Examples: Made example_sdl_opengl3 and example_glfw_opengl3 build with Emscripten. Removed dedicated examples. (#2492, #2494, #3699, #3705)

This commit is contained in:
ocornut 2023-02-02 18:08:17 +01:00
parent 96ab68eee0
commit ce6e6da510
13 changed files with 91 additions and 465 deletions

4
.gitignore vendored
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@ -40,8 +40,8 @@ xcuserdata
examples/*.o.tmp
examples/*.out.js
examples/*.out.wasm
examples/example_emscripten_glfw_opengl3/web/*
examples/example_emscripten_opengl3/web/*
examples/example_glfw_opengl3/web/*
examples/example_sdl_opengl3/web/*
examples/example_emscripten_wgpu/web/*
## JetBrains IDE artifacts

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@ -104,15 +104,10 @@ OSX + OpenGL2 example. <BR>
(NB: imgui_impl_osx.mm is currently not as feature complete as other platforms backends.
You may prefer to use the GLFW Or SDL backends, which will also support Windows and Linux.)
[example_emscripten_opengl3/](https://github.com/ocornut/imgui/blob/master/examples/example_emscripten_opengl3/) <BR>
Emcripten + SDL2 + OpenGL3+/ES2/ES3 example. <BR>
= main.cpp + imgui_impl_sdl.cpp + imgui_impl_opengl3.cpp <BR>
Note that other examples based on SDL or GLFW + OpenGL could easily be modified to work with Emscripten.
We provide this to make the Emscripten differences obvious, and have them not pollute all other examples.
[example_emscripten_wgpu/](https://github.com/ocornut/imgui/blob/master/examples/example_emscripten_wgpu/) <BR>
Emcripten + GLFW + WebGPU example. <BR>
= main.cpp + imgui_impl_glfw.cpp + imgui_impl_wgpu.cpp
Note that the 'example_glfw_opengl3' and 'example_sdl_opengl3' examples also supports Emscripten!
[example_glfw_metal/](https://github.com/ocornut/imgui/blob/master/examples/example_glfw_metal/) <BR>
GLFW (Mac) + Metal example. <BR>
@ -121,18 +116,18 @@ GLFW (Mac) + Metal example. <BR>
[example_glfw_opengl2/](https://github.com/ocornut/imgui/blob/master/examples/example_glfw_opengl2/) <BR>
GLFW + OpenGL2 example (legacy, fixed pipeline). <BR>
= main.cpp + imgui_impl_glfw.cpp + imgui_impl_opengl2.cpp <BR>
**DO NOT USE THIS IF YOUR CODE/ENGINE IS USING MODERN OPENGL (SHADERS, VBO, VAO, etc.)** <BR>
**DO NOT USE THIS IF YOUR CODE/ENGINE IS USING MODERN GL or WEBGL (SHADERS, VBO, VAO, etc.)** <BR>
This code is mostly provided as a reference to learn about Dear ImGui integration, because it is shorter.
If your code is using GL3+ context or any semi modern OpenGL calls, using this renderer is likely to
make things more complicated, will require your code to reset many OpenGL attributes to their initial
If your code is using GL3+ context or any semi modern GL calls, using this renderer is likely to
make things more complicated, will require your code to reset many GL attributes to their initial
state, and might confuse your GPU driver. One star, not recommended.
[example_glfw_opengl3/](https://github.com/ocornut/imgui/blob/master/examples/example_glfw_opengl3/) <BR>
GLFW (Win32, Mac, Linux) + OpenGL3+/ES2/ES3 example (modern, programmable pipeline). <BR>
= main.cpp + imgui_impl_glfw.cpp + imgui_impl_opengl3.cpp <BR>
This uses more modern OpenGL calls and custom shaders. <BR>
This may actually also work with OpenGL 2.x contexts! <BR>
Prefer using that if you are using modern OpenGL in your application (anything with shaders).
This uses more modern GL calls and custom shaders.<BR>
This support building with Emscripten and targetting WebGL.<BR>
Prefer using that if you are using modern GL or WebGL in your application.
[example_glfw_vulkan/](https://github.com/ocornut/imgui/blob/master/examples/example_glfw_vulkan/) <BR>
GLFW (Win32, Mac, Linux) + Vulkan example. <BR>
@ -163,17 +158,18 @@ SDL2 (Mac) + Metal example. <BR>
[example_sdl_opengl2/](https://github.com/ocornut/imgui/blob/master/examples/example_sdl_opengl2/) <BR>
SDL2 (Win32, Mac, Linux etc.) + OpenGL example (legacy, fixed pipeline). <BR>
= main.cpp + imgui_impl_sdl.cpp + imgui_impl_opengl2.cpp <BR>
**DO NOT USE OPENGL2 CODE IF YOUR CODE/ENGINE IS USING MODERN OPENGL (SHADERS, VBO, VAO, etc.)** <BR>
**DO NOT USE OPENGL2 CODE IF YOUR CODE/ENGINE IS USING GL OR WEBGL (SHADERS, VBO, VAO, etc.)** <BR>
This code is mostly provided as a reference to learn about Dear ImGui integration, because it is shorter.
If your code is using GL3+ context or any semi modern OpenGL calls, using this renderer is likely to
make things more complicated, will require your code to reset many OpenGL attributes to their initial
If your code is using GL3+ context or any semi modern GL calls, using this renderer is likely to
make things more complicated, will require your code to reset many GL attributes to their initial
state, and might confuse your GPU driver. One star, not recommended.
[example_sdl_opengl3/](https://github.com/ocornut/imgui/blob/master/examples/example_sdl_opengl3/) <BR>
SDL2 (Win32, Mac, Linux, etc.) + OpenGL3+/ES2/ES3 example. <BR>
= main.cpp + imgui_impl_sdl.cpp + imgui_impl_opengl3.cpp <BR>
This uses more modern OpenGL calls and custom shaders. <BR>
This may actually also work with OpenGL 2.x contexts! <BR>
This uses more modern GL calls and custom shaders. <BR>
This support building with Emscripten and targetting WebGL.<BR>
Prefer using that if you are using modern GL or WebGL in your application.
[example_sdl_sdlrenderer/](https://github.com/ocornut/imgui/blob/master/examples/example_sdl_sdlrenderer/) <BR>
SDL2 (Win32, Mac, Linux, etc.) + SDL_Renderer (most graphics backends are supported underneath) <BR>

