pw_display_driver_imgui/display_driver.cc - pigweed/experimental - Git at Google

 // Copyright 2022 The Pigweed Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License"); you may not
 // use this file except in compliance with the License. You may obtain a copy of
 // the License at
 //
 //     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 // License for the specific language governing permissions and limitations under
 // the License.
 //
 // LCD Facade using imgui running on a host machine.
 // Much of this code is from the imgui example:
 // https://github.com/ocornut/imgui/tree/master/examples/example_glfw_opengl3
 // As well as the wiki page:
 // https://github.com/ocornut/imgui/wiki/Image-Loading-and-Displaying-Examples

 #include "pw_display_driver_imgui/display_driver.h"

 // To silence large number of warnings (at least on macOS).
 #define GL_SILENCE_DEPRECATION

 #if defined(IMGUI_IMPL_OPENGL_ES2)
 #include <GLES2/gl2.h>
 #endif
 #include <GLFW/glfw3.h>  // Will pull in system OpenGL headers

 #include "imgui.h"
 #include "imgui_impl_glfw.h"
 #include "imgui_impl_opengl3.h"
 #include "pw_framebuffer/reader.h"

 using pw::color::color_rgb565_t;
 using pw::framebuffer::Framebuffer;
 using pw::framebuffer::FramebufferReader;
 using pw::framebuffer::PixelFormat;

 namespace pw::display_driver {

 namespace {

 constexpr uint16_t kDisplayWidth = 320;
 constexpr uint16_t kDisplayHeight = 240;
 constexpr size_t kDisplayDataSize = kDisplayWidth * kDisplayHeight;

 // OpenGL texture data.
 GLuint lcd_pixel_data[kDisplayDataSize];

 // imgui state
 bool show_imgui_demo_window = false;
 ImVec4 clear_color = ImVec4(0.27f, 0.27f, 0.27f, 1.00f);
 GLuint lcd_texture = 0;
 GLFWwindow* window;
 int lcd_texture_display_scale = 3;
 int old_lcd_texture_display_scale = 0;
 bool lcd_texture_display_mode_nearest = true;
 bool old_lcd_texture_display_mode_nearest = true;

 ImGuiMousePosition touchscreen_mouse_position;

 void CleanupAndExit() {
   ImGui_ImplOpenGL3_Shutdown();
   ImGui_ImplGlfw_Shutdown();
   ImGui::DestroyContext();

   glfwDestroyWindow(window);
   glfwTerminate();
   exit(0);
 }

 void HelpMarker(const char* desc) {
   ImGui::TextDisabled("(?)");
   if (ImGui::IsItemHovered(ImGuiHoveredFlags_DelayShort)) {
     ImGui::BeginTooltip();
     ImGui::PushTextWrapPos(ImGui::GetFontSize() * 35.0f);
     ImGui::TextUnformatted(desc);
     ImGui::PopTextWrapPos();
     ImGui::EndTooltip();
   }
 }

 void _SetTexturePixel(
     GLuint x, GLuint y, uint8_t r, uint8_t g, uint8_t b, uint8_t a) {
   // Calculate target color
   GLuint target_color;
   GLubyte* colors = (GLubyte*)&target_color;
   colors[0] = r;
   colors[1] = g;
   colors[2] = b;
   colors[3] = a;
   lcd_pixel_data[y * kDisplayWidth + x] = target_color;
 }

 void _SetTexturePixel(GLuint x, GLuint y, uint8_t r, uint8_t g, uint8_t b) {
   _SetTexturePixel(x, y, r, g, b, 255);
 }

 void _SetTexturePixel(GLuint x, GLuint y, color_rgb565_t rgb565) {
   pw::color::ColorRGBA c(rgb565);
   _SetTexturePixel(x, y, c.r, c.g, c.b, 255);
 }

 void UpdateLcdTexture() {
   // Set current texture
   glBindTexture(GL_TEXTURE_2D, lcd_texture);
   // Update texture
   glTexSubImage2D(GL_TEXTURE_2D,
                   0,
                   0,
                   0,
                   kDisplayWidth,
                   kDisplayHeight,
                   GL_RGBA,
                   GL_UNSIGNED_BYTE,
                   lcd_pixel_data);
   // Unbind texture
   glBindTexture(GL_TEXTURE_2D, 0);
 }

 void SetupLcdTexture(GLuint* out_texture) {
   // Create a OpenGL texture identifier
   GLuint image_texture;
   glGenTextures(1, &image_texture);
   glBindTexture(GL_TEXTURE_2D, image_texture);

