imgui prototype

library/VTKExtensions/Rendering/CMakeLists.txt

@@ -6,8 +6,11 @@ f3d_embed_file(
   NAME F3DDefaultHDRI
   BINARY)
 set(sources
+  ${CMAKE_CURRENT_SOURCE_DIR}/imgui_impl_opengl3.cpp
   ${CMAKE_CURRENT_BINARY_DIR}/F3DDefaultHDRI.cxx)
 set(private_headers
+  ${CMAKE_CURRENT_SOURCE_DIR}/imgui_impl_opengl3.h
+  ${CMAKE_CURRENT_SOURCE_DIR}/imgui_impl_opengl3_loader.h
   ${CMAKE_CURRENT_BINARY_DIR}/F3DDefaultHDRI.h)
 
 set(classes
@@ -23,16 +26,21 @@ set(classes
   vtkF3DRenderPass
   vtkF3DRenderer
   vtkF3DRendererWithColoring
+  vtkF3DUIRenderWindow
   )
 
 if(NOT VTK_VERSION VERSION_GREATER_EQUAL 9.2.20220907)
     set(classes ${classes} vtkF3DOrientationMarkerWidget)
 endif()
 
+find_package(imgui REQUIRED)
+
 vtk_module_add_module(f3d::VTKExtensionsRendering
   ${libf3d_vtk_no_install}
   FORCE_STATIC
   CLASSES ${classes}
   SOURCES ${sources}
   PRIVATE_HEADERS ${private_headers}
   )
+
+vtk_module_link(f3d::VTKExtensionsRendering PRIVATE imgui::imgui)

library/VTKExtensions/Rendering/imgui_impl_opengl3.h

@@ -0,0 +1,63 @@
+// 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).
+
+// 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.
+// 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
+
+// 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