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// Dear ImGui: standalone example application for Emscripten, using GLFW + OpenGL3
// (Emscripten is a C++-to-javascript compiler, used to publish executables for the web. See https://emscripten.org/)
// If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
// Read online: https://github.com/ocornut/imgui/tree/master/docs
// This is mostly the same code as the GLFW + OpenGL3 example, simply with the modifications needed to run on Emscripten.
// It is possible to combine both code into a single source file that will compile properly on Desktop and using Emscripten.
// See https://github.com/ocornut/imgui/pull/2492 as an example on how to do just that.
#include "imgui.h"
#include "imgui_impl_glfw.h"
#include "imgui_impl_opengl3.h"
#include <stdio.h>
#include <emscripten.h>
#define GL_SILENCE_DEPRECATION
#if defined(IMGUI_IMPL_OPENGL_ES2)
#include <GLES2/gl2.h>
#endif
#include <GLFW/glfw3.h> // Will drag system OpenGL headers
// Emscripten requires to have full control over the main loop. We're going to store our GLFW book-keeping variables globally.
// Having a single function that acts as a loop prevents us to store state in the stack of said function. So we need some location for this.
GLFWwindow* g_Window = NULL;
static void glfw_error_callback(int error, const char* description)
{
fprintf(stderr, "Glfw Error %d: %s\n", error, description);
}
// For clarity, our main loop code is declared at the end.
static void main_loop(void*);
int main(int, char**)
{
// Setup window
glfwSetErrorCallback(glfw_error_callback);
if (!glfwInit())
return 1;
// For the browser using Emscripten, we are going to use WebGL1 with GL ES2. See the Makefile. for requirement details.
// It is very likely the generated file won't work in many browsers. Firefox is the only sure bet, but I have successfully
// run this code on Chrome for Android for example.
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);
// Create window with graphics context
GLFWwindow* window = glfwCreateWindow(1280, 720, "Dear ImGui GLFW+Emscripten example", NULL, NULL);
if (window == NULL)
return 1;
glfwMakeContextCurrent(window);
glfwSwapInterval(1); // Enable vsync
g_Window = window;
// Setup Dear ImGui context
IMGUI_CHECKVERSION();
ImGui::CreateContext();
ImGuiIO& io = ImGui::GetIO(); (void)io;
//io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard; // Enable Keyboard Controls
//io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad; // Enable Gamepad Controls
// For an Emscripten build we are disabling file-system access, so let's not attempt to do a fopen() of the imgui.ini file.
// You may manually call LoadIniSettingsFromMemory() to load settings from your own storage.
io.IniFilename = NULL;
// Setup Dear ImGui style
ImGui::StyleColorsDark();
//ImGui::StyleColorsLight();
// Setup Platform/Renderer backends
ImGui_ImplGlfw_InitForOpenGL(window, true);
ImGui_ImplOpenGL3_Init(glsl_version);
// Load Fonts
// - 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.
// - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
// - 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).
// - 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.
// - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
// - Read 'docs/FONTS.md' for more instructions and details.
// - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
// - Emscripten allows preloading a file or folder to be accessible at runtime. See Makefile for details.
//io.Fonts->AddFontDefault();
#ifndef IMGUI_DISABLE_FILE_FUNCTIONS
//io.Fonts->AddFontFromFileTTF("fonts/segoeui.ttf", 18.0f);
io.Fonts->AddFontFromFileTTF("fonts/DroidSans.ttf", 16.0f);
//io.Fonts->AddFontFromFileTTF("fonts/Roboto-Medium.ttf", 16.0f);
//io.Fonts->AddFontFromFileTTF("fonts/Cousine-Regular.ttf", 15.0f);
//io.Fonts->AddFontFromFileTTF("fonts/ProggyTiny.ttf", 10.0f);
//ImFont* font = io.Fonts->AddFontFromFileTTF("fonts/ArialUni.ttf", 18.0f, NULL, io.Fonts->GetGlyphRangesJapanese());
//IM_ASSERT(font != NULL);
#endif
// This function call won't return, and will engage in an infinite loop, processing events from the browser, and dispatching them.
emscripten_set_main_loop_arg(main_loop, NULL, 0, true);
}
static void main_loop(void* arg)
{
IM_UNUSED(arg); // We can pass this argument as the second parameter of emscripten_set_main_loop_arg(), but we don't use that.
// Our state (make them static = more or less global) as a convenience to keep the example terse.
static bool show_demo_window = true;
static bool show_another_window = false;
static ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
// Poll and handle events (inputs, window resize, etc.)
// You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
// - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application, or clear/overwrite your copy of the mouse data.
// - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application, or clear/overwrite your copy of the keyboard data.
// Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
glfwPollEvents();
// Start the Dear ImGui frame
ImGui_ImplOpenGL3_NewFrame();
ImGui_ImplGlfw_NewFrame();
ImGui::NewFrame();
// 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_demo_window)
ImGui::ShowDemoWindow(&show_demo_window);
// 2. Show a simple window that we create ourselves. We use a Begin/End pair to create a named window.
{
static float f = 0.0f;
static int counter = 0;
ImGui::Begin("Hello, world!"); // Create a window called "Hello, world!" and append into it.
ImGui::Text("This is some useful text."); // Display some text (you can use a format strings too)
ImGui::Checkbox("Demo Window", &show_demo_window); // Edit bools storing our window open/close state
ImGui::Checkbox("Another Window", &show_another_window);
ImGui::SliderFloat("float", &f, 0.0f, 1.0f); // Edit 1 float using a slider from 0.0f to 1.0f
ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color
if (ImGui::Button("Button")) // Buttons return true when clicked (most widgets return true when edited/activated)
counter++;
ImGui::SameLine();
ImGui::Text("counter = %d", counter);
ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / ImGui::GetIO().Framerate, ImGui::GetIO().Framerate);
ImGui::End();
}
// 3. Show another simple window.
if (show_another_window)
{
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)
ImGui::Text("Hello from another window!");
if (ImGui::Button("Close Me"))
show_another_window = false;
ImGui::End();
}
// Rendering
ImGui::Render();
int display_w, display_h;
glfwGetFramebufferSize(g_Window, &display_w, &display_h);
glViewport(0, 0, display_w, display_h);
glClearColor(clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w);
glClear(GL_COLOR_BUFFER_BIT);
ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
glfwSwapBuffers(g_Window);
}