   // Setup filtering parameters for display
   GLuint display_mode =
       lcd_texture_display_mode_nearest ? GL_NEAREST : GL_LINEAR;
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, display_mode);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, display_mode);
   glTexParameteri(GL_TEXTURE_2D,
                   GL_TEXTURE_WRAP_S,
                   GL_CLAMP_TO_EDGE);  // This is required on WebGL for non
                                       // power-of-two textures
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);  // Same

   // Upload pixels into texture
 #if defined(GL_UNPACK_ROW_LENGTH) && !defined(__EMSCRIPTEN__)
   glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
 #endif
   glTexImage2D(GL_TEXTURE_2D,
                0,
                GL_RGBA,
                kDisplayWidth,
                kDisplayHeight,
                0,
                GL_RGBA,
                GL_UNSIGNED_BYTE,
                lcd_pixel_data);

   glBindTexture(GL_TEXTURE_2D, 0);

   *out_texture = image_texture;
 }

 void glfw_error_callback(int error, const char* description) {
   fprintf(stderr, "Glfw Error %d: %s\n", error, description);
 }

 }  // namespace

 DisplayDriverImgUI::DisplayDriverImgUI() = default;

 Status DisplayDriverImgUI::Init() {
   // Setup window
   glfwSetErrorCallback(glfw_error_callback);
   if (!glfwInit())
     return Status::Internal();

     // Decide GL+GLSL versions
 #if defined(IMGUI_IMPL_OPENGL_ES2)
   // GL ES 2.0 + GLSL 100
   const char* glsl_version = "#version 100";
   glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
   glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
   glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_ES_API);
 #elif defined(__APPLE__)
   // GL 3.2 + GLSL 150
   const char* glsl_version = "#version 150";
   glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
   glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
   glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);  // 3.2+ only
   glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);  // Required on Mac
 #else
   // GL 3.0 + GLSL 130
   const char* glsl_version = "#version 130";
   glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
   glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
   // glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);  // 3.2+
   // only glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // 3.0+ only
 #endif

   // Create window with graphics context
   window = glfwCreateWindow(1280, 800, "pw_display", NULL, NULL);
   if (window == NULL)
     return Status::Internal();
   glfwMakeContextCurrent(window);
   glfwSwapInterval(1);  // Enable vsync

   // Setup Dear ImGui context
   IMGUI_CHECKVERSION();
   ImGui::CreateContext();
   ImGuiIO& io = ImGui::GetIO();
   (void)io;
   // io.Fonts->AddFontFromFileTTF("NotoSans-Regular.ttf", 32.0);

   // Enable Keyboard Controls
   io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
   io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;
   io.ConfigFlags |= ImGuiConfigFlags_DpiEnableScaleFonts;
   // Enable Gamepad Controls
   // io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;

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

   // Setup Platform/Renderer backends
   ImGui_ImplGlfw_InitForOpenGL(window, true);
   ImGui_ImplOpenGL3_Init(glsl_version);

   SetupLcdTexture(&lcd_texture);
   return OkStatus();
 }

 void DisplayDriverImgUI::RecreateLcdTexture() {
   if (old_lcd_texture_display_mode_nearest !=
       lcd_texture_display_mode_nearest) {
     old_lcd_texture_display_mode_nearest = lcd_texture_display_mode_nearest;
     SetupLcdTexture(&lcd_texture);
   }
 }

 void DisplayDriverImgUI::Render() {
   UpdateLcdTexture();

