ImGui pascal bindings

[imcold]

Hi, I'm working on pascal bindings for ImGui. It's a small library for immediate mode user interfaces, that's easy to integrate with SDL + OpenGL (and has examples for integrating with other frameworks / rendering APIs).
This is what the readme says:

dear imgui (AKA ImGui), is a bloat-free graphical user interface library for C++. It outputs optimized vertex buffers that you can render anytime in your 3D-pipeline enabled application. It is fast, portable, renderer agnostic and self-contained (no external dependencies).

ImGui is designed to enable fast iteration and empower programmers to create content creation tools and visualization/ debug tools (as opposed to UI for the average end-user). It favors simplicity and productivity toward this goal, and thus lacks certain features normally found in more high-level libraries.

ImGui is particularly suited to integration in realtime 3D applications, fullscreen applications, embedded applications, games, or any applications on consoles platforms where operating system features are non-standard.

I was looking for a simple gui for my OpenGL projects and it is serving me well so far (and it's even quite fun to use).

The bindings are here: https://github.com/dpethes/imgui-pas
ImGui is a C++ library, therefore a C wrapper dll is needed for other languages. It wraps the the static methods of ImGui classes as functions, which I had to import first and re-create a static class around them to mimic the original interface. I included a demo that shows how to use the library and includes the cimgui.dll build for Windows 64bit.

This is how I use it in my model viewer - though I recommend ImGui's project page for way better examples:

procedure DrawGui;
var
  style: PImGuiStyle;
  file_item: TFileListItem;
  fitem_selected: Boolean = false;
  selected_mesh_name: String;
  selected_item: TFileListItem;
begin
  ImGui_ImplSdlGL2_NewFrame(g_window);

  style := Imgui.GetStyle();
  style^.WindowRounding := 0;

  Imgui.Begin_('Mesh');
    if not g_model_loading_failed then begin
        Imgui.Text(g_model_name);
    end else
        Imgui.Text('mesh loading failed :(');
  Imgui.End_;

  Imgui.Begin_('Rendering options');
    Imgui.Checkbox('points', @view.opts.points);
    Imgui.Checkbox('wireframe', @view.opts.wireframe);
    Imgui.Checkbox('textures', @view.opts.textures);
    Imgui.Checkbox('vertex colors', @view.opts.vcolors);
    if g_model <> nil then
        if Imgui.Button('Export to obj') then
            g_model.ExportObj('rs_exported.obj');
  Imgui.End_;

  selected_mesh_name := EmptyStr;
  Imgui.Begin_('File list');
    //todo filter
    for file_item in g_filelist do begin
        fitem_selected := file_item.name = g_model_name;
        if Imgui.Selectable(file_item.name, fitem_selected) then begin
            selected_mesh_name := file_item.name;
            selected_item := file_item;
        end;
    end;
  Imgui.End_;

  if (selected_mesh_name <> EmptyStr) and (selected_mesh_name <> g_model_name) then begin
      try
        LoadMesh(selected_item);
        g_model_name := selected_mesh_name;
        g_model_loading_failed := false;
      except
        g_model_loading_failed := true;
      end;
  end;
end;