[render] first imgui demo

examples/render/910-viewer-imgui/main.cpp

@@ -22,28 +22,40 @@
 
 #include "get_drawable_mesh.h"
 
+#include <vclib/imgui/imgui_drawer.h>
+#include <vclib/render/drawers/viewer_drawer.h>
+#include <vclib/render/canvas.h>
+#include <vclib/glfw/window_manager.h>
+#include <vclib/render/renderer.h>
+
 #include <imgui.h>
-#include <vclib/glfw_imgui/viewer_window_imgui.h>
 
-class ImguiDemo : public vcl::glfw::ViewerWindowImgui
+template<typename DerivedRenderer>
+class DemoImguiDrawer : public vcl::imgui::ImguiDrawer<DerivedRenderer>
 {
+    using ParentDrawer = vcl::imgui::ImguiDrawer<DerivedRenderer>;
+
 public:
-    ImguiDemo(const std::string& windowTitle) : ViewerWindowImgui(windowTitle)
-    {
-    }
+    using ParentDrawer::ParentDrawer;
 
-    void draw() override
+    virtual void onDraw(uint viewId) override
     {
+        // draw the scene
+        ParentDrawer::onDraw(viewId);
+
         // imgui demo window
         ImGui::ShowDemoWindow();
-
-        // draw the scene
-        ViewerWindowImgui::draw();
     }
 };
 
 int main(int argc, char** argv)
 {
+    using ImguiDemo = vcl::Renderer<
+        vcl::glfw::WindowManager,
+        vcl::Canvas,
+        DemoImguiDrawer,
+        vcl::ViewerDrawer>;
+
     ImguiDemo tw("Viewer GLFW");
 
     // load and set up a drawable mesh

examples/render/CMakeLists.txt

@@ -48,7 +48,7 @@ if (TARGET vclib-processing)
 endif()
 
 if(TARGET vclib-3rd-imgui AND TARGET vclib-3rd-glfw)
-    #add_subdirectory(910-viewer-imgui)
+    add_subdirectory(910-viewer-imgui)
 endif()
 
 add_subdirectory(999-misc)

vclib/render/include/vclib/imgui/imgui_drawer.h

@@ -0,0 +1,119 @@
+/*****************************************************************************
+ * VCLib                                                                     *
+ * Visual Computing Library                                                  *
+ *                                                                           *
+ * Copyright(C) 2021-2024                                                    *
+ * Visual Computing Lab                                                      *
+ * ISTI - Italian National Research Council                                  *
+ *                                                                           *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This program is free software; you can redistribute it and/or modify      *
+ * it under the terms of the Mozilla Public License Version 2.0 as published *
+ * by the Mozilla Foundation; either version 2 of the License, or            *
+ * (at your option) any later version.                                       *
+ *                                                                           *
+ * This program is distributed in the hope that it will be useful,           *
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the              *
+ * Mozilla Public License Version 2.0                                        *
+ * (https://www.mozilla.org/en-US/MPL/2.0/) for more details.                *
+ ****************************************************************************/
+
+#ifndef IMGUI_DRAWER_H
+#define IMGUI_DRAWER_H
+
+#include <vclib/render/drawers/event_drawer.h>
+#include <vclib/render/window_managers.h>
+
+// Include the render backand imgui implementation
+#ifdef VCLIB_RENDER_BACKEND_OPENGL2
+#include <imgui_impl_opengl2.h>
+#elif defined(VCLIB_RENDER_BACKEND_BGFX)
+#include <vclib/bgfx_imgui/imgui_impl_bgfx.h>
+#endif
+
+// Include the event backend imgui implementations
+#ifdef VCLIB_WITH_GLFW
+#include <imgui_impl_glfw.h>
+#endif
+
+namespace vcl::imgui {
+
+template<typename DerivedRenderer>
+class ImguiDrawer : public EventDrawer<DerivedRenderer>
+{
+protected:
+    using DRT = DerivedRenderer;
+
+public:
+    ImguiDrawer()
+    {
+        static_assert(
+            DRT::WINDOW_MANAGER_ID == WindowManagerId::GLFW_WINDOW,
+            "ImGuiDrawer supports only GLFW window manager.");
+    }
+
+    ImguiDrawer(uint, uint) : ImguiDrawer() {}
+
+    virtual void onInit(uint viewId)
+    {
+        // setup ImGui context
+        IMGUI_CHECKVERSION();
+        ImGui::CreateContext();
+        ImGuiIO& io = ImGui::GetIO();
+        // Enable Keyboard Controls
+        io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
+        // Enable Gamepad Controls
+        // io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;
+        // setup ImGui style
+        ImGui::StyleColorsDark();
+
+        if constexpr (DRT::WINDOW_MANAGER_ID == WindowManagerId::GLFW_WINDOW) {
+            GLFWwindow* mWindow =
+                reinterpret_cast<GLFWwindow*>(DRT::DRW::windowPtr(derived()));
+            // setup platform/renderer backends (GLFW and ImGui)
+#ifdef VCLIB_RENDER_BACKEND_OPENGL2
+            ImGui_ImplGlfw_InitForOpenGL(mWindow, true);
+            ImGui_ImplOpenGL2_Init();
+#elif defined(VCLIB_RENDER_BACKEND_BGFX)
+            ImGui_ImplGlfw_InitForOther(mWindow, true);
+            ImGui_ImplBgfx_Init();
+#endif
+        }
+    }
+
+    virtual void onDraw(uint)
+    {
+        // imgui frame
+#ifdef VCLIB_RENDER_BACKEND_OPENGL2
+        ImGui_ImplOpenGL2_NewFrame();
+#elif defined(VCLIB_RENDER_BACKEND_BGFX)
+        ImGui_ImplBgfx_NewFrame();
+#endif
+        if constexpr (DRT::WINDOW_MANAGER_ID == WindowManagerId::GLFW_WINDOW) {
+            ImGui_ImplGlfw_NewFrame();
+        }
+        ImGui::NewFrame();
+    }
+
+    virtual void onPostDraw()
+    {
+        // imgui rendering
+        ImGui::Render();
+#ifdef VCLIB_RENDER_BACKEND_OPENGL2
+        ImGui_ImplOpenGL2_RenderDrawData(ImGui::GetDrawData());
+#elif defined(VCLIB_RENDER_BACKEND_BGFX)
+        ImGui_ImplBgfx_RenderDrawData(ImGui::GetDrawData());
+#endif
+    }
+
+private:
+    auto* derived() { return static_cast<DRT*>(this); }
+
+    const auto* derived() const { return static_cast<const DRT*>(this); }
+};
+
+} // namespace vcl::imgui
+
+#endif // IMGUI_DRAWER_H