1 // ImGui - standalone example application for SDL2 + OpenGL
2 // If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
3 // (SDL is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan graphics context creation, etc.)
4 // (GL3W is a helper library to access OpenGL functions since there is no standard header to access modern OpenGL functions easily. Alternatives are GLEW, Glad, etc.)
5
6 #include "imgui.h"
7 #include "imgui_impl_sdl.h"
8 #include "imgui_impl_opengl3.h"
9 #include <stdio.h>
10 #include <SDL.h>
11
12 // About OpenGL function loaders: modern OpenGL doesn't have a standard header file and requires individual function pointers to be loaded manually.
13 // Helper libraries are often used for this purpose! Here we are supporting a few common ones: gl3w, glew, glad.
14 // You may use another loader/header of your choice (glext, glLoadGen, etc.), or chose to manually implement your own.
15 #if defined(IMGUI_IMPL_OPENGL_LOADER_GL3W)
16 #include <GL/gl3w.h> // Initialize with gl3wInit()
17 #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLEW)
18 #include <GL/glew.h> // Initialize with glewInit()
19 #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD)
20 #include <glad/glad.h> // Initialize with gladLoadGL()
21 #else
22 #include IMGUI_IMPL_OPENGL_LOADER_CUSTOM
23 #endif
24
main(int,char **)25 int main(int, char**)
26 {
27 // Setup SDL
28 if (SDL_Init(SDL_INIT_VIDEO|SDL_INIT_TIMER) != 0)
29 {
30 printf("Error: %s\n", SDL_GetError());
31 return -1;
32 }
33
34 // Decide GL+GLSL versions
35 #if __APPLE__
36 // GL 3.2 Core + GLSL 150
37 const char* glsl_version = "#version 150";
38 SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG); // Always required on Mac
39 SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
40 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
41 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
42 #else
43 // GL 3.0 + GLSL 130
44 const char* glsl_version = "#version 130";
45 SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0);
46 SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
47 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
48 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
49 #endif
50
51 // Create window with graphics context
52 SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
53 SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
54 SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
55 SDL_DisplayMode current;
56 SDL_GetCurrentDisplayMode(0, ¤t);
57 SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+OpenGL3 example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, SDL_WINDOW_OPENGL|SDL_WINDOW_RESIZABLE);
58 SDL_GLContext gl_context = SDL_GL_CreateContext(window);
59 SDL_GL_SetSwapInterval(1); // Enable vsync
60
61 // Initialize OpenGL loader
62 #if defined(IMGUI_IMPL_OPENGL_LOADER_GL3W)
63 bool err = gl3wInit() != 0;
64 #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLEW)
65 bool err = glewInit() != GLEW_OK;
66 #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD)
67 bool err = gladLoadGL() == 0;
68 #endif
69 if (err)
70 {
71 fprintf(stderr, "Failed to initialize OpenGL loader!\n");
72 return 1;
73 }
74
75 // Setup Dear ImGui binding
76 IMGUI_CHECKVERSION();
77 ImGui::CreateContext();
78 ImGuiIO& io = ImGui::GetIO(); (void)io;
79 //io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard; // Enable Keyboard Controls
80
81 ImGui_ImplSDL2_InitForOpenGL(window, gl_context);
82 ImGui_ImplOpenGL3_Init(glsl_version);
83
84 // Setup style
85 ImGui::StyleColorsDark();
86 //ImGui::StyleColorsClassic();
87
88 // Load Fonts
89 // - 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.
90 // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
91 // - 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).
92 // - 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.
93 // - Read 'misc/fonts/README.txt' for more instructions and details.
94 // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
95 //io.Fonts->AddFontDefault();
96 //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
97 //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
98 //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
99 //io.Fonts->AddFontFromFileTTF("../../misc/fonts/ProggyTiny.ttf", 10.0f);
100 //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, NULL, io.Fonts->GetGlyphRangesJapanese());
101 //IM_ASSERT(font != NULL);
102
103 bool show_demo_window = true;
104 bool show_another_window = false;
105 ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
106
107 // Main loop
108 bool done = false;
109 while (!done)
110 {
111 // Poll and handle events (inputs, window resize, etc.)
112 // You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
113 // - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application.
114 // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application.
115 // Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
116 SDL_Event event;
117 while (SDL_PollEvent(&event))
118 {
119 ImGui_ImplSDL2_ProcessEvent(&event);
120 if (event.type == SDL_QUIT)
121 done = true;
122 if (event.type == SDL_WINDOWEVENT && event.window.event == SDL_WINDOWEVENT_CLOSE && event.window.windowID == SDL_GetWindowID(window))
123 done = true;
124 }
125
126 // Start the Dear ImGui frame
127 ImGui_ImplOpenGL3_NewFrame();
128 ImGui_ImplSDL2_NewFrame(window);
129 ImGui::NewFrame();
130
131 // 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!).
132 if (show_demo_window)
133 ImGui::ShowDemoWindow(&show_demo_window);
134
135 // 2. Show a simple window that we create ourselves. We use a Begin/End pair to created a named window.
136 {
137 static float f = 0.0f;
138 static int counter = 0;
139
140 ImGui::Begin("Hello, world!"); // Create a window called "Hello, world!" and append into it.
141
142 ImGui::Text("This is some useful text."); // Display some text (you can use a format strings too)
143 ImGui::Checkbox("Demo Window", &show_demo_window); // Edit bools storing our window open/close state
144 ImGui::Checkbox("Another Window", &show_another_window);
145
146 ImGui::SliderFloat("float", &f, 0.0f, 1.0f); // Edit 1 float using a slider from 0.0f to 1.0f
147 ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color
148
149 if (ImGui::Button("Button")) // Buttons return true when clicked (most widgets return true when edited/activated)
150 counter++;
151 ImGui::SameLine();
152 ImGui::Text("counter = %d", counter);
153
154 ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / ImGui::GetIO().Framerate, ImGui::GetIO().Framerate);
155 ImGui::End();
156 }
157
158 // 3. Show another simple window.
159 if (show_another_window)
160 {
161 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)
162 ImGui::Text("Hello from another window!");
163 if (ImGui::Button("Close Me"))
164 show_another_window = false;
165 ImGui::End();
166 }
167
168 // Rendering
169 ImGui::Render();
170 SDL_GL_MakeCurrent(window, gl_context);
171 glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
172 glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w);
173 glClear(GL_COLOR_BUFFER_BIT);
174 ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
175 SDL_GL_SwapWindow(window);
176 }
177
178 // Cleanup
179 ImGui_ImplOpenGL3_Shutdown();
180 ImGui_ImplSDL2_Shutdown();
181 ImGui::DestroyContext();
182
183 SDL_GL_DeleteContext(gl_context);
184 SDL_DestroyWindow(window);
185 SDL_Quit();
186
187 return 0;
188 }
189