examples/example_android_opengl3/main.cpp - external/github.com/ocornut/imgui - Git at Google

 // dear imgui: standalone example application for Android + OpenGL ES 3
 // If you are new to dear imgui, see examples/README.txt and documentation at the top of imgui.cpp.

 #include "imgui.h"
 #include "imgui_impl_android.h"
 #include "imgui_impl_opengl3.h"
 #include <android/log.h>
 #include <android_native_app_glue.h>
 #include <android/asset_manager.h>
 #include <EGL/egl.h>
 #include <GLES3/gl3.h>

 // Data
 static EGLDisplay           g_EglDisplay = EGL_NO_DISPLAY;
 static EGLSurface           g_EglSurface = EGL_NO_SURFACE;
 static EGLContext           g_EglContext = EGL_NO_CONTEXT;
 static struct android_app*  g_App = NULL;
 static bool                 g_Initialized = false;
 static char                 g_LogTag[] = "ImGuiExample";

 // Forward declarations of helper functions
 static int ShowSoftKeyboardInput();
 static int PollUnicodeChars();
 static int GetAssetData(const char* filename, void** out_data);

 void init(struct android_app* app)
 {
     if (g_Initialized)
         return;

     g_App = app;
     ANativeWindow_acquire(g_App->window);

     // Initialize EGL
     // This is mostly boilerplate code for EGL...
     {
         g_EglDisplay = eglGetDisplay(EGL_DEFAULT_DISPLAY);
         if (g_EglDisplay == EGL_NO_DISPLAY)
             __android_log_print(ANDROID_LOG_ERROR, g_LogTag, "%s", "eglGetDisplay(EGL_DEFAULT_DISPLAY) returned EGL_NO_DISPLAY");

         if (eglInitialize(g_EglDisplay, 0, 0) != EGL_TRUE)
             __android_log_print(ANDROID_LOG_ERROR, g_LogTag, "%s", "eglInitialize() returned with an error");

         const EGLint egl_attributes[] = { EGL_BLUE_SIZE, 8, EGL_GREEN_SIZE, 8, EGL_RED_SIZE, 8, EGL_DEPTH_SIZE, 24, EGL_SURFACE_TYPE, EGL_WINDOW_BIT, EGL_NONE };
         EGLint num_configs = 0;
         if (eglChooseConfig(g_EglDisplay, egl_attributes, nullptr, 0, &num_configs) != EGL_TRUE)
             __android_log_print(ANDROID_LOG_ERROR, g_LogTag, "%s", "eglChooseConfig() returned with an error");
         if (num_configs == 0)
             __android_log_print(ANDROID_LOG_ERROR, g_LogTag, "%s", "eglChooseConfig() returned 0 matching config");

         // Get the first matching config
         EGLConfig egl_config;
         eglChooseConfig(g_EglDisplay, egl_attributes, &egl_config, 1, &num_configs);
         EGLint egl_format;
         eglGetConfigAttrib(g_EglDisplay, egl_config, EGL_NATIVE_VISUAL_ID, &egl_format);
         ANativeWindow_setBuffersGeometry(g_App->window, 0, 0, egl_format);

         const EGLint egl_context_attributes[] = { EGL_CONTEXT_CLIENT_VERSION, 3, EGL_NONE };
         g_EglContext = eglCreateContext(g_EglDisplay, egl_config, EGL_NO_CONTEXT, egl_context_attributes);

         if (g_EglContext == EGL_NO_CONTEXT)
             __android_log_print(ANDROID_LOG_ERROR, g_LogTag, "%s", "eglCreateContext() returned EGL_NO_CONTEXT");

         g_EglSurface = eglCreateWindowSurface(g_EglDisplay, egl_config, g_App->window, NULL);
         eglMakeCurrent(g_EglDisplay, g_EglSurface, g_EglSurface, g_EglContext);
     }

     // Setup Dear ImGui context
     IMGUI_CHECKVERSION();
     ImGui::CreateContext();
     ImGuiIO& io = ImGui::GetIO();

