ImGui Prototype

CMakeLists.txt

@@ -59,13 +59,19 @@ option(F3D_MODULE_EXR "OpenEXR images module" OFF)
 # Use externals
 option(F3D_USE_EXTERNAL_CXXOPTS "Use external cxxopts dependency" OFF)
 option(F3D_USE_EXTERNAL_NLOHMANN_JSON "Use external nlohmann_json dependency" OFF)
+option(F3D_USE_EXTERNAL_IMGUI "Use external imgui dependency" OFF)
 
 if (F3D_USE_EXTERNAL_CXXOPTS)
   find_package(cxxopts REQUIRED)
 endif ()
 if (F3D_USE_EXTERNAL_NLOHMANN_JSON)
   find_package(nlohmann_json REQUIRED)
 endif ()
+if (F3D_USE_EXTERNAL_IMGUI)
+  find_package(imgui REQUIRED)
+else()
+  add_subdirectory(external/imgui)
+endif ()
 
 # VTK dependency
 # Optional components should list VTK modules

application/F3DOptionsParser.cxx

@@ -310,6 +310,7 @@ void ConfigurationOptions::GetOptions(F3DAppOptions& appOptions, f3d::options& o
     this->DeclareOption(grp0, "config", "", "Specify the configuration file to use. absolute/relative path or filename/filestem to search in configuration file locations.", appOptions.UserConfigFile,  LocalHasDefaultNo, MayHaveConfig::NO , "<filePath/filename/fileStem>");
     this->DeclareOption(grp0, "dry-run", "", "Do not read the configuration file", appOptions.DryRun,  HasDefault::YES, MayHaveConfig::NO );
     this->DeclareOption(grp0, "no-render", "", "Do not render anything and quit right after loading the first file, use with --verbose to recover information about a file.", appOptions.NoRender,  HasDefault::YES, MayHaveConfig::YES );
+    this->DeclareOption(grp0, "imgui", "", "Use the experimental window with ImGUI", appOptions.ImGui, HasDefault::YES, MayHaveConfig::YES);
     this->DeclareOption(grp0, "max-size", "", "Maximum size in Mib of a file to load, negative value means unlimited", appOptions.MaxSize,  HasDefault::YES, MayHaveConfig::YES, "<size in Mib>");
     this->DeclareOption(grp0, "load-plugins", "", "List of plugins to load separated with a comma", appOptions.Plugins, LocalHasDefaultNo, MayHaveConfig::YES, "<paths or names>");
     this->DeclareOption(grp0, "scan-plugins", "", "Scan some directories for plugins (result can be incomplete)");

application/F3DOptionsParser.h

@@ -29,6 +29,7 @@ struct F3DAppOptions
   std::string InteractionTestPlayFile = "";
   bool NoBackground = false;
   bool NoRender = false;
+  bool ImGui = false;
   double RefThreshold = 50;
   double MaxSize = -1.0;
 

application/F3DStarter.cxx

@@ -198,6 +198,13 @@ int F3DStarter::Start(int argc, char** argv)
   {
     this->Internals->Engine = std::make_unique<f3d::engine>(f3d::window::Type::NONE);
   }
+  else if (this->Internals->AppOptions.ImGui)
+  {
+    f3d::log::warn("ImGui support is experimental.");
+    this->Internals->Engine = std::make_unique<f3d::engine>(f3d::window::Type::IMGUI);
+    f3d::interactor& interactor = this->Internals->Engine->getInteractor();
+    interactor.start();
+  }
   else
   {
     bool offscreen =
@@ -328,6 +335,18 @@ int F3DStarter::Start(int argc, char** argv)
 
   f3d::log::debug("========== Rendering ==========");
 
+  // TODO
+  if (this->Internals->AppOptions.ImGui) {
+    f3d::interactor& interactor = this->Internals->Engine->getInteractor();
+
+    this->Render();
+
+    // We implement a custom interactor which only has a basic event loop
+    interactor.start();
+
+    return EXIT_SUCCESS;
+  }
+
   if (!this->Internals->AppOptions.NoRender)
   {
     f3d::window& window = this->Internals->Engine->getWindow();

