aurora: DPI scaling fixes (renderer, imgui)

Runtime/CMain.cpp

@@ -417,7 +417,7 @@ public:
   }
 
   void onAppWindowResized(const aurora::WindowSize& size) noexcept override {
-    CGraphics::SetViewportResolution({static_cast<s32>(size.width), static_cast<s32>(size.height)});
+    CGraphics::SetViewportResolution({static_cast<s32>(size.fb_width), static_cast<s32>(size.fb_height)});
   }
 
   void onAppWindowMoved(std::int32_t x, std::int32_t y) noexcept override {

aurora/CMakeLists.txt

@@ -27,9 +27,6 @@ add_library(aurora STATIC
     lib/gfx/movie_player/shader.cpp
     lib/gfx/textured_quad/shader.cpp
     lib/gfx/colored_quad/shader.cpp
-    # TODO move to imgui? or move imgui impl to here?
-    ../extern/imgui/backends/imgui_impl_sdl.cpp
-    ../extern/imgui/backends/imgui_impl_wgpu.cpp
     )
 target_compile_definitions(aurora PRIVATE IMGUI_USER_CONFIG="imconfig_user.h") # IMGUI_USE_WCHAR32
 target_include_directories(aurora PUBLIC include ../Runtime)

aurora/include/aurora/aurora.hpp

@@ -174,6 +174,11 @@ struct Icon {
 struct WindowSize {
   uint32_t width;
   uint32_t height;
+  uint32_t fb_width;
+  uint32_t fb_height;
+  float scale;
+
+  bool operator<=>(const WindowSize& rhs) const = default;
 };
 enum class MouseButton {
   None = 0,

aurora/lib/aurora.cpp

@@ -15,10 +15,10 @@ static logvisor::Module Log("aurora");
 // TODO: Move global state to a class/struct?
 static std::unique_ptr<AppDelegate> g_AppDelegate;
 static std::vector<std::string> g_Args;
-static float g_AppDpi = 1.f;
 
 // SDL
-static SDL_Window* g_Window;
+static SDL_Window* g_window;
+static WindowSize g_windowSize;
 
 // GPU
 using gpu::g_depthBuffer;
@@ -40,7 +40,7 @@ static void set_window_icon(Icon icon) noexcept {
     Log.report(logvisor::Fatal, FMT_STRING("Failed to create icon surface: {}"), SDL_GetError());
     unreachable();
   }
-  SDL_SetWindowIcon(g_Window, iconSurface);
+  SDL_SetWindowIcon(g_window, iconSurface);
   SDL_FreeSurface(iconSurface);
 }
 
@@ -58,26 +58,26 @@ static bool poll_events() noexcept {
       case SDL_WINDOWEVENT_HIDDEN: {
         break;
       }
-      case SDL_WINDOWEVENT_EXPOSED: {
-        break;
-      }
       case SDL_WINDOWEVENT_MOVED: {
         g_AppDelegate->onAppWindowMoved(event.window.data1, event.window.data2);
         break;
       }
+      case SDL_WINDOWEVENT_EXPOSED:
+      case SDL_WINDOWEVENT_DISPLAY_CHANGED:
+      case SDL_WINDOWEVENT_RESIZED:
       case SDL_WINDOWEVENT_SIZE_CHANGED:
-      case SDL_WINDOWEVENT_RESIZED: {
-        gpu::resize_swapchain(event.window.data1, event.window.data2);
-        g_AppDelegate->onAppWindowResized(
-            {static_cast<uint32_t>(event.window.data1), static_cast<uint32_t>(event.window.data2)});
-        break;
-      }
-      case SDL_WINDOWEVENT_MINIMIZED: {
-        // TODO: handle minimized event
-        break;
-      }
+      case SDL_WINDOWEVENT_MINIMIZED:
       case SDL_WINDOWEVENT_MAXIMIZED: {
-        // TODO: handle maximized event
+        const auto size = get_window_size();
+        if (size == g_windowSize) {
+          break;
+        }
+        if (size.scale != g_windowSize.scale) {
+          g_AppDelegate->onAppDisplayScaleChanged(size.scale);
+        }
+        g_windowSize = size;
+        gpu::resize_swapchain(size.fb_width, size.fb_height);
+        g_AppDelegate->onAppWindowResized(size);
         break;
       }
       case SDL_WINDOWEVENT_RESTORED: {
@@ -112,17 +112,6 @@ static bool poll_events() noexcept {
         // TODO: handle hit test?
         break;
       }
-      case SDL_WINDOWEVENT_DISPLAY_CHANGED: {
-        printf("DISPLAY_CHANGED!\n");
-        float scale = 1.0f;
-        if (SDL_GetDisplayDPI(SDL_GetWindowDisplayIndex(g_Window), nullptr, &scale, nullptr) == 0) {
-          scale /= 96.0f;
-          if (g_AppDpi != scale) {
-            g_AppDelegate->onAppDisplayScaleChanged(scale);
-          }
-        }
-        break;
-      }
       }
       break;
     }
@@ -259,30 +248,29 @@ void app_run(std::unique_ptr<AppDelegate> app, Icon icon, int argc, char** argv)
   default:
     break;
   }
-  g_Window = SDL_CreateWindow("Metaforce", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 1280, 720, flags);
-  if (g_Window == nullptr) {
+  g_window = SDL_CreateWindow("Metaforce", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 1280, 720, flags);
+  if (g_window == nullptr) {
     Log.report(logvisor::Fatal, FMT_STRING("Error creating window: {}"), SDL_GetError());
     unreachable();
   }
   set_window_icon(std::move(icon));
 
