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//
// lager - library for functional interactive c++ programs
// Copyright (C) 2017 Juan Pedro Bolivar Puente
//
// This file is part of lager.
//
// lager is free software: you can redistribute it and/or modify
// it under the terms of the MIT License, as detailed in the LICENSE
// file located at the root of this source code distribution,
// or here: <https://github.com/arximboldi/lager/blob/master/LICENSE>
//
#include "../model.hpp"
#include <lager/event_loop/sdl.hpp>
#include <lager/store.hpp>
#include <imgui.h>
#include <imgui_impl_opengl3.h>
#include <imgui_impl_sdl.h>
#include <SDL.h>
#include <SDL_opengl.h>
#include <iostream>
constexpr int window_padding = 48;
constexpr int window_width = 800;
constexpr int window_height = 600;
// Sadly, ImGui sometimes forces us to store transient state, like text inputs.
// We use this store this.
struct ui_state
{
static constexpr std::size_t input_string_size = 1 << 10;
std::array<char, input_string_size> new_todo_input{'\0'};
};
void draw(lager::context<todo::item_action> ctx, const todo::item& i)
{
auto checked = i.done;
if (ImGui::Checkbox("", &checked)) {
ctx.dispatch(todo::toggle_item_action{});
}
ImGui::SameLine();
ImGui::Text("%s", i.text.c_str());
ImGui::SameLine();
if (ImGui::Button("Delete")) {
ctx.dispatch(todo::remove_item_action{});
}
}
void draw(lager::context<todo::model_action> ctx,
const todo::model& m,
ui_state& s)
{
ImGui::SetNextWindowPos({window_padding, window_padding}, ImGuiCond_Once);
ImGui::SetNextWindowSize(
{window_width - 2 * window_padding, window_height - 2 * window_padding},
ImGuiCond_Once);
ImGui::Begin("Todo app");
if (ImGui::BeginPopup("not-implemented")) {
ImGui::Text("Saving and loading have not been implemented!");
ImGui::EndPopup();
}
if (ImGui::Button("Save"))
ImGui::OpenPopup("not-implemented");
ImGui::SameLine();
if (ImGui::Button("Load"))
ImGui::OpenPopup("not-implemented");
ImGui::Separator();
if (ImGui::IsWindowAppearing())
ImGui::SetKeyboardFocusHere();
ImGui::PushItemWidth(-0.1f);
if (ImGui::InputTextWithHint("",
"What do you want to do today?",
s.new_todo_input.data(),
s.input_string_size,
ImGuiInputTextFlags_EnterReturnsTrue)) {
ctx.dispatch(todo::add_todo_action{s.new_todo_input.data()});
s.new_todo_input[0] = '\0';
ImGui::SetKeyboardFocusHere(-1);
}
ImGui::PopItemWidth();
ImGui::Separator();
ImGui::BeginChild("");
{
auto idx = std::size_t{};
for (auto item : m.todos) {
ImGui::PushID(idx);
auto with_idx = [idx](auto&& a) { return std::make_pair(idx, a); };
draw({ctx, with_idx}, item);
ImGui::PopID();
++idx;
}
}
ImGui::EndChild();
ImGui::End();
}
int main()
{
if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER) != 0) {
std::cerr << "Error initializing SDL: " << SDL_GetError() << std::endl;
return -1;
}
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);
SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
auto current = SDL_DisplayMode{};
SDL_GetCurrentDisplayMode(0, ¤t);
auto window =
SDL_CreateWindow("Todo Imgui",
SDL_WINDOWPOS_CENTERED,
SDL_WINDOWPOS_CENTERED,
window_width,
window_height,
SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE |
SDL_WINDOW_ALLOW_HIGHDPI | SDL_WINDOW_SHOWN);
if (!window) {
std::cerr << "Error creating SDL window: " << SDL_GetError()
<< std::endl;
return -1;
}
auto gl_context = SDL_GL_CreateContext(window);
if (!gl_context) {
std::cerr << "Error creating GL context: " << SDL_GetError()
<< std::endl;
return -1;
}
IMGUI_CHECKVERSION();
ImGui::CreateContext();
auto& io = ImGui::GetIO();
io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;
ImGui::StyleColorsDark();
ImGui_ImplSDL2_InitForOpenGL(window, gl_context);
ImGui_ImplOpenGL3_Init(glsl_version);
auto loop = lager::sdl_event_loop{};
auto store = lager::make_store<todo::model_action>(
todo::model{}, lager::with_sdl_event_loop{loop});
auto state = ui_state{};
loop.run(
[&](const SDL_Event& ev) {
ImGui_ImplSDL2_ProcessEvent(&ev);
return ev.type != SDL_QUIT;
},
[&](auto dt) {
ImGui_ImplOpenGL3_NewFrame();
ImGui_ImplSDL2_NewFrame(window);
ImGui::NewFrame();
{
draw(store, store.get(), state);
}
ImGui::Render();
SDL_GL_MakeCurrent(window, gl_context);
auto size = ImGui::GetIO().DisplaySize;
glViewport(0, 0, (int) size.x, (int) size.y);
glClearColor(0, 0, 0, 1);
glClear(GL_COLOR_BUFFER_BIT);
ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
SDL_GL_SwapWindow(window);
});
ImGui_ImplOpenGL3_Shutdown();
ImGui_ImplSDL2_Shutdown();
ImGui::DestroyContext();
SDL_GL_DeleteContext(gl_context);
SDL_DestroyWindow(window);
SDL_Quit();
return 0;
}
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