Added cmake tooling

[pthom]

If you are interested, this is a CMake file that I added. This CMake file was tested under linux, macOS and windows.
I also added a backend "glfw_gl3" for samples.

Feel free to close this PR if you prefer to continue with sharpmake only.

Note: this PR will not compile unless the simple fixes PR was applied before (in order to fix some compilation issues on diverse platforms)

[pthom]

@sammyfreg wrote:

I'm thinking about wanting this CMake file included or not. On one hand, it's good work and definitely nice to have, but on the other hand it might soon get out of date without me dedicating extra time to maintain it too. It is not too complex (the Sharpmake version is a bit more complicated, but could also be used to output a makefile I believe).

My advice is that you should not merge this PR, and leave it opened so that people who are looking for it might find it and know that they need to adapt it because it might be outdated.

[pthom]

@sammyfreg wrote:

The other thing is that we really only need the NetImguiServer application to have multi-platform compiling support. The samples are just a simple demonstration that can easily be compiled without a build system configured, and the NetImgui client code is usually included in an existing project, and is the one that was meant to be truly multi-platform.

By default, here are the options in the cmake file:

option(NETIMGUI_BUILD_CLIENT "Build client" ON)
option(NETIMGUI_BUILD_IMGUI "Build imgui from sources in netImgui" ${PROJECT_IS_TOP_LEVEL})
option(NETIMGUI_BUILD_SAMPLES "Build samples" ${PROJECT_IS_TOP_LEVEL})
option(NETIMGUI_BUILD_SERVER_LIB "Build server lib" ${PROJECT_IS_TOP_LEVEL})
option(NETIMGUI_BUILD_SERVER_APP_SOKOL "Build server app" ${PROJECT_IS_TOP_LEVEL})

i.e.

• the client lib is built by default
• ImGui is built only if compiling netImgui as the main project
• Sample are built only if compiling netImgui as the main project
• The server is built only if compiling netImgui as the main project. In the current state, the server can only be built with Sokol, but users may adapt it quite easily: I left hints in the cmake file for that.

[pthom]

I think I had been too fast in the last push, I added an ifdef inside Code/Sample/Common/main.cpp which probably led the CI to fail. I removed it and I hope that the CI will pass.

Anyhow, it is not very important that it passes since this PR is meant to remain opened and not merged.