     // Disable loading/saving of .ini file from disk.
     // FIXME: Consider using LoadIniSettingsFromMemory() / SaveIniSettingsToMemory() to save in appropriate location for Android.
     io.IniFilename = NULL;

     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsClassic();

     // Setup Platform/Renderer backends
     ImGui_ImplAndroid_Init(g_App->window);
     ImGui_ImplOpenGL3_Init("#version 300 es");

     // Load Fonts
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - If the file cannot be loaded, the function will return NULL. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
     // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Read 'docs/FONTS.md' for more instructions and details.
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
     // - Android: The TTF files have to be placed into the assets/ directory (android/app/src/main/assets), we use our GetAssetData() helper to retrieve them.

     // We load the default font with increased size to improve readability on many devices with "high" DPI.
     // FIXME: Put some effort into DPI awareness.
     // Important: when calling AddFontFromMemoryTTF(), ownership of font_data is transfered by Dear ImGui by default (deleted is handled by Dear ImGui), unless we set FontDataOwnedByAtlas=false in ImFontConfig
     ImFontConfig font_cfg;
     font_cfg.SizePixels = 22.0f;
     io.Fonts->AddFontDefault(&font_cfg);
     //void* font_data;
     //int font_data_size;
     //ImFont* font;
     //font_data_size = GetAssetData("Roboto-Medium.ttf", &font_data);
     //font = io.Fonts->AddFontFromMemoryTTF(font_data, font_data_size, 16.0f);
     //IM_ASSERT(font != NULL);
     //font_data_size = GetAssetData("Cousine-Regular.ttf", &font_data);
     //font = io.Fonts->AddFontFromMemoryTTF(font_data, font_data_size, 15.0f);
     //IM_ASSERT(font != NULL);
     //font_data_size = GetAssetData("DroidSans.ttf", &font_data);
     //font = io.Fonts->AddFontFromMemoryTTF(font_data, font_data_size, 16.0f);
     //IM_ASSERT(font != NULL);
     //font_data_size = GetAssetData("ProggyTiny.ttf", &font_data);
     //font = io.Fonts->AddFontFromMemoryTTF(font_data, font_data_size, 10.0f);
     //IM_ASSERT(font != NULL);
     //font_data_size = GetAssetData("ArialUni.ttf", &font_data);
     //font = io.Fonts->AddFontFromMemoryTTF(font_data, font_data_size, 18.0f, NULL, io.Fonts->GetGlyphRangesJapanese());
     //IM_ASSERT(font != NULL);

     // Arbitrary scale-up
     // FIXME: Put some effort into DPI awareness
     ImGui::GetStyle().ScaleAllSizes(3.0f);

     g_Initialized = true;
 }

 void tick()
 {
     ImGuiIO& io = ImGui::GetIO();
     if (g_EglDisplay == EGL_NO_DISPLAY)
         return;

     // Our state
     static bool show_demo_window = true;
     static bool show_another_window = false;
     static ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);

     // Poll Unicode characters via JNI
     // FIXME: do not call this every frame because of JNI overhead
     PollUnicodeChars();

     // Open on-screen (soft) input if requested by Dear ImGui
     static bool WantTextInputLast = false;
     if (io.WantTextInput && !WantTextInputLast)
         ShowSoftKeyboardInput();
     WantTextInputLast = io.WantTextInput;

     // Start the Dear ImGui frame
     ImGui_ImplOpenGL3_NewFrame();
     ImGui_ImplAndroid_NewFrame();
     ImGui::NewFrame();

     // 1. Show the big demo window (Most of the sample code is in ImGui::ShowDemoWindow()! You can browse its code to learn more about Dear ImGui!).
     if (show_demo_window)
         ImGui::ShowDemoWindow(&show_demo_window);

     // 2. Show a simple window that we create ourselves. We use a Begin/End pair to created a named window.
     {
         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();
     }

     // 3. Show another simple window.
     if (show_another_window)
     {
         ImGui::Begin("Another Window", &show_another_window);   // Pass a pointer to our bool variable (the window will have a closing button that will clear the bool when clicked)
         ImGui::Text("Hello from another window!");
         if (ImGui::Button("Close Me"))
             show_another_window = false;
         ImGui::End();
     }