   // Poll and handle events (inputs, window resize, etc.)
   glfwPollEvents();

   touchscreen_mouse_position.left_button_pressed = false;
   double mouse_xpos = 0, mouse_ypos = 0;
   glfwGetCursorPos(window, &mouse_xpos, &mouse_ypos);
   if (glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_LEFT) == GLFW_PRESS) {
     touchscreen_mouse_position.left_button_pressed = true;
   }

   // Start the Dear ImGui frame
   ImGui_ImplOpenGL3_NewFrame();
   ImGui_ImplGlfw_NewFrame();
   ImGui::NewFrame();
   ImGuiIO& io = ImGui::GetIO();

   int display_w, display_h;
   glfwGetFramebufferSize(window, &display_w, &display_h);

   // Build the empty dockspace background

   static ImGuiDockNodeFlags dockspace_flags = ImGuiDockNodeFlags_None;
   ImGuiWindowFlags window_flags =
       ImGuiWindowFlags_MenuBar | ImGuiWindowFlags_NoDocking;
   const ImGuiViewport* viewport = ImGui::GetMainViewport();
   ImGui::SetNextWindowPos(viewport->WorkPos);
   ImGui::SetNextWindowSize(viewport->WorkSize);
   ImGui::SetNextWindowViewport(viewport->ID);
   ImGui::PushStyleVar(ImGuiStyleVar_WindowRounding, 0.0f);
   ImGui::PushStyleVar(ImGuiStyleVar_WindowBorderSize, 0.0f);
   window_flags |= ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoCollapse |
                   ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoMove;
   window_flags |=
       ImGuiWindowFlags_NoBringToFrontOnFocus | ImGuiWindowFlags_NoNavFocus;

   // 0px padding around the dockspace
   ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(0.0f, 0.0f));
   // Start docspace window
   ImGui::Begin("DockSpace", NULL, window_flags);

   // Create empty dockspace container
   ImGuiID dockspace_id = ImGui::GetID("MyDockSpace");
   ImGui::DockSpace(dockspace_id, ImVec2(0.0f, 0.0f), dockspace_flags);

   ImGui::PopStyleVar();   // Padding around docspace window
   ImGui::PopStyleVar(2);  // WindowRounding and WindowBorderSize

   // Dockspace menu
   if (ImGui::BeginMenuBar()) {
     if (ImGui::BeginMenu("Options")) {
       ImGui::MenuItem("Show Imgui Demo Window", "", &show_imgui_demo_window);
       ImGui::Separator();
       if (ImGui::MenuItem("Quit")) {
         CleanupAndExit();
       }
       ImGui::EndMenu();
     }
     HelpMarker(
         "Window Docking: "
         "\n"
         "- Drag from window title bar or their tab to dock/undock."
         "\n"
         "- Drag from window menu button (upper-left button) to undock an "
         "entire node (all windows)."
         "\n"
         "- Hold SHIFT to disable docking");

     ImGui::EndMenuBar();
   }

   ImGui::End();  // end dockspace

   // 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_imgui_demo_window) {
     ImGui::ShowDemoWindow(&show_imgui_demo_window);
   }

   // Draw Screen(s)

   // Screen 1 Window
   ImGui::Begin("Screen 1");
   // Calculate the display texture draw coordinates
   int scaled_width = kDisplayWidth * lcd_texture_display_scale;
   int scaled_height = kDisplayHeight * lcd_texture_display_scale;

