From a936d0669cb3378559f973899f6c59a2f4bec4c0 Mon Sep 17 00:00:00 2001 From: "Nicolas \"Pixel\" Noble" Date: Sat, 13 Apr 2019 17:25:06 +0200 Subject: [PATCH] Adding standalone Emscripten example. --- examples/example_emscripten/Makefile | 58 ++++++ examples/example_emscripten/README.md | 8 + examples/example_emscripten/main.cpp | 165 ++++++++++++++++++ .../example_emscripten/shell_minimal.html | 153 ++++++++++++++++ 4 files changed, 384 insertions(+) create mode 100644 examples/example_emscripten/Makefile create mode 100644 examples/example_emscripten/README.md create mode 100644 examples/example_emscripten/main.cpp create mode 100644 examples/example_emscripten/shell_minimal.html diff --git a/examples/example_emscripten/Makefile b/examples/example_emscripten/Makefile new file mode 100644 index 000000000..b97933d64 --- /dev/null +++ b/examples/example_emscripten/Makefile @@ -0,0 +1,58 @@ +# +# Makefile to use with emscripten +# See https://emscripten.org/docs/getting_started/downloads.html +# for installation instructions. This Makefile assumes you have +# loaded emscripten's environment. +# +# Running `make` will produce three files: +# - example_emscripten.html +# - example_emscripten.js +# - example_emscripten.wasm +# +# All three are needed to run the demo. + +CC = emcc +CXX = em++ + +EXE = example_emscripten.html +SOURCES = main.cpp +SOURCES += ../imgui_impl_sdl.cpp ../imgui_impl_opengl3.cpp +SOURCES += ../../imgui.cpp ../../imgui_demo.cpp ../../imgui_draw.cpp ../../imgui_widgets.cpp +OBJS = $(addsuffix .o, $(basename $(notdir $(SOURCES)))) +UNAME_S := $(shell uname -s) + +EMS = -s USE_SDL=2 -s USE_WEBGL2=1 -s WASM=1 -s FULL_ES3=1 +EMS += -s ALLOW_MEMORY_GROWTH=1 -s BINARYEN_TRAP_MODE=clamp +EMS += -s DISABLE_EXCEPTION_CATCHING=1 -s EXIT_RUNTIME=1 +EMS += -s ASSERTIONS=1 -s SAFE_HEAP=1 + +CPPFLAGS = -I../ -I../../ +CPPFLAGS += -g -Wall -Wformat -O3 +CPPFLAGS += $(EMS) +LIBS = $(EMS) +LDFLAGS = --shell-file shell_minimal.html + +##--------------------------------------------------------------------- +## BUILD RULES +##--------------------------------------------------------------------- + +%.o:%.cpp + $(CXX) $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $< + +%.o:../%.cpp + $(CXX) $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $< + +%.o:../../%.cpp + $(CXX) $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $< + +%.o:../libs/gl3w/GL/%.c + $(CC) $(CPPFLAGS) $(CFLAGS) -c -o $@ $< + +all: $(EXE) + @echo Build complete for $(EXE) + +$(EXE): $(OBJS) + $(CXX) -o $@ $^ $(LIBS) $(LDFLAGS) + +clean: + rm -f $(EXE) $(OBJS) *.js *.wasm diff --git a/examples/example_emscripten/README.md b/examples/example_emscripten/README.md new file mode 100644 index 000000000..c607ed73c --- /dev/null +++ b/examples/example_emscripten/README.md @@ -0,0 +1,8 @@ + +# 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 + +``` +em++ -I.. -I../.. main.cpp ../imgui_impl_sdl.cpp ../imgui_impl_opengl3.cpp ../../imgui*.cpp -s USE_SDL=2 -s USE_WEBGL2=1 -s WASM=1 -s FULL_ES3=1 -s ALLOW_MEMORY_GROWTH=1 -s BINARYEN_TRAP_MODE=clamp --shell-file shell_minimal.html -o example-emscripten.html +``` diff --git a/examples/example_emscripten/main.cpp b/examples/example_emscripten/main.cpp new file mode 100644 index 000000000..dd31e7b7e --- /dev/null +++ b/examples/example_emscripten/main.cpp @@ -0,0 +1,165 @@ +// dear imgui: standalone example application for Emscripten, using SDL2 + OpenGL3 +// 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. +// +// If you are new to dear imgui, see examples/README.txt and documentation at the top of imgui.cpp. +// (Emscripten is a C++-to-javascript compiler, used to publish executables for the web. See https://emscripten.org/) + +#include "imgui.h" +#include "imgui_impl_sdl.h" +#include "imgui_impl_opengl3.h" +#include +#include +#include +#include + +// Emscripten requires to have full control over the main loop. We're going to store variables from main() to main_loop() here. +// This will also hold some of our persistent data across loops. Remember: imgui is immediate mode, and doesn't store