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@ -1,65 +0,0 @@
<!doctype html>
<html lang="en-us">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, minimum-scale=1, user-scalable=no"/>
<title>Dear ImGui GLFW+Emscripten example</title>
<style>
body { margin: 0; background-color: black }
/*.emscripten {
position: absolute;
top: 0px;
left: 0px;
margin: 0px;
border: 0;
width: 100%;
height: 100%;
overflow: hidden;
display: block;
image-rendering: optimizeSpeed;
image-rendering: -moz-crisp-edges;
image-rendering: -o-crisp-edges;
image-rendering: -webkit-optimize-contrast;
image-rendering: optimize-contrast;
image-rendering: crisp-edges;
image-rendering: pixelated;
-ms-interpolation-mode: nearest-neighbor;
}*/
.emscripten { padding-right: 0; margin-left: auto; margin-right: auto; display: block; }
</style>
</head>
<body>
<canvas class="emscripten" id="canvas" oncontextmenu="event.preventDefault()"></canvas>
<script type='text/javascript'>
var Module = {
preRun: [],
postRun: [],
print: (function() {
return function(text) {
text = Array.prototype.slice.call(arguments).join(' ');
console.log(text);
};
})(),
printErr: function(text) {
text = Array.prototype.slice.call(arguments).join(' ');
console.error(text);
},
canvas: (function() {
var canvas = document.getElementById('canvas');
//canvas.addEventListener("webglcontextlost", function(e) { alert('FIXME: WebGL context lost, please reload the page'); e.preventDefault(); }, false);
return canvas;
})(),
setStatus: function(text) {
console.log("status: " + text);
},
monitorRunDependencies: function(left) {
// no run dependencies to log
}
};
window.onerror = function() {
console.log("onerror: " + event);
};
</script>
{{{ SCRIPT }}}
</body>
</html>