     // Rendering
     ImGui::Render();
     glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
     glClearColor(clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w);
     glClear(GL_COLOR_BUFFER_BIT);
     ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
     eglSwapBuffers(g_EglDisplay, g_EglSurface);
 }

 void shutdown()
 {
     if (!g_Initialized)
         return;

     // Cleanup
     ImGui_ImplOpenGL3_Shutdown();
     ImGui_ImplAndroid_Shutdown();
     ImGui::DestroyContext();

     if (g_EglDisplay != EGL_NO_DISPLAY)
     {
         eglMakeCurrent(g_EglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);

         if (g_EglContext != EGL_NO_CONTEXT)
             eglDestroyContext(g_EglDisplay, g_EglContext);

         if (g_EglSurface != EGL_NO_SURFACE)
             eglDestroySurface(g_EglDisplay, g_EglSurface);

         eglTerminate(g_EglDisplay);
     }

     g_EglDisplay = EGL_NO_DISPLAY;
     g_EglContext = EGL_NO_CONTEXT;
     g_EglSurface = EGL_NO_SURFACE;
     ANativeWindow_release(g_App->window);

     g_Initialized = false;
 }

 static void handleAppCmd(struct android_app* app, int32_t appCmd)
 {
     switch (appCmd)
     {
     case APP_CMD_SAVE_STATE:
         break;
     case APP_CMD_INIT_WINDOW:
         init(app);
         break;
     case APP_CMD_TERM_WINDOW:
         shutdown();
         break;
     case APP_CMD_GAINED_FOCUS:
         break;
     case APP_CMD_LOST_FOCUS:
         break;
     }
 }

 static int32_t handleInputEvent(struct android_app* app, AInputEvent* inputEvent)
 {
     return ImGui_ImplAndroid_HandleInputEvent(inputEvent);
 }

 void android_main(struct android_app* app)
 {
     app->onAppCmd = handleAppCmd;
     app->onInputEvent = handleInputEvent;

     while (true)
     {
         int out_events;
         struct android_poll_source* out_data;

         // Poll all events. If the app is not visible, this loop blocks until g_Initialized == true.
         while (ALooper_pollAll(g_Initialized ? 0 : -1, NULL, &out_events, (void**)&out_data) >= 0)
         {
             // Process one event
             if (out_data != NULL)
                 out_data->process(app, out_data);

             // Exit the app by returning from within the infinite loop
             if (app->destroyRequested != 0)
             {
                 // shutdown() should have been called already while processing the
                 // app command APP_CMD_TERM_WINDOW. But we play save here
                 if (!g_Initialized)
                     shutdown();

                 return;
             }
         }

         // Initiate a new frame
         tick();
     }
 }

 // Unfortunately, there is no way to show the on-screen input from native code.
 // Therefore, we call ShowSoftKeyboardInput() of the main activity implemented in MainActivity.kt via JNI.
 static int ShowSoftKeyboardInput()
 {
     JavaVM* java_vm = g_App->activity->vm;
     JNIEnv* java_env = NULL;

     jint jni_return = java_vm->GetEnv((void**)&java_env, JNI_VERSION_1_6);
     if (jni_return == JNI_ERR)
         return -1;

     jni_return = java_vm->AttachCurrentThread(&java_env, NULL);
     if (jni_return != JNI_OK)
         return -2;

     jclass native_activity_clazz = java_env->GetObjectClass(g_App->activity->clazz);
     if (native_activity_clazz == NULL)
         return -3;

     jmethodID method_id = java_env->GetMethodID(native_activity_clazz, "showSoftInput", "()V");
     if (method_id == NULL)
         return -4;

     java_env->CallVoidMethod(g_App->activity->clazz, method_id);

     jni_return = java_vm->DetachCurrentThread();
     if (jni_return != JNI_OK)
         return -5;