-  gpu::initialize(g_Window);
+  gpu::initialize(g_window);
   gfx::initialize();
-  g_AppDpi = 1.0f;
-  if (SDL_GetDisplayDPI(SDL_GetWindowDisplayIndex(g_Window), nullptr, &g_AppDpi, nullptr) == 0) {
-    g_AppDpi /= 96.0f;
-  }
 
   imgui::create_context();
-  g_AppDelegate->onImGuiInit(g_AppDpi);
-  imgui::initialize(g_Window);
+  const auto size = get_window_size();
+  Log.report(logvisor::Info, FMT_STRING("Using framebuffer size {}x{} scale {}"), size.fb_width, size.fb_height,
+             size.scale);
+  g_AppDelegate->onImGuiInit(size.scale);
+  imgui::initialize(g_window);
   g_AppDelegate->onImGuiAddTextures();
 
   g_AppDelegate->onAppLaunched();
-  g_AppDelegate->onAppWindowResized(get_window_size());
+  g_AppDelegate->onAppWindowResized(size);
 
   while (poll_events()) {
-    imgui::new_frame();
+    imgui::new_frame(g_windowSize);
     if (!g_AppDelegate->onAppIdle(ImGui::GetIO().DeltaTime)) {
       break;
     }
@@ -354,19 +342,26 @@ void app_run(std::unique_ptr<AppDelegate> app, Icon icon, int argc, char** argv)
   imgui::shutdown();
   gfx::shutdown();
   gpu::shutdown();
-  SDL_DestroyWindow(g_Window);
+  SDL_DestroyWindow(g_window);
   SDL_Quit();
 }
 
 std::vector<std::string> get_args() noexcept { return g_Args; }
 
 WindowSize get_window_size() noexcept {
-  int width, height;
-  SDL_GetWindowSize(g_Window, &width, &height);
-  return {static_cast<uint32_t>(width), static_cast<uint32_t>(height)};
+  int width, height, fb_w, fb_h;
+  SDL_GetWindowSize(g_window, &width, &height);
+  SDL_GL_GetDrawableSize(g_window, &fb_w, &fb_h);
+  return {
+      .width = static_cast<uint32_t>(width),
+      .height = static_cast<uint32_t>(height),
+      .fb_width = static_cast<uint32_t>(fb_w),
+      .fb_height = static_cast<uint32_t>(fb_h),
+      .scale = static_cast<float>(fb_w) / static_cast<float>(width),
+  };
 }
 
-void set_window_title(zstring_view title) noexcept { SDL_SetWindowTitle(g_Window, title.c_str()); }
+void set_window_title(zstring_view title) noexcept { SDL_SetWindowTitle(g_window, title.c_str()); }
 
 Backend get_backend() noexcept {
   switch (gpu::g_backendType) {
@@ -392,7 +387,7 @@ Backend get_backend() noexcept {
 std::string_view get_backend_string() noexcept { return magic_enum::enum_name(gpu::g_backendType); }
 
 void set_fullscreen(bool fullscreen) noexcept {
-  SDL_SetWindowFullscreen(g_Window, fullscreen ? SDL_WINDOW_FULLSCREEN : 0);
+  SDL_SetWindowFullscreen(g_window, fullscreen ? SDL_WINDOW_FULLSCREEN : 0);
 }
 
 int32_t get_controller_player_index(uint32_t instance) noexcept { return input::player_index(instance); }
@@ -409,5 +404,6 @@ void controller_rumble(uint32_t instance, uint16_t low_freq_intensity, uint16_t
                        uint32_t duration_ms) noexcept {
   input::controller_rumble(instance, low_freq_intensity, high_freq_intensity, duration_ms);
 }
+
 std::string get_controller_name(uint32_t instance) noexcept { return input::controller_name(instance); }
 } // namespace aurora

aurora/lib/gpu.cpp

@@ -1,10 +1,10 @@
 #include "gpu.hpp"
 
+#include <SDL.h>
 #include <dawn/native/DawnNative.h>
 #include <dawn/webgpu_cpp.h>
 #include <logvisor/logvisor.hpp>
 #include <magic_enum.hpp>
-#include <SDL.h>
 #include <memory>
 
