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nethack.lha
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nethack-3.1
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vision.c
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1993-01-18
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/* SCCS Id: @(#)vision.c 3.1 92/11/14 */
/* Copyright (c) Dean Luick, with acknowledgements to Dave Cohrs, 1990. */
/* NetHack may be freely redistributed. See license for details. */
#include "hack.h"
/* Circles ==================================================================*/
/*
* These numbers are limit offsets for one quadrant of a circle of a given
* radius (the first number of each line) from the source. The number in
* the comment is the element number (so pointers can be set up). Each
* "circle" has as many elements as its radius+1. The radius is the number
* of points away from the source that the limit exists. The radius of the
* offset on the same row as the source *is* included so we don't have to
* make an extra check. For example, a circle of radius 4 has offsets:
*
* XXX +2
* ...X +3
* ....X +4
* ....X +4
* @...X +4
*
*/
static char circle_data[] = {
/* 0*/ 1, 1,
/* 2*/ 2, 2, 1,
/* 5*/ 3, 3, 2, 1,
/* 9*/ 4, 4, 4, 3, 2,
/* 14*/ 5, 5, 5, 4, 3, 2,
/* 20*/ 6, 6, 6, 5, 5, 4, 2,
/* 27*/ 7, 7, 7, 6, 6, 5, 4, 2,
/* 35*/ 8, 8, 8, 7, 7, 6, 6, 4, 2,
/* 44*/ 9, 9, 9, 9, 8, 8, 7, 6, 5, 3,
/* 54*/ 10,10,10,10, 9, 9, 8, 7, 6, 5, 3,
/* 65*/ 11,11,11,11,10,10, 9, 9, 8, 7, 5, 3,
/* 77*/ 12,12,12,12,11,11,10,10, 9, 8, 7, 5, 3,
/* 90*/ 13,13,13,13,12,12,12,11,10,10, 9, 7, 6, 3,
/*104*/ 14,14,14,14,13,13,13,12,12,11,10, 9, 8, 6, 3,
/*119*/ 15,15,15,15,14,14,14,13,13,12,11,10, 9, 8, 6, 3,
/*135*/ 16 /* should be MAX_RADIUS+1; used to terminate range loops -dlc */
};
/*
* These are the starting indexes into the circle_data[] array for a
* circle of a given radius.
*/
static char circle_start[] = {
/* */ 0, /* circles of radius zero are not used */
/* 1*/ 0,
/* 2*/ 2,
/* 3*/ 5,
/* 4*/ 9,
/* 5*/ 14,
/* 6*/ 20,
/* 7*/ 27,
/* 8*/ 35,
/* 9*/ 44,
/*10*/ 54,
/*11*/ 65,
/*12*/ 77,
/*13*/ 90,
/*14*/ 104,
/*15*/ 119,
};
/*===========================================================================*/
/* Vision (arbitrary line of sight) =========================================*/
/*------ global variables ------*/
#if 0 /* (moved to decl.c) */
/* True if we need to run a full vision recalculation. */
boolean vision_full_recalc = 0;
/* Pointers to the current vision array. */
char **viz_array;
#endif
char *viz_rmin, *viz_rmax; /* current vision cs bounds */
/*------ local variables ------*/
static char could_see[2][ROWNO][COLNO]; /* vision work space */
static char *cs_rows0[ROWNO], *cs_rows1[ROWNO];
static char cs_rmin0[ROWNO], cs_rmax0[ROWNO];
static char cs_rmin1[ROWNO], cs_rmax1[ROWNO];
static char viz_clear[ROWNO][COLNO]; /* vision clear/blocked map */
static char *viz_clear_rows[ROWNO];
static char left_ptrs[ROWNO][COLNO]; /* LOS algorithm helpers */
static char right_ptrs[ROWNO][COLNO];
/* Forward declarations. */
static void FDECL(fill_point, (int,int));
static void FDECL(dig_point, (int,int));
static void NDECL(view_init);
static void FDECL(view_from,(int,int,char **,char *,char *,int,
void (*)(int,int,genericptr_t),genericptr_t));
static void FDECL(get_unused_cs, (char ***,char **,char **));
#ifdef REINCARNATION
static void FDECL(rogue_vision, (char **,char *,char *));
#endif
/* Macro definitions that I can't find anywhere. */
#define sign(z) ((z) < 0 ? -1 : ((z) ? 1 : 0 ))
#define abs(z) ((z) < 0 ? -(z) : (z))
/*
* vision_init()
*
* The one-time vision initialization routine.
*
* This must be called before mklev() is called in newgame() [allmain.c],
* or before a game restore. Else we die a horrible death.
*/
void
vision_init()
{
int i;
/* Set up the pointers. */
for (i = 0; i < ROWNO; i++) {
cs_rows0[i] = could_see[0][i];
cs_rows1[i] = could_see[1][i];
viz_clear_rows[i] = viz_clear[i];
}
/* Start out with cs0 as our current array */
viz_array = cs_rows0;
viz_rmin = cs_rmin0;
viz_rmax = cs_rmax0;
vision_full_recalc = 0;
(void) memset((genericptr_t) could_see, 0, sizeof(could_see));
/* Initialize the vision algorithm (currently C or D). */
view_init();
#ifdef VISION_TABLES
/* Note: this initializer doesn't do anything except guarantee that
we're linked properly.
*/
vis_tab_init();
#endif
}
/*
* does_block()
*
* Returns true if the level feature, object, or monster at (x,y) blocks
* sight.
*/
int
does_block(x,y,lev)
int x, y;
register struct rm *lev;
{
struct obj *obj;
struct monst *mon;
/* Features that block . . */
if (IS_ROCK(lev->typ) || (IS_DOOR(lev->typ) &&
(lev->doormask & (D_CLOSED|D_LOCKED|D_TRAPPED) )))
return 1;
if (lev->typ == CLOUD || lev->typ == WATER ||
(lev->typ == MOAT && Underwater))
return 1;
/* Boulders block light. */
for (obj = level.objects[x][y]; obj; obj = obj->nexthere)
if (obj->otyp == BOULDER) return 1;
/* Mimics mimicing a door or boulder block light. */
if ((mon = m_at(x,y)) && (!mon->minvis || See_invisible) &&
((mon->m_ap_type == M_AP_FURNITURE &&
(mon->mappearance == S_hcdoor || mon->mappearance == S_vcdoor)) ||
(mon->m_ap_type == M_AP_OBJECT && mon->mappearance == BOULDER)))
return 1;
return 0;
}
/*
* vision_reset()
*
* This must be called *after* the levl[][] structure is set with the new
* level and the level monsters and objects are in place.
*/
void
vision_reset()
{
int y;
register int x, i, dig_left, block;
register struct rm *lev;
/* Start out with cs0 as our current array */
viz_array = cs_rows0;
viz_rmin = cs_rmin0;
viz_rmax = cs_rmax0;
(void) memset((genericptr_t) could_see, 0, sizeof(could_see));
/* Reset the pointers and clear so that we have a "full" dungeon. */
(void) memset((genericptr_t) viz_clear, 0, sizeof(viz_clear));
/* Dig the level */
for (y = 0; y < ROWNO; y++) {
dig_left = 0;
block = TRUE; /* location (0,y) is always stone; it's !isok() */
lev = &levl[1][y];
for (x = 1; x < COLNO; x++, lev += ROWNO)
if (block != (IS_ROCK(lev->typ) || does_block(x,y,lev))) {
if(block) {
for(i=dig_left; i<x; i++) {
left_ptrs [y][i] = dig_left;
right_ptrs[y][i] = x-1;
}
} else {
i = dig_left;
if(dig_left) dig_left--; /* point at first blocked point */
for(; i<x; i++) {
left_ptrs [y][i] = dig_left;
right_ptrs[y][i] = x;
viz_clear[y][i] = 1;
}
}
dig_left = x;
block = !block;
}
/* handle right boundary; almost identical for blocked/unblocked */
i = dig_left;
if(!block && dig_left) dig_left--; /* point at first blocked point */
for(; i<COLNO; i++) {
left_ptrs [y][i] = dig_left;
right_ptrs[y][i] = (COLNO-1);
viz_clear[y][i] = !block;
}
}
vision_full_recalc = 1; /* we want to run vision_recalc() */
}
/*
* get_unused_cs()
*
* Called from vision_recalc() and at least one light routine. Get pointers
* to the unused vision work area.
*/
static void
get_unused_cs(rows, rmin, rmax)
char ***rows;
char **rmin, **rmax;
{
register int row;
register char *nrmin, *nrmax;
if (viz_array == cs_rows0) {
*rows = cs_rows1;
*rmin = cs_rmin1;
*rmax = cs_rmax1;
} else {
*rows = cs_rows0;
*rmin = cs_rmin0;
*rmax = cs_rmax0;
}
/* return an initialized, unused work area */
nrmin = *rmin;
nrmax = *rmax;
(void) memset((genericptr_t)**rows, 0, ROWNO*COLNO); /* we see nothing */
for (row = 0; row < ROWNO; row++) { /* set row min & max */
*nrmin++ = COLNO-1;
*nrmax++ = 0;
}
}
#ifdef REINCARNATION
/*
* rogue_vision()
*
* Set the "could see" and in sight bits so vision acts just like the old
* rogue game:
*
* + If in a room, the hero can see to the room boundaries.
* + The hero can always see adjacent squares.
