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nethack/src/vision.c
PatR f61cfe7e48 pacify static analyzer - vision.c 
Include some assertions to convince the analyzer that some pointers
can't be Null.  They're Null if 'vis_func' is non-Null but only used
when that function pointer is Null and they have values.

If there's a macro that's defined when the analyzer is running and
undefined when not--or vice versa--it could be used to control NDEBUG
and avoid the assertion code when not analyzing.  That's a bit like
using fake code to pacify 'lint'; however, since the assertions should
never fail, suppressing them isn't really switching to fake code.

I reordered a couple of macros so that the set of them matches the
comment which precedes them and refers to "the last three".  It is
referring to the three within the block comment rather than the macro
defintions but putting those in the same order removes any ambiguity.
2023-01-18 11:57:49 -08:00

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/* NetHack 3.7 vision.c $NHDT-Date: 1657918095 2022/07/15 20:48:15 $ $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.49 $ */
/* Copyright (c) Dean Luick, with acknowledgements to Dave Cohrs, 1990. */
/* NetHack may be freely redistributed. See license for details. */
#include "hack.h"
#include <assert.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
*
*/
const coordxy circle_data[] = {
/* 0*/ 0,
/* 1*/ 1, 1,
/* 3*/ 2, 2, 1,
/* 6*/ 3, 3, 2, 1,
/* 10*/ 4, 4, 4, 3, 2,
/* 15*/ 5, 5, 5, 4, 3, 2,
/* 21*/ 6, 6, 6, 5, 5, 4, 2,
/* 28*/ 7, 7, 7, 6, 6, 5, 4, 2,
/* 36*/ 8, 8, 8, 7, 7, 6, 6, 4, 2,
/* 45*/ 9, 9, 9, 9, 8, 8, 7, 6, 5, 3,
/* 55*/ 10, 10, 10, 10, 9, 9, 8, 7, 6, 5, 3,
/* 66*/ 11, 11, 11, 11, 10, 10, 9, 9, 8, 7, 5, 3,
/* 78*/ 12, 12, 12, 12, 11, 11, 10, 10, 9, 8, 7, 5, 3,
/* 91*/ 13, 13, 13, 13, 12, 12, 12, 11, 10, 10, 9, 7, 6, 3,
/*105*/ 14, 14, 14, 14, 13, 13, 13, 12, 12, 11, 10, 9, 8, 6, 3,
/*120*/ 15, 15, 15, 15, 14, 14, 14, 13, 13, 12, 11, 10, 9, 8, 6, 3,
/*136*/ 16 /* 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. Radius 0 used to be unused, but is now
* used for a single point: temporary light source of a camera flash
* as it traverses its path.
*/
const coordxy circle_start[] = {
/* 0*/ 0,
/* 1*/ 1,
/* 2*/ 3,
/* 3*/ 6,
/* 4*/ 10,
/* 5*/ 15,
/* 6*/ 21,
/* 7*/ 38,
/* 8*/ 36,
/* 9*/ 45,
/*10*/ 55,
/*11*/ 66,
/*12*/ 78,
/*13*/ 91,
/*14*/ 105,
/*15*/ 120,
};
/*==========================================================================*/
/* Vision (arbitrary line of sight)
* =========================================*/
/*------ local variables ------*/
static seenV could_see[2][ROWNO][COLNO]; /* vision work space */
static seenV *cs_rows0[ROWNO], *cs_rows1[ROWNO];
static coordxy cs_rmin0[ROWNO], cs_rmax0[ROWNO];
static coordxy cs_rmin1[ROWNO], cs_rmax1[ROWNO];
static char viz_clear[ROWNO][COLNO]; /* vision clear/blocked map */
static char *viz_clear_rows[ROWNO];
static coordxy left_ptrs[ROWNO][COLNO]; /* LOS algorithm helpers */
static coordxy right_ptrs[ROWNO][COLNO];
/* Forward declarations. */
static void fill_point(int, int);
static void dig_point(int, int);
static void view_init(void);
static void view_from(coordxy, coordxy, seenV **, coordxy *, coordxy *, int,
void (*)(coordxy, coordxy, genericptr_t),
genericptr_t);
static void get_unused_cs(seenV ***, coordxy **, coordxy **);
static void rogue_vision(seenV **, coordxy *, coordxy *);
/* Macro definitions that I can't find anywhere. */
#define sign(z) ((z) < 0 ? -1 : ((z) ? 1 : 0))
#define v_abs(z) ((z) < 0 ? -(z) : (z)) /* don't use abs -- it may exist */
/*
* 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(void)
{
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 */
gv.viz_array = cs_rows0;
gv.viz_rmin = cs_rmin0;
gv.viz_rmax = cs_rmax0;
gv.vision_full_recalc = 0;
(void) memset((genericptr_t) could_see, 0, sizeof(could_see));
/* Initialize the vision algorithm (currently C). */
view_init();
}
/*
* does_block()
*
* Returns true if something at (x,y) blocks sight.
