Problem
I just started using c# and I made this snake game in a console application . It is a bit jittery when i run it in visual studio. How could I improve it to be cleaner and less jittery.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
namespace _2017project1
{
class Program
{
const int SCREEN_MULT = 5;
public const int SCREEN_W = 12 * SCREEN_MULT;
public const int SCREEN_H = 5 * SCREEN_MULT;
static void Main(string[] args)
{
var s = new Snake();
var f = new Fruit();
bool escape = false;
InitGame(s, f);
escape = Welcome(escape);
while (!escape)
{
ResetGame(s, f);
escape = PlayGame(s, f, escape);
if (!escape)
{
escape = DoGameOver(s, escape);
}
}
}
static bool Welcome(bool escape)
{
ConsoleKeyInfo keyInfo;
string[] Instructions = { "Welcome to the snake game", "Your goal is to collect the red fruit", "Use the arrow keys to move around", "Press esc to exit", "Press any key to begin" };
for (int i = 0; i < Instructions.Count(); i++)
{
Console.SetCursorPosition((SCREEN_W / 2) - ((Instructions[i].Length / 2)), (SCREEN_H / 2) + i - (Instructions.Count() / 2));
Console.WriteLine(Instructions[i]);
}
if ((keyInfo = Console.ReadKey(true)).Key == ConsoleKey.Escape)
{
return true;
}
return false;
}
static void InitGame(Snake s, Fruit f)
{
Console.CursorVisible = false;
Console.ForegroundColor = ConsoleColor.Green;
Console.WindowHeight = SCREEN_H;
Console.WindowWidth = SCREEN_W;
}
static bool PlayGame(Snake s, Fruit f, bool escape)
{
ConsoleKeyInfo keyInfo;
Snake.ShowScore(s);
while (true)
{
s.doGrow = false;
Thread.Sleep(Convert.ToInt16(100 / s.speed));
Console.Clear();
if (Console.KeyAvailable == true)
{
keyInfo = Console.ReadKey(true);
switch (keyInfo.Key)
{
case ConsoleKey.UpArrow:
Snake.SetDir(0, -1, s);
break;
case ConsoleKey.DownArrow:
Snake.SetDir(0, 1, s);
break;
case ConsoleKey.RightArrow:
Snake.SetDir(1, 0, s);
break;
case ConsoleKey.LeftArrow:
Snake.SetDir(-1, 0, s);
break;
case ConsoleKey.Escape:
escape = true;
return escape;
}
}
Snake.Eat(s, f);
Snake.Update(s);
if (s.dead)
{
break;
}
Snake.ShowScore(s);
Fruit.Show(f);
Snake.Show(s);
}
return false;
}
static bool DoGameOver(Snake s, bool escape)
{
string[] Instructions = { "Game Over", "Score: " + s.score };
ConsoleKeyInfo keyInfo;
for (int i = 0; i < Instructions.Count(); i++)
{
Console.SetCursorPosition((SCREEN_W / 2) - ((Instructions[i].Length / 2)), (SCREEN_H / 2) + i - (Instructions.Count() / 2));
Console.WriteLine(Instructions[i]);
}
if (s.score > s.highScore)
{
s.highScore = s.score;
Console.SetCursorPosition((SCREEN_W / 2) - 7, (SCREEN_H / 2) + 2);
Console.WriteLine("NEW HIGH SCORE!!!");
}
Console.SetCursorPosition((SCREEN_W / 2) - 6, (SCREEN_H / 2) + 3);
Console.WriteLine("Highscore: " + s.highScore);
Thread.Sleep(3000);
if (!escape)
{
Console.Clear();
Console.SetCursorPosition((SCREEN_W / 2) - 8, (SCREEN_H / 2) - 1);
Console.WriteLine("Press esc to exit");
Console.SetCursorPosition((SCREEN_W / 2) - 12, (SCREEN_H / 2) + 1);
Console.WriteLine("Or press any key play again");
if ((keyInfo = Console.ReadKey(true)).Key == ConsoleKey.Escape)
{
return true;
}
else
{
return false;
}
}
return true;
}
static void ResetGame(Snake s, Fruit f)
{
Fruit.NewPosition(f, s);
Snake.InitSnake(s);
}
}
class Snake
{
const double SPEED_INCREMENT = 0.3;
const int START_LENGTH = 10;
const char SNAKE_CHAR = '@';
const ConsoleColor SNAKE_COLOUR = ConsoleColor.Green;
public int x;
public int y;
public int xDir;
public int yDir;
public int score;
public int highScore = 0;
public double speed;
public bool doGrow;
public bool dead;
public List<int> xPositions = new List<int>();
public List<int> yPositions = new List<int>();
public static void InitSnake(Snake s)
{
s.x = 9;
s.y = 3;
s.xDir = 1;
s.yDir = 0;
s.score = 0;
s.speed = 1.2;
s.doGrow = false;
s.dead = false;
s.xPositions.Clear();
s.yPositions.Clear();
for (int i = START_LENGTH - 1; i >= 0; i--)
{
s.xPositions.Add(s.x - i);