   ImVec2 mouse_pos = ImGui::GetCursorScreenPos();
   ImVec2 mouse_coordinates_of_base_image;
   ImGui::Image((void*)(intptr_t)lcd_texture,
                ImVec2(scaled_width, scaled_height),
                // Top left texure coord
                ImVec2(0.0f, 0.0f),
                // Lower right texture coord
                ImVec2(1.0f, 1.0f),
                // Tint (none applied)
                ImVec4(1.0f, 1.0f, 1.0f, 1.0f),
                // Border color (50% white)
                ImVec4(1.0f, 1.0f, 1.0f, 0.5f));
   mouse_coordinates_of_base_image.x =
       floor((io.MousePos.x - mouse_pos.x) / lcd_texture_display_scale);
   mouse_coordinates_of_base_image.y =
       floor((io.MousePos.y - mouse_pos.y) / lcd_texture_display_scale);
   if (ImGui::IsItemHovered()) {
     ImGui::BeginTooltip();
     ImGui::Text("mouse coords = %.1f, %.1f",
                 mouse_coordinates_of_base_image.x,
                 mouse_coordinates_of_base_image.y);
     ImGui::EndTooltip();
   }
   ImGui::End();  // Screen 1 Window

   // For reference this forces the "Screen 1" window to be docked to the main
   // dockspace:
   //   ImGui::DockBuilderDockWindow("Screen 1", dockspace_id);

   ImGui::Begin("Screen 1 Settings");
   ImGui::Text("Pixel Size = %d x %d", kDisplayWidth, kDisplayHeight);
   ImGui::SliderInt("Integer Scaling", &lcd_texture_display_scale, 1, 10);
   ImGui::Checkbox("Nearest neighbor", &lcd_texture_display_mode_nearest);

   ImGui::Separator();
   touchscreen_mouse_position.position_x = mouse_coordinates_of_base_image.x;
   touchscreen_mouse_position.position_y = mouse_coordinates_of_base_image.y;
   ImGui::Text("Mouse position = %d, %d",
               touchscreen_mouse_position.position_x,
               touchscreen_mouse_position.position_y);
   ImGui::Text("Mouse Left button pressed: %d",
               touchscreen_mouse_position.left_button_pressed);

   // Demo Window toggle
   ImGui::Separator();

   ImGui::Text("Application average %.3f ms/frame (%.1f FPS)",
               1000.0f / ImGui::GetIO().Framerate,
               ImGui::GetIO().Framerate);

   ImGui::End();

   // Done building the UI
   ImGui::Render();

   glViewport(0, 0, display_w, display_h);
   glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w);
   glClear(GL_COLOR_BUFFER_BIT);
   // Render ImGui
   ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());

   glfwSwapBuffers(window);

   if (glfwWindowShouldClose(window)) {
     CleanupAndExit();
   }
 }

 void DisplayDriverImgUI::WriteFramebuffer(Framebuffer framebuffer,
                                           WriteCallback write_callback) {
   PW_ASSERT(framebuffer.is_valid());
   PW_ASSERT(framebuffer.pixel_format() == PixelFormat::RGB565);
   RecreateLcdTexture();

   FramebufferReader reader(framebuffer);
   // Copy frame_buffer into lcd_pixel_data
   for (GLuint x = 0; x < kDisplayWidth; x++) {
     for (GLuint y = 0; y < kDisplayHeight; y++) {
       if (auto c = reader.GetPixel(x, y); c.ok()) {
         _SetTexturePixel(x, y, c.value());
       }
     }
   }

   Render();
   write_callback(std::move(framebuffer), OkStatus());
 }

 Status DisplayDriverImgUI::WriteRow(span<uint16_t> row_pixels,
                                     uint16_t row_idx,
                                     uint16_t col_idx) {
   RecreateLcdTexture();

   for (auto c : row_pixels) {
     _SetTexturePixel(col_idx++, row_idx, c);
   }

   // Rendering here is horribly slow - come up with better solution.
   Render();
   return OkStatus();
 }

 uint16_t DisplayDriverImgUI::GetWidth() const { return kDisplayWidth; }

 uint16_t DisplayDriverImgUI::GetHeight() const { return kDisplayHeight; }

 GLFWwindow* DisplayDriverImgUI::GetGlfwWindow() { return window; }

 ImGuiMousePosition DisplayDriverImgUI::GetImGuiMousePosition() {
   return touchscreen_mouse_position;
 }

