eval.cpp

#include "stdafx.h"
#include "globals.h"

const int ISOLATED = 20;

int EvalPawn(const int s,const int x);
int EvalRook(const int s,const int x);
int queenside_pawns[2],kingside_pawns[2];

extern U64 mask_kingside;
extern U64 mask_queenside;

// pawn defence score 
const int queenside_defence[2][64]=
{
{
	0, 0, 0, 0, 0, 0, 0, 0,
	8,10, 8, 0, 0, 0, 0, 0,
	8, 6, 8, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0
},
{
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	8, 6, 8, 0, 0, 0, 0, 0,
	8,10, 8, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0
}};

// pawn defence score
const int kingside_defence[2][64] =
{
{
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 8,10, 8,
	0, 0, 0, 0, 0, 8, 6, 8,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	8, 6, 8, 0, 0, 8, 8, 8,
	0, 0, 0, 0, 0, 0, 0, 0
},
{
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 8, 6, 8,
	0, 0, 0, 0, 0, 8,10, 8,
	0, 0, 0, 0, 0, 0, 0, 0
} };
/*

Eval() is simple. 
Firstly it adds the square scores for each piece of both sides.
If the opponent does not have a queen it adds the endgame score for each king.
If the opponent has a queen it adds the pawn defence score for each king.
It returns the side to move's score minus the opponent's score.
There are plenty of things that could be added to the eval function.

*/
int Eval()
{
	int score[2] = {0,0};

	queenside_pawns[0] = 0;
	queenside_pawns[1] = 0;
	kingside_pawns[0] = 0;
	kingside_pawns[1] = 0;

	U64 b1;
	int sq;

	//std::fstream streamToLogEval("logEval.txt", std::ios::out);
	
	int countBishops[2] = { 0,0 };

	for(int x=0;x<2;x++)
	{
		b1 = bit_pieces[x][P]; // pawn
		while(b1)
		{
			sq = NextBit(b1);
			b1 &= not_mask[sq];
			score[x] += square_score[x][P][sq];
			score[x] += EvalPawn(x,sq); // Besonderheit bei Pawn
		}
		
		b1 = bit_pieces[x][N]; // knight
		while(b1)
		{
			sq = NextBit(b1);
			b1 &= not_mask[sq];
			score[x] += square_score[x][N][sq];
		}
		
		b1 = bit_pieces[x][B]; // bishop
		while(b1)
		{
			sq = NextBit(b1);
			b1 &= not_mask[sq];
			score[x] += square_score[x][B][sq];
			countBishops[x]++;
		}
		//streamToLogEval << currentDateTime() << ": " << (x ? "Black" : "White") << " owns " << countBishops[x] << " bishops." << std::endl;
		if (countBishops[x] > 1) // Laeuferpaar
			score[x] += BISHOPPAIR;
				
		b1 = bit_pieces[x][R]; // rook
		while(b1)
		{
			sq = NextBit(b1);
			b1 &= not_mask[sq];
			score[x] += square_score[x][R][sq];
			score[x] += EvalRook(x,sq); // Besonderheit bei Rook: EvalRook() evaluates each rook and gives a bonus for being
			                            // on an open file or half - open file.
		}
		
		b1 = bit_pieces[x][Q]; // queen
		while(b1)
		{
			sq = NextBit(b1);
			b1 &= not_mask[sq];
			score[x] += square_score[x][Q][sq];
		}
	}//for

	if (bit_pieces[1][Q] == 0) // If the opponent does not have a queen it adds the endgame score for each king.
	{
		score[0] += king_endgame[0][NextBit(bit_pieces[0][K])];
	}
	else // If the opponent has a queen it adds the pawn defence score for each king.
	{
		if (bit_pieces[0][K] & mask_kingside)
		{
			score[0] += kingside_pawns[0];
		}			
		else if (bit_pieces[0][K] & mask_queenside)
		{
			score[0] += queenside_pawns[0];
		}			
	}

	if (bit_pieces[0][Q] == 0)
	{
		score[1] += king_endgame[1][NextBit(bit_pieces[1][K])];
	}
	else
	{
		if(bit_pieces[1][K] & mask_kingside)
			score[1] += kingside_pawns[1];
		else if(bit_pieces[1][K] & mask_queenside)
			score[1] += queenside_pawns[1];
	}

	// There are plenty of things that could be added to the eval function.

	//streamToLogEval.close();
	return score[side] - score[xside]; // It returns the side to move's score minus the opponent's score.
}
/*

EvalPawn() evaluates each pawn and gives a bonus for passed pawns
and a minus for isolated pawns.

*/
int EvalPawn(const int s, const int sq)
{
	int score = 0;
	int xs = s ^ 1;

	if (!(mask_passed[s][sq] & bit_pieces[xs][P]) && !(mask_path[s][sq] & bit_pieces[s][P]))
	{
		score += passed[s][sq];
	}
	if ((mask_isolated[sq] & bit_pieces[s][P]) == 0)
		score -= ISOLATED;
	kingside_pawns[s] += kingside_defence[s][sq];
	queenside_pawns[s] += queenside_defence[s][sq];

	return score;
}
/*

EvalRook() evaluates each rook and gives a bonus for being
on an open file or half-open file.
*/
int EvalRook(const int s, const int sq)
{
	int score = 0;
	if (!(mask_cols[sq] & bit_pieces[s][P]))
	{
		score = 10;
		if (!(mask_cols[sq] & bit_pieces[s ^ 1][P]))
			score = 20;
	}
	return score;
}