SnakeGame.cs

using PixelEngine;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using GameEngine.Snack.Extentions;

namespace GameEngine.Snack
{
    public class SnakeGame : Game
    {
        private List<SnakeSegment> snake; // Store all segments of snake

        // Coordinates of the food
        private int foodX;
        private int foodY;

        private int score; // Player's score

        private int dir; // Direction of snake

        private bool dead; // Is the snake dead?
        private bool started; // Has the game been started?

        private ISnake snakeCharacter;

        static void Main(string[] args)
        {
           
            // Create an instance
            SnakeGame s = new SnakeGame();
            // Construct the game
            s.Construct(50, 50, 10, 10, 30);
            
            // Start the game
            s.Start();
        }

        // A part of the snake
        private struct SnakeSegment
        {
            public SnakeSegment(int x, int y) : this()
            {
                this.X = x;
                this.Y = y;
            }

            public int X { get; private set; } // X location
            public int Y { get; private set; } // Y location
        }

        // Set the title of the window
        public SnakeGame()
        {
            AppName = "SNAKE!";
            snakeCharacter = new ExampleSnake();
        }

        // Start the game
        public override void OnCreate()
        {
            // Uncomment to make the game fullscreen
            //Enable(Subsystem.Fullscreen);

            Enable(Subsystem.HrText);

            Reset();
        }

        // Reset all fields
        private void Reset()
        {
            // Init and make the snake
            snake = new List<SnakeSegment>();
            for (int i = 0; i < 9; i++)
                snake.Add(new SnakeSegment(i + 20, 15));

            // Set the variables to default values
            foodX = 30;
            foodY = 15;
            //score = 0;
            dir = 3;
            dead = false;

            Seed();
        }

        public override void OnUpdate(float elapsed)
        {
            snakeCharacter.UpdateMap(GetMap());

            CheckStart();
            UpdateSnake();
            DrawGame();

            //GetMap();
            

            Thread.Sleep(100);
        }

        // Draw the game
        private void DrawGame()
        {
            // Clear the screen
            Clear(Pixel.Presets.Black);

            if (started) // Inform the player of their score
                DrawTextHr(new Point(15, 15), snakeCharacter.Name + " score: " + score, Pixel.Presets.Green, 2);
            else // Inform the player to start by pressing enter
                DrawTextHr(new Point(15, 15), "Press Enter To Start", Pixel.Presets.Green, 2);

            // Draw the border
            DrawRect(new Point(0, 0), ScreenWidth - 1, ScreenHeight - 1, Pixel.Presets.Grey);

            // Render snake
            for (int i = 1; i < snake.Count; i++)
                Draw(snake[i].X, snake[i].Y, dead ? Pixel.Presets.Blue : Pixel.Presets.Yellow);

            // Draw snake head
            Draw(snake[0].X, snake[0].Y, dead ? Pixel.Presets.Green : Pixel.Presets.Magenta);

            // Draw food
            Draw(foodX, foodY, Pixel.Presets.Green);
        }

        // Update the snake's position
        private void UpdateSnake()
        {            

            // End game if snake is dead
            if (dead)
                started = false;

            var direction = (SnakeDirection)dir;
            var action = snakeCharacter.GetNextDirection(direction);

            if ( (action == SnakeDirection.Down && direction == SnakeDirection.Up) 
                || (action == SnakeDirection.Up && direction == SnakeDirection.Down)
                || (action == SnakeDirection.Left && direction == SnakeDirection.Right)
                || (action == SnakeDirection.Right && direction == SnakeDirection.Left))
            {
                //can't go to opposite direction
            }
            else
            {
                dir = (int) action;
            }

            int x = snake[0].X, y = snake[0].Y;
            bool u = true, d = true, r = true, l = true;
            for (int i = 1; i < snake.Count; i++)
            {
                if ((snake[i].X == x + 1 && snake[i].Y == y) || x + 1 == ScreenWidth)
                    r = false;
                if ((snake[i].X == x - 1 && snake[i].Y == y) || x - 1 == 0)
                    l = false;
                if ((snake[i].Y == y + 1 && snake[i].X == x) || y + 1 == ScreenHeight - 1)
                    d = false;
                if ((snake[i].Y == y - 1 && snake[i].X == x) || y - 1 == 0)
                    u = false;
            }

