Make SDL context part of the RenderWidget. Much cleaner

src/frontend/RenderWidget.cpp

@@ -1,5 +1,8 @@
 #include <KaizenQt.hpp>
 #include <RenderWidget.hpp>
+#include <imgui.h>
+#include <imgui_impl_sdl3.h>
+#include <imgui_impl_vulkan.h>
 
 RenderWidget::RenderWidget(QWidget *parent) : QWidget(parent) {
   setAttribute(Qt::WA_NativeWindow);
@@ -24,4 +27,38 @@ RenderWidget::RenderWidget(QWidget *parent) : QWidget(parent) {
 
   wsiPlatform = std::make_unique<QtWSIPlatform>(windowHandle());
   windowInfo = std::make_unique<QtParallelRdpWindowInfo>(windowHandle());
+
+  auto winPtr = reinterpret_cast<void *>(winId());
+  auto props = SDL_CreateProperties();
+#ifdef SDL_PLATFORM_LINUX
+  SDL_SetPointerProperty(props, SDL_PROP_WINDOW_CREATE_WAYLAND_WL_SURFACE_POINTER, winPtr);
+  SDL_SetNumberProperty(props, SDL_PROP_WINDOW_X11_WINDOW_NUMBER, static_cast<s64> winPtr);
+#elif SDL_PLATFORM_WINDOWS
+  SDL_SetPointerProperty(props, SDL_PROP_WINDOW_CREATE_WIN32_HWND_POINTER, winPtr);
+#else
+  SDL_SetPointerProperty(props, SDL_PROP_WINDOW_CREATE_COCOA_WINDOW_POINTER, winPtr);
+#endif
+  sdlWindow = SDL_CreateWindowWithProperties(props);
+
+  IMGUI_CHECKVERSION();
+  ImGui::CreateContext();
+  ImGuiIO &io = ImGui::GetIO();
+  (void)io;
+  io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;
+  io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;
+
+  ImGui::StyleColorsDark();
+
+  ImGui_ImplSDL3_InitForVulkan(sdlWindow);
+
+  connect(&timer, &QTimer::timeout, this, &RenderWidget::UpdateEvents);
+  timer.setInterval(16);
+  timer.start();
+}
+
+void RenderWidget::UpdateEvents() {
+  SDL_Event event;
+  while (SDL_PollEvent(&event)) {
+    ImGui_ImplSDL3_ProcessEvent(&event);
+  }
 }