*/
int
does_block(int x, int y, struct rm *lev)
{
struct obj *obj;
struct monst *mon;
int i;
#ifdef DEBUG
/* set DEBUGFILES=seethru in environment to see through bubbles */
if (gs.seethru == 0) { /* init once */
gs.seethru = (wizard && explicitdebug("seethru")) ? 1 : -1;
}
#endif
/* Features that block . . */
if (IS_ROCK(lev->typ) || lev->typ == TREE
|| (IS_DOOR(lev->typ)
&& (lev->doormask & (D_CLOSED | D_LOCKED | D_TRAPPED))))
return 1;
#ifdef DEBUG
if (gs.seethru != 1) {
#endif
if (lev->typ == CLOUD || IS_WATERWALL(lev->typ)
|| (Underwater && is_moat(x, y)))
return 1;
#ifdef DEBUG
} /* gs.seethru */
#endif
/* Boulders block light. */
for (obj = gl.level.objects[x][y]; obj; obj = obj->nexthere)
if (obj->otyp == BOULDER)
return 1;
/* Mimics mimicing a door or boulder or ... block light. */
if ((mon = m_at(x, y)) && (!mon->minvis || See_invisible)
&& is_lightblocker_mappear(mon))
return 1;
#ifdef DEBUG
if (gs.seethru != 1) {
#endif
/* Clouds (poisonous or not) block light. */
for (i = 0; i < gn.n_regions; i++) {
/* Ignore regions with ttl == 0 - expire_gas_cloud must unblock its
* points prior to being removed itself. */
if (gr.regions[i]->ttl > 0 && gr.regions[i]->visible
&& inside_region(gr.regions[i], x, y)) {
return 1;
}
}
#ifdef DEBUG
} /* gs.seethru */
#endif
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(void)
{
int y;
register int x, i, dig_left, block;
register struct rm *lev;
/* Start out with cs0 as our current array */
gv.viz_array = cs_rows0;
gv.viz_rmin = cs_rmin0;
gv.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;
}
}
iflags.vision_inited = 1; /* vision is ready */
gv.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(seenV ***rows, coordxy **rmin, coordxy **rmax)
{
register int row;
register coordxy *nrmin, *nrmax;
if (gv.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 * sizeof (seenV)); /* see nothing */
for (row = 0; row < ROWNO; row++) { /* set row min & max */
*nrmin++ = COLNO - 1;
*nrmax++ = 1;
}
}
/*
* 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(seenV **next, coordxy *rmin, coordxy *rmax)
{
int rnum = levl[u.ux][u.uy].roomno - ROOMOFFSET; /* no SHARED... */
int start, stop, in_door, xhi, xlo, yhi, ylo;
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 = gr.rooms[rnum].ly - 1; zy <= gr.rooms[rnum].hy + 1; zy++) {
rmin[zy] = start = gr.rooms[rnum].lx - 1;
rmax[zy] = stop = gr.rooms[rnum].hx + 1;
for (zx = start; zx <= stop; zx++) {
if (gr.rooms[rnum].rlit) {
next[zy][zx] = COULD_SEE | IN_SIGHT;
levl[zx][zy].seenv = SVALL; /* see the walls */
} else
next[zy][zx] = COULD_SEE;
}
}
}
in_door = levl[u.ux][u.uy].typ == DOOR;
/* Can always see adjacent. */
ylo = max(u.uy - 1, 0);
yhi = min(u.uy + 1, ROWNO - 1);
xlo = max(u.ux - 1, 1);
xhi = min(u.ux + 1, COLNO - 1);
for (zy = ylo; zy <= yhi; zy++) {
if (xlo < rmin[zy])
rmin[zy] = xlo;
if (xhi > rmax[zy])
rmax[zy] = xhi;
for (zx = xlo; zx <= xhi; 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 bits are 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);
}
}
}
/*#define EXTEND_SPINE*/ /* possibly better looking wall-angle */
#ifdef EXTEND_SPINE
static int new_angle(struct rm *, unsigned char *, int, int);
/*
* new_angle()
*
* Return the new angle seen by the hero for this location. The angle
* bit is given in the value pointed at by sv.
