GUI: fix UI scaling on macOS

required patching ImGui D:
but hey, it mostly works! issue #35

CMakeLists.txt

@@ -6,6 +6,10 @@ endif()
 
 project(furnace)
 
+if (APPLE)
+  enable_language(OBJC)
+endif()
+
 set(CMAKE_CXX_STANDARD 14)
 
 set(CMAKE_PROJECT_VERSION_MAJOR 0)
@@ -271,8 +275,8 @@ extern/imgui/imgui.cpp
 extern/imgui/imgui_draw.cpp
 extern/imgui/imgui_tables.cpp
 extern/imgui/imgui_widgets.cpp
-extern/imgui/backends/imgui_impl_sdlrenderer.cpp
-extern/imgui/backends/imgui_impl_sdl.cpp
+extern/imgui_patched/imgui_impl_sdlrenderer.cpp
+extern/imgui_patched/imgui_impl_sdl.cpp
 extern/imgui/misc/cpp/imgui_stdlib.cpp
 extern/igfd/ImGuiFileDialog.cpp
 
@@ -291,6 +295,10 @@ src/gui/debug.cpp
 src/gui/gui.cpp
 )
 
+if (APPLE)
+  list(APPEND GUI_SOURCES src/gui/macstuff.m)
+endif()
+
 if (NOT WIN32 AND NOT APPLE)
   list(APPEND GUI_SOURCES src/gui/icon.c)
 endif()

extern/imgui_patched/imgui_impl_sdl.h

@@ -0,0 +1,38 @@
+// dear imgui: Platform Backend for SDL2
+// This needs to be used along with a Renderer (e.g. DirectX11, OpenGL3, Vulkan..)
+// (Info: SDL2 is a cross-platform general purpose library for handling windows, inputs, graphics context creation, etc.)
+
+// Implemented features:
+//  [X] Platform: Clipboard support.
+//  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy SDL_SCANCODE_* values will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
+//  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
+//  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
+//  [X] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+// Missing features:
+//  [ ] Platform: SDL2 handling of IME under Windows appears to be broken and it explicitly disable the regular Windows IME. You can restore Windows IME by compiling SDL with SDL_DISABLE_WINDOWS_IME.
+//  [ ] Platform: Multi-viewport + Minimized windows seems to break mouse wheel events (at least under Windows).
+
+// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
+// Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
+// If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
+// Read online: https://github.com/ocornut/imgui/tree/master/docs
+
+#pragma once
+#include "imgui.h"      // IMGUI_IMPL_API
+
+struct SDL_Window;
+struct SDL_Renderer;
+typedef union SDL_Event SDL_Event;
+
+IMGUI_IMPL_API bool     ImGui_ImplSDL2_InitForOpenGL(SDL_Window* window, void* sdl_gl_context);
+IMGUI_IMPL_API bool     ImGui_ImplSDL2_InitForVulkan(SDL_Window* window);
+IMGUI_IMPL_API bool     ImGui_ImplSDL2_InitForD3D(SDL_Window* window);
+IMGUI_IMPL_API bool     ImGui_ImplSDL2_InitForMetal(SDL_Window* window);
+IMGUI_IMPL_API bool     ImGui_ImplSDL2_InitForSDLRenderer(SDL_Window* window, SDL_Renderer* renderer);
+IMGUI_IMPL_API void     ImGui_ImplSDL2_Shutdown();
+IMGUI_IMPL_API void     ImGui_ImplSDL2_NewFrame();
+IMGUI_IMPL_API bool     ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event);
+
+#ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
+static inline void ImGui_ImplSDL2_NewFrame(SDL_Window*) { ImGui_ImplSDL2_NewFrame(); } // 1.84: removed unnecessary parameter
+#endif

