1 // Dear ImGui: standalone example application for SDL2 + OpenGL
2 // (SDL is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan/Metal graphics context creation, etc.)
3 // (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.)
4 // If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
5 // Read online: https://github.com/ocornut/imgui/tree/master/docs
6
7 #include "imgui.h"
8 #include "imgui_impl_sdl.h"
9 #include "imgui_impl_opengl3.h"
10 #include <stdio.h>
11 #include <SDL.h>
12
13 #if defined(IMGUI_IMPL_OPENGL_ES2)
14 #include <GLES2/gl2.h>
15 // About Desktop OpenGL function loaders:
16 // Modern desktop OpenGL doesn't have a standard portable header file to load OpenGL function pointers.
17 // Helper libraries are often used for this purpose! Here we are supporting a few common ones (gl3w, glew, glad).
18 // You may use another loader/header of your choice (glext, glLoadGen, etc.), or chose to manually implement your own.
19 #elif defined(IMGUI_IMPL_OPENGL_LOADER_GL3W)
20 #include <GL/gl3w.h> // Initialize with gl3wInit()
21 #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLEW)
22 #include <GL/glew.h> // Initialize with glewInit()
23 #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD)
24 #include <glad/glad.h> // Initialize with gladLoadGL()
25 #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD2)
26 #include <glad/gl.h> // Initialize with gladLoadGL(...) or gladLoaderLoadGL()
27 #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLBINDING2)
28 #define GLFW_INCLUDE_NONE // GLFW including OpenGL headers causes ambiguity or multiple definition errors.
29 #include <glbinding/Binding.h> // Initialize with glbinding::Binding::initialize()
30 #include <glbinding/gl/gl.h>
31 using namespace gl;
32 #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLBINDING3)
33 #define GLFW_INCLUDE_NONE // GLFW including OpenGL headers causes ambiguity or multiple definition errors.
34 #include <glbinding/glbinding.h>// Initialize with glbinding::initialize()
35 #include <glbinding/gl/gl.h>
36 using namespace gl;
37 #else
38 #include IMGUI_IMPL_OPENGL_LOADER_CUSTOM
39 #endif
40
41 // Main code
main(int,char **)42 int main(int, char**)
43 {
44 // Setup SDL
45 // (Some versions of SDL before <2.0.10 appears to have performance/stalling issues on a minority of Windows systems,
46 // depending on whether SDL_INIT_GAMECONTROLLER is enabled or disabled.. updating to latest version of SDL is recommended!)
47 if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER | SDL_INIT_GAMECONTROLLER) != 0)
48 {
49 printf("Error: %s\n", SDL_GetError());
50 return -1;
51 }
52
53 // Decide GL+GLSL versions
54 #if defined(IMGUI_IMPL_OPENGL_ES2)
55 // GL ES 2.0 + GLSL 100
56 const char* glsl_version = "#version 100";
57 SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0);
58 SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES);
59 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
60 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
61 #elif defined(__APPLE__)
62 // GL 3.2 Core + GLSL 150
63 const char* glsl_version = "#version 150";
64 SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG); // Always required on Mac
65 SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
66 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
67 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
68 #else
69 // GL 3.0 + GLSL 130
70 const char* glsl_version = "#version 130";
71 SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0);
72 SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
73 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
74 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
75 #endif
76
77 // Create window with graphics context
78 SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
79 SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
80 SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
81 SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
82 SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+OpenGL3 example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, window_flags);
83 SDL_GLContext gl_context = SDL_GL_CreateContext(window);
84 SDL_GL_MakeCurrent(window, gl_context);
85 SDL_GL_SetSwapInterval(1); // Enable vsync
86
87 // Initialize OpenGL loader
88 #if defined(IMGUI_IMPL_OPENGL_LOADER_GL3W)
89 bool err = gl3wInit() != 0;
90 #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLEW)
91 bool err = glewInit() != GLEW_OK;
92 #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD)
93 bool err = gladLoadGL() == 0;
94 #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD2)
95 bool err = gladLoadGL((GLADloadfunc)SDL_GL_GetProcAddress) == 0; // glad2 recommend using the windowing library loader instead of the (optionally) bundled one.
96 #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLBINDING2)
97 bool err = false;
98 glbinding::Binding::initialize();
99 #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLBINDING3)
100 bool err = false;
101 glbinding::initialize([](const char* name) { return (glbinding::ProcAddress)SDL_GL_GetProcAddress(name); });
102 #else
103 bool err = false; // If you use IMGUI_IMPL_OPENGL_LOADER_CUSTOM, your loader is likely to requires some form of initialization.
