added en passant, version 1

1 files changed, 15 insertions, 0 deletions

diff --git a/chesshelpers.c b/chesshelpers.c
index 2e046c9..b64a0f4 100644
--- a/chesshelpers.c
+++ b/chesshelpers.c
@@ -17,6 +17,7 @@ board_t init_board(int** pieces) {
 //function applies side effects to board values like king move state
 board_t make_move(board_t board, vector_t origin, vector_t end) {
 	int piece = board.pieces[origin.mx][origin.my];
+	int captured = board.pieces[end.mx][end.my];
 	board.pieces[origin.mx][origin.my] = 0;
 	board.pieces[end.mx][end.my] = piece;
 	//white king moved
@@ -62,6 +63,11 @@ board_t make_move(board_t board, vector_t origin, vector_t end) {
 	//this is not an else if! lastPawnMove must be reset
 	if(piece == pawn || piece == pawn + 6) {
 		board.lastPawnMove = origin.mx;
+		//check if move was an en passant capture
+		if(captured == 0 && origin.mx != end.mx) {
+			//kill the enemy pawn
+			board.pieces[end.mx][origin.my] = 0;
+		}
 	}
 	else {
 		//en passant no longer possible
@@ -95,6 +101,15 @@ int is_color(board_t board, vector_t position, int color) {
 		return board.pieces[position.mx][position.my] >= 7;
 	}
 }
+//returns true if a pawn that moved two squares would have been here if it moved one square
+int would_have_been_pawn(board_t board, vector_t position, int color) {
+	if(board.lastPawnMove == position.mx) {
+		if((position.my == 6 && color == 0) || (position.my == 2 && color == 1)) {
+			return 1;
+		}
+	}
+	return 0;
+}
 //converts board coordinates into algebraic notation
 char* get_readable_coords(vector_t position) {
 	char* output = malloc(3 * sizeof(char));