extern/imgui_patched/imgui_impl_sdlrenderer.cpp

@@ -0,0 +1,249 @@
+// dear imgui: Renderer Backend for SDL_Renderer
+// (Requires: SDL 2.0.17+)
+
+// Important to understand: SDL_Renderer is an _optional_ component of SDL.
+// For a multi-platform app consider using e.g. SDL+DirectX on Windows and SDL+OpenGL on Linux/OSX.
+// If your application will want to render any non trivial amount of graphics other than UI,
+// please be aware that SDL_Renderer offers a limited graphic API to the end-user and it might
+// be difficult to step out of those boundaries.
+// However, we understand it is a convenient choice to get an app started easily.
+
+// Implemented features:
+//  [X] Renderer: User texture binding. Use 'SDL_Texture*' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+// Missing features:
+//  [ ] Renderer: Multi-viewport support (multiple windows).
+
+// You can copy and use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
+// If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
+// Read online: https://github.com/ocornut/imgui/tree/master/docs
+
+// CHANGELOG
+//  2021-12-21: Update SDL_RenderGeometryRaw() format to work with SDL 2.0.19.
+//  2021-12-03: Added support for large mesh (64K+ vertices), enable ImGuiBackendFlags_RendererHasVtxOffset flag.
+//  2021-10-06: Backup and restore modified ClipRect/Viewport.
+//  2021-09-21: Initial version.
+
+#include "imgui.h"
+#include "imgui_impl_sdlrenderer.h"
+#if defined(_MSC_VER) && _MSC_VER <= 1500 // MSVC 2008 or earlier
+#include <stddef.h>     // intptr_t
+#else
+#include <stdint.h>     // intptr_t
+#endif
+
+// SDL
+#include <SDL.h>
+#if !SDL_VERSION_ATLEAST(2,0,17)
+#error This backend requires SDL 2.0.17+ because of SDL_RenderGeometry() function
+#endif
+
+// SDL_Renderer data
+struct ImGui_ImplSDLRenderer_Data
+{
+    SDL_Renderer*   SDLRenderer;
+    SDL_Texture*    FontTexture;
+    ImGui_ImplSDLRenderer_Data() { memset(this, 0, sizeof(*this)); }
+};
+
+// Backend data stored in io.BackendRendererUserData to allow support for multiple Dear ImGui contexts
+// It is STRONGLY preferred that you use docking branch with multi-viewports (== single Dear ImGui context + multiple windows) instead of multiple Dear ImGui contexts.
+static ImGui_ImplSDLRenderer_Data* ImGui_ImplSDLRenderer_GetBackendData()
+{
+    return ImGui::GetCurrentContext() ? (ImGui_ImplSDLRenderer_Data*)ImGui::GetIO().BackendRendererUserData : NULL;
+}
+
+// Functions
+bool ImGui_ImplSDLRenderer_Init(SDL_Renderer* renderer)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    IM_ASSERT(io.BackendRendererUserData == NULL && "Already initialized a renderer backend!");
+    IM_ASSERT(renderer != NULL && "SDL_Renderer not initialized!");
+
+    // Setup backend capabilities flags
+    ImGui_ImplSDLRenderer_Data* bd = IM_NEW(ImGui_ImplSDLRenderer_Data)();
+    io.BackendRendererUserData = (void*)bd;
+    io.BackendRendererName = "imgui_impl_sdlrenderer";
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+
+    bd->SDLRenderer = renderer;
+
+    return true;
+}
+
+void ImGui_ImplSDLRenderer_Shutdown()
+{
+    ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData();
+    IM_ASSERT(bd != NULL && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
+
+    ImGui_ImplSDLRenderer_DestroyDeviceObjects();
+
+    io.BackendRendererName = NULL;
+    io.BackendRendererUserData = NULL;
+    IM_DELETE(bd);
+}
+
+static void ImGui_ImplSDLRenderer_SetupRenderState()
+{
+	ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData();
+
+	// Clear out any viewports and cliprect set by the user
+    // FIXME: Technically speaking there are lots of other things we could backup/setup/restore during our render process.
+	SDL_RenderSetViewport(bd->SDLRenderer, NULL);
+	SDL_RenderSetClipRect(bd->SDLRenderer, NULL);
+}
+
+void ImGui_ImplSDLRenderer_NewFrame()
+{
+    ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData();
+    IM_ASSERT(bd != NULL && "Did you call ImGui_ImplSDLRenderer_Init()?");
+
+    if (!bd->FontTexture)
+        ImGui_ImplSDLRenderer_CreateDeviceObjects();
+}
+
+void ImGui_ImplSDLRenderer_RenderDrawData(ImDrawData* draw_data)
+{
+	ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData();
+
+	// If there's a scale factor set by the user, use that instead
+    // If the user has specified a scale factor to SDL_Renderer already via SDL_RenderSetScale(), SDL will scale whatever we pass
+    // to SDL_RenderGeometryRaw() by that scale factor. In that case we don't want to be also scaling it ourselves here.
+    float rsx = 1.0f;
+	float rsy = 1.0f;
+	SDL_RenderGetScale(bd->SDLRenderer, &rsx, &rsy);
+    ImVec2 render_scale;
+	render_scale.x = (rsx == 1.0f) ? draw_data->FramebufferScale.x : 1.0f;
+	render_scale.y = (rsy == 1.0f) ? draw_data->FramebufferScale.y : 1.0f;
+
+	// Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
+	int fb_width = (int)(draw_data->DisplaySize.x * render_scale.x);
+	int fb_height = (int)(draw_data->DisplaySize.y * render_scale.y);
+	if (fb_width == 0 || fb_height == 0)
+		return;
+
+    // Backup SDL_Renderer state that will be modified to restore it afterwards
+    struct BackupSDLRendererState
+    {
+        SDL_Rect    Viewport;
+        bool        ClipEnabled;
+        SDL_Rect    ClipRect;
