gomoku: provide a more gentle introduction to the code

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This commit is contained in:
rillig 2022-05-29 14:50:37 +00:00
parent 7167cb1f23
commit e3d95fb4b0
1 changed files with 14 additions and 9 deletions

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@ -1,4 +1,4 @@
/* $NetBSD: gomoku.h,v 1.51 2022/05/29 14:37:44 rillig Exp $ */
/* $NetBSD: gomoku.h,v 1.52 2022/05/29 14:50:37 rillig Exp $ */
/*
* Copyright (c) 1994
@ -40,27 +40,32 @@
#include <stdio.h>
/*
* The board consists of 19x19 spots, the coordinates are 1-based. The board
* is surrounded by border spots.
* The gomoku 'board' mainly consists of the playing area of BSZ x BSZ spots.
* The playing area uses 1-based coordinates. Around the playing area is a
* rectangle of border spots, to avoid having to check the coordinates when
* calculating spot coordinates. The left and right border overlap, to save a
* few bytes.
*/
#define BSZ 19
#define BAREA ((1 + BSZ + 1) * (BSZ + 1) + 1)
/*
* A 'frame' is a group of five or six contiguous board locations. An
* A 'frame' is a group of five or six contiguous spots on the board. An
* open-ended frame is one with spaces on both ends; otherwise, it is closed.
*/
#define FAREA (2 * BSZ * (BSZ - 4) + 2 * (BSZ - 4) * (BSZ - 4))
/* values for s_occ */
/* The content of a spot on the board; used in s_occ. */
#define BLACK 0
#define WHITE 1
#define EMPTY 2
#define BORDER 3
/* A spot on the board, or in some cases one of the below special values. */
/* A spot on the board, or one of the special values below. */
typedef unsigned short spot_index;
#define PT(x, y) ((x) + (BSZ + 1) * (y))
/* return values for makemove, readinput */
#define MOVEOK 0
#define RESIGN 1
@ -69,11 +74,11 @@ typedef unsigned short spot_index;
#define TIE 4
#define SAVE 5
#define END_OF_INPUT 6
#define PT(x, y) ((x) + (BSZ + 1) * (y))
/*
* A 'combo' is a group of intersecting frames and consists of two numbers:
* 'F' is the number of moves to make the combo non-blockable.
* A 'combo' is a group of intersecting or overlapping frames and consists of
* two numbers:
* 'F' is the number of moves still needed to make the combo non-blockable.
* 'W' is the minimum number of moves needed to win once it can't be blocked.
*
* A 'force' is a combo that is one move away from being non-blockable.