            //// Turn right
            /*           if (GetKey(Key.Right).Pressed)
                       {
                           dir++;
                           if (dir == 4)
                               dir = 0;
                       }

                        //// Turn left
                        if (GetKey(Key.Left).Pressed)
                        {
                            dir--;
                            if (dir == -1)
                                dir = 3;
                        }

            */

            if (snake[0].X > foodX && l)
                dir = 3;
            else if (snake[0].X < foodX && r)
                dir = 1;
            else if (snake[0].Y > foodY && u)
                dir = 0;
            else if (snake[0].Y < foodY && d)
                dir = 2;
            else if(l){
                dir = 3;
            }
            else if(r){
                dir = 1;
            }
            else if(u)
            {
                dir = 0;
            }
            else if(d)
            {
                dir = 2;
            }

            switch (dir)
            {
                case 0: // UP
                    y--;
                    break;
                case 1: // RIGHT
                    x++;
                    break;
                case 2: // DOWN
                    y++;
                    break;
                case 3: // LEFT
                    x--;
                    break;
            }

            if (started)
            {
                // Move in the direction
                snake.Insert(0, new SnakeSegment(x, y));

                // Pop the tail
                snake.RemoveAt(snake.Count - 1);

                CheckCollision();
            }
        }

        // Check for snake's collision
        private void CheckCollision()
        {
            // Check collision with food
            if (snake[0].X == foodX && snake[0].Y == foodY)
            {
                score+= Math.Max(1, snake.Count / 3);
                RandomizeFood();

                snake.Add(new SnakeSegment(snake[snake.Count - 1].X, snake[snake.Count - 1].Y));
            }

            // Check wall collision
            if (snake[0].X <= 0 || snake[0].X >= ScreenWidth || snake[0].Y <= 0 || snake[0].Y >= ScreenHeight - 1)
                dead = true;

            // Check self collision
            for (int i = 1; i < snake.Count; i++)
                if (snake[i].X == snake[0].X && snake[i].Y == snake[0].Y)
                    dead = true;
        }

        // Check if the game is started
        private void CheckStart()
        {
            if (!started)
            {
                // Check if game has to be started
                //if (GetKey(Key.Enter).Pressed)
                {
                    Reset();
                    started = true;
                }
            }
        }

        // Set random location for food
        private void RandomizeFood()
        {
            // Loop while the food is not on empty cell
            while (GetScreenPixel(foodX, foodY) != Pixel.Presets.Black)
            {
                // Set food to random point
                foodX = Random(ScreenWidth);
                foodY = Random(ScreenHeight);
            }
        }


        /// <summary>
        /// Get map 
        /// </summary>
        /// <returns></returns>
        private string GetMap()
        {
            
            var screen = this.GetScreen();

            var mapBuilder = new StringBuilder();

            for (int i = 0; i < screen.GetLength(0); i++)
            {
                Console.WriteLine("");

                for (int j = 0; j < screen.GetLength(1); j++)
                {
                    var pixel = screen[j, i];
                    if (pixel.isWall())
                        mapBuilder.Append("x");

                    else if (pixel.isEmpty())
                        mapBuilder.Append(" ");

                    else if (pixel.isHead())
                        mapBuilder.Append("*");

                    else if (pixel.isBody())
                        mapBuilder.Append("1");

                    else if (pixel.isFood())
                        mapBuilder.Append("7");

                    else if (pixel.isTrap())
                        mapBuilder.Append("6");


                    //Console.Write(mapBuilder[mapBuilder.Length - 1]);

                }
            }


            return mapBuilder.ToString();
        }        
    }

    
}