+    };
+    BackupSDLRendererState old = {};
+    old.ClipEnabled = SDL_RenderIsClipEnabled(bd->SDLRenderer) == SDL_TRUE;
+    SDL_RenderGetViewport(bd->SDLRenderer, &old.Viewport);
+    SDL_RenderGetClipRect(bd->SDLRenderer, &old.ClipRect);
+
+	// Will project scissor/clipping rectangles into framebuffer space
+	ImVec2 clip_off = draw_data->DisplayPos;         // (0,0) unless using multi-viewports
+	ImVec2 clip_scale = render_scale;
+
+    // Render command lists
+    ImGui_ImplSDLRenderer_SetupRenderState();
+    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    {
+        const ImDrawList* cmd_list = draw_data->CmdLists[n];
+        const ImDrawVert* vtx_buffer = cmd_list->VtxBuffer.Data;
+        const ImDrawIdx* idx_buffer = cmd_list->IdxBuffer.Data;
+
+        for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
+        {
+            const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
+            if (pcmd->UserCallback)
+            {
+                // User callback, registered via ImDrawList::AddCallback()
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
+                    ImGui_ImplSDLRenderer_SetupRenderState();
+                else
+                    pcmd->UserCallback(cmd_list, pcmd);
+            }
+            else
+            {
+                // Project scissor/clipping rectangles into framebuffer space
+                ImVec2 clip_min((pcmd->ClipRect.x - clip_off.x) * clip_scale.x, (pcmd->ClipRect.y - clip_off.y) * clip_scale.y);
+                ImVec2 clip_max((pcmd->ClipRect.z - clip_off.x) * clip_scale.x, (pcmd->ClipRect.w - clip_off.y) * clip_scale.y);
+                if (clip_min.x < 0.0f) { clip_min.x = 0.0f; }
+                if (clip_min.y < 0.0f) { clip_min.y = 0.0f; }
+                if (clip_max.x > fb_width) { clip_max.x = (float)fb_width; }
+                if (clip_max.y > fb_height) { clip_max.y = (float)fb_height; }
+                if (clip_max.x <= clip_min.x || clip_max.y <= clip_min.y)
+                    continue;
+
+                SDL_Rect r = { (int)(clip_min.x), (int)(clip_min.y), (int)(clip_max.x - clip_min.x), (int)(clip_max.y - clip_min.y) };
+                SDL_RenderSetClipRect(bd->SDLRenderer, &r);
+
+                const float* xy = (const float*)((const char*)(vtx_buffer + pcmd->VtxOffset) + IM_OFFSETOF(ImDrawVert, pos));
+                const float* uv = (const float*)((const char*)(vtx_buffer + pcmd->VtxOffset) + IM_OFFSETOF(ImDrawVert, uv));
+#if SDL_VERSION_ATLEAST(2,0,19)
+                const SDL_Color* color = (const SDL_Color*)((const char*)(vtx_buffer + pcmd->VtxOffset) + IM_OFFSETOF(ImDrawVert, col)); // SDL 2.0.19+
+#else
+                const int* color = (const int*)((const char*)(vtx_buffer + pcmd->VtxOffset) + IM_OFFSETOF(ImDrawVert, col)); // SDL 2.0.17 and 2.0.18
+#endif
+
+                // Bind texture, Draw
+				SDL_Texture* tex = (SDL_Texture*)pcmd->GetTexID();
+                SDL_RenderGeometryRaw(bd->SDLRenderer, tex,
+                    xy, (int)sizeof(ImDrawVert),
+                    color, (int)sizeof(ImDrawVert),
+                    uv, (int)sizeof(ImDrawVert),
+                    cmd_list->VtxBuffer.Size - pcmd->VtxOffset,
+                    idx_buffer + pcmd->IdxOffset, pcmd->ElemCount, sizeof(ImDrawIdx));
+            }
+        }
+    }
+
+    // Restore modified SDL_Renderer state
+    SDL_RenderSetViewport(bd->SDLRenderer, &old.Viewport);
+    SDL_RenderSetClipRect(bd->SDLRenderer, old.ClipEnabled ? &old.ClipRect : NULL);
+}
+
+// Called by Init/NewFrame/Shutdown
+bool ImGui_ImplSDLRenderer_CreateFontsTexture()
+{
+    ImGuiIO& io = ImGui::GetIO();
+    ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData();
+
+    // Build texture atlas
+    unsigned char* pixels;
+    int width, height;
+    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);   // Load as RGBA 32-bit (75% of the memory is wasted, but default font is so small) because it is more likely to be compatible with user's existing shaders. If your ImTextureId represent a higher-level concept than just a GL texture id, consider calling GetTexDataAsAlpha8() instead to save on GPU memory.
+
+    // Upload texture to graphics system
+    bd->FontTexture = SDL_CreateTexture(bd->SDLRenderer, SDL_PIXELFORMAT_ABGR8888, SDL_TEXTUREACCESS_STATIC, width, height);
+    if (bd->FontTexture == NULL)
+    {
+        SDL_Log("error creating texture");
+        return false;
+    }
+    SDL_UpdateTexture(bd->FontTexture, NULL, pixels, 4 * width);
+    SDL_SetTextureBlendMode(bd->FontTexture, SDL_BLENDMODE_BLEND);
+
+    // Store our identifier
+    io.Fonts->SetTexID((ImTextureID)(intptr_t)bd->FontTexture);
+
+    return true;
+}
+
+void ImGui_ImplSDLRenderer_DestroyFontsTexture()
+{
+    ImGuiIO& io = ImGui::GetIO();
+    ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData();
+    if (bd->FontTexture)
+    {
+        io.Fonts->SetTexID(0);
+        SDL_DestroyTexture(bd->FontTexture);
+        bd->FontTexture = NULL;
+    }
+}
+
+bool ImGui_ImplSDLRenderer_CreateDeviceObjects()
+{
+    return ImGui_ImplSDLRenderer_CreateFontsTexture();
+}
+
+void ImGui_ImplSDLRenderer_DestroyDeviceObjects()
+{
+    ImGui_ImplSDLRenderer_DestroyFontsTexture();
+}

