Graph), all works nice...

Now I want to do some custom rendering:

• adding Command Buffer to the main camera, or

• render some objects using ortho camera into render texture with simple HLSL-unlit shader (to render object masks for custom effects etc.)

However, it seems that in SRP we cannot insert custom Command Buffer into camera...
HDRP: https://forum.unity.com/threads/hdrp-how-to-add-command-buffer-to-camera.568870/
LWRP: https://forum.unity.com/threads/lwrp-and-camera-command-buffers.537682/

Is it even possible with SRP? I've not found anything about that on the forums, and if someone even asked, the thread was unanswered. Not even on github examples. I know I can make my custom SRP, but that would be just too much work so reverting back to the default pipeline would be much easier.

Anyone got the Command Buffers or rendering masks using the HDRP working? Thanks!

 

LWRP supports CB. Use Scriptable Render Pass API.
And in this video you find link to blurred glass CB (Unity sample of CommandBuffers) in LWRP.
And Github link: https://github.com/UnityTechnologies/LWRPScriptableRenderPass_ExampleLibrary

 

Is it also possible with the HDRP?

 

AFAIK - no

 

any news? I'd prefer good ones, like "will be available in the next release"

 

I'm also very curious to know if the HDRP will be gaining hook points for custom object rendering in the near future.

 

Any news on this ?

 

Hey everyone, I'm working on a hairworks integration project,
today I upgraded my project to HDRP, and I found out that
there is a HDAdditionalCameraData component on the camera,
and it has a customRender event you can use to override default rendering logic,
you can do anything there with ScriptableRenderContext and CommandBuffer.

Don't know about you guys, but I only need to set render targets and issue my plugin event there,
the rest is up to my native plugin, so It worked perfectly for me.

 

Yes, that's what I use also (shadow camera and fx camera). But careful if your cameras are not all at the same place, unity matrixes are not reliable. Also, if you manage to render something with drawrenderer, it would be very nice of you to put an example code
I had to modify mine twice already to make it work and now it's not working (again) since the last update (2019.2 a8 HDRP 5.9).

 

that is awesome!

 

What stage of the render pipeline does the customRender event render to? We have an asset that directly modifies the GBuffer using Camera.AddCommandBuffer with the correct CameraEvent, but customRender doesn't seem to have an equivalent (I don't know HDRP very well, so maybe that's wrapped up somewhere in the ScriptableRenderContext).

 

It completly bypasses the render pipeline. It's not like an injection at a specific stage. If you look at the code of the HDRP, you'll see that if there's a customRender, it executes it and skip the rest of the rendering for this camera.
I use it to calculate a shadowmap (that I use later on the main cam) and some other kind of depth maps (that I used later in post process, but I'm blocked with the PPV3 right now)

 

Ah that's unfortunate, definitely not what we need! Thanks anyway

 

Hi,
How can I extract Shadow Map data in HDRP, using a custom HDRP shader.
Can any one help me on this

 

After 1.5+ year HDRP still does not have command buffers or some functional and LWRP removed some feature like a "IAfterTransparentPass" etc....
Good job!

 

It is amazing how these pipelines are the most advertised thing in Unity and they simply not work yet.

Frankly is hard to believe what is happening to Unity and to Asset Store lately, is like a very very bad nightmare.

 

Is there any update on this?

 

For what it's worth darkydoodle's approach works to an extent to replace image effects done previously with OnRenderImage() callback. I scratched my head a good while for this, so I thought I'd share a basic duct tape solution until the next update. It probably won't help the OP though. I referred to keijiro's github for this: https://github.com/keijiro/HdrpBlitter
I'm using Unity 2019.2.0f1 with HDRP 6.9.1. The effect is the VHS scrambling seen here: https://twitter.com/niko_stenberg/status/1161896916076154880

- Set up a target render texture on your main camera, I do this in Update()

Code (CSharp):

1.  
2. RenderTexture rt = mainCamera.targetTexture;
3. if (rt == null)
4. {
5.     rt = new RenderTexture(Screen.width, Screen.height, 24, RenderTextureFormat.Default, 0);
6.     mainCamera.targetTexture = rt;
7. }
8. else if (rt.width != Screen.width || rt.height != Screen.height)
9. {
10.     rt.Release();
11.     rt = new RenderTexture(Screen.width, Screen.height, 24, RenderTextureFormat.Default, 0);
12.     mainCamera.targetTexture = rt;
13. }
14.  