     return 0;
 }

 // Unfortunately, the native KeyEvent implementation has no getUnicodeChar() function.
 // Therefore, we implement the processing of KeyEvents in MainActivity.kt and poll
 // the resulting Unicode characters here via JNI and send them to Dear ImGui.
 static int PollUnicodeChars()
 {
     JavaVM* java_vm = g_App->activity->vm;
     JNIEnv* java_env = NULL;

     jint jni_return = java_vm->GetEnv((void**)&java_env, JNI_VERSION_1_6);
     if (jni_return == JNI_ERR)
         return -1;

     jni_return = java_vm->AttachCurrentThread(&java_env, NULL);
     if (jni_return != JNI_OK)
         return -2;

     jclass native_activity_clazz = java_env->GetObjectClass(g_App->activity->clazz);
     if (native_activity_clazz == NULL)
         return -3;

     jmethodID method_id = java_env->GetMethodID(native_activity_clazz, "pollUnicodeChar", "()I");
     if (method_id == NULL)
         return -4;

     // Send the actual characters to Dear ImGui
     ImGuiIO& io = ImGui::GetIO();
     jint unicode_character;
     while ((unicode_character = java_env->CallIntMethod(g_App->activity->clazz, method_id)) != 0)
         io.AddInputCharacter(unicode_character);

     jni_return = java_vm->DetachCurrentThread();
     if (jni_return != JNI_OK)
         return -5;

     return 0;
 }

 // Helper to retrieve data placed into the assets/ directory (android/app/src/main/assets)
 static int GetAssetData(const char* filename, void** outData)
 {
     int num_bytes = 0;
     AAsset* asset_descriptor = AAssetManager_open(g_App->activity->assetManager, filename, AASSET_MODE_BUFFER);
     if (asset_descriptor)
     {
         num_bytes = AAsset_getLength(asset_descriptor);
         *outData = IM_ALLOC(num_bytes);
         int64_t num_bytes_read = AAsset_read(asset_descriptor, *outData, num_bytes);
         AAsset_close(asset_descriptor);
         IM_ASSERT(num_bytes_read == num_bytes);
     }
     return num_bytes;
 }
	// dear imgui: standalone example application for Android + OpenGL ES 3
	// If you are new to dear imgui, see examples/README.txt and documentation at the top of imgui.cpp.

	#include "imgui.h"
	#include "imgui_impl_android.h"
	#include "imgui_impl_opengl3.h"
	#include <android/log.h>
	#include <android_native_app_glue.h>
	#include <android/asset_manager.h>
	#include <EGL/egl.h>
	#include <GLES3/gl3.h>

	// Data
	static EGLDisplay g_EglDisplay = EGL_NO_DISPLAY;
	static EGLSurface g_EglSurface = EGL_NO_SURFACE;
	static EGLContext g_EglContext = EGL_NO_CONTEXT;
	static struct android_app* g_App = NULL;
	static bool g_Initialized = false;
	static char g_LogTag[] = "ImGuiExample";

	// Forward declarations of helper functions
	static int ShowSoftKeyboardInput();
	static int PollUnicodeChars();
	static int GetAssetData(const char* filename, void** out_data);

	void init(struct android_app* app)
	{
	if (g_Initialized)
	return;

	g_App = app;
	ANativeWindow_acquire(g_App->window);

	// Initialize EGL
	// This is mostly boilerplate code for EGL...
	{
	g_EglDisplay = eglGetDisplay(EGL_DEFAULT_DISPLAY);
	if (g_EglDisplay == EGL_NO_DISPLAY)
	__android_log_print(ANDROID_LOG_ERROR, g_LogTag, "%s", "eglGetDisplay(EGL_DEFAULT_DISPLAY) returned EGL_NO_DISPLAY");

	if (eglInitialize(g_EglDisplay, 0, 0) != EGL_TRUE)
	__android_log_print(ANDROID_LOG_ERROR, g_LogTag, "%s", "eglInitialize() returned with an error");

	const EGLint egl_attributes[] = { EGL_BLUE_SIZE, 8, EGL_GREEN_SIZE, 8, EGL_RED_SIZE, 8, EGL_DEPTH_SIZE, 24, EGL_SURFACE_TYPE, EGL_WINDOW_BIT, EGL_NONE };
	EGLint num_configs = 0;
	if (eglChooseConfig(g_EglDisplay, egl_attributes, nullptr, 0, &num_configs) != EGL_TRUE)
	__android_log_print(ANDROID_LOG_ERROR, g_LogTag, "%s", "eglChooseConfig() returned with an error");
	if (num_configs == 0)
	__android_log_print(ANDROID_LOG_ERROR, g_LogTag, "%s", "eglChooseConfig() returned 0 matching config");

