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/* $NetBSD: makemaze.c,v 1.12 2021/05/02 12:50:45 rillig Exp $ */
/*
* Copyright (c) 1983-2003, Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* + Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* + 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.
* + Neither the name of the University of California, San Francisco 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 COPYRIGHT HOLDERS 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 COPYRIGHT
* OWNER 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.
*/
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: makemaze.c,v 1.12 2021/05/02 12:50:45 rillig Exp $");
#endif /* not lint */
#include "hunt.h"
#define ISCLEAR(y,x) (Maze[y][x] == SPACE)
#define ODD(n) ((n) & 01)
#if 0
#define NPERM 24
#define NDIR 4
static const int dirs[NPERM][NDIR] = {
{0,1,2,3}, {3,0,1,2}, {0,2,3,1}, {0,3,2,1},
{1,0,2,3}, {2,3,0,1}, {0,2,1,3}, {2,3,1,0},
{1,0,3,2}, {1,2,0,3}, {3,1,2,0}, {2,0,3,1},
{1,3,0,2}, {0,3,1,2}, {1,3,2,0}, {2,0,1,3},
{0,1,3,2}, {3,1,0,2}, {2,1,0,3}, {1,2,3,0},
{2,1,3,0}, {3,0,2,1}, {3,2,0,1}, {3,2,1,0}
};
static const int incr[NDIR][2] = {
{0, 1}, {1, 0}, {0, -1}, {-1, 0}
};
/*
* candig:
* Is it legal to clear this spot?
*/
static bool
candig(int y, int x)
{
int i;
if (ODD(x) && ODD(y))
return false; /* can't touch ODD spots */
if (y < UBOUND || y >= DBOUND)
return false; /* Beyond vertical bounds, NO */
if (x < LBOUND || x >= RBOUND)
return false; /* Beyond horizontal bounds, NO */
if (ISCLEAR(y, x))
return false; /* Already clear, NO */
i = ISCLEAR(y, x + 1);
i += ISCLEAR(y, x - 1);
if (i > 1)
return false; /* Introduces cycle, NO */
i += ISCLEAR(y + 1, x);
if (i > 1)
return false; /* Introduces cycle, NO */
i += ISCLEAR(y - 1, x);
if (i > 1)
return false; /* Introduces cycle, NO */
return true; /* OK */
}
static void
dig(int y, int x)
{
const int *dp;
const int *ip;
int ny, nx;
const int *endp;
Maze[y][x] = SPACE; /* Clear this spot */
dp = dirs[rand_num(NPERM)];
endp = &dp[NDIR];
while (dp < endp) {
ip = &incr[*dp++][0];
ny = y + *ip++;
nx = x + *ip;
if (candig(ny, nx))
dig(ny, nx);
}
}
#endif
static void
dig_maze(int x, int y)
{
int tx, ty;
int i, j;
int order[4];
#define MNORTH 0x1
#define MSOUTH 0x2
#define MEAST 0x4
#define MWEST 0x8
tx = ty = 0;
Maze[y][x] = SPACE;
order[0] = MNORTH;
for (i = 1; i < 4; i++) {
j = rand_num(i + 1);
order[i] = order[j];
order[j] = 0x1 << i;
}
for (i = 0; i < 4; i++) {
switch (order[i]) {
case MNORTH:
tx = x;
ty = y - 2;
break;
case MSOUTH:
tx = x;
ty = y + 2;
break;
case MEAST:
tx = x + 2;
ty = y;
break;
case MWEST:
tx = x - 2;
ty = y;
break;
}
if (tx < 0 || ty < 0 || tx >= WIDTH || ty >= HEIGHT)
continue;
if (Maze[ty][tx] == SPACE)
continue;
Maze[(y + ty) / 2][(x + tx) / 2] = SPACE;
dig_maze(tx, ty);
}
}
static void
remap(void)
{
int y, x;
char *sp;
int stat;
for (y = 0; y < HEIGHT; y++)
for (x = 0; x < WIDTH; x++) {
sp = &Maze[y][x];
if (*sp == SPACE)
continue;
stat = 0;
if (y - 1 >= 0 && Maze[y - 1][x] != SPACE)
stat |= NORTH;
if (y + 1 < HEIGHT && Maze[y + 1][x] != SPACE)
stat |= SOUTH;
if (x + 1 < WIDTH && Maze[y][x + 1] != SPACE)
stat |= EAST;
if (x - 1 >= 0 && Maze[y][x - 1] != SPACE)
stat |= WEST;
switch (stat) {
case WEST | EAST:
case EAST:
case WEST:
*sp = WALL1;
break;
case NORTH | SOUTH:
case NORTH:
case SOUTH:
*sp = WALL2;
break;
case 0:
#ifdef RANDOM
*sp = DOOR;
#endif
#ifdef REFLECT
*sp = rand_num(2) ? WALL4 : WALL5;
#endif
break;
default:
*sp = WALL3;
break;
}
}
memcpy(Orig_maze, Maze, sizeof Maze);
}
void
makemaze(void)
{
char *sp;
int y, x;
/*
* fill maze with walls
*/
sp = &Maze[0][0];
while (sp < &Maze[HEIGHT - 1][WIDTH])
*sp++ = DOOR;
x = rand_num(WIDTH / 2) * 2 + 1;
y = rand_num(HEIGHT / 2) * 2 + 1;
dig_maze(x, y);
remap();
}
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