Added a GLFW/Vulkan backend.

[grahamreeds]

Note: I developed this in a container as not to pollute my wider WSL installation.

This may not work as intended as I am currently having trouble with the project that intends to consume this having trouble building and having it exist in its workspace (another docker container).

[giladreich]

Hi @grahamreeds, thanks for the PR! :) I'll try to have a look sometime this week or weekend and hopefully merge it if all good.

[giladreich]

Hi @grahamreeds, I just briefly had a look at your changes.

First off, many thanks for your efforts! It looks great for the most part.

Secondly, I'm afraid there is a problem with my initial approach of how I implemented the dependent cmake options (cmake_dependent_option). This will lead to other problems as we add more platforms and renderers (backends) in the long run.

I believe since we're externalizing this library and there could be so many combinations between the variant of Platforms and Renderers (e.g. SDL2 platform could run with dx{9,10,11,12}, vulkan, opengl{2,3} or sdlrenderer{2,3} etc.. renderers), then the existing approach won't scale. Therefore we need to completely separate the examples from the main build. This means if I know now I'm going to use ImGui with SDL2 and DX11, then the scope of the build should only be for what I chose.

I also remember I added myself a note here:

cmake-imgui/CMakeOptions.cmake

Line 21 in 1c50275

# TODO: Validate configurations based on the given input combination

to add validation for the given options, since I probably realized at the time that this doesn't scale.

Let me think about it more. Maybe tomorrow in the evening I may have some time to look or weekend and update this repo a little and add more examples.