*
* For T walls and crosswall, just setting the angle bit, even though
* it is technically correct, doesn't look good. If we can see the
* next position beyond the current one and it is a wall that we can
* see, then we want to extend a spine of the T to connect with the wall
* that is beyond. Example:
*
* Correct, but ugly Extend T spine
*
* | ... | ...
* | ... <-- wall beyond & floor --> | ...
* | ... | ...
* Unseen --> ... | ...
* spine +-... <-- trwall & doorway --> +-...
* | ... | ...
*
*
* @ <-- hero --> @
*
*
* We fake the above check by only checking if the horizontal
* & vertical positions adjacent to the crosswall and T wall are
* unblocked. Then, _in general_ we can see beyond. Generally,
* this is good enough.
*
* + When this function is called we don't have all of the seen
* information (we're doing a top down scan in vision_recalc).
* We would need to scan once to set all IN_SIGHT and COULD_SEE
* bits, then again to correctly set the seenv bits.
* + I'm trying to make this as cheap as possible. The display
* & vision eat up too much CPU time.
*
*
* Note: Even as I write this, I'm still not convinced. There are too
* many exceptions. I may have to bite the bullet and do more
* checks. - Dean 2/11/93
*/
static int
new_angle(struct rm *lev, unsigned char *sv, int row, int col)
{
register int res = *sv;
/*
* Do extra checks for crosswalls and T walls if we see them from
* an angle.
*/
if (lev->typ >= CROSSWALL && lev->typ <= TRWALL) {
switch (res) {
case SV0:
if (col > 0 && viz_clear[row][col - 1])
res |= SV7;
if (row > 0 && viz_clear[row - 1][col])
res |= SV1;
break;
case SV2:
if (row > 0 && viz_clear[row - 1][col])
res |= SV1;
if (col < COLNO - 1 && viz_clear[row][col + 1])
res |= SV3;
break;
case SV4:
if (col < COLNO - 1 && viz_clear[row][col + 1])
res |= SV3;
if (row < ROWNO - 1 && viz_clear[row + 1][col])
res |= SV5;
break;
case SV6:
if (row < ROWNO - 1 && viz_clear[row + 1][col])
res |= SV5;
if (col > 0 && viz_clear[row][col - 1])
res |= SV7;
break;
}
}
return res;
}
#else
/*
* new_angle()
*
* Return the new angle seen by the hero for this location. The angle
* bit is given in the value pointed at by sv.
*
* The other parameters are not used.
*/
#define new_angle(lev, sv, row, col) (*sv)
#endif
/*
* 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()]
* + When toggling temporary blindness, in case additional events
* impacted by vision occur during the same move [make_blinded()]
*
* 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(int control)
{
extern const seenV seenv_matrix[3][3]; /* from display.c */
static coordxy colbump[COLNO + 1]; /* cols to bump sv */
seenV **temp_array; /* points to the old vision array */
seenV **next_array; /* points to the new vision array */
seenV *next_row; /* row pointer for the new array */
seenV *old_row; /* row pointer for the old array */
coordxy *next_rmin; /* min pointer for the new array */
coordxy *next_rmax; /* max pointer for the new array */
const coordxy *ranges; /* circle ranges -- used for xray & night vision */
int row = 0; /* 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 */
const seenV *sv; /* ptr to seen angle bits */
int oldseenv; /* previous seenv value */
gv.vision_full_recalc = 0; /* reset flag */
if (gi.in_mklev || !iflags.vision_inited)
return;
/*
* 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 can see you even when you're in a pit.