*
* We set the in_sight bit here as well to escape a bug that shows up
* due to the one-sided lit wall hack.
*/
static void
rogue_vision(next, rmin, rmax)
char **next; /* could_see array pointers */
char *rmin, *rmax;
{
int rnum = levl[u.ux][u.uy].roomno - ROOMOFFSET; /* no SHARED... */
int start, stop, in_door;
register int zx, zy;
/* If in a lit room, we are able to see to its boundaries. */
/* If dark, set COULD_SEE so various spells work -dlc */
if (rnum >= 0) {
for (zy = rooms[rnum].ly-1; zy <= rooms[rnum].hy+1; zy++) {
rmin[zy] = start = rooms[rnum].lx-1;
rmax[zy] = stop = rooms[rnum].hx+1;
for (zx = start; zx <= stop; zx++) {
if (rooms[rnum].rlit) {
next[zy][zx] = COULD_SEE | IN_SIGHT;
levl[zx][zy].seen = 1; /* see the walls */
} else
next[zy][zx] = COULD_SEE;
}
}
}
in_door = levl[u.ux][u.uy].typ == DOOR;
/* Can always see adjacent. */
for (zy = u.uy-1; zy <= u.uy+1; zy++) {
rmin[zy] = min(rmin[zy],u.ux-1);
rmax[zy] = max(rmax[zy],u.ux+1);
for (zx = u.ux-1; zx <= u.ux+1; zx++) {
next[zy][zx] = COULD_SEE | IN_SIGHT;
/*
* Yuck, update adjacent non-diagonal positions when in a doorway.
* We need to do this to catch the case when we first step into
* a room. The room's walls were not seen from the outside, but
* now are seen (the seen bit is set just above). However, the
* positions are not updated because they were already in sight.
* So, we have to do it here.
*/
if (in_door && (zx == u.ux || zy == u.uy)) newsym(zx,zy);
}
}
}
#endif /* REINCARNATION */
/*
* vision_recalc()
*
* Do all of the heavy vision work. Recalculate all locations that could
* possibly be seen by the hero --- if the location were lit, etc. Note
* which locations are actually seen because of lighting. Then add to
* this all locations that be seen by hero due to night vision and x-ray
* vision. Finally, compare with what the hero was able to see previously.
* Update the difference.
*
* This function is usually called only when the variable 'vision_full_recalc'
* is set. The following is a list of places where this function is called,
* with three valid values for the control flag parameter:
*
* Control flag = 0. A complete vision recalculation. Generate the vision
* tables from scratch. This is necessary to correctly set what the hero
* can see. (1) and (2) call this routine for synchronization purposes, (3)
* calls this routine so it can operate correctly.
*
* + After the monster move, before input from the player. [moveloop()]
* + At end of moveloop. [moveloop() ??? not sure why this is here]
* + Right before something is printed. [pline()]
* + Right before we do a vision based operation. [do_clear_area()]
* + screen redraw, so we can renew all positions in sight. [docrt()]
*
* Control flag = 1. An adjacent vision recalculation. The hero has moved
* one square. Knowing this, it might be possible to optimize the vision
* recalculation using the current knowledge. This is presently unimplemented
* and is treated as a control = 0 call.
*
* + Right after the hero moves. [domove()]
*
* Control flag = 2. Turn off the vision system. Nothing new will be
* displayed, since nothing is seen. This is usually done when you need
* a newsym() run on all locations in sight, or on some locations but you
* don't know which ones.
*
* + Before a screen redraw, so all positions are renewed. [docrt()]
* + Right before the hero arrives on a new level. [goto_level()]
* + Right after a scroll of light is read. [litroom()]
* + After an option has changed that affects vision [parseoptions()]
* + Right after the hero is swallowed. [gulpmu()]
* + Just before bubbles are moved. [movebubbles()]
*/
void
vision_recalc(control)
int control;
{
char **temp_array; /* points to the old vision array */
char **next_array; /* points to the new vision array */
char *next_row; /* row pointer for the new array */
char *old_row; /* row pointer for the old array */
char *next_rmin; /* min pointer for the new array */
char *next_rmax; /* max pointer for the new array */
char *ranges; /* circle ranges -- used for xray & night vision */
int row; /* row counter (outer loop) */
int start, stop; /* inner loop starting/stopping index */
int dx, dy; /* one step from a lit door or lit wall (see below) */
register int col; /* inner loop counter */
register struct rm *lev; /* pointer to current pos */
struct rm *flev; /* pointer to position in "front" of current pos */
vision_full_recalc = 0; /* reset flag */
#ifdef GCC_WARN
row = 0;
#endif
/*
* Either the light sources have been taken care of, or we must
* recalculate them here.
*/
/* Get the unused could see, row min, and row max arrays. */
get_unused_cs(&next_array, &next_rmin, &next_rmax);
/* You see nothing, nothing can see you --- if swallowed or refreshing. */
if (u.uswallow || control == 2) {
/* do nothing -- get_unused_cs() nulls out the new work area */
} else if (Blind) {
/*
* Calculate the could_see array even when blind so that monsters
* can see you, even if you can't see them. Note that the current
* setup allows:
*
* + Monsters to see with the "new" vision, even on the rogue
* level.
*
* + Monsters to see you even when you're in a pit.
*/
view_from(u.uy, u.ux, next_array, next_rmin, next_rmax,
0,(void(*)())0,(genericptr_t)0);
/*
* Our own version of the update loop below. We know we can't see
* anything, so we only need update positions we used to be able
* to see.
*/
temp_array = viz_array; /* set viz_array so newsym() will work */
viz_array = next_array;
for (row = 0; row < ROWNO; row++) {
old_row = temp_array[row];
/* Find the min and max positions on the row. */
start = min(viz_rmin[row], next_rmin[row]);
stop = max(viz_rmax[row], next_rmax[row]);
for (col = start; col <= stop; col++)
if (old_row[col] & IN_SIGHT) newsym(col,row);
}
/* skip the normal update loop */
goto skip;
}
#ifdef REINCARNATION
else if (Is_rogue_level(&u.uz)) {
rogue_vision(next_array,next_rmin,next_rmax);
}
#endif
else {
int has_night_vision = 1; /* hero has night vision */
if (Underwater && !Is_waterlevel(&u.uz)) {
/*
* The hero is under water. Only see surrounding locations if
* they are also underwater. This overrides night vision but
* does not override x-ray vision.
*/
has_night_vision = 0;
for (row = u.uy-1; row <= u.uy+1; row++)
for (col = u.ux-1; col <= u.ux+1; col++) {
if (!isok(col,row) || !is_pool(col,row)) continue;
next_rmin[row] = min(next_rmin[row], col);
next_rmax[row] = max(next_rmax[row], col);
next_array[row][col] = IN_SIGHT;
}
}
/* if in a pit, just update for immediate locations */
else if (u.utrap && u.utraptype == TT_PIT) {
for (row = u.uy-1; row <= u.uy+1; row++) {
if (row < 0) continue; if (row >= ROWNO) break;
next_rmin[row] = max( 0, u.ux - 1);
next_rmax[row] = min(COLNO-1, u.ux + 1);
next_row = next_array[row];
for(col=next_rmin[row]; col <= next_rmax[row]; col++)
next_row[col] = IN_SIGHT;
}
} else
view_from(u.uy, u.ux, next_array, next_rmin, next_rmax,
0,(void(*)())0,(genericptr_t)0);
/*
* Set the IN_SIGHT bit for xray and night vision.
*/
if (u.xray_range >= 0) {
if (u.xray_range) {
ranges = circle_ptr(u.xray_range);
for (row = u.uy-u.xray_range; row <= u.uy+u.xray_range; row++) {
if (row < 0) continue; if (row >= ROWNO) break;
dy = abs(u.uy-row); next_row = next_array[row];
start = max( 0, u.ux - ranges[dy]);
stop = min(COLNO-1, u.ux + ranges[dy]);
for (col = start; col <= stop; col++) {
next_row[col] |= IN_SIGHT;
levl[col][row].seen = 1; /* we see walls */
}
next_rmin[row] = min(start, next_rmin[row]);
next_rmax[row] = max(stop, next_rmax[row]);
}
} else { /* range is 0 */
next_array[u.uy][u.ux] |= IN_SIGHT;
levl[u.ux][u.uy].seen = 1;
next_rmin[u.uy] = min(u.ux, next_rmin[u.uy]);
next_rmax[u.uy] = max(u.ux, next_rmax[u.uy]);
}
}
if (has_night_vision && u.xray_range < u.nv_range) {
if (!u.nv_range) { /* range is 0 */
next_array[u.uy][u.ux] |= IN_SIGHT;
levl[u.ux][u.uy].seen = 1;
next_rmin[u.uy] = min(u.ux, next_rmin[u.uy]);
next_rmax[u.uy] = max(u.ux, next_rmax[u.uy]);
} else if (u.nv_range > 0) {
ranges = circle_ptr(u.nv_range);
for (row = u.uy-u.nv_range; row <= u.uy+u.nv_range; row++) {
if (row < 0) continue; if (row >= ROWNO) break;
dy = abs(u.uy-row); next_row = next_array[row];
start = max( 0, u.ux - ranges[dy]);
stop = min(COLNO-1, u.ux + ranges[dy]);
for (col = start; col <= stop; col++)
if (next_row[col]) next_row[col] |= IN_SIGHT;
next_rmin[row] = min(start, next_rmin[row]);
next_rmax[row] = max(stop, next_rmax[row]);
}
}
}
}
/*
* Make the viz_array the new array so that cansee() will work correctly.
