FlappyBug: Introduce a new Flappy Bug game

This introduces a Flappy Bug game. It's pretty simple currently, but is
playable.

Base/res/apps/FlappyBug.af

@@ -0,0 +1,4 @@
+[App]
+Name=Flappy Bug
+Executable=/bin/FlappyBug
+Category=Games

Userland/Games/CMakeLists.txt

@@ -1,6 +1,7 @@
 add_subdirectory(2048)
 add_subdirectory(Breakout)
 add_subdirectory(Chess)
+add_subdirectory(FlappyBug)
 add_subdirectory(GameOfLife)
 add_subdirectory(Hearts)
 add_subdirectory(Minesweeper)

Userland/Games/FlappyBug/CMakeLists.txt

@@ -0,0 +1,7 @@
+set(SOURCES
+    main.cpp
+    Game.cpp
+)
+
+serenity_app(FlappyBug ICON app-flappybug)
+target_link_libraries(FlappyBug LibGUI)

Userland/Games/FlappyBug/Game.cpp

@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2021, Mim Hufford <mim@hotmail.co.uk>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "Game.h"
+#include <AK/Random.h>
+
+namespace FlappyBug {
+
+Game::Game()
+{
+    set_override_cursor(Gfx::StandardCursor::Hidden);
+    start_timer(16);
+    reset();
+}
+
+void Game::reset()
+{
+    m_active = false;
+    m_difficulty = 1;
+    m_bug.reset();
+    m_obstacle.reset();
+}
+
+void Game::timer_event(Core::TimerEvent&)
+{
+    tick();
+}
+
+void Game::paint_event(GUI::PaintEvent& event)
+{
+    GUI::Painter painter(*this);
+    painter.add_clip_rect(event.rect());
+
+    painter.fill_rect(rect(), Color::Black);
+
+    painter.fill_rect(enclosing_int_rect(m_obstacle.top_rect()), Color::White);
+    painter.fill_rect(enclosing_int_rect(m_obstacle.bottom_rect()), Color::White);
+    painter.fill_ellipse(enclosing_int_rect(m_bug.rect()), Color::Red);
+
+    painter.draw_text({ 10, 10, 100, 100 }, String::formatted("{}", m_difficulty), Gfx::TextAlignment::TopLeft, Color::Green);
+}
+
+void Game::keydown_event(GUI::KeyEvent& event)
+{
+    switch (event.key()) {
+    case Key_Escape:
+        GUI::Application::the()->quit();
+        break;
+    default:
+        m_active = true;
+        m_bug.flap();
+        break;
+    }
+}
+
+void Game::tick()
+{
+    if (m_active) {
+        m_difficulty += 0.0001f;
+
+        m_bug.fall();
+        m_bug.apply_velocity();
+        m_obstacle.x -= 4 + m_difficulty;
+
+        if (m_bug.y > game_height || m_bug.y < 0) {
+            reset();
+        }
+
+        if (m_bug.rect().intersects(m_obstacle.top_rect()) || m_bug.rect().intersects(m_obstacle.bottom_rect())) {
+            reset();
+        }
+
+        if (m_obstacle.x < 0) {
+            m_obstacle.reset();
+        }
+    }
+
+    update();
+}
+
+}

Userland/Games/FlappyBug/Game.h

@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2021, Mim Hufford <mim@hotmail.co.uk>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Optional.h>
+#include <LibGUI/Application.h>
+#include <LibGUI/Painter.h>
+#include <LibGUI/Widget.h>
+#include <LibGfx/Bitmap.h>
+#include <LibGfx/Font.h>
+#include <LibGfx/StandardCursor.h>
+
+namespace FlappyBug {
+
+class Game final : public GUI::Widget {
+    C_OBJECT(Game);
+
+public:
+    static const int game_width = 560;
+    static const int game_height = 480;
+
+private:
+    Game();
+
+    virtual void paint_event(GUI::PaintEvent&) override;
+    virtual void keydown_event(GUI::KeyEvent&) override;
+    virtual void timer_event(Core::TimerEvent&) override;
+
+    void tick();
+    void reset();
+
+    struct Bug {
+        const float x { 50 };
+        const float radius { 10 };
+        const float starting_y { 200 };
+        float y {};
+        float velocity {};
+
+        void reset()
+        {
+            y = starting_y;
+        }
+
+        Gfx::FloatRect rect() const
+        {
+            return { x - radius, y - radius, radius * 2, radius * 2 };
+        }
+
+        void flap()
+        {
+            const float flap_strength = 15.0f;
+            velocity = -flap_strength;
+        }
+
+        void fall()
+        {
+            const float gravity = 1.0f;
+            velocity += gravity;
+        }
+
+        void apply_velocity()
+        {
+            y += velocity;
+        }
+    };
+
+    struct Obstacle {
+        const float width { 20 };
+        float x;
+        float gap_top_y { 200 };
+        float gap_height { 175 };
+
+        void reset()
+        {
+            x = game_width;
+        }
+
+        Gfx::FloatRect top_rect() const
+        {
+            return { x - width, 0, width, gap_top_y };
+        }
+
+        Gfx::FloatRect bottom_rect() const
+        {
+            return { x - width, gap_top_y + gap_height, width, game_height - gap_top_y - gap_height };
+        }
+    };
+
+    Bug m_bug;
+    Obstacle m_obstacle;
+    bool m_active;
+    float m_difficulty;
+};
+
+}

Userland/Games/FlappyBug/main.cpp

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2021, Mim Hufford <mim@hotmail.co.uk>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "Game.h"
+#include <LibGUI/Application.h>
+#include <LibGUI/Icon.h>
+#include <LibGUI/Menu.h>
+#include <LibGUI/Menubar.h>
+#include <LibGUI/Window.h>
+#include <unistd.h>
+
+int main(int argc, char** argv)
+{
+    if (pledge("stdio rpath wpath cpath recvfd sendfd cpath unix", nullptr) < 0) {
+        perror("pledge");
+        return 1;
+    }
+
+    auto app = GUI::Application::construct(argc, argv);
+
+    if (pledge("stdio rpath wpath cpath recvfd sendfd", nullptr) < 0) {
+        perror("pledge");
+        return 1;
+    }
+
+    if (unveil("/res", "r") < 0) {
+        perror("unveil");
+        return 1;
+    }
+
+    if (unveil(nullptr, nullptr) < 0) {
+        perror("unveil");
+        return 1;
+    }
+
+    auto window = GUI::Window::construct();
+    window->resize(FlappyBug::Game::game_width, FlappyBug::Game::game_height);
+    auto app_icon = GUI::Icon::default_icon("app-flappybug");
+    window->set_icon(app_icon.bitmap_for_size(16));
+    window->set_title("Flappy Bug");
+    window->set_double_buffering_enabled(false);
+    window->set_resizable(false);
+    window->set_main_widget<FlappyBug::Game>();
+    window->show();
+
+    auto menubar = GUI::Menubar::construct();
+
+    auto& game_menu = menubar->add_menu("&Game");
+    game_menu.add_action(GUI::CommonActions::make_quit_action([](auto&) {
+        GUI::Application::the()->quit();
+    }));
+
+    auto& help_menu = menubar->add_menu("&Help");
+    help_menu.add_action(GUI::CommonActions::make_about_action("Flappy Bug", app_icon, window));
+
+    window->set_menubar(move(menubar));
+
+    return app->exec();
+}