1// Dear ImGui: standalone example application for GLFW + OpenGL 3, using programmable pipeline
2// (GLFW is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan/Metal graphics context creation, etc.)
3
4// Learn about Dear ImGui:
5// - FAQ https://dearimgui.com/faq
6// - Getting Started https://dearimgui.com/getting-started
7// - Documentation https://dearimgui.com/docs (same as your local docs/ folder).
8// - Introduction, links and more at the top of imgui.cpp
9
10#include "imgui.h"
11#include "imgui_impl_glfw.h"
12#include "imgui_impl_opengl3.h"
13#include <stdio.h>
14#define GL_SILENCE_DEPRECATION
15#if defined(IMGUI_IMPL_OPENGL_ES2)
16#include <GLES2/gl2.h>
17#endif
18#include <GLFW/glfw3.h> // Will drag system OpenGL headers
19
20// [Win32] Our example includes a copy of glfw3.lib pre-compiled with VS2010 to maximize ease of testing and compatibility with old VS compilers.
21// To link with VS2010-era libraries, VS2015+ requires linking with legacy_stdio_definitions.lib, which we do using this pragma.
22// Your own project should not be affected, as you are likely to link with a newer binary of GLFW that is adequate for your version of Visual Studio.
23#if defined(_MSC_VER) && (_MSC_VER >= 1900) && !defined(IMGUI_DISABLE_WIN32_FUNCTIONS)
24#pragma comment(lib, "legacy_stdio_definitions")
25#endif
26
27// This example can also compile and run with Emscripten! See 'Makefile.emscripten' for details.
28#ifdef __EMSCRIPTEN__
29#include "../libs/emscripten/emscripten_mainloop_stub.h"
30#endif
31
32static void glfw_error_callback(int error, const char* description)
33{
34 fprintf(stderr, format: "GLFW Error %d: %s\n", error, description);
35}
36
37// Main code
38int main(int, char**)
39{
40 glfwSetErrorCallback(cbfun: glfw_error_callback);
41 if (!glfwInit())
42 return 1;
43
44 // Decide GL+GLSL versions
45#if defined(IMGUI_IMPL_OPENGL_ES2)
46 // GL ES 2.0 + GLSL 100 (WebGL 1.0)
47 const char* glsl_version = "#version 100";
48 glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
49 glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
50 glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_ES_API);
51#elif defined(IMGUI_IMPL_OPENGL_ES3)
52 // GL ES 3.0 + GLSL 300 es (WebGL 2.0)
53 const char* glsl_version = "#version 300 es";
54 glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
55 glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
56 glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_ES_API);
57#elif defined(__APPLE__)
58 // GL 3.2 + GLSL 150
59 const char* glsl_version = "#version 150";
60 glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
61 glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
62 glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); // 3.2+ only
63 glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // Required on Mac
64#else
65 // GL 3.0 + GLSL 130
66 const char* glsl_version = "#version 130";
67 glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, value: 3);
68 glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, value: 0);
69 //glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); // 3.2+ only
70 //glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // 3.0+ only
71#endif
72
73 // Create window with graphics context
74 GLFWwindow* window = glfwCreateWindow(width: 1280, height: 720, title: "Dear ImGui GLFW+OpenGL3 example", monitor: nullptr, share: nullptr);
75 if (window == nullptr)
76 return 1;
77 glfwMakeContextCurrent(window);
78 glfwSwapInterval(interval: 1); // Enable vsync
79
80 // Setup Dear ImGui context
81 IMGUI_CHECKVERSION();
82 ImGui::CreateContext();
83 ImGuiIO& io = ImGui::GetIO(); (void)io;
84 io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard; // Enable Keyboard Controls
85 io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad; // Enable Gamepad Controls
86 io.ConfigFlags |= ImGuiConfigFlags_DockingEnable; // Enable Docking
87 io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable; // Enable Multi-Viewport / Platform Windows
88 //io.ConfigViewportsNoAutoMerge = true;
89 //io.ConfigViewportsNoTaskBarIcon = true;
90
91 // Setup Dear ImGui style
92 ImGui::StyleColorsDark();
93 //ImGui::StyleColorsLight();
94
95 // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
96 ImGuiStyle& style = ImGui::GetStyle();
97 if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
98 {
99 style.WindowRounding = 0.0f;
100 style.Colors[ImGuiCol_WindowBg].w = 1.0f;
101 }
102
103 // Setup Platform/Renderer backends
104 ImGui_ImplGlfw_InitForOpenGL(window, install_callbacks: true);
105#ifdef __EMSCRIPTEN__
106 ImGui_ImplGlfw_InstallEmscriptenCallbacks(window, "#canvas");
107#endif
108 ImGui_ImplOpenGL3_Init(glsl_version);
109
110 // Load Fonts
111 // - 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.
112 // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
113 // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
114 // - 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.
115 // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
116 // - Read 'docs/FONTS.md' for more instructions and details.