*/
temp_array = viz_array;
viz_array = next_array;
/*
* The main update loop. Here we do two things:
*
* + Set the IN_SIGHT bit for places that we could see and are lit.
* + Reset changed places.
*
* There are two things that make deciding what the hero can see
* difficult:
*
* 1. Walls. Walls are only seen as walls from the inside of a room.
* On the outside they look like stone. The "seen" bit in the rm
* structure is used in the display system to decide what to
* display, but it is here where we decide to set the seen bit.
* In this case the wall must already be in sight (either by night
* vision or could be seen and lit) *and* we must see the wall
* from across a room-typ square.
*
* 2. Directional lighting. Items that block light create problems.
* The worst offenders are doors. Suppose a door to a lit room
* is closed. It is lit on one side, but not on the other. How
* do you know? You have to check the closest adjacent position.
* Even so, that is not entirely correct. But it seems close
* enough for now.
*/
for (row = 0; row < ROWNO; row++) {
dy = u.uy - row; dy = sign(dy);
next_row = next_array[row]; old_row = temp_array[row];
/* Find the min and max positions on the row. */
start = min(viz_rmin[row], next_rmin[row]);
stop = max(viz_rmax[row], next_rmax[row]);
lev = &levl[start][row];
for (col = start; col <= stop; col++, lev += ROWNO) {
if (next_row[col] & IN_SIGHT) {
/*
* We see this position because of night- or xray-vision.
*
* Check for "unseen" walls.
*/
if ( (!lev->seen || (lev->diggable & W_REPAIRED)) &&
(IS_WALL(lev->typ) || lev->typ == SDOOR) ) {
/* Check the closest adjacent position. */
dx = u.ux - col; dx = sign(dx);
flev = &(levl[col+dx][row+dy]);
/* If it was a non-corridor "open" area, we see the wall */
if ((ZAP_POS(flev->typ) && (flev->typ != CORR)) ||
(lev->diggable & W_REPAIRED)) {
lev->seen = 1; /* we've seen it */
lev->diggable &= ~W_REPAIRED;
/* Make sure newly "seen" walls show up */
newsym(col,row);
}
/* Update position if it was not in sight before. */
else if (!(old_row[col]&IN_SIGHT)) newsym(col,row);
}
/* Update position if it was not in sight before. */
else if ( !(old_row[col] & IN_SIGHT) ) {
lev->seen = 1;
newsym(col,row);
}
}
else if ( next_row[col] && lev->lit ) {
/*
* We see this position because it is lit.
*
* It is assumed here that lit walls are lit from the
* inside of the room, Hence, walls are not "seen"
* unless we can see them from across a lit room square.
*/
if (IS_WALL(lev->typ) || lev->typ == SDOOR) {
/* Check the closest adjacent position. */
dx = u.ux - col; dx = sign(dx);
flev = &(levl[col+dx][row+dy]);
/*
* If it is a non-corridor "open" area, and it is lit,
* then we see the wall as a wall.
*
* What happens when the hero is standing on this
* location (dx == dy == 0)?
*/
if (ZAP_POS(flev->typ) && (flev->typ != CORR) &&
flev->lit) {
next_row[col] |= IN_SIGHT; /* we see it */
if (!lev->seen || (lev->diggable & W_REPAIRED)) {
lev->seen = 1; /* see it as a wall */
lev->diggable &= ~W_REPAIRED;
/*
* Force an update on the position, even if it
* was previously in sight. Reason: the hero
* could have been in a corridor or outside of
* an undiscovered wall and then teleported into
* the room. The wall was in sight before, but
* seen as stone. Now we need to see it as a
* wall.
*/
newsym(col,row);
}
} else
goto not_in_sight; /* we don't see it */
} else if (IS_DOOR(lev->typ) && !viz_clear[row][col]) {
/*
* Make sure doors, boulders or mimics don't show up
* at the end of dark hallways. We do this by checking
* the adjacent position. If it is lit, then we can see
* the door, otherwise we can't.
*/
dx = u.ux - col; dx = sign(dx);
flev = &(levl[col+dx][row+dy]);
if (flev->lit) {
next_row[col] |= IN_SIGHT; /* we see it */
/* Update position if it was not in sight before. */
if (!(old_row[col] & IN_SIGHT)) newsym(col,row);
} else
goto not_in_sight; /* we don't see it */
} else {
next_row[col] |= IN_SIGHT; /* we see it */
/* Update position if it was not in sight before. */
if ( !(old_row[col] & IN_SIGHT) ) {
lev->seen = 1;
newsym(col,row);
}
}
} else if (next_row[col] && lev->waslit ) {
/*
* If we make it here, the hero _could see_ the location
* (next_row[col] is true), but doesn't see it (lit is false).
* However, the hero _remembers_ it as lit (waslit is true).
* The hero can now see that it is not lit, so change waslit
* and update the location.
*/
lev->waslit = 0; /* remember lit condition */
newsym(col,row);
}
/*
* At this point we know that the row position is *not* in
* sight. If the old one *was* in sight, then clean up the
* position.
*/
else {
not_in_sight:
if (old_row[col] & IN_SIGHT) newsym(col,row);
}
} /* end for col . . */
} /* end for row . . */
skip:
newsym(u.ux,u.uy); /* Make sure the hero shows up! */
/* Set the new min and max pointers. */
viz_rmin = next_rmin;
viz_rmax = next_rmax;
}
/*
* block_point()
*
* Make the location opaque to light.
*/
void
block_point(x,y)
int x, y;
{
fill_point(y,x);
/* recalc light sources here? */
/*
* We have to do a full vision recalculation if we "could see" the
* location. Why? Suppose some monster opened a way so that the
* hero could see a lit room. However, the position of the opening
* was out of night-vision range of the hero. Suddenly the hero should
* see the lit room.
*/
if (viz_array[y][x]) vision_full_recalc = 1;
}
/*
* unblock_point()
*
* Make the location transparent to light.
*/
void
unblock_point(x,y)
int x, y;
{
dig_point(y,x);
/* recalc light sources here? */
if (viz_array[y][x]) vision_full_recalc = 1;
}
/*===========================================================================*\
| |
| Everything below this line uses (y,x) instead of (x,y) --- the |
| algorithms are faster if they are less recursive and can scan |
| on a row longer. |
| |
\*===========================================================================*/
/* ========================================================================= *\
Left and Right Pointer Updates
\* ========================================================================= */
/*
* LEFT and RIGHT pointer rules
*
*
* **NOTE** The rules changed on 4/4/90. This comment reflects the
* new rules. The change was so that the stone-wall optimization
* would work.
*
* OK, now the tough stuff. We must maintain our left and right
* row pointers. The rules are as follows:
*
* Left Pointers:
* ______________
*
* + If you are a clear spot, your left will point to the first
* stone to your left. If there is none, then point the first
* legal position in the row (0).
*
* + If you are a blocked spot, then your left will point to the
* left-most blocked spot to your left that is connected to you.
* This means that a left-edge (a blocked spot that has an open
* spot on its left) will point to itself.
*
*
* Right Pointers:
* ---------------
* + If you are a clear spot, your right will point to the first
* stone to your right. If there is none, then point the last
* legal position in the row (COLNO-1).
*
* + If you are a blocked spot, then your right will point to the
* right-most blocked spot to your right that is connected to you.
* This means that a right-edge (a blocked spot that has an open
* spot on its right) will point to itself.
*/
static void
dig_point(row,col)
int row,col;
{
int i;
if (viz_clear[row][col]) return; /* already done */
viz_clear[row][col] = 1;
/*
* Boundary cases first.
*/
if (col == 0) { /* left edge */
if (viz_clear[row][1]) {
right_ptrs[row][0] = right_ptrs[row][1];
} else {
right_ptrs[row][0] = 1;
for (i = 1; i <= right_ptrs[row][1]; i++)
left_ptrs[row][i] = 1;
}
} else if (col == (COLNO-1)) { /* right edge */
if (viz_clear[row][COLNO-2]) {
left_ptrs[row][COLNO-1] = left_ptrs[row][COLNO-2];
} else {
left_ptrs[row][COLNO-1] = COLNO-2;
for (i = left_ptrs[row][COLNO-2]; i < COLNO-1; i++)
right_ptrs[row][i] = COLNO-2;
}
}
/*
* At this point, we know we aren't on the boundaries.
