Impossible to create VK_DESCRIPTOR_TYPE_STORAGE_IMAGE properly

[Shinkeys]

Issue Description
As I understood to use aforementioned texture of type storage image you need to use public RWTexture2D<uint2> lightsGrid; in slang, however that's not necessary in some cases, for example in the fragment shader.

If would change that to be Texture2D(readonly) it produces this error:

vkCreateGraphicsPipelines(): pCreateInfos[0].pStages[1] SPIR-V (VK_SHADER_STAGE_FRAGMENT_BIT) uses descriptor [Set 0, Binding 1, variable "lightsGrid"] of type VK_DESCRIPTOR_TYPE_STORAGE_IMAGE but expected VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE or VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER.

To use storage images in the fragment shader in Vulkan without validation errors you need to enable deviceFeatures2.features.fragmentStoresAndAtomics = VK_TRUE; device feature, which might be undesired in some cases.

Expected Behavior
Read only storage image for the fragment stage

Actual Behavior
Must use read write image inside of fragment stage, which forces to enable vulkan device feature.

Environment:

• Slang Version 2025.12.1
• Windows 11

[csyonghe]

Can you just use Texture2D with SAMPLED_IMAGE?

[Shinkeys]

Maybe I didn't get your idea, but I need to write to this texture in the compute shader then I read it in the fragment stage, so I can't use that. I store the data inside of image, so I use storage image

[csyonghe]

What I meant is you can create the same texture object, but create a SampledImage view and bind that view when executing fragment shader, and create a StorageImage view and bind that into the compute shader. Would that work?