s.yPositions.Add(s.y);
}
}
public static void SetDir(int x, int y, Snake s)
{
if (s.xDir != -x && s.yDir != -y)
{
s.xDir = x;
s.yDir = y;
}
}
public static void Update(Snake s)
{
s.x = s.x + s.xDir;
s.y = s.y + s.yDir;
if (IsGameOver(s))
{
s.dead = true;
}
s.xPositions.Add(s.x);
s.yPositions.Add(s.y);
if (!s.doGrow)
{
s.xPositions.RemoveAt(0);
s.yPositions.RemoveAt(0);
}
}
public static void Eat(Snake s, Fruit f)
{
if (s.x == f.x && s.y == f.y)
{
s.speed = s.speed + SPEED_INCREMENT;
s.score++;
Fruit.NewPosition(f, s);
s.doGrow = true;
}
}
public static void Show(Snake s)
{
Console.ForegroundColor = ConsoleColor.Green;
for (int i = 0; i < s.xPositions.Count(); i++)
{
Console.SetCursorPosition(s.xPositions[i], s.yPositions[i]);
Console.Write(SNAKE_CHAR);
}
}
public static void ShowScore(Snake s)
{
Console.ForegroundColor = SNAKE_COLOUR;
Console.SetCursorPosition(0, 0);
Console.WriteLine("Score: " + s.score);
}
static bool IsGameOver(Snake s)
{
if (s.x < 0 || s.x > Program.SCREEN_W - 1 || s.y < 0 || s.y > Program.SCREEN_H - 1)
{
return true;
}
for (int i = 0; i < s.xPositions.Count(); i++)
{
if (s.xPositions[i] == s.x && s.yPositions[i] == s.y)
{
return true;
}
}
return false;
}
}
class Fruit
{
const ConsoleColor FRUIT_COLOUR = ConsoleColor.Red;
const ConsoleColor BACK_COLOUR = ConsoleColor.Black;
const int fruitPosBuffer = 2;
public int x = 10;
public int y = 10;
public static void Show(Fruit f)
{
Console.SetCursorPosition(f.x, f.y);
Console.BackgroundColor = FRUIT_COLOUR;
Console.WriteLine(" ");
Console.BackgroundColor = BACK_COLOUR;
}
public static void NewPosition(Fruit f, Snake s)
{
int newX;
int newY;
Random pos = new Random();
do
{
newX = pos.Next(fruitPosBuffer, Program.SCREEN_W - fruitPosBuffer);
newY = pos.Next(fruitPosBuffer, Program.SCREEN_H - fruitPosBuffer);
} while (ValidPos(f, s, newX, newY) == false);
f.x = newX;
f.y = newY;
}
static bool ValidPos(Fruit f, Snake s, int newX, int newY)
{
if (newX == f.x || newY == f.y)
{
return false;
}
if (s.xPositions.Contains(newX) || s.yPositions.Contains(newY))
{
return false;
}
else
{
return true;
}
}
}
}
Solution
In your main game loop, rather than call Console.Clear() and repainting all your content (which can cause some flicker), just update the previous frame with any changes. This means that initially you’ll want to draw everything, but after that you only need to update stuff when it changes. When the fruit moves, erase the old position (unless it is covered by the snake) and draw it in the new one. When the snake is updated, erase from the old location and draw it in the new. If you can have multiple things occupying the same space, then this can be easier to implement if you erase anything that is moving, then redraw the entire screen (since you won’t have to consider what to erase a part of the screen with).
Your jerkiness is probably because you call Thread.Sleep with a fixed interval. The actual interval will be the sleep time plus however long it takes to run the rest of the code in your game loop plus variation in the exact duration of the Sleep. Consider using System.Environment.GetTickCount() in the duration calculation. You’d call that right after the sleep ends, save it in a variable (properly initialized before the loop), then the sleep duration would be your current time minus the elapsed time (another call to GetTickCount() minus the previous value), checking for overflow (duration less than 0). Also, the sleep is better positioned at the end of the game loop, rather than the beginning (as you’ll get a sleep before the first draw of the game screen with what you have).
In your Fruit class, create a member variable to hold your Random generator. Your current code creates a new one, with a new seed, every time you need a new fruit, which can create less-than-random results if it is called too frequently.
Consider creating a Point class to hold X and Y values.