_CameraDepthTexture in Compute Shader

Unity Engine
,
1

Hi everyone.

I’m trying to pass the _CameraDepthTexture global shader propery to my compute shader using

Shader.SetTextureFromGlobal(kernel, "DepthTexture", "_CameraDepthTexture")
but i get this error:
Compute shader (PS_procedural): Property (DepthTexture) at kernel index (2) has mismatching texture dimension (expected 2, got 5).

So it seems like it’s not a 2D texture even if inside ShaderVariables.hlsl it is defined as: TEXTURE2D_X(_CameraDepthTexture);

and it’s sampled with :

{
return LOAD_TEXTURE2D_X_LOD(_CameraDepthTexture, pixelCoords, 0).r;
}

This approach used to work fine when using the legacy rendering pipeline. So what’s wrong with _CameraDepthTexture dimensions in HDRP? Am I missing something?

Is there another way to get the camera depth texture without using another camera and a render texture? Maybe a Custom Pass?

[P.S.] similar thread : Accessing Depth rendertexture in HDRP and pass it to Compute Shaders

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2

So I incidentally just started working on a HDRP post processing effect that uses a compute shader. I also got the mismatching texture dimension error. I managed to make it go away by declaring my texture in the compute shader using TEXTURE2D_X(). Below is a stripped down version of the working code:

#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl" // required by the below file (I believe)
#include "Packages/com.unity.render-pipelines.high-definition/Runtime/ShaderLibrary/ShaderVariables.hlsl" // for TEXTURE2D_X() and RW_TEXTURE2D_X

#pragma kernel CSMain

TEXTURE2D_X(_Source);
RW_TEXTURE2D_X(float4, _Destination);

[numthreads(8,8,1)]
void CSMain (uint3 id : SV_DispatchThreadID)
{
    // how to read from a texture
    float4 myValue = _Source[ COORD_TEXTURE2D_X(id.xy) ];

    // how to write to the texture
    _Destination[ COORD_TEXTURE2D_X(id.xy) ] = myValue;
}

I gleaned this from Accumulation.compute which is in HDRP package under Runtime > RenderPipeline > Accumulation > Shaders. I’ve yet to try fetching the depth buffer, but if I get it working I’ll come back to add to this thread

3 Likes
3

As promised, an update:

I got my compute shader and the associated CustomPostProcessVolumeComponent working.

Sampling the depth texture was as simple as adding the #includes from my first post and using LoadCameraDepth()

I should also note that the effect still didn’t render in play mode unless I used Resources.Load() to initialize the compute shader in the volume’s Setup(). In other words, if you use a public reference and drag in a compute shader you will find that it is null upon entering play mode and your effect will not work