*/
else if (viz_clear[row][col-1] && viz_clear[row][col+1]) {
/* Both sides clear */
for (i = left_ptrs[row][col-1]; i <= col; i++) {
if (!viz_clear[row][i]) continue; /* catch non-end case */
right_ptrs[row][i] = right_ptrs[row][col+1];
}
for (i = col; i <= right_ptrs[row][col+1]; i++) {
if (!viz_clear[row][i]) continue; /* catch non-end case */
left_ptrs[row][i] = left_ptrs[row][col-1];
}
} else if (viz_clear[row][col-1]) {
/* Left side clear, right side blocked. */
for (i = col+1; i <= right_ptrs[row][col+1]; i++)
left_ptrs[row][i] = col+1;
for (i = left_ptrs[row][col-1]; i <= col; i++) {
if (!viz_clear[row][i]) continue; /* catch non-end case */
right_ptrs[row][i] = col+1;
}
left_ptrs[row][col] = left_ptrs[row][col-1];
} else if (viz_clear[row][col+1]) {
/* Right side clear, left side blocked. */
for (i = left_ptrs[row][col-1]; i < col; i++)
right_ptrs[row][i] = col-1;
for (i = col; i <= right_ptrs[row][col+1]; i++) {
if (!viz_clear[row][i]) continue; /* catch non-end case */
left_ptrs[row][i] = col-1;
}
right_ptrs[row][col] = right_ptrs[row][col+1];
} else {
/* Both sides blocked */
for (i = left_ptrs[row][col-1]; i < col; i++)
right_ptrs[row][i] = col-1;
for (i = col+1; i <= right_ptrs[row][col+1]; i++)
left_ptrs[row][i] = col+1;
left_ptrs[row][col] = col-1;
right_ptrs[row][col] = col+1;
}
}
static void
fill_point(row,col)
int row, col;
{
int i;
if (!viz_clear[row][col]) return;
viz_clear[row][col] = 0;
if (col == 0) {
if (viz_clear[row][1]) { /* adjacent is clear */
right_ptrs[row][0] = 0;
} else {
right_ptrs[row][0] = right_ptrs[row][1];
for (i = 1; i <= right_ptrs[row][1]; i++)
left_ptrs[row][i] = 0;
}
} else if (col == COLNO-1) {
if (viz_clear[row][COLNO-2]) { /* adjacent is clear */
left_ptrs[row][COLNO-1] = COLNO-1;
} else {
left_ptrs[row][COLNO-1] = left_ptrs[row][COLNO-2];
for (i = left_ptrs[row][COLNO-2]; i < COLNO-1; i++)
right_ptrs[row][i] = COLNO-1;
}
}
/*
* Else we know that we are not on an edge.
*/
else if (viz_clear[row][col-1] && viz_clear[row][col+1]) {
/* Both sides clear */
for (i = left_ptrs[row][col-1]+1; i <= col; i++)
right_ptrs[row][i] = col;
if (!left_ptrs[row][col-1]) /* catch the end case */
right_ptrs[row][0] = col;
for (i = col; i < right_ptrs[row][col+1]; i++)
left_ptrs[row][i] = col;
if (right_ptrs[row][col+1] == COLNO-1) /* catch the end case */
left_ptrs[row][COLNO-1] = col;
} else if (viz_clear[row][col-1]) {
/* Left side clear, right side blocked. */
for (i = col; i <= right_ptrs[row][col+1]; i++)
left_ptrs[row][i] = col;
for (i = left_ptrs[row][col-1]+1; i < col; i++)
right_ptrs[row][i] = col;
if (!left_ptrs[row][col-1]) /* catch the end case */
right_ptrs[row][i] = col;
right_ptrs[row][col] = right_ptrs[row][col+1];
} else if (viz_clear[row][col+1]) {
/* Right side clear, left side blocked. */
for (i = left_ptrs[row][col-1]; i <= col; i++)
right_ptrs[row][i] = col;
for (i = col+1; i < right_ptrs[row][col+1]; i++)
left_ptrs[row][i] = col;
if (right_ptrs[row][col+1] == COLNO-1) /* catch the end case */
left_ptrs[row][i] = col;
left_ptrs[row][col] = left_ptrs[row][col-1];
} else {
/* Both sides blocked */
for (i = left_ptrs[row][col-1]; i <= col; i++)
right_ptrs[row][i] = right_ptrs[row][col+1];
for (i = col; i <= right_ptrs[row][col+1]; i++)
left_ptrs[row][i] = left_ptrs[row][col-1];
}
}
/*===========================================================================*/
/*===========================================================================*/
/* Use either algorithm C or D. See the config.h for more details. =========*/
/*
* Variables local to both Algorithms C and D.
*/
static int start_row;
static int start_col;
static int step;
static char **cs_rows;
static char *cs_left;
static char *cs_right;
static void FDECL((*vis_func), (int,int,genericptr_t));
static genericptr_t varg;
/*
* Both Algorithms C and D use the following macros.
*
* good_row(z) - Return TRUE if the argument is a legal row.
* set_cs(rowp,col) - Set the local could see array.
* set_min(z) - Save the min value of the argument and the current
* row minimum.
* set_max(z) - Save the max value of the argument and the current
* row maximum.
*
* The last three macros depend on having local pointers row_min, row_max,
* and rowp being set correctly.
*/
#define set_cs(rowp,col) (rowp[col] = COULD_SEE)
#define good_row(z) ((z) >= 0 && (z) < ROWNO)
#define set_min(z) if (*row_min > (z)) *row_min = (z)
#define set_max(z) if (*row_max < (z)) *row_max = (z)
#define is_clear(row,col) viz_clear_rows[row][col]
/*
* clear_path() expanded into 4 macros/functions:
*
* q1_path()
* q2_path()
* q3_path()
* q4_path()
*
* "Draw" a line from the start to the given location. Stop if we hit
* something that blocks light. The start and finish points themselves are
* not checked, just the points between them. These routines do _not_
* expect to be called with the same starting and stopping point.
*
* These routines use the generalized integer Bresenham's algorithm (fast
* line drawing) for all quadrants. The algorithm was taken from _Procedural
* Elements for Computer Graphics_, by David F. Rogers. McGraw-Hill, 1985.
*/
#ifdef MACRO_CPATH /* quadrant calls are macros */
/*
* When called, the result is in "result".
* The first two arguments (srow,scol) are one end of the path. The next
* two arguments (row,col) are the destination. The last argument is
* used as a C language label. This means that it must be different
* in each pair of calls.
*/
/*
* Quadrant I (step < 0).
*/
#define q1_path(srow,scol,y2,x2,label) \
{ \
int dx, dy; \
register int k, err, x, y, dxs, dys; \
\
x = (scol); y = (srow); \
dx = (x2) - x; dy = y - (y2); \
\
result = 0; /* default to a blocked path */\
\
dxs = dx << 1; /* save the shifted values */\
dys = dy << 1; \
if (dy > dx) { \
err = dxs - dy; \
\
for (k = dy-1; k; k--) { \
if (err >= 0) { \
x++; \
err -= dys; \
} \
y--; \
err += dxs; \
if (!is_clear(y,x)) goto label;/* blocked */\
} \
} else { \
err = dys - dx; \
\
for (k = dx-1; k; k--) { \
if (err >= 0) { \
y--; \
err -= dxs; \
} \
x++; \
err += dys; \
if (!is_clear(y,x)) goto label;/* blocked */\
} \
} \
\
result = 1; \
}
/*
* Quadrant IV (step > 0).
*/
#define q4_path(srow,scol,y2,x2,label) \
{ \
int dx, dy; \
register int k, err, x, y, dxs, dys; \
\
x = (scol); y = (srow); \
dx = (x2) - x; dy = (y2) - y; \
\
result = 0; /* default to a blocked path */\
\
dxs = dx << 1; /* save the shifted values */\
dys = dy << 1; \
if (dy > dx) { \
err = dxs - dy; \
\
for (k = dy-1; k; k--) { \
if (err >= 0) { \
x++; \
err -= dys; \
} \
y++; \
err += dxs; \
if (!is_clear(y,x)) goto label;/* blocked */\
} \
\
} else { \
err = dys - dx; \
\
for (k = dx-1; k; k--) { \
if (err >= 0) { \
y++; \
err -= dxs; \
} \
x++; \
err += dys; \
if (!is_clear(y,x)) goto label;/* blocked */\
} \
} \
\
result = 1; \
}
/*
* Quadrant II (step < 0).
*/
#define q2_path(srow,scol,y2,x2,label) \
{ \
int dx, dy; \
register int k, err, x, y, dxs, dys; \
\
x = (scol); y = (srow); \
dx = x - (x2); dy = y - (y2); \
\
result = 0; /* default to a blocked path */\
\
dxs = dx << 1; /* save the shifted values */\
dys = dy << 1; \
if (dy > dx) { \
err = dxs - dy; \
\
for (k = dy-1; k; k--) { \
if (err >= 0) { \
x--; \
err -= dys; \
} \
y--; \
err += dxs; \
if (!is_clear(y,x)) goto label;/* blocked */\
} \
} else { \
err = dys - dx; \
\
for (k = dx-1; k; k--) { \
if (err >= 0) { \
y--; \
err -= dxs; \
} \
x--; \
err += dys; \
if (!is_clear(y,x)) goto label;/* blocked */\
} \
} \
\
result = 1; \
}
/*
* Quadrant III (step > 0).