 #include "dawn/BackendBinding.hpp"
@@ -168,7 +168,7 @@ void initialize(SDL_Window* window) {
   {
     int width = 0;
     int height = 0;
-    SDL_GetWindowSize(window, &width, &height);
+    SDL_GL_GetDrawableSize(window, &width, &height);
     g_graphicsConfig = GraphicsConfig{
         .width = static_cast<uint32_t>(width),
         .height = static_cast<uint32_t>(height),

aurora/lib/imgui.cpp

@@ -2,15 +2,20 @@
 
 #include "gpu.hpp"
 
+#include <SDL.h>
+#include <aurora/aurora.hpp>
 #include <aurora/imgui.hpp>
-#include <backends/imgui_impl_sdl.h>
-#include <backends/imgui_impl_wgpu.h>
 #include <dawn/webgpu_cpp.h>
 
+#include "../extern/imgui/backends/imgui_impl_sdl.cpp"
+#include "../extern/imgui/backends/imgui_impl_wgpu.cpp"
+
 namespace aurora::imgui {
 using gpu::g_device;
 using gpu::g_queue;
 
+static float g_scale;
+
 void create_context() noexcept {
   IMGUI_CHECKVERSION();
   ImGui::CreateContext();
@@ -19,9 +24,9 @@ void create_context() noexcept {
 }
 
 void initialize(SDL_Window* window) noexcept {
-  // this just passes through to ImGui_ImplSDL2_Init (private)
-  // may need to change in the future
-  ImGui_ImplSDL2_InitForMetal(window);
+  ImGui_ImplSDL2_Init(window, nullptr);
+  // Disable MouseCanUseGlobalState for scaling purposes
+  ImGui_ImplSDL2_GetBackendData()->MouseCanUseGlobalState = false;
   ImGui_ImplWGPU_Init(g_device.Get(), 1, static_cast<WGPUTextureFormat>(gpu::g_graphicsConfig.colorFormat));
 }
 
@@ -31,17 +36,35 @@ void shutdown() noexcept {
   ImGui::DestroyContext();
 }
 
-void process_event(const SDL_Event& event) noexcept { ImGui_ImplSDL2_ProcessEvent(&event); }
+void process_event(const SDL_Event& event) noexcept {
+  auto newEvent = event;
+  if (newEvent.type == SDL_MOUSEMOTION) {
+    auto& io = ImGui::GetIO();
+    // Scale up mouse coordinates
+    io.AddMousePosEvent(static_cast<float>(newEvent.motion.x) * g_scale,
+                        static_cast<float>(newEvent.motion.y) * g_scale);
+    return;
+  }
+  ImGui_ImplSDL2_ProcessEvent(&newEvent);
+}
 
-void new_frame() noexcept {
+void new_frame(const WindowSize& size) noexcept {
   ImGui_ImplWGPU_NewFrame();
   ImGui_ImplSDL2_NewFrame();
+
+  // Render at full DPI
+  g_scale = size.scale;
+  ImGui::GetIO().DisplaySize = ImVec2{static_cast<float>(size.fb_width), static_cast<float>(size.fb_height)};
   ImGui::NewFrame();
 }
 
 void render(const wgpu::RenderPassEncoder& pass) noexcept {
   ImGui::Render();
-  ImGui_ImplWGPU_RenderDrawData(ImGui::GetDrawData(), pass.Get());
+
+  auto* data = ImGui::GetDrawData();
+  // io.DisplayFramebufferScale is informational; we're rendering at full DPI
+  data->FramebufferScale = {1.f, 1.f};
+  ImGui_ImplWGPU_RenderDrawData(data, pass.Get());
 }
 
 ImTextureID add_texture(uint32_t width, uint32_t height, ArrayRef<uint8_t> data) noexcept {

aurora/lib/imgui.hpp

@@ -7,12 +7,16 @@ namespace wgpu {
 class RenderPassEncoder;
 } // namespace wgpu
 
+namespace aurora {
+struct WindowSize;
+} // namespace aurora
+
 namespace aurora::imgui {
 void create_context() noexcept;
 void initialize(SDL_Window* window) noexcept;
 void shutdown() noexcept;
 
 void process_event(const SDL_Event& event) noexcept;
-void new_frame() noexcept;
+void new_frame(const WindowSize& size) noexcept;
 void render(const wgpu::RenderPassEncoder& pass) noexcept;
 } // namespace aurora::imgui

imgui/ImGuiEngine.cpp

@@ -59,6 +59,7 @@ void ImGuiEngine_Initialize(float scale) {
   ImGuiEngine::fontLarge = io.Fonts->AddFont(&fontConfig);
 
   auto& style = ImGui::GetStyle();
+  style = {}; // Reset sizes
   style.WindowPadding = ImVec2(15, 15);
   style.WindowRounding = 5.0f;
   style.FrameBorderSize = 1.f;

imgui/ImGuiEngine.hpp

@@ -12,7 +12,6 @@ public:
   static ImTextureID metaforceIcon;
 };
 
-// Called from Rust
 void ImGuiEngine_Initialize(float scale);
 void ImGuiEngine_AddTextures();