Fix color representation for texture in example

[atbentley]

I'm a bit over my head here but it seems like dear imgui expects colours to come in linear rgb space, so when we need to load textures we need to override the deafault Repr which is set to Srgb.

Does this mean if I want to use a texture in rendy and in dear imgui I need to load it twice? Once with Srgb for rendy and once with Unorm for dear imgui. I think this memory inefficient but computationally fast, so it's probably the right choice for now. However it does seem like there are some open discussions and even a PR for allowing dear imgui to work directly with srgb, if that gets resolved then there might be a away to use a single texture handle for both rendy and dear imgui.

Before:

After:

[vladbat00]

Hey, thanks for the PR!

Regarding your concern:

Does this mean if I want to use a texture in rendy and in dear imgui I need to load it twice?

I don't think so, I guess you can just choose the representation format which is compatible with imgui - and that's all. I can't see any reason why another image handle would be needed there.

Though I'm by no means rendy/Vulkan expert, maybe we could summon @zakarumych to the discussion

[vladbat00]

Well, as far as it works correctly (definitely better in this aspect than it was), I'm happy to merge it