117 // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
118 // - Our Emscripten build process allows embedding fonts to be accessible at runtime from the "fonts/" folder. See Makefile.emscripten for details.
119 //io.Fonts->AddFontDefault();
120 //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
121 //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
122 //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
123 //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
124 //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
125 //IM_ASSERT(font != nullptr);
126
127 // Our state
128 bool show_demo_window = true;
129 bool show_another_window = false;
130 ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
131
132 // Main loop
133#ifdef __EMSCRIPTEN__
134 // For an Emscripten build we are disabling file-system access, so let's not attempt to do a fopen() of the imgui.ini file.
135 // You may manually call LoadIniSettingsFromMemory() to load settings from your own storage.
136 io.IniFilename = nullptr;
137 EMSCRIPTEN_MAINLOOP_BEGIN
138#else
139 while (!glfwWindowShouldClose(window))
140#endif
141 {
142 // Poll and handle events (inputs, window resize, etc.)
143 // You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
144 // - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application, or clear/overwrite your copy of the mouse data.
145 // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application, or clear/overwrite your copy of the keyboard data.
146 // Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
147 glfwPollEvents();
148 if (glfwGetWindowAttrib(window, GLFW_ICONIFIED) != 0)
149 {
150 ImGui_ImplGlfw_Sleep(milliseconds: 10);
151 continue;
152 }
153
154 // Start the Dear ImGui frame
155 ImGui_ImplOpenGL3_NewFrame();
156 ImGui_ImplGlfw_NewFrame();
157 ImGui::NewFrame();
158
159 // 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!).
160 if (show_demo_window)
161 ImGui::ShowDemoWindow(p_open: &show_demo_window);
162
163 // 2. Show a simple window that we create ourselves. We use a Begin/End pair to create a named window.
164 {
165 static float f = 0.0f;
166 static int counter = 0;
167
168 ImGui::Begin(name: "Hello, world!"); // Create a window called "Hello, world!" and append into it.
169
170 ImGui::Text(fmt: "This is some useful text."); // Display some text (you can use a format strings too)
171 ImGui::Checkbox(label: "Demo Window", v: &show_demo_window); // Edit bools storing our window open/close state
172 ImGui::Checkbox(label: "Another Window", v: &show_another_window);
173
174 ImGui::SliderFloat(label: "float", v: &f, v_min: 0.0f, v_max: 1.0f); // Edit 1 float using a slider from 0.0f to 1.0f
175 ImGui::ColorEdit3(label: "clear color", col: (float*)&clear_color); // Edit 3 floats representing a color
176
177 if (ImGui::Button(label: "Button")) // Buttons return true when clicked (most widgets return true when edited/activated)
178 counter++;
179 ImGui::SameLine();
180 ImGui::Text(fmt: "counter = %d", counter);
181
182 ImGui::Text(fmt: "Application average %.3f ms/frame (%.1f FPS)", 1000.0f / io.Framerate, io.Framerate);
183 ImGui::End();
184 }
185
186 // 3. Show another simple window.
187 if (show_another_window)
188 {
189 ImGui::Begin(name: "Another Window", p_open: &show_another_window); // Pass a pointer to our bool variable (the window will have a closing button that will clear the bool when clicked)
190 ImGui::Text(fmt: "Hello from another window!");
191 if (ImGui::Button(label: "Close Me"))
192 show_another_window = false;
193 ImGui::End();
194 }
195
196 // Rendering
197 ImGui::Render();
198 int display_w, display_h;
199 glfwGetFramebufferSize(window, width: &display_w, height: &display_h);
200 glViewport(x: 0, y: 0, width: display_w, height: display_h);
201 glClearColor(red: clear_color.x * clear_color.w, green: clear_color.y * clear_color.w, blue: clear_color.z * clear_color.w, alpha: clear_color.w);
202 glClear(GL_COLOR_BUFFER_BIT);
203 ImGui_ImplOpenGL3_RenderDrawData(draw_data: ImGui::GetDrawData());
204
205 // Update and Render additional Platform Windows
206 // (Platform functions may change the current OpenGL context, so we save/restore it to make it easier to paste this code elsewhere.
207 // For this specific demo app we could also call glfwMakeContextCurrent(window) directly)
208 if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
209 {
210 GLFWwindow* backup_current_context = glfwGetCurrentContext();
211 ImGui::UpdatePlatformWindows();
212 ImGui::RenderPlatformWindowsDefault();
213 glfwMakeContextCurrent(window: backup_current_context);
214 }
215
216 glfwSwapBuffers(window);
217 }
218#ifdef __EMSCRIPTEN__
219 EMSCRIPTEN_MAINLOOP_END;
220#endif
221
222 // Cleanup
223 ImGui_ImplOpenGL3_Shutdown();
224 ImGui_ImplGlfw_Shutdown();
225 ImGui::DestroyContext();
226
227 glfwDestroyWindow(window);
228 glfwTerminate();
229
230 return 0;
231}
232

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source code of imgui/examples/example_glfw_opengl3/main.cpp