Read Texture2DArray from GPU to CPU for compute shader

[sstrong]

How can I read Textures back from a RWTexture2DArray in a compute shader to my C# code? I’d like to do something like the following abbreviated code:

Texture2DArray tex2DArray = new Texture2DArray(width, height, numTextures, TextureFormat.ARGB32, false, true);
..
computeShader.SetTexture(kernalId, rwTex2DArray, tex2DArray);
..
computeShader.Dispatch(kernalId, threadGroupX, 1, 1);
..
// READ Texture2DArray from GPU to CPU


// Dispose of Texture2DArray
UnityEngine.Object.Destroy(tex2DArray);

[Olmi]

Hi @sstrong ,

You need to use RenderTexture with dimension parameter configured to tex2DArray and in your compute shader use
RWTexture2DArray.

Then read the data back to CPU-side with AsyncGPUReadback. You could then copy this data to separate slices of Texture2D with SetPixels/GetPixels.

Check this good thread to get the all critical information needed:

Upload and write to RenderTexture as Texture2DArray in Compute shader !?

Hi, i need to create a render texture and set it as a Tex2DArrayto a compute shader and then work on every texture in the array. How one can access a specific index of the array in Compute Shader… let’s say i would just like to apply a red color to the first texture, green to the second and blue to the third… !? rendTex = new RenderTexture(1024, 1024, 24, RenderTextureFormat.Default, RenderTextureReadWrite.Default); rendTex.dimension = UnityEngine.Rendering.TextureDimension.Tex2DArray; rendTex.…

I don’t know if it’s possible to read that array without that AsyncGPUReadback, as Texture2DArray doesn’t have ReadPixels as you probably noticed and I don’t know any other way.

[sstrong]

@Olmi

Hi @sstrong ,

You need to use RenderTexture with dimension parameter configured to tex2DArray and in your compute shader use
RWTexture2DArray.

Then read the data back to CPU-side with AsyncGPUReadback. You could then copy this data to separate slices of Texture2D with SetPixels/GetPixels.

Check this good thread to get the all critical information needed:
https://discussions.unity.com/t/676951

I don’t know if it’s possible to read that array without that AsyncGPUReadback, as Texture2DArray doesn’t have ReadPixels as you probably noticed and I don’t know any other way.

Yeah, have seen that thread. I wanted something that I could read synchronously as it is part of code that does other things too. I’m already using Texture2DArray as input without needing RenderTexture with dimension parameter (works fine).

Currently I’m using a computebuffer for this scenario but I’d like to switch to RWTexture2DArrays.