improving bot

1 files changed, 17 insertions, 8 deletions

diff --git a/src/bot.cpp b/src/bot.cpp
index 4137f05..dc58fe0 100644
--- a/src/bot.cpp
+++ b/src/bot.cpp
@@ -57,7 +57,7 @@ int ROOK_TABLE[64] = {
     0,  0,  5,  10, 10, 5,  0,  0,  //
 };
 
-const int SEARCH_DEPTH = 4;
+const int SEARCH_DEPTH = 5;
 
 #include <fstream>
 
@@ -89,6 +89,7 @@ Move EngineGetBestMove(Game *b) {
     float beta = INFINITY;
 
     float eval = minimax(SEARCH_DEPTH - 1, &TestBoard, alpha, beta);
+
     if (b->turn) {
       if (eval > BestEval) {
         BestEval = eval;
@@ -105,11 +106,11 @@ Move EngineGetBestMove(Game *b) {
 }
 float minimax(int depth, Game *b, float alpha, float beta) {
   if (depth == 0) {
-    return EvaluateBoardForWhite(b);
+    return EvaluateBoardForWhite(b, depth);
   }
   auto moves = GetLegalMoves(b);
   if (moves.size() == 0) {
-    return EvaluateBoardForWhite(b);
+    return EvaluateBoardForWhite(b, depth);
   }
   if (b->turn) {
     float bestEval = -INFINITY;
@@ -118,7 +119,11 @@ float minimax(int depth, Game *b, float alpha, float beta) {
       Game next = *b;
       PlayMove(move, &next);
 
-      float eval = minimax(depth - 1, &next, alpha, beta);
+      int newDepth = depth - 1;
+      if (IsPieceTypeAttacked(b, KING, b->turn)) {
+        newDepth += 1;
+      };
+      float eval = minimax(newDepth, &next, alpha, beta);
       bestEval = std::max(bestEval, eval);
 
       alpha = std::max(alpha, bestEval);
@@ -136,7 +141,11 @@ float minimax(int depth, Game *b, float alpha, float beta) {
       Game next = *b;
       PlayMove(move, &next);
 
-      float eval = minimax(depth - 1, &next, alpha, beta);
+      int newDepth = depth - 1;
+      if (IsPieceTypeAttacked(b, KING, b->turn)) {
+        newDepth += 1;
+      };
+      float eval = minimax(newDepth, &next, alpha, beta);
 
       BestEval = std::min(BestEval, eval);
 
@@ -150,17 +159,17 @@ float minimax(int depth, Game *b, float alpha, float beta) {
 }
 int PSTIndex(int square, bool white) { return white ? square : (56 ^ square); }
 
-float EvaluateBoardForWhite(Game *b) {
+float EvaluateBoardForWhite(Game *b, int depth) {
   float score = 0;
 
   bool isStaleMate = false;
   GetLegalMoves(b);
 
   if (b->state == WHITE_WON) {
-    return MATE;
+    return MATE - depth;
   }
   if (b->state == BLACK_WON) {
-    return -MATE;
+    return -MATE + depth;
   }
   if (b->state == STALEMATE || b->state == DRAW) {
     isStaleMate = true;