*/
view_from(u.uy, u.ux, next_array, next_rmin, next_rmax, 0,
(void (*)(coordxy, coordxy, genericptr_t)) 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 = gv.viz_array; /* set gv.viz_array so newsym() will work */
gv.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(gv.viz_rmin[row], next_rmin[row]);
stop = max(gv.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;
} else if (Is_rogue_level(&u.uz)) {
rogue_vision(next_array, next_rmin, next_rmax);
} else {
int lo_col, 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;
lo_col = max(u.ux - 1, 1);
for (row = u.uy - 1; row <= u.uy + 1; row++)
for (col = lo_col; 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 | COULD_SEE;
}
/* 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(1, 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 | COULD_SEE;
}
} else
view_from(u.uy, u.ux, next_array, next_rmin, next_rmax, 0,
(void (*)(coordxy, coordxy, genericptr_t)) 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 = v_abs(u.uy - row);
next_row = next_array[row];
start = max(1, u.ux - ranges[dy]);
stop = min(COLNO - 1, u.ux + ranges[dy]);
for (col = start; col <= stop; col++) {
char old_row_val = next_row[col];
next_row[col] |= IN_SIGHT;
oldseenv = levl[col][row].seenv;
levl[col][row].seenv = SVALL; /* see all! */
/* Update if previously not in sight or new angle. */
if (!(old_row_val & IN_SIGHT) || oldseenv != SVALL)
newsym(col, row);
}
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].seenv = SVALL;
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].seenv = SVALL;
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 = v_abs(u.uy - row);
next_row = next_array[row];
start = max(1, 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]);
}
}
}
}
/* Set the correct bits for all light sources. */
do_light_sources(next_array);
/*
* Make the viz_array the new array so that cansee() will work correctly.
*/
temp_array = gv.viz_array;
gv.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 is one thing that make deciding what the hero can see
* difficult:
*
* 1. 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.
*/
colbump[u.ux] = colbump[u.ux + 1] = 1;
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(gv.viz_rmin[row], next_rmin[row]);
stop = max(gv.viz_rmax[row], next_rmax[row]);
lev = &levl[start][row];
sv = &seenv_matrix[dy + 1][start < u.ux ? 0 : (start > u.ux ? 2 : 1)];
for (col = start; col <= stop;
lev += ROWNO, sv += (int) colbump[++col]) {
if (next_row[col] & IN_SIGHT) {
/*
* We see this position because of night- or xray-vision.
*/
oldseenv = lev->seenv;
lev->seenv |=
new_angle(lev, sv, row, col); /* update seen angle */
/* Update pos if previously not in sight or new angle. */
if (!(old_row[col] & IN_SIGHT) || oldseenv != lev->seenv)
newsym(col, row);
} else if ((next_row[col] & COULD_SEE)
&& (lev->lit || (next_row[col] & TEMP_LIT))) {
/*
* We see this position because it is lit.
*/
if ((IS_DOOR(lev->typ) || lev->typ == SDOOR
|| IS_WALL(lev->typ)) && !viz_clear[row][col]) {
/*
* Make sure doors, walls, 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 or wall, otherwise we can't.
*/
dx = u.ux - col;
dx = sign(dx);
flev = &(levl[col + dx][row + dy]);
if (flev->lit
|| next_array[row + dy][col + dx] & TEMP_LIT) {
next_row[col] |= IN_SIGHT; /* we see it */
oldseenv = lev->seenv;
lev->seenv |= new_angle(lev, sv, row, col);
/* Update pos if previously not in sight or new
* angle.*/
if (!(old_row[col] & IN_SIGHT)
|| oldseenv != lev->seenv)
newsym(col, row);
} else
goto not_in_sight; /* we don't see it */
} else {
next_row[col] |= IN_SIGHT; /* we see it */
oldseenv = lev->seenv;
lev->seenv |= new_angle(lev, sv, row, col);
/* Update pos if previously not in sight or new angle. */
if (!(old_row[col] & IN_SIGHT) || oldseenv != lev->seenv)
newsym(col, row);
}
} else if ((next_row[col] & COULD_SEE) && lev->waslit) {
/*
* If we make it here, the hero _could see_ the location,
* but doesn't see it (location is not lit).
* 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 normal
* sight. That is, the position is could be seen, but is dark
* or LOS is just plain blocked.
*
* Update the position if:
* o If the old one *was* in sight. We may need to clean up
* the glyph -- E.g. darken room spot, etc.
* o If we now could see the location (yet the location is not
* lit), but previously we couldn't see the location, or vice
* versa. Update the spot because there there may be an
* infrared monster there.