	// Get the first matching config
	EGLConfig egl_config;
	eglChooseConfig(g_EglDisplay, egl_attributes, &egl_config, 1, &num_configs);
	EGLint egl_format;
	eglGetConfigAttrib(g_EglDisplay, egl_config, EGL_NATIVE_VISUAL_ID, &egl_format);
	ANativeWindow_setBuffersGeometry(g_App->window, 0, 0, egl_format);

	const EGLint egl_context_attributes[] = { EGL_CONTEXT_CLIENT_VERSION, 3, EGL_NONE };
	g_EglContext = eglCreateContext(g_EglDisplay, egl_config, EGL_NO_CONTEXT, egl_context_attributes);

	if (g_EglContext == EGL_NO_CONTEXT)
	__android_log_print(ANDROID_LOG_ERROR, g_LogTag, "%s", "eglCreateContext() returned EGL_NO_CONTEXT");

	g_EglSurface = eglCreateWindowSurface(g_EglDisplay, egl_config, g_App->window, NULL);
	eglMakeCurrent(g_EglDisplay, g_EglSurface, g_EglSurface, g_EglContext);
	}

	// Setup Dear ImGui context
	IMGUI_CHECKVERSION();
	ImGui::CreateContext();
	ImGuiIO& io = ImGui::GetIO();

	// Disable loading/saving of .ini file from disk.
	// FIXME: Consider using LoadIniSettingsFromMemory() / SaveIniSettingsToMemory() to save in appropriate location for Android.
	io.IniFilename = NULL;

	// Setup Dear ImGui style
	ImGui::StyleColorsDark();
	//ImGui::StyleColorsClassic();

	// Setup Platform/Renderer backends
	ImGui_ImplAndroid_Init(g_App->window);
	ImGui_ImplOpenGL3_Init("#version 300 es");

	// Load Fonts
	// - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
	// - If the file cannot be loaded, the function will return NULL. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
	// - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
	// - Read 'docs/FONTS.md' for more instructions and details.
	// - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
	// - Android: The TTF files have to be placed into the assets/ directory (android/app/src/main/assets), we use our GetAssetData() helper to retrieve them.

	// We load the default font with increased size to improve readability on many devices with "high" DPI.
	// FIXME: Put some effort into DPI awareness.
	// Important: when calling AddFontFromMemoryTTF(), ownership of font_data is transfered by Dear ImGui by default (deleted is handled by Dear ImGui), unless we set FontDataOwnedByAtlas=false in ImFontConfig
	ImFontConfig font_cfg;
	font_cfg.SizePixels = 22.0f;
	io.Fonts->AddFontDefault(&font_cfg);
	//void* font_data;
	//int font_data_size;
	//ImFont* font;
	//font_data_size = GetAssetData("Roboto-Medium.ttf", &font_data);
	//font = io.Fonts->AddFontFromMemoryTTF(font_data, font_data_size, 16.0f);
	//IM_ASSERT(font != NULL);
	//font_data_size = GetAssetData("Cousine-Regular.ttf", &font_data);
	//font = io.Fonts->AddFontFromMemoryTTF(font_data, font_data_size, 15.0f);
	//IM_ASSERT(font != NULL);
	//font_data_size = GetAssetData("DroidSans.ttf", &font_data);
	//font = io.Fonts->AddFontFromMemoryTTF(font_data, font_data_size, 16.0f);
	//IM_ASSERT(font != NULL);
	//font_data_size = GetAssetData("ProggyTiny.ttf", &font_data);
	//font = io.Fonts->AddFontFromMemoryTTF(font_data, font_data_size, 10.0f);
	//IM_ASSERT(font != NULL);
	//font_data_size = GetAssetData("ArialUni.ttf", &font_data);
	//font = io.Fonts->AddFontFromMemoryTTF(font_data, font_data_size, 18.0f, NULL, io.Fonts->GetGlyphRangesJapanese());
	//IM_ASSERT(font != NULL);

