1 // dear imgui: standalone example application for GLFW + OpenGL2, using legacy fixed pipeline
2 // If you are new to dear imgui, see examples/README.txt and documentation at the top of imgui.cpp.
3 // (GLFW is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan graphics context creation, etc.)
4 
5 // **DO NOT USE THIS CODE IF YOUR CODE/ENGINE IS USING MODERN OPENGL (SHADERS, VBO, VAO, etc.)**
6 // **Prefer using the code in the example_glfw_opengl2/ folder**
7 // See imgui_impl_glfw.cpp for details.
8 
9 #include "imgui.h"
10 #include "imgui_impl_glfw.h"
11 #include "imgui_impl_opengl2.h"
12 #include <stdio.h>
13 #include <GLFW/glfw3.h>
14 
15 // [Win32] Our example includes a copy of glfw3.lib pre-compiled with VS2010 to maximize ease of testing and compatibility with old VS compilers.
16 // To link with VS2010-era libraries, VS2015+ requires linking with legacy_stdio_definitions.lib, which we do using this pragma.
17 // 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.
18 #if defined(_MSC_VER) && (_MSC_VER >= 1900) && !defined(IMGUI_DISABLE_WIN32_FUNCTIONS)
19 #pragma comment(lib, "legacy_stdio_definitions")
20 #endif
21 
glfw_error_callback(int error,const char * description)22 static void glfw_error_callback(int error, const char* description)
23 {
24     fprintf(stderr, "Glfw Error %d: %s\n", error, description);
25 }
26 
main(int,char **)27 int main(int, char**)
28 {
29     // Setup window
30     glfwSetErrorCallback(glfw_error_callback);
31     if (!glfwInit())
32         return 1;
33     GLFWwindow* window = glfwCreateWindow(1280, 720, "Dear ImGui GLFW+OpenGL2 example", NULL, NULL);
34     if (window == NULL)
35         return 1;
36     glfwMakeContextCurrent(window);
37     glfwSwapInterval(1); // Enable vsync
38 
39     // Setup Dear ImGui context
40     IMGUI_CHECKVERSION();
41     ImGui::CreateContext();
42     ImGuiIO& io = ImGui::GetIO(); (void)io;
43     //io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;  // Enable Keyboard Controls
44     //io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;   // Enable Gamepad Controls
45 
46     // Setup Dear ImGui style
47     ImGui::StyleColorsDark();
48     //ImGui::StyleColorsClassic();
49 
50     // Setup Platform/Renderer bindings
51     ImGui_ImplGlfw_InitForOpenGL(window, true);
52     ImGui_ImplOpenGL2_Init();
53 
54     // Load Fonts
55     // - 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.
56     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
57     // - 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).
58     // - 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.
59     // - Read 'misc/fonts/README.txt' for more instructions and details.
60     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
61     //io.Fonts->AddFontDefault();
62     //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
63     //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
64     //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
65     //io.Fonts->AddFontFromFileTTF("../../misc/fonts/ProggyTiny.ttf", 10.0f);
66     //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, NULL, io.Fonts->GetGlyphRangesJapanese());
67     //IM_ASSERT(font != NULL);
68 
69     bool show_demo_window = true;
70     bool show_another_window = false;
71     ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
72 
73     // Main loop
74     while (!glfwWindowShouldClose(window))
75     {
76         // Poll and handle events (inputs, window resize, etc.)
77         // You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
78         // - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application.
79         // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application.
80         // Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
81         glfwPollEvents();
82 
83         // Start the Dear ImGui frame
84         ImGui_ImplOpenGL2_NewFrame();
85         ImGui_ImplGlfw_NewFrame();
86         ImGui::NewFrame();
87 
88         // 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!).
89         if (show_demo_window)
90             ImGui::ShowDemoWindow(&show_demo_window);
91 
92         // 2. Show a simple window that we create ourselves. We use a Begin/End pair to created a named window.
93         {
94             static float f = 0.0f;
95             static int counter = 0;
96 
97             ImGui::Begin("Hello, world!");                          // Create a window called "Hello, world!" and append into it.
98 
99             ImGui::Text("This is some useful text.");               // Display some text (you can use a format strings too)
100             ImGui::Checkbox("Demo Window", &show_demo_window);      // Edit bools storing our window open/close state
101             ImGui::Checkbox("Another Window", &show_another_window);
102 
103             ImGui::SliderFloat("float", &f, 0.0f, 1.0f);            // Edit 1 float using a slider from 0.0f to 1.0f
104             ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color
105 
106             if (ImGui::Button("Button"))                            // Buttons return true when clicked (most widgets return true when edited/activated)
107                 counter++;
108             ImGui::SameLine();
109             ImGui::Text("counter = %d", counter);
110 
111             ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / ImGui::GetIO().Framerate, ImGui::GetIO().Framerate);
112             ImGui::End();
113         }
114 
115         // 3. Show another simple window.
116         if (show_another_window)
117         {
118             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)
119             ImGui::Text("Hello from another window!");
120             if (ImGui::Button("Close Me"))
121                 show_another_window = false;
122             ImGui::End();
123         }
124 
125         // Rendering
126         ImGui::Render();
127         int display_w, display_h;
128         glfwGetFramebufferSize(window, &display_w, &display_h);
129         glViewport(0, 0, display_w, display_h);
130         glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w);
131         glClear(GL_COLOR_BUFFER_BIT);
132         //glUseProgram(0); // You may want this if using this code in an OpenGL 3+ context where shaders may be bound, but prefer using the GL3+ code.
133         ImGui_ImplOpenGL2_RenderDrawData(ImGui::GetDrawData());
134 
135         glfwMakeContextCurrent(window);
136         glfwSwapBuffers(window);
137     }
138 
139     // Cleanup
140     ImGui_ImplOpenGL2_Shutdown();
141     ImGui_ImplGlfw_Shutdown();
142     ImGui::DestroyContext();
143 
144     glfwDestroyWindow(window);
145     glfwTerminate();
146 
147     return 0;
148 }
149