state. +// 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. +struct MainLoopVars { + SDL_Window* window = NULL; + SDL_GLContext gl_context = NULL; + bool show_demo_window = true; + bool show_another_window = false; + ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f); +}; + +// For clarity, our main loop code is declared at the end. +void main_loop(void*); + +int main(int, char**) +{ + MainLoopVars vars; + + // Setup SDL + if (SDL_Init(SDL_INIT_VIDEO|SDL_INIT_TIMER) != 0) + { + printf("Error: %s\n", SDL_GetError()); + return -1; + } + + // For the browser using emscripten, we are going to use WebGL2 with GLES3. See the Makefile.emscripten 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 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, 3); + 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, ¤t); + SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI); + vars.window = SDL_CreateWindow("Dear ImGui SDL2+OpenGL3 example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, window_flags); + vars.gl_context = SDL_GL_CreateContext(vars.window); + if (!vars.gl_context) { + fprintf(stderr, "Failed to initialize WebGL context!\n"); + return 1; + } + 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 + + // Setup Dear ImGui style + ImGui::StyleColorsDark(); + //ImGui::StyleColorsClassic(); + + // Setup Platform/Renderer bindings + ImGui_ImplSDL2_InitForOpenGL(vars.window, vars.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. + // - Read 'misc/fonts/README.txt' 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 \\ ! + //io.Fonts->AddFontDefault(); + //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f); + //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f); + //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f); + //io.Fonts->AddFontFromFileTTF("../../misc/fonts/ProggyTiny.ttf", 10.0f); + //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, NULL, io.Fonts->GetGlyphRangesJapanese()); + //IM_ASSERT(font != NULL); + + // 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, &vars, 0, true); +} + +void main_loop(void* arg) { + MainLoopVars* vars = (MainLoopVars*) arg; + ImGuiIO& io = ImGui::GetIO(); + + // 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. + // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application. + // 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(vars->window); + 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 (vars->show_demo_window) + ImGui::ShowDemoWindow(&vars->show_demo_window); + + // 2. Show a simple window that we create ourselves. We use a Begin/End pair to created 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", &vars->show_demo_window); // Edit bools storing our window open/close state + ImGui::Checkbox("Another Window", &vars->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*)&vars->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 (vars->show_another_window) + { + ImGui::Begin("Another Window", &vars->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")) + vars->show_another_window = false; + ImGui::End(); + } + + // Rendering + ImGui::Render(); + SDL_GL_MakeCurrent(vars->window, vars->gl_context); + glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y); + glClearColor(vars->clear_color.x, vars->clear_color.y, vars->clear_color.z, vars->clear_color.w); + glClear(GL_COLOR_BUFFER_BIT); + ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData()); + SDL_GL_SwapWindow(vars->window); +} diff --git a/examples/example_emscripten/shell_minimal.html b/examples/example_emscripten/shell_minimal.html new file mode 100644 index 000000000..3c5ef8caf --- /dev/null +++ b/examples/example_emscripten/shell_minimal.html @@ -0,0 +1,153 @@ + + + + + + Emscripten-Generated Code + + + +
+
emscripten
+
Downloading...
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+ +
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+ +
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+ Resize canvas + Lock/hide mouse pointer +     + +
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+ +
+ + {{{ SCRIPT }}} + +