public TetraBlock PopNextTetraBlock()
{
TetraBlock next = _tetraArray[0];
ShuffleTetraBlock();
return(next);
}
private void ShuffleTetraBlock()
{
int arraySize = _tetraArray.Length;
// foreach tetrablock of the list generate random swaping
while (arraySize > 1)
{
int newPos = _randomGenerator.Next(arraySize--);
TetraBlock tb = _tetraArray[arraySize];
_tetraArray[arraySize] = _tetraArray[newPos];
_tetraArray[newPos] = tb;
}
}
public override BlockLinerState Update(IBlockLiner gamestate, GameTime delta)
{
// select tetrablock
TetraBlock next = gamestate.PopNextTetraBlock();
Block[,] gameArea = gamestate.GameArea;
try
{
// add new tetra to gameArea
AddTetra(next, gameArea);
}
catch (UnplacableBlockException)
{
return(gamestate.GetStateInstance(Type.GameOver));
}
return(gamestate.GetStateInstance(Type.Falling));
}
private static void AddTetra(TetraBlock tetra, Block[,] matrix)
{
int xMiddle = matrix.GetLength(0) / 2;
int y = 0;
// checking free space
bool freeSpace = true;
bool[,] pattern = tetra.Pattern;
for (int xt = 0; xt < pattern.GetLength(0); xt++)
{
for (int yt = 0; yt < pattern.GetLength(1); yt++)
{
int xMatrix = xMiddle + xt;
int yMatrix = y + yt;
if (pattern[xt, yt] && matrix[xMatrix, yMatrix] != null)
{
freeSpace = false;
goto End;
}
}
}
End:
if (freeSpace)
{
for (int xt = 0; xt < pattern.GetLength(0); xt++)
{
for (int yt = 0; yt < pattern.GetLength(1); yt++)
{
int xMatrix = xMiddle + xt;
int yMatrix = y + yt;
matrix[xMatrix, yMatrix] = (pattern[xt, yt]) ? new Block(xMatrix, yMatrix, true) : null;
}
}
}
else
{
throw new UnplacableBlockException();
}
}