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## How to Build
- You need to install Emscripten from https://emscripten.org/docs/getting_started/downloads.html, and have the environment variables set, as described in https://emscripten.org/docs/getting_started/downloads.html#installation-instructions
- Depending on your configuration, in Windows you may need to run `emsdk/emsdk_env.bat` in your console to access the Emscripten command-line tools.
- You may also refer to our [Continuous Integration setup](https://github.com/ocornut/imgui/tree/master/.github/workflows) for Emscripten setup.
- Then build using `make` while in the `example_emscripten_opengl3/` directory.
## How to Run
To run on a local machine:
- `make serve` will use Python3 to spawn a local webserver, you can then browse http://localhost:8000 to access your build.
- Otherwise, generally you will need a local webserver:
- Quoting [https://emscripten.org/docs/getting_started](https://emscripten.org/docs/getting_started/Tutorial.html#generating-html):<br>
_"Unfortunately several browsers (including Chrome, Safari, and Internet Explorer) do not support file:// [XHR](https://emscripten.org/docs/site/glossary.html#term-xhr) requests, and cant load extra files needed by the HTML (like a .wasm file, or packaged file data as mentioned lower down). For these browsers youll need to serve the files using a [local webserver](https://emscripten.org/docs/getting_started/FAQ.html#faq-local-webserver) and then open http://localhost:8000/hello.html."_
- Emscripten SDK has a handy `emrun` command: `emrun web/example_emscripten_opengl3.html --browser firefox` which will spawn a temporary local webserver (in Firefox). See https://emscripten.org/docs/compiling/Running-html-files-with-emrun.html for details.
- You may use Python 3 builtin webserver: `python -m http.server -d web` (this is what `make serve` uses).
- You may use Python 2 builtin webserver: `cd web && python -m SimpleHTTPServer`.
- If you are accessing the files over a network, certain browsers, such as Firefox, will restrict Gamepad API access to secure contexts only (e.g. https only).
## Obsolete features:
- Emscripten 2.0 (August 2020) obsoleted the fastcomp backend, only llvm is supported.
- Emscripten 1.39.0 (October 2019) obsoleted the `BINARYEN_TRAP_MODE=clamp` compilation flag which was required with version older than 1.39.0 to avoid rendering artefacts. See [#2877](https://github.com/ocornut/imgui/issues/2877) for details. If you use an older version, uncomment this line in the Makefile: `#EMS += -s BINARYEN_TRAP_MODE=clamp`