	// Arbitrary scale-up
	// FIXME: Put some effort into DPI awareness
	ImGui::GetStyle().ScaleAllSizes(3.0f);

	g_Initialized = true;
	}

	void tick()
	{
	ImGuiIO& io = ImGui::GetIO();
	if (g_EglDisplay == EGL_NO_DISPLAY)
	return;

	// Our state
	static bool show_demo_window = true;
	static bool show_another_window = false;
	static ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);

	// Poll Unicode characters via JNI
	// FIXME: do not call this every frame because of JNI overhead
	PollUnicodeChars();

	// Open on-screen (soft) input if requested by Dear ImGui
	static bool WantTextInputLast = false;
	if (io.WantTextInput && !WantTextInputLast)
	ShowSoftKeyboardInput();
	WantTextInputLast = io.WantTextInput;

	// Start the Dear ImGui frame
	ImGui_ImplOpenGL3_NewFrame();
	ImGui_ImplAndroid_NewFrame();
	ImGui::NewFrame();

	// 1. Show the big demo window (Most of the sample code is in ImGui::ShowDemoWindow()! You can browse its code to learn more about Dear ImGui!).
	if (show_demo_window)
	ImGui::ShowDemoWindow(&show_demo_window);

	// 2. Show a simple window that we create ourselves. We use a Begin/End pair to created a named window.
	{
	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();
	}

	// 3. Show another simple window.
	if (show_another_window)
	{
	ImGui::Begin("Another Window", &show_another_window); // Pass a pointer to our bool variable (the window will have a closing button that will clear the bool when clicked)
	ImGui::Text("Hello from another window!");
	if (ImGui::Button("Close Me"))
	show_another_window = false;
	ImGui::End();
	}

	// Rendering
	ImGui::Render();
	glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
	glClearColor(clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w);
	glClear(GL_COLOR_BUFFER_BIT);
	ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
	eglSwapBuffers(g_EglDisplay, g_EglSurface);
	}

	void shutdown()
	{
	if (!g_Initialized)
	return;

	// Cleanup
	ImGui_ImplOpenGL3_Shutdown();
	ImGui_ImplAndroid_Shutdown();
	ImGui::DestroyContext();

	if (g_EglDisplay != EGL_NO_DISPLAY)
	{
	eglMakeCurrent(g_EglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);

	if (g_EglContext != EGL_NO_CONTEXT)
	eglDestroyContext(g_EglDisplay, g_EglContext);

	if (g_EglSurface != EGL_NO_SURFACE)
	eglDestroySurface(g_EglDisplay, g_EglSurface);

	eglTerminate(g_EglDisplay);
	}

	g_EglDisplay = EGL_NO_DISPLAY;
	g_EglContext = EGL_NO_CONTEXT;
	g_EglSurface = EGL_NO_SURFACE;
	ANativeWindow_release(g_App->window);

	g_Initialized = false;
	}

	static void handleAppCmd(struct android_app* app, int32_t appCmd)
	{
	switch (appCmd)
	{
	case APP_CMD_SAVE_STATE:
	break;
	case APP_CMD_INIT_WINDOW:
	init(app);
	break;
	case APP_CMD_TERM_WINDOW:
	shutdown();
	break;
	case APP_CMD_GAINED_FOCUS:
	break;
	case APP_CMD_LOST_FOCUS:
	break;
	}
	}

	static int32_t handleInputEvent(struct android_app* app, AInputEvent* inputEvent)
	{
	return ImGui_ImplAndroid_HandleInputEvent(inputEvent);
	}

	void android_main(struct android_app* app)
	{
	app->onAppCmd = handleAppCmd;
	app->onInputEvent = handleInputEvent;

	while (true)
	{
	int out_events;
	struct android_poll_source* out_data;