*/
#define q3_path(srow,scol,y2,x2,label) \
{ \
int dx, dy; \
register int k, err, x, y, dxs, dys; \
\
x = (scol); y = (srow); \
dx = x - (x2); dy = (y2) - y; \
\
result = 0; /* default to a blocked path */\
\
dxs = dx << 1; /* save the shifted values */\
dys = dy << 1; \
if (dy > dx) { \
err = dxs - dy; \
\
for (k = dy-1; k; k--) { \
if (err >= 0) { \
x--; \
err -= dys; \
} \
y++; \
err += dxs; \
if (!is_clear(y,x)) goto label;/* blocked */\
} \
\
} else { \
err = dys - dx; \
\
for (k = dx-1; k; k--) { \
if (err >= 0) { \
y++; \
err -= dxs; \
} \
x--; \
err += dys; \
if (!is_clear(y,x)) goto label;/* blocked */\
} \
} \
\
result = 1; \
}
#else /* quadrants are really functions */
static int FDECL(_q1_path, (int,int,int,int));
static int FDECL(_q2_path, (int,int,int,int));
static int FDECL(_q3_path, (int,int,int,int));
static int FDECL(_q4_path, (int,int,int,int));
#define q1_path(sy,sx,y,x,dummy) result = _q1_path(sy,sx,y,x)
#define q2_path(sy,sx,y,x,dummy) result = _q2_path(sy,sx,y,x)
#define q3_path(sy,sx,y,x,dummy) result = _q3_path(sy,sx,y,x)
#define q4_path(sy,sx,y,x,dummy) result = _q4_path(sy,sx,y,x)
/*
* Quadrant I (step < 0).
*/
static int
_q1_path(srow,scol,y2,x2)
int scol, srow, y2, x2;
{
int dx, dy;
register int k, err, x, y, dxs, dys;
x = scol; y = srow;
dx = x2 - x; dy = y - y2;
dxs = dx << 1; /* save the shifted values */
dys = dy << 1;
if (dy > dx) {
err = dxs - dy;
for (k = dy-1; k; k--) {
if (err >= 0) {
x++;
err -= dys;
}
y--;
err += dxs;
if (!is_clear(y,x)) return 0; /* blocked */
}
} else {
err = dys - dx;
for (k = dx-1; k; k--) {
if (err >= 0) {
y--;
err -= dxs;
}
x++;
err += dys;
if (!is_clear(y,x)) return 0;/* blocked */
}
}
return 1;
}
/*
* Quadrant IV (step > 0).
*/
static int
_q4_path(srow,scol,y2,x2)
int scol, srow, y2, x2;
{
int dx, dy;
register int k, err, x, y, dxs, dys;
x = scol; y = srow;
dx = x2 - x; dy = y2 - y;
dxs = dx << 1; /* save the shifted values */
dys = dy << 1;
if (dy > dx) {
err = dxs - dy;
for (k = dy-1; k; k--) {
if (err >= 0) {
x++;
err -= dys;
}
y++;
err += dxs;
if (!is_clear(y,x)) return 0; /* blocked */
}
} else {
err = dys - dx;
for (k = dx-1; k; k--) {
if (err >= 0) {
y++;
err -= dxs;
}
x++;
err += dys;
if (!is_clear(y,x)) return 0;/* blocked */
}
}
return 1;
}
/*
* Quadrant II (step < 0).
*/
static int
_q2_path(srow,scol,y2,x2)
int scol, srow, y2, x2;
{
int dx, dy;
register int k, err, x, y, dxs, dys;
x = scol; y = srow;
dx = x - x2; dy = y - y2;
dxs = dx << 1; /* save the shifted values */
dys = dy << 1;
if (dy > dx) {
err = dxs - dy;
for (k = dy-1; k; k--) {
if (err >= 0) {
x--;
err -= dys;
}
y--;
err += dxs;
if (!is_clear(y,x)) return 0; /* blocked */
}
} else {
err = dys - dx;
for (k = dx-1; k; k--) {
if (err >= 0) {
y--;
err -= dxs;
}
x--;
err += dys;
if (!is_clear(y,x)) return 0;/* blocked */
}
}
return 1;
}
/*
* Quadrant III (step > 0).
*/
static int
_q3_path(srow,scol,y2,x2)
int scol, srow, y2, x2;
{
int dx, dy;
register int k, err, x, y, dxs, dys;
x = scol; y = srow;
dx = x - x2; dy = y2 - y;
dxs = dx << 1; /* save the shifted values */
dys = dy << 1;
if (dy > dx) {
err = dxs - dy;
for (k = dy-1; k; k--) {
if (err >= 0) {
x--;
err -= dys;
}
y++;
err += dxs;
if (!is_clear(y,x)) return 0; /* blocked */
}
} else {
err = dys - dx;
for (k = dx-1; k; k--) {
if (err >= 0) {
y++;
err -= dxs;
}
x--;
err += dys;
if (!is_clear(y,x)) return 0;/* blocked */
}
}
return 1;
}
#endif /* quadrants are functions */
/*
* Use vision tables to determine if there is a clear path from
* (col1,row1) to (col2,row2). This is used by:
* m_cansee()
* m_canseeu()
*/
boolean
clear_path(col1,row1,col2,row2)
int col1, row1, col2, row2;
{
int result;
if(col1 < col2) {
if(row1 > row2) {
q1_path(row1,col1,row2,col2,cleardone);
} else {
q4_path(row1,col1,row2,col2,cleardone);
}
} else {
if(row1 > row2) {
q2_path(row1,col1,row2,col2,cleardone);
} else if(row1 == row2 && col1 == col2) {
result = 1;
} else {
q3_path(row1,col1,row2,col2,cleardone);
}
}
cleardone:
return result;
}
#ifdef VISION_TABLES
/*===========================================================================*\
GENERAL LINE OF SIGHT
Algorithm D
\*===========================================================================*/
/*
* Indicate caller for the shadow routines.
*/
#define FROM_RIGHT 0
#define FROM_LEFT 1
/*
* Include the table definitions.
*/
#include "vis_tab.h"
/* 3D table pointers. */
static close2d *close_dy[CLOSE_MAX_BC_DY];
static far2d *far_dy[FAR_MAX_BC_DY];
static void FDECL(right_side, (int,int,int,int,int,int,int,char*));
static void FDECL(left_side, (int,int,int,int,int,int,int,char*));
static int FDECL(close_shadow, (int,int,int,int));
static int FDECL(far_shadow, (int,int,int,int));
/*
* Initialize algorithm D's table pointers. If we don't have these,
* then we do 3D table lookups. Verrrry slow.
*/
static void
view_init()
{
int i;
for (i = 0; i < CLOSE_MAX_BC_DY; i++)
close_dy[i] = &close_table[i];
for (i = 0; i < FAR_MAX_BC_DY; i++)
far_dy[i] = &far_table[i];
}
/*
* If the far table has an entry of OFF_TABLE, then the far block prevents
* us from seeing the location just above/below it. I.e. the first visible
* location is one *before* the block.
*/
#define OFF_TABLE 0xff
static int
close_shadow(side,this_row,block_row,block_col)
int side,this_row,block_row,block_col;
{
register int sdy, sdx, pdy, offset;
/*
* If on the same column (block_row = -1), then we can see it.
*/
if (block_row < 0) return block_col;
/* Take explicit absolute values. Adjust. */
if ((sdy = (start_row-block_row)) < 0) sdy = -sdy; --sdy; /* src dy */
if ((sdx = (start_col-block_col)) < 0) sdx = -sdx; /* src dx */
if ((pdy = (block_row-this_row)) < 0) pdy = -pdy; /* point dy */
if (sdy < 0 || sdy >= CLOSE_MAX_SB_DY || sdx >= CLOSE_MAX_SB_DX ||
pdy >= CLOSE_MAX_BC_DY) {
impossible("close_shadow: bad value");
return block_col;
}
offset = close_dy[sdy]->close[sdx][pdy];
if (side == FROM_RIGHT)
return block_col + offset;
return block_col - offset;
}
static int
far_shadow(side,this_row,block_row,block_col)
int side,this_row,block_row,block_col;
{
register int sdy, sdx, pdy, offset;
/*
* Take care of a bug that shows up only on the borders.
*
* If the block is beyond the border, then the row is negative. Return
* the block's column number (should be 0 or COLNO-1).
*
* Could easily have the column be -1, but then wouldn't know if it was
* the left or right border.
*/
if (block_row < 0) return block_col;
/* Take explicit absolute values. Adjust. */
if ((sdy = (start_row-block_row)) < 0) sdy = -sdy; /* src dy */
if ((sdx = (start_col-block_col)) < 0) sdx = -sdx; --sdx; /* src dx */
if ((pdy = (block_row-this_row)) < 0) pdy = -pdy; --pdy; /* point dy */
if (sdy >= FAR_MAX_SB_DY || sdx < 0 || sdx >= FAR_MAX_SB_DX ||
pdy < 0 || pdy >= FAR_MAX_BC_DY) {
impossible("far_shadow: bad value");
return block_col;
}
if ((offset = far_dy[sdy]->far_q[sdx][pdy]) == OFF_TABLE) offset = -1;
if (side == FROM_RIGHT)
return block_col + offset;
return block_col - offset;
}
/*
* right_side()
*
* Figure out what could be seen on the right side of the source.
*/
static void
right_side(row, cb_row, cb_col, fb_row, fb_col, left, right_mark, limits)
int row; /* current row */
int cb_row, cb_col; /* close block row and col */
int fb_row, fb_col; /* far block row and col */
int left; /* left mark of the previous row */
int right_mark; /* right mark of previous row */
char *limits; /* points at range limit for current row, or NULL */
{
register int i;
register char *rowp;
int hit_stone = 0;
int left_shadow, right_shadow, loc_right;
int lblock_col; /* local block column (current row) */
int nrow, deeper;
char *row_min; /* left most */
char *row_max; /* right most */
int lim_max; /* right most limit of circle */
nrow = row + step;
deeper = good_row(nrow) && (!limits || (*limits >= *(limits+1)));
if(!vis_func) {
rowp = cs_rows[row];
row_min = &cs_left[row];
row_max = &cs_right[row];
}
if(limits) {
lim_max = start_col + *limits;
if(lim_max > COLNO-1) lim_max = COLNO-1;
if(right_mark > lim_max) right_mark = lim_max;
limits++; /* prepare for next row */
} else
lim_max = COLNO-1;
/*
* Get the left shadow from the close block. This value could be
* illegal.
