Mujoco_WASM/python/mujoco/experimental/netimgui/Code/Sample/SampleNoBackend/SampleNoBackend.cpp

// Adapted for Google: removed NETIMGUI_IMPLEMENTATION (sources compiled
// separately), updated include paths for third_party layout.

//=================================================================================================
// SAMPLE NO BACKEND
//-------------------------------------------------------------------------------------------------
// Demonstration of using Dear ImGui without any Backend support.
// This way, user can use DearImgui without any code needed for drawing / input
// management, since it is all handled by the NetImgui remote server instead.
// Useful when this code is running on hardward without any display and/or
// convenient input.
//
// Because we are not using any Backend code, this Sample is a little bit
// different from the others. All of its code is included in this file (except
// for Dear ImGui sources) and does not rely on some shared sample source file.
//
// This sample compile both 'Dear Imgui' and 'NetImgui' sources directly
// (not using their project version in the solution)
//
// NOTE:	This sample is also use in backward compatibility test with
// older Dear ImGui versions,
//			making it easier to compile Dear Imgui without any OS
//specific code (Backends)
//
// NOTE:	This is also an excellent example of own little is needed to add
// NetImgui support
//			to a project. It doesn't handle Font DPI regeneration,
//keeping things simple.
//=================================================================================================

#include <stdio.h>

#include <chrono>
#include <thread>

#include "NetImgui_Api.h"
#include "Source/Fonts/Roboto_Medium.cpp"

namespace SampleNoBackend {

enum eSampleState : uint8_t {
  Start,
  Disconnected,
  Connected,
};

//=================================================================================================
// Initialize the Dear Imgui Context and the NetImgui library
//=================================================================================================
bool Client_Startup() {
  IMGUI_CHECKVERSION();
  ImGui::CreateContext();
  ImGuiIO& io = ImGui::GetIO();
  io.BackendFlags |=
      ImGuiBackendFlags_HasGamepad;  // Enable NetImgui Gamepad support
  io.DisplaySize = ImVec2(8, 8);

  ImFontConfig FontConfig = {};
  const char FontName[] = "Roboto Medium";
  memcpy(FontConfig.Name, FontName, sizeof(FontName));
  io.Fonts->AddFontFromMemoryCompressedTTF(Roboto_Medium_compressed_data,
                                           Roboto_Medium_compressed_size, 16.f,
                                           &FontConfig);
#if !NETIMGUI_IMGUI_TEXTURES_ENABLED
  io.Fonts->Build();
  io.Fonts->SetTexID(0);
#endif

  ImGui::StyleColorsDark();

  if (!NetImgui::Startup()) return false;

  return true;
}

//=================================================================================================
// Release resources
//=================================================================================================
void Client_Shutdown() {
  NetImgui::Shutdown();
  ImGui::DestroyContext(ImGui::GetCurrentContext());
}

//=================================================================================================
// Manage connection to NetImguiServer
//=================================================================================================
void Client_Connect(eSampleState& sampleState) {
  constexpr char zClientName[] = "SampleNoBackend (ImGui " IMGUI_VERSION ")";
  if (sampleState == eSampleState::Start) {
    printf("- Connecting to NetImguiServer to (127.0.0.1:%i)... ",
           NetImgui::kDefaultServerPort);
    NetImgui::ConnectToApp(zClientName, "localhost");
    while (NetImgui::IsConnectionPending());
    bool bSuccess = NetImgui::IsConnected();
    sampleState =
        bSuccess ? eSampleState::Connected : eSampleState::Disconnected;
    printf(bSuccess ? "Success\n" : "Failed\n");
    if (!bSuccess) {
      printf("- Waiting for a connection from NetImguiServer on port %i... ",
             NetImgui::kDefaultClientPort);
      NetImgui::ConnectFromApp(zClientName);
    }
  } else if (sampleState == eSampleState::Disconnected &&
             NetImgui::IsConnected()) {
    sampleState = eSampleState::Connected;
    printf("CONNECTED\n");
  } else if (sampleState == eSampleState::Connected &&
             !NetImgui::IsConnected()) {
    sampleState = eSampleState::Disconnected;
    printf("DISCONNECTED\n");
    printf("- Waiting for a connection from NetImguiServer on port %i... ",
           NetImgui::kDefaultClientPort);
    NetImgui::ConnectFromApp(zClientName);
  }
}

//=================================================================================================
// Render all of our Dear ImGui Content (when appropriate)
//=================================================================================================
void Client_Draw(bool& bQuit) {
  if (NetImgui::IsConnected() && NetImgui::NewFrame(true)) {
    ImGui::ShowDemoWindow();

    ImGui::SetNextWindowPos(ImVec2(32, 48), ImGuiCond_Once);
    ImGui::SetNextWindowSize(ImVec2(400, 400), ImGuiCond_Once);
    if (ImGui::Begin("Sample No Backend", nullptr)) {
      ImGui::TextColored(ImVec4(0.1, 1, 0.1, 1), "Client:");
      ImGui::TextUnformatted(" DearImgui Version: " IMGUI_VERSION);
      ImGui::TextUnformatted(" NetImgui Version:  " NETIMGUI_VERSION);
      ImGui::TextUnformatted("");
      ImGui::SameLine();
      bQuit = ImGui::Button("  Quit  ");
      if (ImGui::IsItemHovered()) ImGui::SetTooltip("Terminate this sample.");
      ImGui::NewLine();
      ImGui::TextColored(ImVec4(0.1, 1, 0.1, 1), "Description:");
      ImGui::TextWrapped(
          "This sample demonstate the ability to use Dear ImGui without any "
          "Backend. "
          "Rely instead on NetImgui to remotely handle drawing and inputs. "
          "This avoids the need for rendering/input/window management code on "
          "the client itself.");
    }
    ImGui::End();

    NetImgui::EndFrame();
  }
}

}  // namespace SampleNoBackend

int main(int, char**) {
  printf(
      "========================================================================"
      "========\n");
  printf("  NetImgui Sample: No Backend\n");
  printf(
      "========================================================================"
      "========\n");
  printf(
      " Demonstrate 'Dear ImGui' + 'NetImgui' for a UI displayed on a remote "
      "server.\n");
  printf(" Dear ImGui : " IMGUI_VERSION "\n");
  printf(" NetImgui   : " NETIMGUI_VERSION "\n");
  printf(" ['Ctrl + C' to quit]\n");
  printf(
      "------------------------------------------------------------------------"
      "--------\n");
  if (!SampleNoBackend::Client_Startup()) {
    printf("Failed initializing NetImgui.");
    SampleNoBackend::Client_Shutdown();
    return -1;
  }

  // Main loop
  bool bQuit = false;
  SampleNoBackend::eSampleState sampleState =
      SampleNoBackend::eSampleState::Start;
  while (!bQuit) {
    // Avoids high CPU/GPU usage by releasing this thread until enough time has
    // passed
    static auto sLastTime = std::chrono::steady_clock::now();
    std::chrono::duration<float> elapsedSec =
        std::chrono::steady_clock::now() - sLastTime;
    if (elapsedSec.count() < 1.f / 120.f) {
      std::this_thread::sleep_for(std::chrono::microseconds(250));
      continue;
    }
    sLastTime = std::chrono::steady_clock::now();

    // Sample Update
    SampleNoBackend::Client_Connect(sampleState);
    SampleNoBackend::Client_Draw(bQuit);
  }

  // Cleanup
  SampleNoBackend::Client_Shutdown();
  return 0;
}