extern/imgui_patched/imgui_impl_sdlrenderer.h

@@ -0,0 +1,31 @@
+// dear imgui: Renderer Backend for SDL_Renderer
+// (Requires: SDL 2.0.17+)
+
+// Important to understand: SDL_Renderer is an _optional_ component of SDL.
+// For a multi-platform app consider using e.g. SDL+DirectX on Windows and SDL+OpenGL on Linux/OSX.
+// If your application will want to render any non trivial amount of graphics other than UI,
+// please be aware that SDL_Renderer offers a limited graphic API to the end-user and it might
+// be difficult to step out of those boundaries.
+// However, we understand it is a convenient choice to get an app started easily.
+
+// Implemented features:
+//  [X] Renderer: User texture binding. Use 'SDL_Texture*' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+// Missing features:
+//  [ ] Renderer: Multi-viewport support (multiple windows).
+
+#pragma once
+#include "imgui.h"      // IMGUI_IMPL_API
+
+struct SDL_Renderer;
+
+IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer_Init(SDL_Renderer* renderer);
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer_Shutdown();
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer_NewFrame();
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer_RenderDrawData(ImDrawData* draw_data);
+
+// Called by Init/NewFrame/Shutdown
+IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer_CreateFontsTexture();
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer_DestroyFontsTexture();
+IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer_CreateDeviceObjects();
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer_DestroyDeviceObjects();