*/
left_shadow = close_shadow(FROM_RIGHT,row,cb_row,cb_col);
/*
* Mark all stone walls as seen before the left shadow. All this work
* for a special case.
*
* NOTE. With the addition of this code in here, it is now *required*
* for the algorithm to work correctly. If this is commented out,
* change the above assignment so that left and not left_shadow is the
* variable that gets the shadow.
*/
while (left <= right_mark) {
loc_right = right_ptrs[row][left];
if(loc_right > lim_max) loc_right = lim_max;
if (viz_clear_rows[row][left]) {
if (loc_right >= left_shadow) {
left = left_shadow; /* opening ends beyond shadow */
break;
}
left = loc_right;
loc_right = right_ptrs[row][left];
if(loc_right > lim_max) loc_right = lim_max;
if (left == loc_right) return; /* boundary */
/* Shadow covers opening, beyond right mark */
if (left == right_mark && left_shadow > right_mark) return;
}
if (loc_right > right_mark) /* can't see stone beyond the mark */
loc_right = right_mark;
if(vis_func) {
for (i = left; i <= loc_right; i++) (*vis_func)(i, row, varg);
} else {
for (i = left; i <= loc_right; i++) set_cs(rowp,i);
set_min(left); set_max(loc_right);
}
if (loc_right == right_mark) return; /* all stone */
if (loc_right >= left_shadow) hit_stone = 1;
left = loc_right + 1;
}
/*
* At this point we are at the first visible clear spot on or beyond
* the left shadow, unless the left shadow is an illegal value. If we
* have "hit stone" then we have a stone wall just to our left.
*/
/*
* Get the right shadow. Make sure that it is a legal value.
*/
if ((right_shadow = far_shadow(FROM_RIGHT,row,fb_row,fb_col)) >= COLNO)
right_shadow = COLNO-1;
/*
* Make vertical walls work the way we want them. In this case, we
* note when the close block blocks the column just above/beneath
* it (right_shadow < fb_col [actually right_shadow == fb_col-1]). If
* the location is filled, then we want to see it, so we put the
* right shadow back (same as fb_col).
*/
if (right_shadow < fb_col && !viz_clear_rows[row][fb_col])
right_shadow = fb_col;
if(right_shadow > lim_max) right_shadow = lim_max;
/*
* Main loop. Within the range of sight of the previous row, mark all
* stone walls as seen. Follow open areas recursively.
*/
while (left <= right_mark) {
/* Get the far right of the opening or wall */
loc_right = right_ptrs[row][left];
if(loc_right > lim_max) loc_right = lim_max;
if (!viz_clear_rows[row][left]) {
hit_stone = 1; /* use stone on this row as close block */
/*
* We can see all of the wall until the next open spot or the
* start of the shadow caused by the far block (right).
*
* Can't see stone beyond the right mark.
*/
if (loc_right > right_mark) loc_right = right_mark;
if(vis_func) {
for (i = left; i <= loc_right; i++) (*vis_func)(i, row, varg);
} else {
for (i = left; i <= loc_right; i++) set_cs(rowp,i);
set_min(left); set_max(loc_right);
}
if (loc_right == right_mark) return; /* hit the end */
left = loc_right + 1;
loc_right = right_ptrs[row][left];
if(loc_right > lim_max) loc_right = lim_max;
/* fall through... we know at least one position is visible */
}
/*
* We are in an opening.
*
* If this is the first open spot since the could see area (this is
* true if we have hit stone), get the shadow generated by the wall
* just to our left.
*/
if (hit_stone) {
lblock_col = left-1; /* local block column */
left = close_shadow(FROM_RIGHT,row,row,lblock_col);
if (left > lim_max) break; /* off the end */
}
/*
* Check if the shadow covers the opening. If it does, then
* move to end of the opening. A shadow generated on from a
* wall on this row does *not* cover the wall on the right
* of the opening.
*/
if (left >= loc_right) {
if (loc_right == lim_max) { /* boundary */
if (left == lim_max) {
if(vis_func) (*vis_func)(lim_max, row, varg);
else {
set_cs(rowp,lim_max); /* last pos */
set_max(lim_max);
}
}
return; /* done */
}
left = loc_right;
continue;
}
/*
* If the far wall of the opening (loc_right) is closer than the
* shadow limit imposed by the far block (right) then use the far
* wall as our new far block when we recurse.
*
* If the limits are the the same, and the far block really exists
* (fb_row >= 0) then do the same as above.
*
* Normally, the check would be for the far wall being closer OR EQUAL
* to the shadow limit. However, there is a bug that arises from the
* fact that the clear area pointers end in an open space (if it
* exists) on a boundary. This then makes a far block exist where it
* shouldn't --- on a boundary. To get around that, I had to
* introduce the concept of a non-existent far block (when the
* row < 0). Next I have to check for it. Here is where that check
* exists.
*/
if ((loc_right < right_shadow) ||
(fb_row >= 0 && loc_right == right_shadow)) {
if(vis_func) {
for (i = left; i <= loc_right; i++) (*vis_func)(i, row, varg);
} else {
for (i = left; i <= loc_right; i++) set_cs(rowp,i);
set_min(left); set_max(loc_right);
}
if (deeper) {
if (hit_stone)
right_side(nrow,row,lblock_col,row,loc_right,
left,loc_right,limits);
else
right_side(nrow,cb_row,cb_col,row,loc_right,
left,loc_right,limits);
}
/*
* The following line, setting hit_stone, is needed for those
* walls that are only 1 wide. If hit stone is *not* set and
* the stone is only one wide, then the close block is the old
* one instead one on the current row. A way around having to
* set it here is to make left = loc_right (not loc_right+1) and
* let the outer loop take care of it. However, if we do that
* then we then have to check for boundary conditions here as
* well.
*/
hit_stone = 1;
left = loc_right+1;
}
/*
* The opening extends beyond the right mark. This means that
* the next far block is the current far block.
*/
else {
if(vis_func) {
for (i=left; i <= right_shadow; i++) (*vis_func)(i, row, varg);
} else {
for (i = left; i <= right_shadow; i++) set_cs(rowp,i);
set_min(left); set_max(right_shadow);
}
if (deeper) {
if (hit_stone)
right_side(nrow, row,lblock_col,fb_row,fb_col,
left,right_shadow,limits);
else
right_side(nrow,cb_row, cb_col,fb_row,fb_col,
left,right_shadow,limits);
}
return; /* we're outta here */
}
}
}
/*
* left_side()
*
* This routine is the mirror image of right_side(). Please see right_side()
* for blow by blow comments.
