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#include "evaluate.hpp"
#include "board/board.hpp"
#include "moves.hpp"
#include <cassert>
#include <cstdlib>
#include <iostream>
constexpr int PAWN_VALUE = 100;
constexpr int KNIGHT_VALUE = 320;
constexpr int BISHOP_VALUE = 400;
constexpr int ROOK_VALUE = 500;
constexpr int QUEEN_VALUE = 900;
constexpr int MATE = 10000;
static int PAWN_TABLE[64] = {
0, 0, 0, 0, 0, 0, 0, 0, // last rank promotes to a quuen
50, 50, 50, 50, 50, 50, 50, 50, // comments to stop formating to ruin it
10, 10, 20, 35, 35, 20, 10, 10, //
5, 5, 10, 30, 30, 10, 5, 5, //
0, 0, 0, 25, 25, 0, 0, 0, //
5, -5, -10, 0, 0, -10, -5, 5, //
5, 10, 10, -20, -20, 10, 10, 5, //
0, 0, 0, 0, 0, 0, 0, 0 //
};
static int KNIGHT_TABLE[64] = {
-50, -40, -30, -30, -30, -30, -40, -50, //
-40, -20, 0, 0, 0, 0, -20, -40, //
-30, 0, 10, 15, 15, 10, 0, -30, //
-30, 5, 15, 20, 20, 15, 5, -30, //
-30, 0, 15, 20, 20, 15, 0, -30, //
-30, 5, 10, 15, 15, 10, 5, -30, //
-40, -20, 0, 5, 5, 0, -20, -40, //
-50, -40, -30, -30, -30, -30, -40, -50, //
};
static int BISHOP_TABLE[64] = {
-20, -10, -10, -10, -10, -10, -10, -20, //
-10, 5, 0, 0, 0, 0, 5, -10, //
-10, 10, 10, 10, 10, 10, 10, -10, //
-10, 0, 10, 15, 15, 10, 0, -10, //
-10, 5, 5, 10, 10, 5, 5, -10, //
-10, 0, 5, 10, 10, 5, 0, -10, //
-10, 0, 0, 0, 0, 0, 0, -10, //
-20, -10, -10, -10, -10, -10, -10, -20, //
};
static int ROOK_TABLE[64] = {
0, 0, 5, 10, 10, 5, 0, 0, //
5, 10, 10, 10, 10, 10, 10, 5, //
-5, 0, 0, 0, 0, 0, 0, -5, //
-5, 0, 0, 5, 5, 0, 0, -5, //
-5, 0, 0, 5, 5, 0, 0, -5, //
-5, 0, 0, 0, 0, 0, 0, -5, //
5, 10, 10, 10, 10, 10, 10, 5, //
0, 0, 5, 10, 10, 5, 0, 0, //
};
static int QUEEN_TABLE[64] = {
-20, -10, -10, -5, -5, -10, -10, -20, //
-10, 0, 0, 0, 0, 0, 0, -10, //
-10, 0, 5, 5, 5, 5, 0, -10, //
-5, 0, 5, 5, 5, 5, 0, -5, //
0, 0, 5, 5, 5, 5, 0, -5, //
-10, 5, 5, 5, 5, 5, 0, -10, //
-10, 0, 5, 0, 0, 0, 0, -10, //
-20, -10, -10, -5, -5, -10, -10, -20, //
};
static int KING_TABLE_EARLY[64] = {
-30, -40, -40, -50, -50, -40, -40, -30, //
-30, -40, -40, -50, -50, -40, -40, -30, //
-30, -40, -40, -50, -50, -40, -40, -30, //
-30, -40, -40, -50, -50, -40, -40, -30, //
-20, -30, -30, -40, -40, -30, -30, -20, //
-10, -20, -20, -20, -20, -20, -20, -10, //
20, 20, 0, 0, 0, 0, 20, 20, //
20, 30, 10, 0, 0, 10, 30, 20, //
};
int EvaluateBoard(Game *g) {
int score = EvaluateBoardForWhite(g);
return g->turn ? score : score * -1;
};
/*
* i cound have come up with better name.
* this function just takes square and if color is black rotate it
*/
static int RotateBoardForBlack(const int square, const bool color) {
return color ? square : (56 ^ square);
}
static int ForceKingToEdgeBonus(const Position enemyKing,
const Position myKing) {
int bonus = 0;
// Push enemy king toward edge
const int distToCenter =
std::abs(enemyKing.file - 3) + std::abs(enemyKing.rank - 3);
bonus += distToCenter * 10;
// Bring own king closer
const int kingDistance = std::abs(myKing.file - enemyKing.file) +
std::abs(myKing.rank - enemyKing.rank);
bonus += (14 - kingDistance) * 5;
return bonus;
}
int CountBoardMaterial(Game *g) {
int score = 0;
uint64_t piece_bitboard = g->PieceBitboard;
while (piece_bitboard != 0) {
int i = __builtin_ctzll(piece_bitboard);
piece_bitboard &= piece_bitboard - 1;
const Piece piece = g->pieces[i];
if (piece.type == NONEPIECE) {
assert(false && "in piece bitboard found none piece");
std::cout << "Internal error\n";
exit(1);
}
int value = 0;
switch (piece.type) {
case PAWN:
value = PAWN_VALUE;
value += PAWN_TABLE[RotateBoardForBlack(i, piece.color)];
break;
case KNIGHT:
value = KNIGHT_VALUE;
value += KNIGHT_TABLE[RotateBoardForBlack(i, piece.color)];
break;
case BISHOP:
value = BISHOP_VALUE;
value += BISHOP_TABLE[RotateBoardForBlack(i, piece.color)];
break;
case ROOK:
value = ROOK_VALUE;
value += ROOK_TABLE[RotateBoardForBlack(i, piece.color)];
break;
case QUEEN:
value = QUEEN_VALUE;
value += QUEEN_TABLE[RotateBoardForBlack(i, piece.color)];
break;
case KING:
value = KING_TABLE_EARLY[RotateBoardForBlack(i, piece.color)];
break;
default:
break;
}
if (piece.color) {
score += value;
} else {
score -= value;
}
}
return score;
};
bool IsEndgame(const Game *g) {
int queens = 0;
int rooks = 0;
for (const Piece &piece : g->pieces) {
switch (piece.type) {
case QUEEN:
queens++;
break;
case ROOK:
rooks++;
break;
default:
break;
}
}
return queens == 0 || (queens == 2 && rooks <= 1);
}
int EvaluateBoardForWhite(Game *g) {
g->state = GetNewGameState(g);
switch (g->state) {
case WHITE_WON:
return MATE;
case BLACK_WON:
return -MATE;
case DRAW:
return 0;
case TURN:
break;
}
int score = 0;
score += CountBoardMaterial(g);
Position whiteKing = FindKing(g, true);
Position blackKing = FindKing(g, false);
if (IsEndgame(g)) {
score += ForceKingToEdgeBonus(blackKing, whiteKing);
score -= ForceKingToEdgeBonus(whiteKing, blackKing);
}
return score;
}
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