	// Poll all events. If the app is not visible, this loop blocks until g_Initialized == true.
	while (ALooper_pollAll(g_Initialized ? 0 : -1, NULL, &out_events, (void**)&out_data) >= 0)
	{
	// Process one event
	if (out_data != NULL)
	out_data->process(app, out_data);

	// Exit the app by returning from within the infinite loop
	if (app->destroyRequested != 0)
	{
	// shutdown() should have been called already while processing the
	// app command APP_CMD_TERM_WINDOW. But we play save here
	if (!g_Initialized)
	shutdown();

	return;
	}
	}

	// Initiate a new frame
	tick();
	}
	}

	// Unfortunately, there is no way to show the on-screen input from native code.
	// Therefore, we call ShowSoftKeyboardInput() of the main activity implemented in MainActivity.kt via JNI.
	static int ShowSoftKeyboardInput()
	{
	JavaVM* java_vm = g_App->activity->vm;
	JNIEnv* java_env = NULL;

	jint jni_return = java_vm->GetEnv((void**)&java_env, JNI_VERSION_1_6);
	if (jni_return == JNI_ERR)
	return -1;

	jni_return = java_vm->AttachCurrentThread(&java_env, NULL);
	if (jni_return != JNI_OK)
	return -2;

	jclass native_activity_clazz = java_env->GetObjectClass(g_App->activity->clazz);
	if (native_activity_clazz == NULL)
	return -3;

	jmethodID method_id = java_env->GetMethodID(native_activity_clazz, "showSoftInput", "()V");
	if (method_id == NULL)
	return -4;

	java_env->CallVoidMethod(g_App->activity->clazz, method_id);

	jni_return = java_vm->DetachCurrentThread();
	if (jni_return != JNI_OK)
	return -5;

	return 0;
	}

	// Unfortunately, the native KeyEvent implementation has no getUnicodeChar() function.
	// Therefore, we implement the processing of KeyEvents in MainActivity.kt and poll
	// the resulting Unicode characters here via JNI and send them to Dear ImGui.
	static int PollUnicodeChars()
	{
	JavaVM* java_vm = g_App->activity->vm;
	JNIEnv* java_env = NULL;

	jint jni_return = java_vm->GetEnv((void**)&java_env, JNI_VERSION_1_6);
	if (jni_return == JNI_ERR)
	return -1;

	jni_return = java_vm->AttachCurrentThread(&java_env, NULL);
	if (jni_return != JNI_OK)
	return -2;

	jclass native_activity_clazz = java_env->GetObjectClass(g_App->activity->clazz);
	if (native_activity_clazz == NULL)
	return -3;

	jmethodID method_id = java_env->GetMethodID(native_activity_clazz, "pollUnicodeChar", "()I");
	if (method_id == NULL)
	return -4;

	// Send the actual characters to Dear ImGui
	ImGuiIO& io = ImGui::GetIO();
	jint unicode_character;
	while ((unicode_character = java_env->CallIntMethod(g_App->activity->clazz, method_id)) != 0)
	io.AddInputCharacter(unicode_character);

	jni_return = java_vm->DetachCurrentThread();
	if (jni_return != JNI_OK)
	return -5;

	return 0;
	}

	// Helper to retrieve data placed into the assets/ directory (android/app/src/main/assets)
	static int GetAssetData(const char* filename, void** outData)
	{
	int num_bytes = 0;
	AAsset* asset_descriptor = AAssetManager_open(g_App->activity->assetManager, filename, AASSET_MODE_BUFFER);
	if (asset_descriptor)
	{
	num_bytes = AAsset_getLength(asset_descriptor);
	*outData = IM_ALLOC(num_bytes);
	int64_t num_bytes_read = AAsset_read(asset_descriptor, *outData, num_bytes);
	AAsset_close(asset_descriptor);
	IM_ASSERT(num_bytes_read == num_bytes);
	}
	return num_bytes;
	}