*/
static void
left_side(row, cb_row, cb_col, fb_row, fb_col, left_mark, right, limits)
int row; /* the current row */
int cb_row, cb_col; /* close block row and col */
int fb_row, fb_col; /* far block row and col */
int left_mark; /* left mark of previous row */
int right; /* right mark of the previous row */
char *limits;
{
register int i;
register char *rowp;
int hit_stone = 0;
int left_shadow, right_shadow, loc_left;
int lblock_col; /* local block column (current row) */
int nrow, deeper;
char *row_min; /* left most */
char *row_max; /* right most */
int lim_min;
nrow = row + step;
deeper = good_row(nrow) && (!limits || (*limits >= *(limits+1)));
if(!vis_func) {
rowp = cs_rows[row];
row_min = &cs_left[row];
row_max = &cs_right[row];
}
if(limits) {
lim_min = start_col - *limits;
if(lim_min < 0) lim_min = 0;
if(left_mark < lim_min) left_mark = lim_min;
limits++; /* prepare for next row */
} else
lim_min = 0;
/* This value could be illegal. */
right_shadow = close_shadow(FROM_LEFT,row,cb_row,cb_col);
while ( right >= left_mark ) {
loc_left = left_ptrs[row][right];
if(loc_left < lim_min) loc_left = lim_min;
if (viz_clear_rows[row][right]) {
if (loc_left <= right_shadow) {
right = right_shadow; /* opening ends beyond shadow */
break;
}
right = loc_left;
loc_left = left_ptrs[row][right];
if(loc_left < lim_min) loc_left = lim_min;
if (right == loc_left) return; /* boundary */
}
if (loc_left < left_mark) /* can't see beyond the left mark */
loc_left = left_mark;
if(vis_func) {
for (i = loc_left; i <= right; i++) (*vis_func)(i, row, varg);
} else {
for (i = loc_left; i <= right; i++) set_cs(rowp,i);
set_min(loc_left); set_max(right);
}
if (loc_left == left_mark) return; /* all stone */
if (loc_left <= right_shadow) hit_stone = 1;
right = loc_left - 1;
}
/* At first visible clear spot on or beyond the right shadow. */
if ((left_shadow = far_shadow(FROM_LEFT,row,fb_row,fb_col)) < 0)
left_shadow = 0;
/* Do vertical walls as we want. */
if (left_shadow > fb_col && !viz_clear_rows[row][fb_col])
left_shadow = fb_col;
if(left_shadow < lim_min) left_shadow = lim_min;
while (right >= left_mark) {
loc_left = left_ptrs[row][right];
if (!viz_clear_rows[row][right]) {
hit_stone = 1; /* use stone on this row as close block */
/* We can only see walls until the left mark */
if (loc_left < left_mark) loc_left = left_mark;
if(vis_func) {
for (i = loc_left; i <= right; i++) (*vis_func)(i, row, varg);
} else {
for (i = loc_left; i <= right; i++) set_cs(rowp,i);
set_min(loc_left); set_max(right);
}
if (loc_left == left_mark) return; /* hit end */
right = loc_left - 1;
loc_left = left_ptrs[row][right];
if (loc_left < lim_min) loc_left = lim_min;
/* fall through...*/
}
/* We are in an opening. */
if (hit_stone) {
lblock_col = right+1; /* stone block (local) */
right = close_shadow(FROM_LEFT,row,row,lblock_col);
if (right < lim_min) return; /* off the end */
}
/* Check if the shadow covers the opening. */
if (right <= loc_left) {
/* Make a boundary condition work. */
if (loc_left == lim_min) { /* at boundary */
if (right == lim_min) {
if(vis_func) (*vis_func)(lim_min, row, varg);
else {
set_cs(rowp,lim_min); /* caught the last pos */
set_min(lim_min);
}
}
return; /* and break out the loop */
}
right = loc_left;
continue;
}
/* If the far wall of the opening is closer than the shadow limit. */
if ((loc_left > left_shadow) ||
(fb_row >= 0 && loc_left == left_shadow)) {
if(vis_func) {
for (i = loc_left; i <= right; i++) (*vis_func)(i, row, varg);
} else {
for (i = loc_left; i <= right; i++) set_cs(rowp,i);
set_min(loc_left); set_max(right);
}
if (deeper) {
if (hit_stone)
left_side(nrow,row,lblock_col,row,loc_left,
loc_left,right,limits);
else
left_side(nrow,cb_row,cb_col,row,loc_left,
loc_left,right,limits);
}
hit_stone = 1; /* needed for walls of width 1 */
right = loc_left-1;
}
/* The opening extends beyond the left mark. */
else {
if(vis_func) {
for (i=left_shadow; i <= right; i++) (*vis_func)(i, row, varg);
} else {
for (i = left_shadow; i <= right; i++) set_cs(rowp,i);
set_min(left_shadow); set_max(right);
}
if (deeper) {
if (hit_stone)
left_side(nrow,row,lblock_col,fb_row,fb_col,
left_shadow,right,limits);
else
left_side(nrow,cb_row,cb_col,fb_row,fb_col,
left_shadow,right,limits);
}
return; /* we're outta here */
}
}
}
/*
* view_from
*
* Calculate a view from the given location. Initialize and fill a
* ROWNOxCOLNO array (could_see) with all the locations that could be
* seen from the source location. Initialize and fill the left most
* and right most boundaries of what could be seen.
*/
static void
view_from(srow,scol,loc_cs_rows,left_most,right_most, range, func, arg)
int srow, scol; /* source row and column */
char **loc_cs_rows; /* could_see array (row pointers) */
char *left_most, *right_most; /* limits of what could be seen */
int range; /* 0 if unlimited */
void FDECL((*func), (int,int,genericptr_t));
genericptr_t arg;
{
register int i;
char *rowp;
int nrow, left, right, left_row, right_row;
char *limits;
/* Set globals for near_shadow(), far_shadow(), etc. to use. */
start_col = scol;
start_row = srow;
cs_rows = loc_cs_rows;
cs_left = left_most;
cs_right = right_most;
vis_func = func;
varg = arg;
/* Find the left and right limits of sight on the starting row. */
if (viz_clear_rows[srow][scol]) {
left = left_ptrs[srow][scol];
right = right_ptrs[srow][scol];
} else {
left = (!scol) ? 0 :
(viz_clear_rows[srow][scol-1] ? left_ptrs[srow][scol-1] : scol-1);
right = (scol == COLNO-1) ? COLNO-1 :
(viz_clear_rows[srow][scol+1] ? right_ptrs[srow][scol+1] : scol+1);
}
if(range) {
if(range > MAX_RADIUS || range < 1)
panic("view_from called with range %d", range);
limits = circle_ptr(range) + 1; /* start at next row */
if(left < scol - range) left = scol - range;
if(right > scol + range) right = scol + range;
} else
limits = (char*) 0;
if(func) {
for (i = left; i <= right; i++) (*func)(i, srow, arg);
} else {
/* Row optimization */
rowp = cs_rows[srow];
/* We know that we can see our row. */
for (i = left; i <= right; i++) set_cs(rowp,i);
cs_left[srow] = left;
cs_right[srow] = right;
}
/* The far block has a row number of -1 if we are on an edge. */
right_row = (right == COLNO-1) ? -1 : srow;
left_row = (!left) ? -1 : srow;
/*
* Check what could be seen in quadrants.
*/
if ( (nrow = srow+1) < ROWNO ) {
step = 1; /* move down */
if (scol<COLNO-1)
right_side(nrow,-1,scol,right_row,right,scol,right,limits);
if (scol)
left_side(nrow,-1,scol,left_row, left, left, scol,limits);
}
if ( (nrow = srow-1) >= 0 ) {
step = -1; /* move up */
if (scol<COLNO-1)
right_side(nrow,-1,scol,right_row,right,scol,right,limits);
if (scol)
left_side(nrow,-1,scol,left_row, left, left, scol,limits);
}
}
#else /*===== End of algorithm D =====*/
/*===========================================================================*\
GENERAL LINE OF SIGHT
Algorithm C
\*===========================================================================*/
/*
* Defines local to Algorithm C.
*/
static void FDECL(right_side, (int,int,int,char*));
static void FDECL(left_side, (int,int,int,char*));
/* Initialize algorithm C (nothing). */
static void
view_init()
{
}
/*
* Mark positions as visible on one quadrant of the right side. The
* quadrant is determined by the value of the global variable step.
*/
static void
right_side(row, left, right_mark, limits)
int row; /* current row */
int left; /* first (left side) visible spot on prev row */
int right_mark; /* last (right side) visible spot on prev row */
char *limits; /* points at range limit for current row, or NULL */
{
int right; /* right limit of "could see" */
int right_edge; /* right edge of an opening */
int nrow; /* new row (calculate once) */
int deeper; /* if TRUE, call self as needed */
int result; /* set by q?_path() */
register int i; /* loop counter */
register char *rowp; /* row optimization */
char *row_min; /* left most [used by macro set_min()] */
char *row_max; /* right most [used by macro set_max()] */
int lim_max; /* right most limit of circle */
#ifdef GCC_WARN
rowp = row_min = row_max = 0;
#endif
nrow = row + step;
/*
* Can go deeper if the row is in bounds and the next row is within
* the circle's limit. We tell the latter by checking to see if the next
* limit value is the start of a new circle radius (meaning we depend
* on the structure of circle_data[]).
*/
deeper = good_row(nrow) && (!limits || (*limits >= *(limits+1)));
if(!vis_func) {
rowp = cs_rows[row]; /* optimization */
row_min = &cs_left[row];
row_max = &cs_right[row];
}
if(limits) {
lim_max = start_col + *limits;
if(lim_max > COLNO-1) lim_max = COLNO-1;
if(right_mark > lim_max) right_mark = lim_max;
limits++; /* prepare for next row */
} else
lim_max = COLNO-1;
while (left <= right_mark) {
right_edge = right_ptrs[row][left];
if(right_edge > lim_max) right_edge = lim_max;
if (!is_clear(row,left)) {
/*
* Jump to the far side of a stone wall. We can set all
* the points in between as seen.
*
* If the right edge goes beyond the right mark, check to see
* how much we can see.
*/
if (right_edge > right_mark) {
/*
* If the mark on the previous row was a clear position,
* the odds are that we can actually see part of the wall
* beyond the mark on this row. If so, then see one beyond
* the mark. Otherwise don't. This is a kludge so corners
* with an adjacent doorway show up in nethack.
*/
right_edge = is_clear(row-step,right_mark) ?
right_mark+1 : right_mark;
}
if(vis_func) {
for (i = left; i <= right_edge; i++) (*vis_func)(i, row, varg);
} else {
for (i = left; i <= right_edge; i++) set_cs(rowp,i);
set_min(left); set_max(right_edge);
}
left = right_edge + 1; /* no limit check necessary */
continue;
}
/* No checking needed if our left side is the start column. */
if (left != start_col) {
/*
* Find the left side. Move right until we can see it or we run
* into a wall.
*/
for (; left <= right_edge; left++) {
if (step < 0) {
q1_path(start_row,start_col,row,left,rside1);
} else {
q4_path(start_row,start_col,row,left,rside1);
}
rside1: /* used if q?_path() is a macro */
if (result) break;
}
/*
* Check for boundary conditions. We *need* check (2) to break
* an infinite loop where:
*
* left == right_edge == right_mark == lim_max.
*
*/
if (left > lim_max) return; /* check (1) */
if (left == lim_max) { /* check (2) */
if(vis_func) (*vis_func)(lim_max, row, varg);
else {
set_cs(rowp,lim_max);
set_max(lim_max);
}
return;
}
/*
* Check if we can see any spots in the opening. We might
* (left == right_edge) or might not (left == right_edge+1) have
* been able to see the far wall. Make sure we *can* see the
* wall (remember, we can see the spot above/below this one)
* by backing up.