external/imgui/CMakeLists.txt

@@ -0,0 +1,29 @@
+# Dear ImGui
+add_library(imgui INTERFACE)
+add_library(imgui::imgui ALIAS imgui)
+
+set(IMGUI_DIR ${CMAKE_CURRENT_SOURCE_DIR})
+set(IMGUI_SOURCES
+    imgui_demo.cpp
+    imgui_draw.cpp
+    imgui_tables.cpp
+    imgui_widgets.cpp
+    imgui.cpp
+
+    imconfig.h
+    imgui_internal.h
+    imgui.h
+    imstb_rectpack.h
+    imstb_textedit.h
+    imstb_truetype.h
+
+    # integration with opengl
+    backends/imgui_impl_opengl3.cpp
+    backends/imgui_impl_opengl3.h
+    backends/imgui_impl_opengl3_loader.h
+)
+list(TRANSFORM IMGUI_SOURCES PREPEND ${IMGUI_DIR}/)
+
+target_sources(imgui INTERFACE ${IMGUI_SOURCES})
+target_include_directories(imgui INTERFACE ${IMGUI_DIR})
+target_include_directories(imgui INTERFACE ${IMGUI_DIR}/backends)

external/imgui/backends/imgui_impl_opengl3.h

@@ -0,0 +1,67 @@
+// dear imgui: Renderer Backend for modern OpenGL with shaders / programmatic pipeline
+// - Desktop GL: 2.x 3.x 4.x
+// - Embedded GL: ES 2.0 (WebGL 1.0), ES 3.0 (WebGL 2.0)
+// This needs to be used along with a Platform Backend (e.g. GLFW, SDL, Win32, custom..)
+
+// Implemented features:
+//  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices (Desktop OpenGL only).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+
+// About WebGL/ES:
+// - You need to '#define IMGUI_IMPL_OPENGL_ES2' or '#define IMGUI_IMPL_OPENGL_ES3' to use WebGL or OpenGL ES.
+// - This is done automatically on iOS, Android and Emscripten targets.
+// - For other targets, the define needs to be visible from the imgui_impl_opengl3.cpp compilation unit. If unsure, define globally or in imconfig.h.
+
+// 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.
+// Learn about Dear ImGui:
+// - FAQ                  https://dearimgui.com/faq
+// - Getting Started      https://dearimgui.com/getting-started
+// - Documentation        https://dearimgui.com/docs (same as your local docs/ folder).
+// - Introduction, links and more at the top of imgui.cpp
+
+// About GLSL version:
+//  The 'glsl_version' initialization parameter should be nullptr (default) or a "#version XXX" string.
+//  On computer platform the GLSL version default to "#version 130". On OpenGL ES 3 platform it defaults to "#version 300 es"
+//  Only override if your GL version doesn't handle this GLSL version. See GLSL version table at the top of imgui_impl_opengl3.cpp.
+
+#pragma once
+#include "imgui.h"      // IMGUI_IMPL_API
+#ifndef IMGUI_DISABLE
+
+// Backend API
+IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_Init(const char* glsl_version = nullptr);
+IMGUI_IMPL_API void     ImGui_ImplOpenGL3_Shutdown();
+IMGUI_IMPL_API void     ImGui_ImplOpenGL3_NewFrame();
+IMGUI_IMPL_API void     ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data);
+
+// (Optional) Called by Init/NewFrame/Shutdown
+IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_CreateFontsTexture();
+IMGUI_IMPL_API void     ImGui_ImplOpenGL3_DestroyFontsTexture();
+IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_CreateDeviceObjects();
+IMGUI_IMPL_API void     ImGui_ImplOpenGL3_DestroyDeviceObjects();
+
+// Specific OpenGL ES versions
+//#define IMGUI_IMPL_OPENGL_ES2     // Auto-detected on Emscripten
+//#define IMGUI_IMPL_OPENGL_ES3     // Auto-detected on iOS/Android
+
+// You can explicitly select GLES2 or GLES3 API by using one of the '#define IMGUI_IMPL_OPENGL_LOADER_XXX' in imconfig.h or compiler command-line.
+#if !defined(IMGUI_IMPL_OPENGL_ES2) \
+ && !defined(IMGUI_IMPL_OPENGL_ES3)
+
+// Try to detect GLES on matching platforms
+#if defined(__APPLE__)
+#include <TargetConditionals.h>
+#endif
+#if (defined(__APPLE__) && (TARGET_OS_IOS || TARGET_OS_TV)) || (defined(__ANDROID__))
+#define IMGUI_IMPL_OPENGL_ES3               // iOS, Android  -> GL ES 3, "#version 300 es"
+#elif defined(__EMSCRIPTEN__) || defined(__amigaos4__)
+#define IMGUI_IMPL_OPENGL_ES2               // Emscripten    -> GL ES 2, "#version 100"
+#else
+// Otherwise imgui_impl_opengl3_loader.h will be used.
+#endif
+
+#endif
+
+#endif // #ifndef IMGUI_DISABLE