- Set up a second camera to render after the main camera
- On a script on the second camera subscribe to the customRender event, I do this in OnEnable()

Code (CSharp):

1.  
2. var HDData = GetComponent<HDAdditionalCameraData>();
3. if (HDData != null)
4.     HDData.customRender += CustomRender;
5.  

- In the CustomRender function pass the render texture to your shader and execute a command buffer to render a full screen triangle

Code (CSharp):

1.  
2. void CustomRender(ScriptableRenderContext context, HDCamera camera)
3. {
4.     if (camera == null || camera.camera == null) return;
5.  
6.     RenderTexture RT = Camera.main.targetTexture;
7.  
8.     if (RT == null)
9.         return;
10.  
11.     // Target ID
12.     var rt = camera.camera.targetTexture;
13.     var rtid = rt != null ?
14.         new RenderTargetIdentifier(rt) :
15.         new RenderTargetIdentifier(BuiltinRenderTextureType.CameraTarget);
16.  
17.     // Shader uniforms
18.     rewindEffectMaterial.SetFloat(globalIntensityId, imageEffectIntensity);
19.     rewindEffectMaterial.SetTexture(mainTexId, RT);
20.     passthroughMaterial.SetTexture(mainTexId, RT);
21.  
22.     // Blit
23.     if (effectCB == null)
24.     {
25.         effectCB = new CommandBuffer();
26.         effectCB.name = "Rewind effect";
27.         CoreUtils.DrawFullScreen(effectCB, rewindEffectMaterial, rtid);
28.     }
29.     if (passthroughCB == null)
30.     {
31.         passthroughCB = new CommandBuffer();
32.         passthroughCB.name = "Rewind effect passthrough";
33.         CoreUtils.DrawFullScreen(passthroughCB, passthroughMaterial, rtid);
34.     }
35.     if (imageEffectIntensity == 0f)
36.         context.ExecuteCommandBuffer(passthroughCB);
37.     else
38.         context.ExecuteCommandBuffer(effectCB);
39. }
40.  

This function should always blit something. I'm using two materials to just blit the RT as is, if there's no effect to be done. You may need other managing in your particular case.

Here's the passthrough shader for reference. Modify to suit your image effect needs.

Code (CSharp):

1.  
2. Shader "reLive/BlitPassthroughHDRP"
3. {
4.     Properties
5.     {
6.         [HideInInspector]_MainTex("Base (RGB)", 2D) = "white" {}
7.     }
8.  
9.     HLSLINCLUDE
10.  
11. #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl"
12. #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Color.hlsl"
13. #include "Packages/com.unity.render-pipelines.high-definition/Runtime/ShaderLibrary/ShaderVariables.hlsl"
14.  
15.     float2 FixVFlip(float2 texcoord)
16.     {
17. #if UNITY_UV_STARTS_AT_TOP
18.         bool flip = _ProjectionParams.x > 0;
19. #else
20.         bool flip = _ProjectionParams.x < 0;
21. #endif
22.         if (flip) texcoord.y = _RTHandleScale.y - texcoord.y;
23.         return texcoord;
24.     }
25.  
26.     TEXTURE2D(_MainTex);
27.     SAMPLER(sampler_MainTex);
28.  
29.     // Vertex shader (procedural fullscreen triangle)
30.     void Vertex(
31.         uint vertexID : SV_VertexID,
32.         out float4 positionCS : SV_POSITION,
33.         out float2 texcoord : TEXCOORD0
34.     )
35.     {
36.         positionCS = GetFullScreenTriangleVertexPosition(vertexID);
37.         texcoord = FixVFlip(GetFullScreenTriangleTexCoord(vertexID));
38.     }
39.  
40.     // Fragment shader
41.     float4 Fragment(
42.         float4 positionCS : SV_POSITION,
43.         float2 texcoord : TEXCOORD0
44.     ) : SV_Target
45.     {
46.         // just output the texture
47.         return SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, texcoord);
48.     }
49.     ENDHLSL
50.  
51.     SubShader
52.     {
53.         Cull Off ZWrite Off ZTest Always
54.         Pass
55.         {
56.             HLSLPROGRAM
57.             #pragma vertex Vertex
58.             #pragma fragment Fragment
59.             ENDHLSL
60.         }
61.     }
62. }
63.  

 

The happiness is near https://github.com/Unity-Technologies/ScriptableRenderPipeline/pull/4317
I hope it will get into 7.x release

 

Can I use this method to generate a

_CameraNormalsTexture

and make a custom shader graph node that samples that texture? I won't to achieve the internal edge detection shader, but every article points to something legacy or non-HDRP...

 

Someone pleaaase.. Edge detection in HDRP seems to be a massive problem