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// Dear ImGui: standalone example application for Emscripten, using SDL2 + OpenGL3
// (Emscripten is a C++-to-javascript compiler, used to publish executables for the web. See https://emscripten.org/)
// If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
// Read online: https://github.com/ocornut/imgui/tree/master/docs
// This is mostly the same code as the SDL2 + OpenGL3 example, simply with the modifications needed to run on Emscripten.
// It is possible to combine both code into a single source file that will compile properly on Desktop and using Emscripten.
// See https://github.com/ocornut/imgui/pull/2492 as an example on how to do just that.
#include "imgui.h"
#include "imgui_impl_sdl.h"
#include "imgui_impl_opengl3.h"
#include <stdio.h>
#include <emscripten.h>
#include <SDL.h>
#include <SDL_opengles2.h>
// Emscripten requires to have full control over the main loop. We're going to store our SDL book-keeping variables globally.
// Having a single function that acts as a loop prevents us to store state in the stack of said function. So we need some location for this.
SDL_Window* g_Window = NULL;
// For clarity, our main loop code is declared at the end.
static void main_loop(void*);
int main(int, char**)
{
// Setup SDL
if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER | SDL_INIT_GAMECONTROLLER) != 0)
{
printf("Error: %s\n", SDL_GetError());
return -1;
}
// For the browser using Emscripten, we are going to use WebGL1 with GL ES2. See the Makefile. for requirement details.
// It is very likely the generated file won't work in many browsers. Firefox is the only sure bet, but I have successfully
// run this code on Chrome for Android for example.
const char* glsl_version = "#version 100";
//const char* glsl_version = "#version 300 es";
SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
// Create window with graphics context
SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
SDL_DisplayMode current;
SDL_GetCurrentDisplayMode(0, &current);
SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL+Emscripten example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, window_flags);
SDL_GLContext gl_context = SDL_GL_CreateContext(window);
if (!gl_context)
{
fprintf(stderr, "Failed to initialize GL context!\n");
return 1;
}
SDL_GL_MakeCurrent(window, gl_context);
SDL_GL_SetSwapInterval(1); // Enable vsync
// Setup Dear ImGui context
IMGUI_CHECKVERSION();
ImGui::CreateContext();
ImGuiIO& io = ImGui::GetIO(); (void)io;
//io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard; // Enable Keyboard Controls
//io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad; // Enable Gamepad Controls
// For an Emscripten build we are disabling file-system access, so let's not attempt to do a fopen() of the imgui.ini file.
// You may manually call LoadIniSettingsFromMemory() to load settings from your own storage.
io.IniFilename = NULL;
// Setup Dear ImGui style
ImGui::StyleColorsDark();
//ImGui::StyleColorsLight();
// Setup Platform/Renderer backends
ImGui_ImplSDL2_InitForOpenGL(window, gl_context);
ImGui_ImplOpenGL3_Init(glsl_version);
// Load Fonts
// - 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.
// - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
// - 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).
// - 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.
// - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
// - Read 'docs/FONTS.md' for more instructions and details.
// - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
// - Emscripten allows preloading a file or folder to be accessible at runtime. See Makefile for details.
//io.Fonts->AddFontDefault();
#ifndef IMGUI_DISABLE_FILE_FUNCTIONS
//io.Fonts->AddFontFromFileTTF("fonts/segoeui.ttf", 18.0f);
io.Fonts->AddFontFromFileTTF("fonts/DroidSans.ttf", 16.0f);
//io.Fonts->AddFontFromFileTTF("fonts/Roboto-Medium.ttf", 16.0f);
//io.Fonts->AddFontFromFileTTF("fonts/Cousine-Regular.ttf", 15.0f);
//io.Fonts->AddFontFromFileTTF("fonts/ProggyTiny.ttf", 10.0f);
//ImFont* font = io.Fonts->AddFontFromFileTTF("fonts/ArialUni.ttf", 18.0f, NULL, io.Fonts->GetGlyphRangesJapanese());
//IM_ASSERT(font != NULL);
#endif
// This function call won't return, and will engage in an infinite loop, processing events from the browser, and dispatching them.
g_Window = window;
emscripten_set_main_loop_arg(main_loop, NULL, 0, true);
}
static void main_loop(void* arg)
{
ImGuiIO& io = ImGui::GetIO();
IM_UNUSED(arg); // We can pass this argument as the second parameter of emscripten_set_main_loop_arg(), but we don't use that.
// Our state (make them static = more or less global) as a convenience to keep the example terse.
static bool show_demo_window = true;
static bool show_another_window = false;
static ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
// Poll and handle events (inputs, window resize, etc.)
// You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
// - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application, or clear/overwrite your copy of the mouse data.
// - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application, or clear/overwrite your copy of the keyboard data.
// Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
SDL_Event event;
while (SDL_PollEvent(&event))
{
ImGui_ImplSDL2_ProcessEvent(&event);
// Capture events here, based on io.WantCaptureMouse and io.WantCaptureKeyboard
}
// Start the Dear ImGui frame
ImGui_ImplOpenGL3_NewFrame();
ImGui_ImplSDL2_NewFrame();
ImGui::NewFrame();
// 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_demo_window)
ImGui::ShowDemoWindow(&show_demo_window);
// 2. Show a simple window that we create ourselves. We use a Begin/End pair to create a named window.
{
static float f = 0.0f;
static int counter = 0;
ImGui::Begin("Hello, world!"); // Create a window called "Hello, world!" and append into it.
ImGui::Text("This is some useful text."); // Display some text (you can use a format strings too)
ImGui::Checkbox("Demo Window", &show_demo_window); // Edit bools storing our window open/close state
ImGui::Checkbox("Another Window", &show_another_window);
ImGui::SliderFloat("float", &f, 0.0f, 1.0f); // Edit 1 float using a slider from 0.0f to 1.0f
ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color
if (ImGui::Button("Button")) // Buttons return true when clicked (most widgets return true when edited/activated)
counter++;
ImGui::SameLine();
ImGui::Text("counter = %d", counter);
ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / ImGui::GetIO().Framerate, ImGui::GetIO().Framerate);
ImGui::End();
}
// 3. Show another simple window.
if (show_another_window)
{
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)
ImGui::Text("Hello from another window!");
if (ImGui::Button("Close Me"))
show_another_window = false;
ImGui::End();
}
// Rendering
ImGui::Render();
glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
glClearColor(clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w);
glClear(GL_COLOR_BUFFER_BIT);
ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
SDL_GL_SwapWindow(g_Window);
}

