1 files changed, 172 insertions, 0 deletions
diff --git a/src/snake.cpp b/src/snake.cpp
new file mode 100644
index 0000000..6f18670
--- /dev/null
+++ b/src/snake.cpp
@@ -0,0 +1,172 @@
+#include "snake.h"
+
+#include <QWidget>
+#include <QPaintEvent>
+#include <QPainter>
+#include <QRectF>
+#include <QTimer>
+#include <QDebug>
+
+#define SCALING (16)
+
+#define DIR_UP 0
+#define DIR_DOWN 1
+#define DIR_LEFT 2
+#define DIR_RIGHT 3
+
+#define FIELD(x,y) _field[(x) + ((y) * _width)]
+#define FIELD_FREE 0
+#define FIELD_SNAKE 1
+#define FIELD_FOOD 2
+
+Snake::Snake(QWidget *widget)
+   : _widget(widget),
+     _field(nullptr),
+     _direction(DIR_UP)
+{
+    _width = widget->width() / SCALING;
+    _height = widget->height() / SCALING;
+    _snakeLen = 5;
+    if (_width <= 0 || _height <= 0)
+        return;
+    _field = (int*)calloc(_width * _height, sizeof(*_field));
+    _x = _y = -1;
+    qDebug() << "Field:" << _width << _height;
+    QTimer *t = new QTimer(widget);
+    t->start(100);
+    // Game logic
+    QTimer::connect(t, &QTimer::timeout, [this]() {
+        switch (_direction) {
+        case DIR_UP:
+            _y--; break;
+        case DIR_DOWN:
+            _y++; break;
+        case DIR_LEFT:
+            _x--; break;
+        case DIR_RIGHT:
+            _x++; break;
+        }
+        if (_x < 0 || _x >= _width || _y < 0 || _y >= _height ||
+                FIELD(_x, _y) == FIELD_SNAKE) {
+            // Snek ded
+            qDebug() << "DEATH";
+            memset(_field, 0, sizeof(*_field) * _width * _height);
+            _x = _width / 2;
+            _y = _height / 2;
+            _snake.clear();
+            _widget->update();
+            _snakeLen = 5;
+            addFood();
+            return;
+        }
+        // Normal
+        if (_snake.size() >= _snakeLen) {
+            const QPoint &p = _snake.front();
+            if (FIELD(p.x(), p.y()) == FIELD_SNAKE) {
+                FIELD(p.x(), p.y()) = FIELD_FREE;
+                _widget->update(p.x() * SCALING, p.y() * SCALING, SCALING, SCALING);
+            }
+            _snake.pop_front();
+        }
+        if (FIELD(_x, _y) == FIELD_FOOD) {
+            if (qrand() % _snakeLen > 40) {
+                _snakeLen = 10;
+                while (_snake.size() > _snakeLen) {
+                    _snake.pop_front();
+                }
+                addFood();
+            } else {
+                _snakeLen += 5;
+            }
+            addFood();
+        }
+        FIELD(_x, _y) = FIELD_SNAKE;
+        _snake.append(QPoint(_x, _y));
+        _widget->update(_x * SCALING, _y * SCALING, SCALING, SCALING);
+        // AI
+        int what[4], dist[4];
+        int best = 0;
+        scanDir(0, -1, what[DIR_UP], dist[DIR_UP]);
+        scanDir(0, 1, what[DIR_DOWN], dist[DIR_DOWN]);
+        scanDir(-1, 0, what[DIR_LEFT], dist[DIR_LEFT]);
+        scanDir(1, 0, what[DIR_RIGHT], dist[DIR_RIGHT]);
+        for (int i = 1; i < 4; ++i) {
+            if (what[i] == FIELD_FOOD) {
+                if (what[best] != FIELD_FOOD || dist[best] > dist[i]) {
+                    best = i;
+                }
+            } else if (what[best] != FIELD_FOOD && dist[i] > dist[best]) {
+                best = i;
+            }
+        }
+        if (what[best] == FIELD_FOOD) {
+            _direction = best;
+        } else if (dist[_direction] <= 1) {
+            _direction = best;
+        }
+    });
+}
+
+Snake::~Snake()
+{
+    free(_field);
+}
+
+void Snake::scanDir(int dx, int dy, int &what, int &dist)
+{
+    int x = _x;
+    int y = _y;
+    dist = 0;
+    for (;;) {
+        x += dx;
+        y += dy;
+        dist++;
+        if (x < 0 || x >= _width || y < 0 || y >= _height) {
+            what = FIELD_SNAKE;
+            return;
+        }
+        if (FIELD(x, y) != FIELD_FREE) {
+            what = FIELD(x, y);
+            return;
+        }
+    }
+}
+
+void Snake::addFood()
+{
+    for (int i = 0; i < 10; ++i) {
+        int x = qrand() % _width;
+        int y = qrand() % _height;
+        if (FIELD(x, y) != FIELD_FOOD) {
+            FIELD(x, y) = FIELD_FOOD;
+            _widget->update(x * SCALING, y * SCALING, SCALING, SCALING);
+            break;
+        }
+    }
+}
+
+void Snake::paint(QPaintEvent *event)
+{
+    QPainter p(_widget);
+    const int width = qMin(_width, (event->rect().x() + event->rect().width() + SCALING - 1) / SCALING);
+    const int height = qMin(_height, (event->rect().y() + event->rect().height() + SCALING - 1) / SCALING);
+    for (int y = event->rect().y() / SCALING; y < height; ++y) {
+        if (y < 0)
+            continue;
+        for (int x = event->rect().x() / SCALING; x < width; ++x) {
+            if (x < 0)
+                continue;
+            switch (FIELD(x, y)) {
+            case FIELD_FOOD:
+                p.setBrush(Qt::green);
+                break;
+            case FIELD_SNAKE:
+                p.setBrush(Qt::white);
+                break;
+            default:
+                continue;
+            }
+            p.drawRect(x * SCALING, y * SCALING, SCALING-1, SCALING-1);
+        }
+    }
+}