Snake: Flesh out a basic snake game :^)

3 files changed, 190 insertions, 7 deletions

diff --git a/Games/Snake/SnakeGame.cpp b/Games/Snake/SnakeGame.cpp
index e69de29bb2..a0ed4175ad 100644
--- a/Games/Snake/SnakeGame.cpp
+++ b/Games/Snake/SnakeGame.cpp
@@ -0,0 +1,151 @@
+#include "SnakeGame.h"
+#include <LibGUI/GPainter.h>
+#include <stdlib.h>
+#include <time.h>
+
+SnakeGame::SnakeGame(GWidget* parent)
+    : GWidget(parent)
+{
+    srand(time(nullptr));
+    reset();
+}
+
+SnakeGame::~SnakeGame()
+{
+}
+
+void SnakeGame::reset()
+{
+    m_head = { m_rows / 2, m_columns / 2 };
+    m_tail.clear_with_capacity();
+    m_length = 2;
+    stop_timer();
+    start_timer(120);
+    spawn_fruit();
+}
+
+bool SnakeGame::is_available(const Coordinate& coord)
+{
+    for (int i = 0; i < m_tail.size(); ++i) {
+        if (m_tail[i] == coord)
+            return false;
+    }
+    if (m_head == coord)
+        return false;
+    if (m_fruit == coord)
+        return false;
+    return true;
+}
+
+void SnakeGame::spawn_fruit()
+{
+    Coordinate coord;
+    for (;;) {
+        coord.row = rand() % m_rows;
+        coord.column = rand() % m_columns;
+        if (is_available(coord))
+            break;
+    }
+    m_fruit = coord;
+}
+
+void SnakeGame::timer_event(CTimerEvent&)
+{
+    m_tail.prepend(m_head);
+
+    if (m_tail.size() > m_length)
+        m_tail.take_last();
+
+    m_head.row += m_vertical_velocity;
+    m_head.column += m_horizontal_velocity;
+
+    m_last_vertical_velocity = m_vertical_velocity;
+    m_last_horizontal_velocity = m_horizontal_velocity;
+
+    if (m_head.row >= m_rows)
+        m_head.row = 0;
+    if (m_head.row < 0)
+        m_head.row = m_rows - 1;
+    if (m_head.column >= m_columns)
+        m_head.column = 0;
+    if (m_head.column < 0)
+        m_head.column = m_columns - 1;
+
+    for (int i = 0; i < m_tail.size(); ++i) {
+        if (m_head == m_tail[i]) {
+            game_over();
+            return;
+        }
+    }
+
+    if (m_head == m_fruit) {
+        ++m_length;
+        spawn_fruit();
+    }
+    update();
+}
+
+void SnakeGame::keydown_event(GKeyEvent& event)
+{
+    switch (event.key()) {
+    case KeyCode::Key_A:
+    case KeyCode::Key_Left:
+        if (m_last_horizontal_velocity == 1)
+            break;
+        m_vertical_velocity = 0;
+        m_horizontal_velocity = -1;
+        break;
+    case KeyCode::Key_D:
+    case KeyCode::Key_Right:
+        if (m_last_horizontal_velocity == -1)
+            break;
+        m_vertical_velocity = 0;
+        m_horizontal_velocity = 1;
+        break;
+    case KeyCode::Key_W:
+    case KeyCode::Key_Up:
+        if (m_last_vertical_velocity == 1)
+            break;
+        m_vertical_velocity = -1;
+        m_horizontal_velocity = 0;
+        break;
+    case KeyCode::Key_S:
+    case KeyCode::Key_Down:
+        if (m_last_vertical_velocity == -1)
+            break;
+        m_vertical_velocity = 1;
+        m_horizontal_velocity = 0;
+        break;
+    default:
+        break;
+    }
+}
+
+void SnakeGame::paint_event(GPaintEvent& event)
+{
+    GPainter painter(*this);
+    painter.fill_rect(event.rect(), Color::Black);
+
+    auto game_rect = rect();
+    auto cell_size = Size(game_rect.width() / m_columns, game_rect.height() / m_rows);
+
+    auto cell_rect = [&] (const Coordinate& coord) -> Rect {
+        return {
+            coord.column * cell_size.width(),
+            coord.row * cell_size.height(),
+            cell_size.width(),
+            cell_size.height()
+        };
+    };
+
+    painter.fill_rect(cell_rect(m_head), Color::Yellow);
+    for (auto& coord : m_tail)
+        painter.fill_rect(cell_rect(coord), Color::from_rgb(0xaaaa00));
+
+    painter.fill_rect(cell_rect(m_fruit), Color::Red);
+}
+
+void SnakeGame::game_over()
+{
+    reset();
+}
diff --git a/Games/Snake/SnakeGame.h b/Games/Snake/SnakeGame.h
index 01e13aabbf..2e8d04c00d 100644
--- a/Games/Snake/SnakeGame.h
+++ b/Games/Snake/SnakeGame.h
@@ -4,8 +4,43 @@
 
 class SnakeGame : public GWidget {
 public:
-    explicit SnakeGame(GWidget* parent);
+    explicit SnakeGame(GWidget* parent = nullptr);
+    virtual ~SnakeGame() override;
+
+    void reset();
 
 private:
     virtual void paint_event(GPaintEvent&) override;
+    virtual void keydown_event(GKeyEvent&) override;
+    virtual void timer_event(CTimerEvent&) override;
+
+    struct Coordinate {
+        int row { 0 };
+        int column { 0 };
+
+        bool operator==(const Coordinate& other) const
+        {
+            return row == other.row && column == other.column;
+        }
+    };
+
+    void game_over();
+    void spawn_fruit();
+    bool is_available(const Coordinate&);
+
+    int m_rows { 20 };
+    int m_columns { 20 };
+
+    int m_horizontal_velocity { 1 };
+    int m_vertical_velocity { 0 };
+
+    int m_last_horizontal_velocity { 1 };
+    int m_last_vertical_velocity { 0 };
+
+    Coordinate m_head;
+    Vector<Coordinate> m_tail;
+
+    Coordinate m_fruit;
+
+    int m_length { 0 };
 };
diff --git a/Games/Snake/main.cpp b/Games/Snake/main.cpp
index 6443761bfa..7cf72b64ff 100644
--- a/Games/Snake/main.cpp
+++ b/Games/Snake/main.cpp
@@ -13,13 +13,10 @@ int main(int argc, char** argv)
 
     auto* window = new GWindow;
     window->set_title("Snake");
-    window->set_rect(100, 100, 139, 175);
+    window->set_rect(100, 100, 300, 300);
 
-    auto* widget = new GWidget;
-    window->set_main_widget(widget);
-    widget->set_layout(make<GBoxLayout>(Orientation::Vertical));
-
-    auto* game = new SnakeGame(widget);
+    auto* game = new SnakeGame;
+    window->set_main_widget(game);
 
     auto menubar = make<GMenuBar>();