Question How to have both a Depth and Normal camera in the same HDRP Scene

Hi There!

I'm working on a project where I need to have both an RGB color camera as well as a Depth camera in the same scene. I'm using:

• Unity 2021.3.10f1
• HDRP 12.1.7

I've created a standard HDRP scene, added a Camera (named Depth camera) and attached a volume to it so only one camera should render Depth.



I have the RGB camera rendering to Display 1, and the Depth camera to Display 2 for testing.

I've also made sure to add the Custom Post Process script to the project settings:




In the volume attached the the Depth camera, I selected "Add override" -> "Post Processing" -> "Custom" -> DepthExample

After doing that however, the entire scene changes to a Depth map, also on both cameras so the effect is not constrained to the volume.



I also have test code that uses the Unity example for creating GrayScale using HDRP, and I get the same behaviour.

Code (CSharp):

1. using UnityEngine;
2. using UnityEngine.Rendering;
3. using UnityEngine.Rendering.HighDefinition;
4. using System;
5.  
6. [Serializable, VolumeComponentMenu("Post-processing/Custom/DepthExample")]
7. public sealed class DepthExample : CustomPostProcessVolumeComponent, IPostProcessComponent
8. {
9.     [Tooltip("Controls the intensity of the effect.")]
10.     public ClampedFloatParameter depthDistance = new ClampedFloatParameter(1f, 0f, 32f);
11.     public ClampedFloatParameter intensity = new ClampedFloatParameter(0f, 0f, 1f);
12.  
13.     Material m_Material;
14.  
15.     public bool IsActive() => m_Material != null;
16.  
17.     public override CustomPostProcessInjectionPoint injectionPoint => CustomPostProcessInjectionPoint.AfterPostProcess;
18.  
19.     public override void Setup()
20.     {
21.         if (Shader.Find("Hidden/Shader/DepthExample") != null)
22.             m_Material = new Material(Shader.Find("Hidden/Shader/DepthExample"));
23.     }
24.  
25.  
26.     public override void Render(CommandBuffer cmd, HDCamera camera, RTHandle source, RTHandle destination)
27.     {
28.  
29.         if (m_Material == null)
30.             return;
31.  
32.  
33.         // Packing multiple float paramters into one float4 uniform
34.         Vector4 parameters = new Vector4(depthDistance.value, depthDistance.value, depthDistance.value, depthDistance.value);
35.         m_Material.SetVector("_Params", parameters);
36.         m_Material.SetTexture("_InputTexture", source);
37.  
38.         m_Material.SetFloat("_Intensity", intensity.value);  //< Test code for testing the grayscal effect
39.         cmd.Blit(source, destination, m_Material, 0);
40.  
41.         //HDUtils.DrawFullScreen(cmd, m_Material, destination);
42.     }
43.  
44.     public override void Cleanup() => CoreUtils.Destroy(m_Material);
45. }

Here is my shader code (with grayscale test code embedded, just uncomment the return you want:

Code (CSharp):

1. Shader "Hidden/Shader/DepthExample"
2. {
3.     Properties
4.     {
5.         // This property is necessary to make the CommandBuffer.Blit bind the source texture to _MainTex
6.         _MainTex("Main Texture", 2DArray) = "grey" {}
7.     }
8.  
9.     HLSLINCLUDE
10.  
11.     #pragma target 4.5
12.     #pragma only_renderers d3d11 playstation xboxone xboxseries vulkan metal switch
13.  
14.     #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl"
15.     #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Color.hlsl"
16.     #include "Packages/com.unity.render-pipelines.high-definition/Runtime/ShaderLibrary/ShaderVariables.hlsl"
17.     #include "Packages/com.unity.render-pipelines.high-definition/Runtime/PostProcessing/Shaders/FXAA.hlsl"
18.     #include "Packages/com.unity.render-pipelines.high-definition/Runtime/PostProcessing/Shaders/RTUpscale.hlsl"
19.  
20.     struct Attributes
21.     {
22.         uint vertexID : SV_VertexID;
23.         UNITY_VERTEX_INPUT_INSTANCE_ID
24.     };
25.  
26.     struct Varyings
27.     {
28.         float4 positionCS : SV_POSITION;
29.         float2 texcoord   : TEXCOORD0;
30.         UNITY_VERTEX_OUTPUT_STEREO
31.  
32.     };
33.  
34.     Varyings Vert(Attributes input)
35.     {
36.         Varyings output;
37.  
38.         UNITY_SETUP_INSTANCE_ID(input);
39.         UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(output);
40.  
41.         output.positionCS = GetFullScreenTriangleVertexPosition(input.vertexID);
42.         output.texcoord = GetFullScreenTriangleTexCoord(input.vertexID);
43.  
44.         return output;
45.     }
46.  
47.  
48.  
49.     // List of properties to control your post process effect
50.     float _Intensity;
51.     TEXTURE2D_X(_MainTex);
52.  
53.     float4 _Params;
54.     #define _Distance _Params.w
55.     TEXTURE2D_X(_InputTexture);
56.     TEXTURE2D(_DepthTexture);
57.     int _RunOnce = 0;
58.  
59.     float4 CustomPostProcess(Varyings input) : SV_Target
60.     {
61.         UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(input);
62.  
63.  
64.         /////////////////////////////////////////////////////////////////////
65.         /*
66.          * Code below generates grayscale output. Used for testing the shader
67.          */
68.         float3 sourceColor = SAMPLE_TEXTURE2D_X(_MainTex, s_linear_clamp_sampler, input.texcoord).xyz;
69.  
70.         // Apply greyscale effect
71.         float3 color = lerp(sourceColor, Luminance(sourceColor), _Intensity);
72.  
73.         /////////////////////////////////////////////////////////////////////
74.  
75.         /*
76.          * Code below generates Depth output.
77.          */
78.         uint2 positionSS = input.texcoord * _ScreenSize.xy;
79.  
80.         // Depth
81.         float depth = LoadCameraDepth(positionSS);
82.         float linearEyeDepth = LinearEyeDepth(depth, _ZBufferParams);
83.         float coc = saturate(_Distance / linearEyeDepth);
84.  
85.    
86.         return float4(color, 1); //< Test code for testing grayscale effect
87.         //return coc;
88.     }
89.  
90.     ENDHLSL
91.  
92.     SubShader
93.     {
94.         Pass
95.         {
96.             Name "DepthExample"
97.  
98.             ZWrite Off
99.             ZTest Always
100.             Blend Off
101.             Cull Off
102.  
103.             HLSLPROGRAM
104.                 #pragma fragment CustomPostProcess
105.                 #pragma vertex Vert
106.             ENDHLSL
107.         }
108.     }
109.  
110.     Fallback Off
111. }

I've also attached a unity package I exported of this project, really hope someone can help me with this! I don't need the grayscale effect, just the Depth effect, and for the life of me I can't figure this one out!

I've seen tutorials online where this could also be done using Shader Graph with custom passes and reading / writing to custom buffers ( see this link ) , but this only works with 2022.2 (which is still in beta), and I can't use beta builds at this stage, really prefer to stick to LTS if possible.

 

What is a "Depth Effect"? (Just wondering if there is a different approach, like distant fog or camera blur.)

 

It's a grayscale image where pixels are scaled between 0 and 1 depending on how far the object is from the camera. I actually managed to get something working using Shader Graph, I'll share it here in case anyone needs something similar. Please feel free to share tips on how to imropove things in case I messed something up!