View File

@ -6,7 +6,7 @@
# This Makefile assumes you have loaded emscripten's environment.
# (On Windows, you may need to execute emsdk_env.bat or encmdprompt.bat ahead)
#
# Running `make` will produce three files:
# Running `make -f Makefile.emscripten` will produce three files:
# - web/index.html
# - web/index.js
# - web/index.wasm
@ -32,7 +32,6 @@ EMS =
##---------------------------------------------------------------------
# ("EMS" options gets added to both CPPFLAGS and LDFLAGS, whereas some options are for linker only)
EMS += -s DISABLE_EXCEPTION_CATCHING=1
LDFLAGS += -s USE_GLFW=3 -s WASM=1 -s ALLOW_MEMORY_GROWTH=1 -s NO_EXIT_RUNTIME=0 -s ASSERTIONS=1
@ -60,7 +59,7 @@ endif
CPPFLAGS += -I$(IMGUI_DIR) -I$(IMGUI_DIR)/backends
#CPPFLAGS += -g
CPPFLAGS += -Wall -Wformat -Os $(EMS)
LDFLAGS += --shell-file shell_minimal.html
# LDFLAGS += --shell-file ../libs/emscripten/shell_minimal.html
LDFLAGS += $(EMS)
##---------------------------------------------------------------------

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@ -3,6 +3,8 @@
// If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
// Read online: https://github.com/ocornut/imgui/tree/master/docs
// This example can also compile and run with Emscripten. See Makefile.emscripten for details.
#include "imgui.h"
#include "imgui_impl_glfw.h"
#include "imgui_impl_opengl3.h"
@ -25,6 +27,11 @@ static GLFWwindow* g_AppWindow = NULL;
// Forward declarations of helper functions
void MainLoopStep();
#ifdef __EMSCRIPTEN__
#include <emscripten.h>
void MainLoopForEmscripten(void*) { MainLoopStep(); }
#endif
static void glfw_error_callback(int error, const char* description)
{
fprintf(stderr, "GLFW Error %d: %s\n", error, description);
@ -91,6 +98,7 @@ int main(int, char**)
// - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
// - Read 'docs/FONTS.md' for more instructions and details.
// - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
// - Our Emscripten build process allows embedding fonts to be accessible at runtime from the "fonts/" folder. See Makefile.emscripten for details.
//io.Fonts->AddFontDefault();
//io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
//io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
@ -100,8 +108,17 @@ int main(int, char**)
//IM_ASSERT(font != NULL);
// Main loop
#ifndef __EMSCRIPTEN__
// Desktop Build
while (!glfwWindowShouldClose(window))
MainLoopStep();
#else
// Emscripten Build
// For an Emscripten build we are disabling file-system access, so let's not attempt to do a fopen() of the imgui.ini file.
// You may manually call LoadIniSettingsFromMemory() to load settings from your own storage.
io.IniFilename = NULL;
emscripten_set_main_loop_arg(MainLoopForEmscripten, NULL, 0, true);
#endif
// Cleanup
ImGui_ImplOpenGL3_Shutdown();

