private void check_small_diagonal(int diagonal, ref bool white_made_a_line, ref bool black_made_a_line)
{
int sequence_size = 0;
for (int i = 0; i < 5; i++)
{
hole_state hole = hole_state.is_empty;
switch (diagonal)
{
case 0: hole = board[(i + 1) * 6 + i]; break;
case 1: hole = board[i * 6 + i + 1]; break;
case 2: hole = board[(i + 1) * 6 + 5 - i]; break;
case 3: hole = board[i * 6 + 4 - i]; break;
default: break;
}
if (hole == hole_state.is_empty)
{
break; //speed up, can't be any line there
}
if (hole == hole_state.has_white && sequence_size >= 0)
{
if (sequence_size < 0)
{
return; //speedup
}
++sequence_size;
if (sequence_size == 5)
{
white_made_a_line = true; break;
}
}
else if (hole == hole_state.has_black && sequence_size <= 0)
{
if (sequence_size > 0)
{
return; //speedup
}
--sequence_size;
if (sequence_size == -5)
{
black_made_a_line = true; break;
}
}
else
{
sequence_size = 0;
}
}
}
/// <summary>
/// check if game has ended, and if there is a winner
/// </summary>
/// <param name="player"> player = null if draw or game did not end, false if whites win (= to turn value)</param>
/// <returns>true if ended</returns>
public bool game_ended(out bool?player)
{
bool board_full = true;
bool white_made_a_line = false;
bool black_made_a_line = false;
int sequence_size;//counts positive 4 white and negative 4 black to avoid using another var
//could also check horizontals and verticals in one iteration using more memory, not sure what is best
//check horizontals and if board is full
for (int line = 0; line < 6; ++line)
{
if (board_full)
{
if (board[line * 6] == hole_state.is_empty)
{
board_full = false;
}
}
sequence_size = (int)board[line * 6];
for (int row = 1; row < 6; ++row)
{
hole_state hole = board[line * 6 + row];
if (hole == hole_state.is_empty)
{
board_full = false;
if (row != 5)
{
break; //speed up, can't be any line there
}
}
if (hole == hole_state.has_white)
{
if (sequence_size < 0)
{
sequence_size = 0;
}
++sequence_size;
if (sequence_size == 5)
{
white_made_a_line = true; break;
}
}
else if (hole == hole_state.has_black)
{
if (sequence_size > 0)
{
sequence_size = 0;
}
--sequence_size;
if (sequence_size == -5)
{
black_made_a_line = true; break;
}
}
else
{
sequence_size = 0;
}
}
}
//check verticals
for (int row = 0; row < 6; ++row)
{
sequence_size = (int)board[row];
for (int line = 1; line < 6; ++line)
{
hole_state hole = board[line * 6 + row];
if (hole == hole_state.is_empty)
{
if (line != 5)
{
break; //speed up, can't be any line there
}
}
if (hole == hole_state.has_white)
{
if (sequence_size < 0)
{
sequence_size = 0;
}
++sequence_size;
if (sequence_size == 5)
{
white_made_a_line = true; break;
}
}
else if (hole == hole_state.has_black)
{
if (sequence_size > 0)
{
sequence_size = 0;
}
--sequence_size;
if (sequence_size == -5)
{
black_made_a_line = true; break;
}
}
else
{
sequence_size = 0;
}
}
}
//check 2 larger diagonals
sequence_size = (int)board[0];
for (int i = 1; i < 6; i++)
{
hole_state hole = board[i * 6 + i];
if (hole == hole_state.is_empty)
{
if (i != 5)
{
break; //speed up, can't be any line there
}
}
if (hole == hole_state.has_white)
{
if (sequence_size < 0)
{
sequence_size = 0;
}
++sequence_size;
if (sequence_size == 5)
{
white_made_a_line = true; break;
}
}
else if (hole == hole_state.has_black)
{
if (sequence_size > 0)
{
sequence_size = 0;
}
--sequence_size;
if (sequence_size == -5)
{
black_made_a_line = true; break;
}
}
else
{
sequence_size = 0;
}
}
sequence_size = (int)board[5];
for (int i = 1; i < 6; i++)
{
hole_state hole = board[i * 6 + 5 - i];
if (hole == hole_state.is_empty)
{
if (i != 5)
{
break; //speed up, can't be any line there
}
}
if (hole == hole_state.has_white)
{
if (sequence_size < 0)
{
sequence_size = 0;
}
++sequence_size;
if (sequence_size == 5)
{
white_made_a_line = true; break;
}
}
else if (hole == hole_state.has_black)
{
if (sequence_size > 0)
{
sequence_size = 0;
}
--sequence_size;
if (sequence_size == -5)
{
black_made_a_line = true; break;
}
}
else
{
sequence_size = 0;
}
}
//check 4 smaller diagonals
for (int i = 0; i < 4; i++)
{
check_small_diagonal(i, ref white_made_a_line, ref black_made_a_line);
}
if (white_made_a_line && !black_made_a_line)
{
player = whites_turn;
}
else if (!white_made_a_line && black_made_a_line)
{
player = blacks_turn;
}
else
{
player = null;
}
if (turn_state == turn_state_rotate)
{
board_full = false;
}
return(board_full || black_made_a_line || white_made_a_line);
}