104 #endif
105 if (err)
106 {
107 fprintf(stderr, "Failed to initialize OpenGL loader!\n");
108 return 1;
109 }
110
111 // Setup Dear ImGui context
112 IMGUI_CHECKVERSION();
113 ImGui::CreateContext();
114 ImGuiIO& io = ImGui::GetIO(); (void)io;
115 io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard; // Enable Keyboard Controls
116 //io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad; // Enable Gamepad Controls
117 io.ConfigFlags |= ImGuiConfigFlags_DockingEnable; // Enable Docking
118 io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable; // Enable Multi-Viewport / Platform Windows
119 //io.ConfigViewportsNoAutoMerge = true;
120 //io.ConfigViewportsNoTaskBarIcon = true;
121
122 // Setup Dear ImGui style
123 ImGui::StyleColorsDark();
124 //ImGui::StyleColorsClassic();
125
126 // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
127 ImGuiStyle& style = ImGui::GetStyle();
128 if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
129 {
130 style.WindowRounding = 0.0f;
131 style.Colors[ImGuiCol_WindowBg].w = 1.0f;
132 }
133
134 // Setup Platform/Renderer backends
135 ImGui_ImplSDL2_InitForOpenGL(window, gl_context);
136 ImGui_ImplOpenGL3_Init(glsl_version);
137
138 // Load Fonts
139 // - 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.
140 // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
141 // - 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).
142 // - 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.
143 // - Read 'docs/FONTS.md' for more instructions and details.
144 // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
145 //io.Fonts->AddFontDefault();
146 //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
147 //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
148 //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
149 //io.Fonts->AddFontFromFileTTF("../../misc/fonts/ProggyTiny.ttf", 10.0f);
150 //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, NULL, io.Fonts->GetGlyphRangesJapanese());
151 //IM_ASSERT(font != NULL);
152
153 // Our state
154 bool show_demo_window = true;
155 bool show_another_window = false;
156 ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
157
158 // Main loop
159 bool done = false;
160 while (!done)
161 {
162 // Poll and handle events (inputs, window resize, etc.)
163 // You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
164 // - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application.
165 // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application.
166 // Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
167 SDL_Event event;
168 while (SDL_PollEvent(&event))
169 {
170 ImGui_ImplSDL2_ProcessEvent(&event);
171 if (event.type == SDL_QUIT)
172 done = true;
173 if (event.type == SDL_WINDOWEVENT && event.window.event == SDL_WINDOWEVENT_CLOSE && event.window.windowID == SDL_GetWindowID(window))
174 done = true;
175 }
176
177 // Start the Dear ImGui frame
178 ImGui_ImplOpenGL3_NewFrame();
179 ImGui_ImplSDL2_NewFrame();
180 ImGui::NewFrame();
181
182 // 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!).
183 if (show_demo_window)
184 ImGui::ShowDemoWindow(&show_demo_window);
185
186 // 2. Show a simple window that we create ourselves. We use a Begin/End pair to created a named window.
187 {
188 static float f = 0.0f;
189 static int counter = 0;
190
191 ImGui::Begin("Hello, world!"); // Create a window called "Hello, world!" and append into it.
192
193 ImGui::Text("This is some useful text."); // Display some text (you can use a format strings too)
194 ImGui::Checkbox("Demo Window", &show_demo_window); // Edit bools storing our window open/close state
195 ImGui::Checkbox("Another Window", &show_another_window);
196
197 ImGui::SliderFloat("float", &f, 0.0f, 1.0f); // Edit 1 float using a slider from 0.0f to 1.0f
198 ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color
199
200 if (ImGui::Button("Button")) // Buttons return true when clicked (most widgets return true when edited/activated)
201 counter++;
202 ImGui::SameLine();
203 ImGui::Text("counter = %d", counter);
204
205 ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / ImGui::GetIO().Framerate, ImGui::GetIO().Framerate);
206 ImGui::End();
207 }
208
209 // 3. Show another simple window.
210 if (show_another_window)
211 {
212 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)
213 ImGui::Text("Hello from another window!");
214 if (ImGui::Button("Close Me"))
215 show_another_window = false;
216 ImGui::End();
217 }
218
219 // Rendering
220 ImGui::Render();
221 glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
222 glClearColor(clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w);
223 glClear(GL_COLOR_BUFFER_BIT);
224 ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
225
226 // Update and Render additional Platform Windows
227 // (Platform functions may change the current OpenGL context, so we save/restore it to make it easier to paste this code elsewhere.
228 // For this specific demo app we could also call SDL_GL_MakeCurrent(window, gl_context) directly)
229 if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
230 {
231 SDL_Window* backup_current_window = SDL_GL_GetCurrentWindow();
232 SDL_GLContext backup_current_context = SDL_GL_GetCurrentContext();
233 ImGui::UpdatePlatformWindows();
234 ImGui::RenderPlatformWindowsDefault();
235 SDL_GL_MakeCurrent(backup_current_window, backup_current_context);
236 }
237
238 SDL_GL_SwapWindow(window);
239 }
240
241 // Cleanup
242 ImGui_ImplOpenGL3_Shutdown();
243 ImGui_ImplSDL2_Shutdown();
244 ImGui::DestroyContext();
245
246 SDL_GL_DeleteContext(gl_context);
247 SDL_DestroyWindow(window);
248 SDL_Quit();
249
250 return 0;
251 }
252