View File

@ -6,7 +6,7 @@
# This Makefile assumes you have loaded emscripten's environment.
# (On Windows, you may need to execute emsdk_env.bat or encmdprompt.bat ahead)
#
# Running `make` will produce three files:
# Running `make -f Makefile.emscripten` will produce three files:
# - web/index.html
# - web/index.js
# - web/index.wasm
@ -60,7 +60,7 @@ endif
CPPFLAGS += -I$(IMGUI_DIR) -I$(IMGUI_DIR)/backends
#CPPFLAGS += -g
CPPFLAGS += -Wall -Wformat -Os $(EMS)
LDFLAGS += --shell-file shell_minimal.html
LDFLAGS += --shell-file ../libs/emscripten/shell_minimal.html
LDFLAGS += $(EMS)
##---------------------------------------------------------------------

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@ -1,12 +1,13 @@
# How to Build
- On Windows with Visual Studio's IDE
## Windows with Visual Studio's IDE
Use the provided project file (.vcxproj). Add to solution (imgui_examples.sln) if necessary.
- On Windows with Visual Studio's CLI
## Windows with Visual Studio's CLI
Use build_win32.bat or directly:
```
set SDL2_DIR=path_to_your_sdl2_folder
cl /Zi /MD /I.. /I..\.. /I%SDL2_DIR%\include main.cpp ..\..\backends\imgui_impl_sdl.cpp ..\..\backends\imgui_impl_opengl3.cpp ..\..\imgui*.cpp /FeDebug/example_sdl_opengl3.exe /FoDebug/ /link /libpath:%SDL2_DIR%\lib\x86 SDL2.lib SDL2main.lib opengl32.lib /subsystem:console
@ -15,15 +16,42 @@ cl /Zi /MD /I.. /I..\.. /I%SDL2_DIR%\include main.cpp ..\..\backends\imgui_impl_
cl /Zi /MD /I.. /I..\.. /I%SDL2_DIR%\include main.cpp ..\..\backends\imgui_impl_sdl.cpp ..\..\backends\imgui_impl_opengl3.cpp ..\..\imgui*.cpp /FeDebug/example_sdl_opengl3.exe /FoDebug/ /link /libpath:%SDL2_DIR%\lib\x64 SDL2.lib SDL2main.lib opengl32.lib /subsystem:console
```
- On Linux and similar Unixes
## Linux and similar Unixes
Use our Makefile or directly:
```
c++ `sdl2-config --cflags` -I .. -I ../.. -I ../../backends main.cpp ../../backends/imgui_impl_sdl.cpp ../../backends/imgui_impl_opengl3.cpp ../../imgui*.cpp `sdl2-config --libs` -lGL -ldl
c++ `sdl2-config --cflags` -I .. -I ../.. -I ../../backends
main.cpp ../../backends/imgui_impl_sdl.cpp ../../backends/imgui_impl_opengl3.cpp ../../imgui*.cpp
`sdl2-config --libs` -lGL -ldl
```
- On Mac OS X
## macOS
Use our Makefile or directly:
```
brew install sdl2
c++ `sdl2-config --cflags` -I .. -I ../.. -I ../../backends main.cpp ../../backends/imgui_impl_sdl.cpp ../../backends/imgui_impl_opengl3.cpp ../../imgui*.cpp `sdl2-config --libs` -framework OpenGl -framework CoreFoundation
c++ `sdl2-config --cflags` -I .. -I ../.. -I ../../backends
main.cpp ../../backends/imgui_impl_sdl.cpp ../../backends/imgui_impl_opengl3.cpp ../../imgui*.cpp
`sdl2-config --libs` -framework OpenGl -framework CoreFoundation
```
## Emscripten
**Building**
You need to install Emscripten from https://emscripten.org/docs/getting_started/downloads.html, and have the environment variables set, as described in https://emscripten.org/docs/getting_started/downloads.html#installation-instructions
- Depending on your configuration, in Windows you may need to run `emsdk/emsdk_env.bat` in your console to access the Emscripten command-line tools.
- You may also refer to our [Continuous Integration setup](https://github.com/ocornut/imgui/tree/master/.github/workflows) for Emscripten setup.
- Then build using `make -f Makefile.emscripten` while in the current directory.
**Running an Emscripten project**
To run on a local machine:
- `make -f Makefile.emscripten serve` will use Python3 to spawn a local webserver, you can then browse http://localhost:8000 to access your build.
- Otherwise, generally you will need a local webserver. Quoting [https://emscripten.org/docs/getting_started](https://emscripten.org/docs/getting_started/Tutorial.html#generating-html):<br>
_"Unfortunately several browsers (including Chrome, Safari, and Internet Explorer) do not support file:// [XHR](https://emscripten.org/docs/site/glossary.html#term-xhr) requests, and cant load extra files needed by the HTML (like a .wasm file, or packaged file data as mentioned lower down). For these browsers youll need to serve the files using a [local webserver](https://emscripten.org/docs/getting_started/FAQ.html#faq-local-webserver) and then open http://localhost:8000/hello.html."_
- Emscripten SDK has a handy `emrun` command: `emrun web/index.html --browser firefox` which will spawn a temporary local webserver (in Firefox). See https://emscripten.org/docs/compiling/Running-html-files-with-emrun.html for details.
- You may use Python 3 builtin webserver: `python -m http.server -d web` (this is what `make serve` uses).
- You may use Python 2 builtin webserver: `cd web && python -m SimpleHTTPServer`.
- If you are accessing the files over a network, certain browsers, such as Firefox, will restrict Gamepad API access to secure contexts only (e.g. https only).

