Use sampler2DMS with VK_SAMPLE_COUNT_1_BIT?

If I remember right, in OpenGL we could use an MSAA texture with 1x sampling. This is convenient when you have a shader written to handle multisampling, but you have MSAA disabled, because you don’t have to load a different shader just to handle this one setting.

In Vulkan, it seems that texture sampling is controlled purely by the VkSampleCountFlagBits value when a VkImage is created. Is it possible to somehow use a sampler2DMS in GLSL with a 1x sampled texture in Vulkan?

No. A multisample image in Vulkan is an image where each pixel has multiple samples.

That being said, I do believe it is legal in Vulkan (definitely with descriptor indexing, but I’m not sure about before that) to declare two variables with the same descriptor set and binding indices. Then you can use a uniform to decide which one to sample from.