 }  // namespace pw::display_driver
	// Copyright 2022 The Pigweed Authors
	//
	// Licensed under the Apache License, Version 2.0 (the "License"); you may not
	// use this file except in compliance with the License. You may obtain a copy of
	// the License at
	//
	// https://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
	// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
	// License for the specific language governing permissions and limitations under
	// the License.
	//
	// LCD Facade using imgui running on a host machine.
	// Much of this code is from the imgui example:
	// https://github.com/ocornut/imgui/tree/master/examples/example_glfw_opengl3
	// As well as the wiki page:
	// https://github.com/ocornut/imgui/wiki/Image-Loading-and-Displaying-Examples

	#include "pw_display_driver_imgui/display_driver.h"

	// To silence large number of warnings (at least on macOS).
	#define GL_SILENCE_DEPRECATION

	#if defined(IMGUI_IMPL_OPENGL_ES2)
	#include <GLES2/gl2.h>
	#endif
	#include <GLFW/glfw3.h> // Will pull in system OpenGL headers

	#include "imgui.h"
	#include "imgui_impl_glfw.h"
	#include "imgui_impl_opengl3.h"
	#include "pw_framebuffer/reader.h"

	using pw::color::color_rgb565_t;
	using pw::framebuffer::Framebuffer;
	using pw::framebuffer::FramebufferReader;
	using pw::framebuffer::PixelFormat;

	namespace pw::display_driver {

	namespace {

	constexpr uint16_t kDisplayWidth = 320;
	constexpr uint16_t kDisplayHeight = 240;
	constexpr size_t kDisplayDataSize = kDisplayWidth * kDisplayHeight;

	// OpenGL texture data.
	GLuint lcd_pixel_data[kDisplayDataSize];

	// imgui state
	bool show_imgui_demo_window = false;
	ImVec4 clear_color = ImVec4(0.27f, 0.27f, 0.27f, 1.00f);
	GLuint lcd_texture = 0;
	GLFWwindow* window;
	int lcd_texture_display_scale = 3;
	int old_lcd_texture_display_scale = 0;
	bool lcd_texture_display_mode_nearest = true;
	bool old_lcd_texture_display_mode_nearest = true;

	ImGuiMousePosition touchscreen_mouse_position;

	void CleanupAndExit() {
	ImGui_ImplOpenGL3_Shutdown();
	ImGui_ImplGlfw_Shutdown();
	ImGui::DestroyContext();

	glfwDestroyWindow(window);
	glfwTerminate();
	exit(0);
	}

	void HelpMarker(const char* desc) {
	ImGui::TextDisabled("(?)");
	if (ImGui::IsItemHovered(ImGuiHoveredFlags_DelayShort)) {
	ImGui::BeginTooltip();
	ImGui::PushTextWrapPos(ImGui::GetFontSize() * 35.0f);
	ImGui::TextUnformatted(desc);
	ImGui::PopTextWrapPos();
	ImGui::EndTooltip();
	}
	}

	void _SetTexturePixel(
	GLuint x, GLuint y, uint8_t r, uint8_t g, uint8_t b, uint8_t a) {
	// Calculate target color
	GLuint target_color;
	GLubyte* colors = (GLubyte*)&target_color;
	colors[0] = r;
	colors[1] = g;
	colors[2] = b;
	colors[3] = a;
	lcd_pixel_data[y * kDisplayWidth + x] = target_color;
	}

	void _SetTexturePixel(GLuint x, GLuint y, uint8_t r, uint8_t g, uint8_t b) {
	_SetTexturePixel(x, y, r, g, b, 255);
	}

	void _SetTexturePixel(GLuint x, GLuint y, color_rgb565_t rgb565) {
	pw::color::ColorRGBA c(rgb565);
	_SetTexturePixel(x, y, c.r, c.g, c.b, 255);
	}

	void UpdateLcdTexture() {
	// Set current texture
	glBindTexture(GL_TEXTURE_2D, lcd_texture);
	// Update texture
	glTexSubImage2D(GL_TEXTURE_2D,
	0,
	0,
	0,
	kDisplayWidth,
	kDisplayHeight,
	GL_RGBA,
	GL_UNSIGNED_BYTE,
	lcd_pixel_data);
	// Unbind texture
	glBindTexture(GL_TEXTURE_2D, 0);
	}

	void SetupLcdTexture(GLuint* out_texture) {
	// Create a OpenGL texture identifier
	GLuint image_texture;
	glGenTextures(1, &image_texture);
	glBindTexture(GL_TEXTURE_2D, image_texture);