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@ -3,6 +3,8 @@
// If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
// Read online: https://github.com/ocornut/imgui/tree/master/docs
// This example can also compile and run with Emscripten. See Makefile.emscripten for details.
#include "imgui.h"
#include "imgui_impl_sdl.h"
#include "imgui_impl_opengl3.h"
@ -19,6 +21,10 @@ static SDL_Window* g_AppWindow = NULL;
// Forward declarations of helper functions
bool MainLoopStep();
#ifdef __EMSCRIPTEN__
#include <emscripten.h>
void MainLoopForEmscripten(void*) { MainLoopStep(); }
#endif
// Main code
int main(int, char**)
@ -88,6 +94,7 @@ int main(int, char**)
// - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
// - Read 'docs/FONTS.md' for more instructions and details.
// - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
// - Our Emscripten build process allows embedding fonts to be accessible at runtime from the "fonts/" folder. See Makefile.emscripten for details.
//io.Fonts->AddFontDefault();
//io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
//io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
@ -97,11 +104,20 @@ int main(int, char**)
//IM_ASSERT(font != NULL);
// Main loop
#ifndef __EMSCRIPTEN__
// Desktop Build
while (true)
{
if (!MainLoopStep())
break;
}
#else
// Emscripten Build
// For an Emscripten build we are disabling file-system access, so let's not attempt to do a fopen() of the imgui.ini file.
// You may manually call LoadIniSettingsFromMemory() to load settings from your own storage.
io.IniFilename = NULL;
emscripten_set_main_loop_arg(MainLoopForEmscripten, NULL, 0, true);
#endif
// Cleanup
ImGui_ImplOpenGL3_Shutdown();

View File

@ -3,9 +3,10 @@
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, minimum-scale=1, user-scalable=no"/>
<title>Dear ImGui SDL+Emscripten example</title>
<title>Dear ImGui Emscripten example</title>
<style>
body { margin: 0; background-color: black }
/* FIXME: with our GLFW example this block seems to break resizing and io.DisplaySize gets stuck */
.emscripten {
position: absolute;
top: 0px;

View File

@ -5994,6 +5994,9 @@ void ImGui::ShowAboutWindow(bool* p_open)
#endif
#ifdef __clang_version__
ImGui::Text("define: __clang_version__=%s", __clang_version__);
#endif
#ifdef __EMSCRIPTEN__
ImGui::Text("define: __EMSCRIPTEN__");
#endif
ImGui::Separator();
ImGui::Text("io.BackendPlatformName: %s", io.BackendPlatformName ? io.BackendPlatformName : "NULL");