minix/games/tetris/shapes.c

/*	$NetBSD: shapes.c,v 1.8 2009/05/25 04:33:53 dholland Exp $	*/

/*-
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek and Darren F. Provine.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)shapes.c	8.1 (Berkeley) 5/31/93
 */

/*
 * Tetris shapes and related routines.
 *
 * Note that the first 7 are `well known'.
 */

#include <sys/cdefs.h>
#include "tetris.h"

#define	TL	-B_COLS-1	/* top left */
#define	TC	-B_COLS		/* top center */
#define	TR	-B_COLS+1	/* top right */
#define	ML	-1		/* middle left */
#define	MR	1		/* middle right */
#define	BL	B_COLS-1	/* bottom left */
#define	BC	B_COLS		/* bottom center */
#define	BR	B_COLS+1	/* bottom right */

const struct shape shapes[] = {
	/* 0*/	{ 7,	{ TL, TC, MR, } },
	/* 1*/	{ 8,	{ TC, TR, ML, } },
	/* 2*/	{ 9,	{ ML, MR, BC, } },
	/* 3*/	{ 3,	{ TL, TC, ML, } },
	/* 4*/	{ 12,	{ ML, BL, MR, } },
	/* 5*/	{ 15,	{ ML, BR, MR, } },
	/* 6*/	{ 18,	{ ML, MR, 2   } },	/* sticks out */
	/* 7*/	{ 0,	{ TC, ML, BL, } },
	/* 8*/	{ 1,	{ TC, MR, BR, } },
	/* 9*/	{ 10,	{ TC, MR, BC, } },
	/*10*/	{ 11,	{ TC, ML, MR, } },
	/*11*/	{ 2,	{ TC, ML, BC, } },
	/*12*/	{ 13,	{ TC, BC, BR, } },
	/*13*/	{ 14,	{ TR, ML, MR, } },
	/*14*/	{ 4,	{ TL, TC, BC, } },
	/*15*/	{ 16,	{ TR, TC, BC, } },
	/*16*/	{ 17,	{ TL, MR, ML, } },
	/*17*/	{ 5,	{ TC, BC, BL, } },
	/*18*/	{ 6,	{ TC, BC, 2*B_COLS } }	/* sticks out */
};

/*
 * Return true iff the given shape fits in the given position,
 * taking the current board into account.
 */
int
fits_in(const struct shape *shape, int pos)
{
	const int *o = shape->off;

	if (board[pos] || board[pos + *o++] || board[pos + *o++] ||
	    board[pos + *o])
		return 0;
	return 1;
}

/*
 * Write the given shape into the current board, turning it on
 * if `onoff' is 1, and off if `onoff' is 0.
 */
void
place(const struct shape *shape, int pos, int onoff)
{
	const int *o = shape->off;

	board[pos] = onoff;
	board[pos + *o++] = onoff;
	board[pos + *o++] = onoff;
	board[pos + *o] = onoff;
}