public unsafe bool Update()
{
// Workout where new head of snake will go
var newHeadX = HeadX;
var newHeadY = HeadY;
switch (_direction)
{
case Direction.Left: newHeadX--; break;
case Direction.Right: newHeadX++; break;
case Direction.Up: newHeadY--; break;
case Direction.Down: newHeadY++; break;
}
newHeadX = GraphicHelper.WrapAround(newHeadX, Graphics.ScreenWidth / 2);
newHeadY = GraphicHelper.WrapAround(newHeadY, Graphics.ScreenHeight);
// Does new head hit body of snake?
if (GetBoardItem(newHeadX, newHeadY))
{
return(false);
}
// Add new head
_snakeHead++;
_snakeHead %= _maxLength;
_snakeXs[_snakeHead] = newHeadX;
_snakeYs[_snakeHead] = newHeadY;
// Move tail of snake
if (_actualLength == _desiredLength)
{
_snakeTail++;
_snakeTail %= _maxLength;
}
else
{
_actualLength++;
}
return(true);
}
private unsafe Result Run(/* ref FrameBuffer fb */)
{
const int MAX_LENGTH = 80;
var snakeXs = stackalloc int[MAX_LENGTH];
var snakeYs = stackalloc int[MAX_LENGTH];
// Initialise Xs & Ys to -1
for (int i = 0; i < MAX_LENGTH; i++)
{
snakeXs[i] = -1;
snakeYs[i] = -1;
}
const int bits = 128 * 48;
const int boardSize = (bits) / 32;
var board = stackalloc int[boardSize];
for (int i = 0; i < 192; i++)
{
board[i] = 0;
}
var startX = GraphicHelper.WrapAround((byte)_random.Next(), Graphics.ScreenWidth / 2);
var startY = GraphicHelper.WrapAround((byte)_random.Next(), Graphics.ScreenHeight);
var s = new Snake(startX, startY, snakeXs, snakeYs, board, MAX_LENGTH, (Direction)(_random.Next() % 4));
MakeFood(s, out int foodX, out int foodY);
SetPixel(foodX, foodY, Color.White);
SetPixel(s.HeadX, s.HeadY, Color.White);
SetBoardItem(board, s.HeadX, s.HeadY, true);
while (true)
{
if (Console.KeyAvailable)
{
ConsoleKeyInfo ki = Console.ReadKey(true);
int kc = ki.KeyChar;
switch (kc)
{
case 10: s.SetCourse(Direction.Down); break;
case 91: s.SetCourse(Direction.Up); break;
case 8: s.SetCourse(Direction.Left); break;
case 9: s.SetCourse(Direction.Right); break;
}
}
var oldTailX = s.TailX;
var oldTailY = s.TailY;
if (!s.Update())
{
return(Result.Loss);
}
SetPixel(oldTailX, oldTailY, Color.Black);
SetPixel(s.HeadX, s.HeadY, Color.White);
SetBoardItem(board, oldTailX, oldTailY, false);
SetBoardItem(board, s.HeadX, s.HeadY, true);
if (s.HitTest(foodX, foodY))
{
if (s.Extend())
{
MakeFood(s, out foodX, out foodY);
SetPixel(foodX, foodY, Color.White);
}
else
{
return(Result.Win);
}
}
Thread.Sleep(30);
}
}
