rotated.htm

《电脑游戏中的人工智能制作》

<CENTER>
<TABLE border=1 cellPadding=0 cellSpacing=0 cols=9 width="25%">
  <CAPTION><B>Knight Attack Board From D5</B></CAPTION>
  <TBODY>
  <TR>
    <TD></TD>
    <TD>
      <CENTER><B>H</B></CENTER></TD>
    <TD>
      <CENTER><B>G</B></CENTER></TD>
    <TD>
      <CENTER><B>F</B></CENTER></TD>
    <TD>
      <CENTER><B>E</B></CENTER></TD>
    <TD>
      <CENTER><B>D</B></CENTER></TD>
    <TD>
      <CENTER><B>C</B></CENTER></TD>
    <TD>
      <CENTER><B>B</B></CENTER></TD>
    <TD>
      <CENTER><B>A</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>1</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>2</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>3</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>4</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>5</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER><B>N</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>6</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>7</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>8</B></CENTER></TD></TR></TBODY></TABLE><BR>
<TABLE border=1 cellPadding=0 cellSpacing=0 cols=9 width="25%">
  <CAPTION><B>King Attack Board From D5</B></CAPTION>
  <TBODY>
  <TR>
    <TD></TD>
    <TD>
      <CENTER><B>H</B></CENTER></TD>
    <TD>
      <CENTER><B>G</B></CENTER></TD>
    <TD>
      <CENTER><B>F</B></CENTER></TD>
    <TD>
      <CENTER><B>E</B></CENTER></TD>
    <TD>
      <CENTER><B>D</B></CENTER></TD>
    <TD>
      <CENTER><B>C</B></CENTER></TD>
    <TD>
      <CENTER><B>B</B></CENTER></TD>
    <TD>
      <CENTER><B>A</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>1</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>2</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>3</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>4</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>5</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD>
      <CENTER><B>K</B></CENTER></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>6</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>7</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>8</B></CENTER></TD></TR></TBODY></TABLE><BR>
<TABLE border=1 cellPadding=0 cellSpacing=0 cols=9 width="25%">
  <CAPTION><B>Black Pawn Attack Board From D5</B></CAPTION>
  <TBODY>
  <TR>
    <TD></TD>
    <TD>
      <CENTER><B>H</B></CENTER></TD>
    <TD>
      <CENTER><B>G</B></CENTER></TD>
    <TD>
      <CENTER><B>F</B></CENTER></TD>
    <TD>
      <CENTER><B>E</B></CENTER></TD>
    <TD>
      <CENTER><B>D</B></CENTER></TD>
    <TD>
      <CENTER><B>C</B></CENTER></TD>
    <TD>
      <CENTER><B>B</B></CENTER></TD>
    <TD>
      <CENTER><B>A</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>1</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>2</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>3</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>4</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>5</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER><B>P</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>6</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>7</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>8</B></CENTER></TD></TR></TBODY></TABLE></CENTER>
<P>With rooks, bishops, and queens, things aren't quite so simple. For example, 
a rook attacks every square on its rank and file, up to and including the first 
piece it encounters, or, in the absence of a piece, to the boundary of the chess 
board. In other words, the rook's attack board will look different for each 
possible "state of the rank" and "state of the file." Given that each rank and 
file has eight squares, and each square has two possible states (occupied or 
empty), there are 2^8 (256) possible states for each rank and file. 
</P><B><U>Using rotated bitboards to compute rook attacks</U></B><BR>
<P>The easiest method for computing a rook's attack board is to compute the 
bitboard of squares it attacks on its rank, then the bitboard of squares it 
attacks on its file, then perform a logical OR of the two. </P>
<CENTER>
<TABLE border=1 cellPadding=0 cellSpacing=0 cols=9 width="25%">
  <TBODY>
  <TR>
    <TD></TD>
    <TD>
      <CENTER><B>H</B></CENTER></TD>
    <TD>
      <CENTER><B>G</B></CENTER></TD>
    <TD>
      <CENTER><B>F</B></CENTER></TD>
    <TD>
      <CENTER><B>E</B></CENTER></TD>
    <TD>
      <CENTER><B>D</B></CENTER></TD>
    <TD>
      <CENTER><B>C</B></CENTER></TD>
    <TD>
      <CENTER><B>B</B></CENTER></TD>
    <TD>
      <CENTER><B>A</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>1</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>2</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>3</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>4</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>5</B></CENTER></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>6</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>7</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>8</B></CENTER></TD></TR></TBODY></TABLE><BR><B>OR</B><BR><BR>
<TABLE border=1 cellPadding=0 cellSpacing=0 cols=9 width="25%">
  <TBODY>
  <TR>
    <TD></TD>
    <TD>
      <CENTER><B>H</B></CENTER></TD>
    <TD>
      <CENTER><B>G</B></CENTER></TD>
    <TD>
      <CENTER><B>F</B></CENTER></TD>
    <TD>
      <CENTER><B>E</B></CENTER></TD>
    <TD>
      <CENTER><B>D</B></CENTER></TD>
    <TD>
      <CENTER><B>C</B></CENTER></TD>
    <TD>
      <CENTER><B>B</B></CENTER></TD>
    <TD>
      <CENTER><B>A</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>1</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>2</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>3</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>4</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>5</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>6</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>7</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>8</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR></TBODY></TABLE><BR><B>Equals</B><BR><BR>
<TABLE border=1 cellPadding=0 cellSpacing=0 cols=9 width="25%">
  <TBODY>
  <TR>
    <TD></TD>
    <TD>
      <CENTER><B>H</B></CENTER></TD>
    <TD>
      <CENTER><B>G</B></CENTER></TD>
    <TD>
      <CENTER><B>F</B></CENTER></TD>
    <TD>
      <CENTER><B>E</B></CENTER></TD>
    <TD>
      <CENTER><B>D</B></CENTER></TD>
    <TD>
      <CENTER><B>C</B></CENTER></TD>
    <TD>
      <CENTER><B>B</B></CENTER></TD>
    <TD>
      <CENTER><B>A</B></CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>1</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>2</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>3</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>4</B></CENTER></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD></TD>
    <TD>
      <CENTER>x</CENTER></TD></TR>
  <TR>
    <TD>
      <CENTER><B>5</B></CENTER></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD>
      <CENTER>x</CENTER></TD>
    <TD>
      <CENTER>x</CENTER></TD>