*/
if (left >= right_edge) {
left = right_edge; /* for the case left == right_edge+1 */
continue;
}
}
/*
* Find the right side. If the marker from the previous row is
* closer than the edge on this row, then we have to check
* how far we can see around the corner (under the overhang). Stop
* at the first non-visible spot or we actually hit the far wall.
*
* Otherwise, we know we can see the right edge of the current row.
*
* This must be a strict less than so that we can always see a
* horizontal wall, even if it is adjacent to us.
*/
if (right_mark < right_edge) {
for (right = right_mark; right <= right_edge; right++) {
if (step < 0) {
q1_path(start_row,start_col,row,right,rside2);
} else {
q4_path(start_row,start_col,row,right,rside2);
}
rside2: /* used if q?_path() is a macro */
if (!result) break;
}
--right; /* get rid of the last increment */
}
else
right = right_edge;
/*
* We have the range that we want. Set the bits. Note that
* there is no else --- we no longer handle splinters.
*/
if (left <= right) {
/*
* An ugly special case. If you are adjacent to a vertical wall
* and it has a break in it, then the right mark is set to be
* start_col. We *want* to be able to see adjacent vertical
* walls, so we have to set it back.
*/
if (left == right && left == start_col &&
start_col < (COLNO-1) && !is_clear(row,start_col+1))
right = start_col+1;
if(right > lim_max) right = lim_max;
/* set the bits */
if(vis_func)
for (i = left; i <= right; i++) (*vis_func)(i, row, varg);
else {
for (i = left; i <= right; i++) set_cs(rowp,i);
set_min(left); set_max(right);
}
/* recursive call for next finger of light */
if (deeper) right_side(nrow,left,right,limits);
left = right + 1; /* no limit check necessary */
}
}
}
/*
* This routine is the mirror image of right_side(). See right_side() for
* extensive comments.
*/
static void
left_side(row, left_mark, right, limits)
int row, left_mark, right;
char *limits;
{
int left, left_edge, nrow, deeper, result;
register int i;
register char *rowp;
char *row_min, *row_max;
int lim_min;
#ifdef GCC_WARN
rowp = row_min = row_max = 0;
#endif
nrow = row+step;
deeper = good_row(nrow) && (!limits || (*limits >= *(limits+1)));
if(!vis_func) {
rowp = cs_rows[row];
row_min = &cs_left[row];
row_max = &cs_right[row];
}
if(limits) {
lim_min = start_col - *limits;
if(lim_min < 0) lim_min = 0;
if(left_mark < lim_min) left_mark = lim_min;
limits++; /* prepare for next row */
} else
lim_min = 0;
while (right >= left_mark) {
left_edge = left_ptrs[row][right];
if(left_edge < lim_min) left_edge = lim_min;
if (!is_clear(row,right)) {
/* Jump to the far side of a stone wall. */
if (left_edge < left_mark) {
/* Maybe see more (kludge). */
left_edge = is_clear(row-step,left_mark) ?
left_mark-1 : left_mark;
}
if(vis_func) {
for (i = left_edge; i <= right; i++) (*vis_func)(i, row, varg);
} else {
for (i = left_edge; i <= right; i++) set_cs(rowp,i);
set_min(left_edge); set_max(right);
}
right = left_edge - 1; /* no limit check necessary */
continue;
}
if (right != start_col) {
/* Find the right side. */
for (; right >= left_edge; right--) {
if (step < 0) {
q2_path(start_row,start_col,row,right,lside1);
} else {
q3_path(start_row,start_col,row,right,lside1);
}
lside1: /* used if q?_path() is a macro */
if (result) break;
}
/* Check for boundary conditions. */
if (right < lim_min) return;
if (right == lim_min) {
if(vis_func) (*vis_func)(lim_min, row, varg);
else {
set_cs(rowp,lim_min);
set_min(lim_min);
}
return;
}
/* Check if we can see any spots in the opening. */
if (right <= left_edge) {
right = left_edge;
continue;
}
}
/* Find the left side. */
if (left_mark > left_edge) {
for (left = left_mark; left >= left_edge; --left) {
if (step < 0) {
q2_path(start_row,start_col,row,left,lside2);
} else {
q3_path(start_row,start_col,row,left,lside2);
}
lside2: /* used if q?_path() is a macro */
if (!result) break;
}
left++; /* get rid of the last decrement */
}
else
left = left_edge;
if (left <= right) {
/* An ugly special case. */
if (left == right && right == start_col &&
start_col > 0 && !is_clear(row,start_col-1))
left = start_col-1;
if(left < lim_min) left = lim_min;
if(vis_func)
for (i = left; i <= right; i++) (*vis_func)(i, row, varg);
else {
for (i = left; i <= right; i++) set_cs(rowp,i);
set_min(left); set_max(right);
}
/* Recurse */
if (deeper) left_side(nrow,left,right,limits);
right = left - 1; /* no limit check necessary */
}
}
}
/*
* Calculate all possible visible locations from the given location
* (srow,scol). NOTE this is (y,x)! Mark the visible locations in the
* array provided.
*/
static void
view_from(srow, scol, loc_cs_rows, left_most, right_most, range, func, arg)
int srow, scol; /* starting row and column */
char **loc_cs_rows; /* pointers to the rows of the could_see array */
char *left_most; /* min mark on each row */
char *right_most; /* max mark on each row */
int range; /* 0 if unlimited */
void FDECL((*func), (int,int,genericptr_t));
genericptr_t arg;
{
register int i; /* loop counter */
char *rowp; /* optimization for setting could_see */
int nrow; /* the next row */
int left; /* the left-most visible column */
int right; /* the right-most visible column */
char *limits; /* range limit for next row */
/* Set globals for q?_path(), left_side(), and right_side() to use. */
start_col = scol;
start_row = srow;
cs_rows = loc_cs_rows; /* 'could see' rows */
cs_left = left_most;
cs_right = right_most;
vis_func = func;
varg = arg;
/*
* Determine extent of sight on the starting row.
*/
if (is_clear(srow,scol)) {
left = left_ptrs[srow][scol];
right = right_ptrs[srow][scol];
} else {
/*
* When in stone, you can only see your adjacent squares, unless
* you are on an array boundary or a stone/clear boundary.
*/
left = (!scol) ? 0 :
(is_clear(srow,scol-1) ? left_ptrs[srow][scol-1] : scol-1);
right = (scol == COLNO-1) ? COLNO-1 :
(is_clear(srow,scol+1) ? right_ptrs[srow][scol+1] : scol+1);
}
if(range) {
if(range > MAX_RADIUS || range < 1)
panic("view_from called with range %d", range);
limits = circle_ptr(range) + 1; /* start at next row */
if(left < scol - range) left = scol - range;
if(right > scol + range) right = scol + range;
} else
limits = (char*) 0;
if(func) {
for (i = left; i <= right; i++) (*func)(i, srow, arg);
} else {
/* Row pointer optimization. */
rowp = cs_rows[srow];
/* We know that we can see our row. */
for (i = left; i <= right; i++) set_cs(rowp,i);
cs_left[srow] = left;
cs_right[srow] = right;
}
/*
* Check what could be seen in quadrants. We need to check for valid
* rows here, since we don't do it in the routines right_side() and
* left_side() [ugliness to remove extra routine calls].
*/
if ( (nrow = srow+1) < ROWNO ) { /* move down */
step = 1;
if (scol < COLNO-1) right_side(nrow, scol, right, limits);
if (scol) left_side (nrow, left, scol, limits);
}
if ( (nrow = srow-1) >= 0 ) { /* move up */
step = -1;
if (scol < COLNO-1) right_side(nrow, scol, right, limits);
if (scol) left_side (nrow, left, scol, limits);
}
}
#endif /*===== End of algorithm C =====*/
/*
* AREA OF EFFECT "ENGINE"
*
* Calculate all possible visible locations as viewed from the given location
* (srow,scol) within the range specified. Perform "func" with (x, y) args and
* additional argument "arg" for each square.
*
* If not centered on the hero, just forward arguments to view_from(); it
* will call "func" when necessary. If the hero is the center, use the
* vision matrix and reduce extra work.
*/
void
do_clear_area(scol,srow,range,func,arg)
int scol, srow, range;
void FDECL((*func), (int,int,genericptr_t));
genericptr_t arg;
{
/* If not centered on hero, do the hard work of figuring the area */
if (scol != u.ux || srow != u.uy)
view_from(srow, scol, (char **)0, NULL, NULL, range, func, arg);
else {
register int x;
int y, min_x, max_x, max_y, offset;
char *limits;
if (range > MAX_RADIUS || range < 1)
panic("do_clear_area: illegal range %d", range);
if(vision_full_recalc)
vision_recalc(0); /* recalc vision if dirty */
limits = circle_ptr(range);
if ((max_y = (srow + range)) >= ROWNO) max_y = ROWNO-1;
if ((y = (srow - range)) < 0) y = 0;
for (; y <= max_y; y++) {
offset = limits[abs(y-srow)];
if((min_x = (scol - offset)) < 0) min_x = 0;
if((max_x = (scol + offset)) >= COLNO) max_x = COLNO-1;
for (x = min_x; x <= max_x; x++)
if (couldsee(x, y))
(*func)(x, y, arg);
}
}
}
/*vision.c*/