	// Setup filtering parameters for display
	GLuint display_mode =
	lcd_texture_display_mode_nearest ? GL_NEAREST : GL_LINEAR;
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, display_mode);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, display_mode);
	glTexParameteri(GL_TEXTURE_2D,
	GL_TEXTURE_WRAP_S,
	GL_CLAMP_TO_EDGE); // This is required on WebGL for non
	// power-of-two textures
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); // Same

	// Upload pixels into texture
	#if defined(GL_UNPACK_ROW_LENGTH) && !defined(__EMSCRIPTEN__)
	glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
	#endif
	glTexImage2D(GL_TEXTURE_2D,
	0,
	GL_RGBA,
	kDisplayWidth,
	kDisplayHeight,
	0,
	GL_RGBA,
	GL_UNSIGNED_BYTE,
	lcd_pixel_data);

	glBindTexture(GL_TEXTURE_2D, 0);

	*out_texture = image_texture;
	}

	void glfw_error_callback(int error, const char* description) {
	fprintf(stderr, "Glfw Error %d: %s\n", error, description);
	}

	} // namespace

	DisplayDriverImgUI::DisplayDriverImgUI() = default;

	Status DisplayDriverImgUI::Init() {
	// Setup window
	glfwSetErrorCallback(glfw_error_callback);
	if (!glfwInit())
	return Status::Internal();

	// Decide GL+GLSL versions
	#if defined(IMGUI_IMPL_OPENGL_ES2)
	// GL ES 2.0 + GLSL 100
	const char* glsl_version = "#version 100";
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
	glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_ES_API);
	#elif defined(__APPLE__)
	// GL 3.2 + GLSL 150
	const char* glsl_version = "#version 150";
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); // 3.2+ only
	glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // Required on Mac
	#else
	// GL 3.0 + GLSL 130
	const char* glsl_version = "#version 130";
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
	// glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); // 3.2+
	// only glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // 3.0+ only
	#endif

	// Create window with graphics context
	window = glfwCreateWindow(1280, 800, "pw_display", NULL, NULL);
	if (window == NULL)
	return Status::Internal();
	glfwMakeContextCurrent(window);
	glfwSwapInterval(1); // Enable vsync

	// Setup Dear ImGui context
	IMGUI_CHECKVERSION();
	ImGui::CreateContext();
	ImGuiIO& io = ImGui::GetIO();
	(void)io;
	// io.Fonts->AddFontFromFileTTF("NotoSans-Regular.ttf", 32.0);

	// Enable Keyboard Controls
	io.ConfigFlags \|= ImGuiConfigFlags_NavEnableKeyboard;
	io.ConfigFlags \|= ImGuiConfigFlags_DockingEnable;
	io.ConfigFlags \|= ImGuiConfigFlags_DpiEnableScaleFonts;
	// Enable Gamepad Controls
	// io.ConfigFlags \|= ImGuiConfigFlags_NavEnableGamepad;

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

	// Setup Platform/Renderer backends
	ImGui_ImplGlfw_InitForOpenGL(window, true);
	ImGui_ImplOpenGL3_Init(glsl_version);

	SetupLcdTexture(&lcd_texture);
	return OkStatus();
	}

	void DisplayDriverImgUI::RecreateLcdTexture() {
	if (old_lcd_texture_display_mode_nearest !=
	lcd_texture_display_mode_nearest) {
	old_lcd_texture_display_mode_nearest = lcd_texture_display_mode_nearest;
	SetupLcdTexture(&lcd_texture);
	}
	}

	void DisplayDriverImgUI::Render() {
	UpdateLcdTexture();

