basic imgui integration

.gitmodules

@@ -4,3 +4,6 @@
 [submodule "lib/easyloggingpp"]
 	path = lib/easyloggingpp
 	url = git@github.com:amrayn/easyloggingpp.git
+[submodule "lib/imgui"]
+	path = lib/imgui
+	url = git@github.com:ocornut/imgui.git

CMakeLists.txt

@@ -11,10 +11,23 @@ include_directories("src/")
 include_directories("gl/include")
 include_directories("lib/easyloggingpp/src")
 add_subdirectory(lib/glm EXCLUDE_FROM_ALL)
+include_directories("lib/imgui")
+include_directories("lib/imgui/backends")
 
 add_subdirectory(src)
 add_subdirectory(src/animation)
 add_subdirectory(src/demo)
 
+set(SOURCE
+        ${SOURCE}
+        ${CMAKE_SOURCE_DIR}/lib/imgui/imgui.cpp
+        ${CMAKE_SOURCE_DIR}/lib/imgui/imgui_demo.cpp
+        ${CMAKE_SOURCE_DIR}/lib/imgui/imgui_draw.cpp
+        ${CMAKE_SOURCE_DIR}/lib/imgui/imgui_tables.cpp
+        ${CMAKE_SOURCE_DIR}/lib/imgui/imgui_widgets.cpp
+        ${CMAKE_SOURCE_DIR}/lib/imgui/backends/imgui_impl_glfw.cpp
+        ${CMAKE_SOURCE_DIR}/lib/imgui/backends/imgui_impl_opengl3.cpp
+        )
+
 add_executable(demo main.cpp gl/src/glad.c ${SOURCE} lib/easyloggingpp/src/easylogging++.cc)
 target_link_libraries(demo glfw OpenGL::GL)

main.cpp

@@ -1,5 +1,9 @@
 #include <memory>
 
+#include "imgui.h"
+#include "imgui_impl_glfw.h"
+#include "imgui_impl_opengl3.h"
+
 #include "peripherals_glfw.h"
 #include "demo/demo_engine.h"
 #include "timer.h"
@@ -208,8 +212,49 @@ int main() {
 
     glBindFramebuffer(GL_FRAMEBUFFER, 0);
 
+
+    IMGUI_CHECKVERSION();
+    ImGui::CreateContext();
+    ImGuiIO& io = ImGui::GetIO(); (void)io;
+    ImGui::StyleColorsDark();
+
+    // Setup Platform/Renderer backends
+    ImGui_ImplGlfw_InitForOpenGL(((peripherals_glfw*)&peripherals)->get_window(), true);
+    ImGui_ImplOpenGL3_Init("#version 150");
+
     timer timer1;
+    ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
+    bool show_demo_window = false;
+    bool show_another_window = false;
+
     while (!peripherals.should_close() && timer1.seconds_since_start() < DEMO_LENGTH_IN_SECONDS) {
+        ImGui_ImplOpenGL3_NewFrame();
+        ImGui_ImplGlfw_NewFrame();
+        ImGui::NewFrame();
+
+        {
+            static float f = 0.0f;
+            static int counter = 0;
+
+            ImGui::Begin("Hello, world!");                          // Create a window called "Hello, world!" and append into it.
+
+            ImGui::Text("This is some useful text.");               // Display some text (you can use a format strings too)
+            ImGui::Checkbox("Demo Window", &show_demo_window);      // Edit bools storing our window open/close state
+            ImGui::Checkbox("Another Window", &show_another_window);
+
+            ImGui::SliderFloat("float", &f, 0.0f, 1.0f);            // Edit 1 float using a slider from 0.0f to 1.0f
+            ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color
+
+            if (ImGui::Button("Button"))                            // Buttons return true when clicked (most widgets return true when edited/activated)
+                counter++;
+            ImGui::SameLine();
+            ImGui::Text("counter = %d", counter);
+
+            ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / ImGui::GetIO().Framerate, ImGui::GetIO().Framerate);
+            ImGui::End();
+        }
+
+
         double elapsedSeconds = timer1.seconds_since_start();
         bigSphere->mesh_ = mesh_generator::extrude(mesh_generator::sphere(50, 50), {200, 201, 100, 101, 400, 401}, 0.05,
                                                    (int) ((sin(elapsedSeconds) + 0.5) * 40));
@@ -231,6 +276,9 @@ int main() {
         demoPartClear.process(demoPartClear.normalizeTime(elapsedSeconds));
         demoPartScene.process(demoPartScene.normalizeTime(elapsedSeconds));
 
+        ImGui::Render();
+        ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
+
         peripherals.swap_buffers();
         peripherals.poll_events();
     }

src/peripherals_glfw.cpp

@@ -72,4 +72,8 @@ bool peripherals_glfw::should_close() {
     return glfwWindowShouldClose(window);
 }
 
+GLFWwindow *peripherals_glfw::get_window() const {
+    return window;
+}
+
 END_NAMESPACE

src/peripherals_glfw.h

@@ -13,6 +13,7 @@ public:
 	void swap_buffers() override;
     void poll_events() override;
 	bool should_close() override;
+    GLFWwindow* get_window() const;
 
 	::GLFWwindow *window;
 };