entt VS imgui

EnTT is a popular alternative to flecs for C++, which has different performance/memory characteristics.

https://pastebin.com/VPypiitk This is a very small experiment i did to learn the metaprogramming features. its an ECS library using the same model as entt (https://github.com/skypjack/entt). In 200 lines or so it does the equivalent of a few thousand lines of template heavy Cpp while compiling instantly and generating good debug code.

Some walkthrough:

Line 8 declares a SparseSet type as a fairly typical template. its just a struct with arrays of type T inside. Next lines implement getters/setters for this data structure

Line 46 Base_Registry things get interesting. This is a struct that holds a bunch of SparseSet of different types, and providers getters/setters for them by type. It uses code generation to do this. The initial #insert at the start of the class injects codegen that creates structure members from the type list the struct gets on its declaration. Note also how type-lists are a native structure in the lang, no need for variadics.

Line 99 i decide to do variadic style tail templates anyway for fun. I implement a function that takes a typelist and returns the tail, and the struct is created through recursion as one would do in cpp. Getters and setters for the View struct are also implemented through recursion

Line 143 has the for expansion. This is how you overload the for loop functionality to create custom iterators.

The rest of the code is just some basic test code that runs the thing.

Since we wanted a common game simulation that would be on both the server and the client we looked into a few libraries that would fit our ECS needs. It was decided we were going to write this common part of our game in C++, but rust was considered. C++ was a familiar language for us so naturally EnTT and flecs came up right away. I had used EnTT before, writing some small demo projects, so our choice was made based on familiarity. In order to integrate with Unity we created a small C interface to communicate between our simulation code and Unity’s C#. Here’s close to what it looked like. I removed some parts for brevity sake.

Are you sure you don't want to use a C++ package manager? Libtcod is on Vcpkg and with that setup you could add the fmt library or EnTT. fmt fixes C++'s string handling and EnTT fixes everything wrong with the entities of the previous tutorials.

There's also a performance question. While we can now use Blueprint nativization to convert Blueprints to C++ the result will be a fairly naive version, fast enough for most purposes but not if you're trying to push every bit of performance. This is where you're looking at making sure you're hitting things such as using the CPU cache as well as possible for an ECS system (Look at ENTT or Flecs if you want to see what they're about and why you'd want one), or a system needing to process massive amounts of data quickly such as the Voxel Plugin.

For a modern engine you’re probably best looking at Unity’s DOTS. You may also want to check out some of the different open source ECS libraries such as flecs and EnTT are two popular ones for C++, but there’s lots of them. Largely you’ll see lots of different approaches taken, all with their own pros and cons. Not all of them will be performant (some focus more on the design benefits) while others will be optimised for certain use cases. What you should prioritise will depend on your specific needs.

You can think of DynaMix as combining one of these libraries with an ECS like entt(https://github.com/skypjack/entt)

include(cmake/CPM.cmake) function(raylib_imgui_setup_dependencies) message(STATUS "Include Dear ImGui") FetchContent_Declare( ImGui GIT_REPOSITORY https://github.com/ocornut/imgui GIT_TAG 277ae93c41314ba5f4c7444f37c4319cdf07e8cf) # v1.90.4 FetchContent_MakeAvailable(ImGui) FetchContent_GetProperties(ImGui SOURCE_DIR IMGUI_DIR) add_library( imgui STATIC ${imgui_SOURCE_DIR}/imgui.cpp ${imgui_SOURCE_DIR}/imgui_draw.cpp ${imgui_SOURCE_DIR}/imgui_widgets.cpp ${imgui_SOURCE_DIR}/imgui_tables.cpp) target_include_directories(imgui INTERFACE ${imgui_SOURCE_DIR}) include(cmake/CPM.cmake) message(STATUS "Include dbg-macro") cpmaddpackage( "gh:sharkdp/dbg-macro#fb9976f410f8b29105818b20278cd0be0e853fe8" )# v0.5.1 message(STATUS "Include fmtlib") cpmaddpackage("gh:fmtlib/fmt#e69e5f977d458f2650bb346dadf2ad30c5320281" )# 10.x message(STATUS "Include raylib") cpmaddpackage("gh:raysan5/raylib#ae50bfa2cc569c0f8d5bc4315d39db64005b1b0" )# v5.0 message(STATUS "Include spdlog") cpmaddpackage("gh:gabime/spdlog#7c02e204c92545f869e2f04edaab1f19fe8b19fd" )# v1.13.0 message(STATUS "Include rlImGui") FetchContent_Declare( rlImGui GIT_REPOSITORY https://github.com/raylib-extras/rlImGui GIT_TAG d765c1ef3d37cf939f88aaa272a59a2713d654c9) FetchContent_MakeAvailable(rlImGui) FetchContent_GetProperties(rlImGui SOURCE_DIR RLIMGUI_DIR) add_library(rlimgui STATIC ${rlimgui_SOURCE_DIR}/rlImgui.cpp) target_link_libraries(rlimgui PRIVATE imgui raylib) target_include_directories(rlimgui INTERFACE ${rlimgui_SOURCE_DIR}) endfunction()

Immediate mode is a fuzzy concept, as witnessed by this writeup: https://github.com/ocornut/imgui/wiki/About-the-IMGUI-paradi...

It's fun to see the evolution in e.g. these examples of image loading for Dear Imgui:

https://github.com/ocornut/imgui/wiki/Image-Loading-and-Disp...

DirectX9 will even load the image for you, DirectX11 okay we get a few more structures to fill out, DirectX12 is where it goes off the rails and we are filling out a bunch of UNKNOWN DONT_CARE JUST_DO_IT. Then of course Vulkan is the one that gets the big fat "this probably won't actually work for you" warning.

I understand whats happening, but you know sometimes I just want to display a fucking image.

ImGui is engine/GPU agnostic

Themeing isn't a just a retained mode thing, you can do wonders with immediate UIs, even thought (dear)ImGui doesn't provide much, you can still do wonders: https://github.com/ocornut/imgui/issues/707#issuecomment-362...

More on that topic: https://www.youtube.com/watch?v=Z1qyvQsjK5Y

Bonus: If you want to make desktop app with UI, then this is another great C++ library and it's also simple to learn as well. https://github.com/ocornut/imgui.

AFAIK the Rust equivalent to C++'s Dear ImGui is egui.

They use a Dear ImGui, a C++ GUI library.

Aside from bugs and driver issues, Wayland has some unfortunate design limitations. For example, Dear ImGui multi-viewports don't work because "Wayland doesn't let application read or write windows positions."

https://github.com/ocornut/imgui/wiki/Multi-Viewports

This is a feature available on Windows, macOS, and of course X11. Making choices like this means desktop Linux becomes even more of a weird island that nobody wants to support.