	// Poll and handle events (inputs, window resize, etc.)
	glfwPollEvents();

	touchscreen_mouse_position.left_button_pressed = false;
	double mouse_xpos = 0, mouse_ypos = 0;
	glfwGetCursorPos(window, &mouse_xpos, &mouse_ypos);
	if (glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_LEFT) == GLFW_PRESS) {
	touchscreen_mouse_position.left_button_pressed = true;
	}

	// Start the Dear ImGui frame
	ImGui_ImplOpenGL3_NewFrame();
	ImGui_ImplGlfw_NewFrame();
	ImGui::NewFrame();
	ImGuiIO& io = ImGui::GetIO();

	int display_w, display_h;
	glfwGetFramebufferSize(window, &display_w, &display_h);

	// Build the empty dockspace background

	static ImGuiDockNodeFlags dockspace_flags = ImGuiDockNodeFlags_None;
	ImGuiWindowFlags window_flags =
	ImGuiWindowFlags_MenuBar \| ImGuiWindowFlags_NoDocking;
	const ImGuiViewport* viewport = ImGui::GetMainViewport();
	ImGui::SetNextWindowPos(viewport->WorkPos);
	ImGui::SetNextWindowSize(viewport->WorkSize);
	ImGui::SetNextWindowViewport(viewport->ID);
	ImGui::PushStyleVar(ImGuiStyleVar_WindowRounding, 0.0f);
	ImGui::PushStyleVar(ImGuiStyleVar_WindowBorderSize, 0.0f);
	window_flags \|= ImGuiWindowFlags_NoTitleBar \| ImGuiWindowFlags_NoCollapse \|
	ImGuiWindowFlags_NoResize \| ImGuiWindowFlags_NoMove;
	window_flags \|=
	ImGuiWindowFlags_NoBringToFrontOnFocus \| ImGuiWindowFlags_NoNavFocus;

	// 0px padding around the dockspace
	ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(0.0f, 0.0f));
	// Start docspace window
	ImGui::Begin("DockSpace", NULL, window_flags);

	// Create empty dockspace container
	ImGuiID dockspace_id = ImGui::GetID("MyDockSpace");
	ImGui::DockSpace(dockspace_id, ImVec2(0.0f, 0.0f), dockspace_flags);

	ImGui::PopStyleVar(); // Padding around docspace window
	ImGui::PopStyleVar(2); // WindowRounding and WindowBorderSize

	// Dockspace menu
	if (ImGui::BeginMenuBar()) {
	if (ImGui::BeginMenu("Options")) {
	ImGui::MenuItem("Show Imgui Demo Window", "", &show_imgui_demo_window);
	ImGui::Separator();
	if (ImGui::MenuItem("Quit")) {
	CleanupAndExit();
	}
	ImGui::EndMenu();
	}
	HelpMarker(
	"Window Docking: "
	"\n"
	"- Drag from window title bar or their tab to dock/undock."
	"\n"
	"- Drag from window menu button (upper-left button) to undock an "
	"entire node (all windows)."
	"\n"
	"- Hold SHIFT to disable docking");

	ImGui::EndMenuBar();
	}

	ImGui::End(); // end dockspace

	// 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_imgui_demo_window) {
	ImGui::ShowDemoWindow(&show_imgui_demo_window);
	}

	// Draw Screen(s)

	// Screen 1 Window
	ImGui::Begin("Screen 1");
	// Calculate the display texture draw coordinates
	int scaled_width = kDisplayWidth * lcd_texture_display_scale;
	int scaled_height = kDisplayHeight * lcd_texture_display_scale;

