Enable ImGui for use in Fahrenheit.

[fkelava]

This did not initially work because of missing DX11/Win32 backend enablement.

ImGui.NET does not bundle/wrap the backends, so that is out of the question. We can therefore do two things:

• Write our own that includes them;
• Perform ImGui enablement from C++ and include the imgui_impl_*.h headers verbatim.

[fkelava]

Rough procedure for compiling an amended ImGui.NET/cimgui:

• git clone https://luajit.org/git/luajit.git
• From a Developer PowerShell, run the supplied msvcbuild.bat
• Copy luajit.exe, lua51.dll to some arbitrary folder, and the contents of src/jit to a folder lua/jit in the same place as the former two
• git clone --recursive https://github.com/cimgui/cimgui.git
• In generator/generator.bat, edit the set PATH directive to include your LuaJIT folder
• In generator/generator.bat, have the luajit directive read ./generator.lua cl "internal noimstrv" dx11 win32 %*
• Run generator/generator.bat
• Amend the top-level CMakeLists.txt as such:

  #general settings
  file(GLOB IMGUI_SOURCES
  cimgui.cpp
  imgui/imgui.cpp
  imgui/imgui_draw.cpp
  imgui/imgui_demo.cpp
  imgui/imgui_widgets.cpp
  imgui/backends/imgui_impl_win32.cpp
  imgui/backends/imgui_impl_dx11.cpp
  ${TABLES_SOURCE}
  )

• Open the folder in Visual Studio, select Manage Configurations
• Set the Toolset to msvc_x86_x64, save, then compile
• git clone https://github.com/ImGuiNET/ImGui.NET
• Place the new cimgui.dll in deps/cimgui/win_x86
• In src\CodeGenerator\definitions\cimgui, place cimgui's generator/output/{impl_definitions,definitions,structs_and_enums}.json
• Patch CodeGenerator's ImguiDefinitions.cs according to: https://github.com/equilibrium-hub/ImGui.NET/commit/696c9b7a71a0e8adf19a0f108a1550e0075e41c3#diff-8a4f306bfae678663d6bfafdb3b902f8afe3246a28ccd14e1d3379d22476b152R42-R48, https://github.com/equilibrium-hub/ImGui.NET/commit/696c9b7a71a0e8adf19a0f108a1550e0075e41c3#diff-8a4f306bfae678663d6bfafdb3b902f8afe3246a28ccd14e1d3379d22476b152R108
• Build CodeGenerator, run CodeGenerator, place its output under ImGui.NET's Generated folder
• Build it for x86

[fkelava]

Fahrenheit will bring LuaJIT, cimgui and ImGui.NET in as submodules and provide build scripts as soon as it is confirmed that this, in fact, works.

[fkelava]

Partial: a4bfe84cd2b4db532f1532a5e46722a648462802, 2abe70869d83f42f59dc92cc9842163bc2751679

[fkelava]

Enablement complete as of 1236a99545a845a1201859f4c5e9ae28fa500491.

Rendering hook still requires implementation, but beyond that we are- hopefully- done.

[EvelynTSMG]

@fkelava did it :3

[fkelava]

Commit of this functionality is still pending a better way to handle D3D/DXGI method invocation.

For a proof of concept I used Vortice.Windows, but this bundles an unacceptable amount of runtime dependencies. The relevant parts need to be "lifted" into Fahrenheit, but this is not trivial because we are dealing with COM interop.

At the very least we need:

• IDXGISwapChain::GetBuffer
• ID3D11Device::CreateRenderTargetView
• ID3D11DeviceContext::OMSetRenderTargets
• A way to Release the pointer obtained from GetBuffer.

[fkelava]

Implementation complete as of 650abb23560f016e7c0da2a0d4582a266af66571.

API bindings not yet set (i.e. that the ImGui core module invokes other modules' ImGui rendering callbacks), but the module can be used for internal testing even pending that.

At long last, we've done it.

[EvelynTSMG]

(Closing this issue requires me to implement the actually allowing mods to render things using imgui part)