	ImVec2 mouse_pos = ImGui::GetCursorScreenPos();
	ImVec2 mouse_coordinates_of_base_image;
	ImGui::Image((void*)(intptr_t)lcd_texture,
	ImVec2(scaled_width, scaled_height),
	// Top left texure coord
	ImVec2(0.0f, 0.0f),
	// Lower right texture coord
	ImVec2(1.0f, 1.0f),
	// Tint (none applied)
	ImVec4(1.0f, 1.0f, 1.0f, 1.0f),
	// Border color (50% white)
	ImVec4(1.0f, 1.0f, 1.0f, 0.5f));
	mouse_coordinates_of_base_image.x =
	floor((io.MousePos.x - mouse_pos.x) / lcd_texture_display_scale);
	mouse_coordinates_of_base_image.y =
	floor((io.MousePos.y - mouse_pos.y) / lcd_texture_display_scale);
	if (ImGui::IsItemHovered()) {
	ImGui::BeginTooltip();
	ImGui::Text("mouse coords = %.1f, %.1f",
	mouse_coordinates_of_base_image.x,
	mouse_coordinates_of_base_image.y);
	ImGui::EndTooltip();
	}
	ImGui::End(); // Screen 1 Window

	// For reference this forces the "Screen 1" window to be docked to the main
	// dockspace:
	// ImGui::DockBuilderDockWindow("Screen 1", dockspace_id);

	ImGui::Begin("Screen 1 Settings");
	ImGui::Text("Pixel Size = %d x %d", kDisplayWidth, kDisplayHeight);
	ImGui::SliderInt("Integer Scaling", &lcd_texture_display_scale, 1, 10);
	ImGui::Checkbox("Nearest neighbor", &lcd_texture_display_mode_nearest);

	ImGui::Separator();
	touchscreen_mouse_position.position_x = mouse_coordinates_of_base_image.x;
	touchscreen_mouse_position.position_y = mouse_coordinates_of_base_image.y;
	ImGui::Text("Mouse position = %d, %d",
	touchscreen_mouse_position.position_x,
	touchscreen_mouse_position.position_y);
	ImGui::Text("Mouse Left button pressed: %d",
	touchscreen_mouse_position.left_button_pressed);

	// Demo Window toggle
	ImGui::Separator();

	ImGui::Text("Application average %.3f ms/frame (%.1f FPS)",
	1000.0f / ImGui::GetIO().Framerate,
	ImGui::GetIO().Framerate);

	ImGui::End();

	// Done building the UI
	ImGui::Render();

	glViewport(0, 0, display_w, display_h);
	glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w);
	glClear(GL_COLOR_BUFFER_BIT);
	// Render ImGui
	ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());

	glfwSwapBuffers(window);

	if (glfwWindowShouldClose(window)) {
	CleanupAndExit();
	}
	}

	void DisplayDriverImgUI::WriteFramebuffer(Framebuffer framebuffer,
	WriteCallback write_callback) {
	PW_ASSERT(framebuffer.is_valid());
	PW_ASSERT(framebuffer.pixel_format() == PixelFormat::RGB565);
	RecreateLcdTexture();

	FramebufferReader reader(framebuffer);
	// Copy frame_buffer into lcd_pixel_data
	for (GLuint x = 0; x < kDisplayWidth; x++) {
	for (GLuint y = 0; y < kDisplayHeight; y++) {
	if (auto c = reader.GetPixel(x, y); c.ok()) {
	_SetTexturePixel(x, y, c.value());
	}
	}
	}

	Render();
	write_callback(std::move(framebuffer), OkStatus());
	}

	Status DisplayDriverImgUI::WriteRow(span<uint16_t> row_pixels,
	uint16_t row_idx,
	uint16_t col_idx) {
	RecreateLcdTexture();

	for (auto c : row_pixels) {
	_SetTexturePixel(col_idx++, row_idx, c);
	}

	// Rendering here is horribly slow - come up with better solution.
	Render();
	return OkStatus();
	}

	uint16_t DisplayDriverImgUI::GetWidth() const { return kDisplayWidth; }

	uint16_t DisplayDriverImgUI::GetHeight() const { return kDisplayHeight; }

	GLFWwindow* DisplayDriverImgUI::GetGlfwWindow() { return window; }

	ImGuiMousePosition DisplayDriverImgUI::GetImGuiMousePosition() {
	return touchscreen_mouse_position;
	}

	} // namespace pw::display_driver