*/
} else {
not_in_sight:
if ((old_row[col] & IN_SIGHT)
|| ((next_row[col] & COULD_SEE)
^ (old_row[col] & COULD_SEE)))
newsym(col, row);
}
} /* end for col . . */
} /* end for row . . */
colbump[u.ux] = colbump[u.ux + 1] = 0;
skip:
/* This newsym() caused a crash delivering msg about failure to open
* dungeon file init_dungeons() -> panic() -> done(11) ->
* vision_recalc(2) -> newsym() -> crash! u.ux and u.uy are 0 and
* gp.program_state.panicking == 1 under those circumstances
*/
if (!gp.program_state.panicking)
newsym(u.ux, u.uy); /* Make sure the hero shows up! */
/* Set the new min and max pointers. */
gv.viz_rmin = next_rmin;
gv.viz_rmax = next_rmax;
recalc_mapseen();
}
/*
* block_point()
*
* Make the location opaque to light.
*/
void
block_point(int x, int y)
{
#ifdef DEBUG
/* set DEBUGFILES=seethru in environment to see through clouds & water */
if (gs.seethru == 0) { /* init once */
gs.seethru = (wizard && explicitdebug("seethru")) ? 1 : -1;
}
if (gs.seethru == 1) {
if (!does_block(x, y, &levl[x][y]))
return;
}
#endif
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 (gv.viz_array[y][x])
gv.vision_full_recalc = 1;
}
/*
* unblock_point()
*
* Make the location transparent to light.
*/
void
unblock_point(int x, int y)
{
dig_point(y, x);
/* recalc light sources here? */
if (gv.viz_array[y][x])
gv.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(int row, int 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(int row, int 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];
}
}
/*==========================================================================*/
/*==========================================================================*/
/*
* Variables local to Algorithm C.
*/
static int start_row;
static int start_col;
static int step;
static seenV **cs_rows;
static coordxy *cs_left;
static coordxy *cs_right;
static void (*vis_func)(coordxy, coordxy, genericptr_t);
static genericptr_t varg;
/*
* Algorithm C uses 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.
*
* The assertions are included to pacify a static source code analyzer.
* Compile with NDEBUG defined to suppress them.
*/
#define is_clear(row, col) viz_clear_rows[row][col]
#define good_row(z) ((z) >= 0 && (z) < ROWNO)
#define set_cs(rowp, col) \
do { \
assert(rowp != NULL); \
rowp[col] = COULD_SEE; \
} while (0)
#define set_min(z) \
do { \
assert(row_min != NULL); \
if (*row_min > (z)) \
*row_min = (z); \
} while (0)
#define set_max(z) \
do { \
assert(row_max != NULL); \
if (*row_max < (z)) \
*row_max = (z); \
} while (0)
/*
* 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 /* !MACRO_CPATH -- quadrants are really functions */
static int _q1_path(int, int, int, int);
static int _q2_path(int, int, int, int);
static int _q3_path(int, int, int, int);
static int _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(int scol, int srow, int y2, int 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(int scol, int srow, int y2, int 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(int scol, int srow, int y2, int 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(int scol, int srow, int y2, int 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 /* ?MACRO_CPATH */
/*
* 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()
* do_light_sources()
*/
boolean
clear_path(int col1, int row1, int col2, int 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);
}
}
#ifdef MACRO_CPATH
cleardone:
#endif
return (boolean) result;
}
/*==========================================================================*\
GENERAL LINE OF SIGHT
Algorithm C
\*==========================================================================*/
/*
* Defines local to Algorithm C.
*/
static void right_side(int, int, int, const coordxy *);
static void left_side(int, int, int, const coordxy *);
/* Initialize algorithm C (nothing). */
static void
view_init(void)
{
}
/*
* Mark positions as visible on one quadrant of the right side. The
* quadrant is determined by the value of the global variable step.
*
* Arguments:
* row current row
* left first (left side) visible spot on prev row
* right_mark last (right side) visible spot on prev row
* limits points at range limit for current row, or NULL
*/
static void
right_side(
int row,
int left,
int right_mark,
const coordxy *limits)
{
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 seenV *rowp = NULL; /* row optimization */
coordxy *row_min = NULL; /* left most [used by macro set_min()] */
coordxy *row_max = NULL; /* right most [used by macro set_max()] */
int lim_max; /* right most limit of circle */
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(
int row,
int left_mark,
int right,
const coordxy *limits)
{
int left, left_edge, nrow, deeper, result;
register int i;
register seenV *rowp = NULL;
coordxy *row_min = NULL;
coordxy *row_max = NULL;
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;
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.
*
* Arguments
* srow, scol starting row and column
* loc_cs_rows pointers to the rows of the could_see array
* left_most min mark on each row
* right_most max mark on each row
* range 0 if unlimited
* func function to call on each spot
* arg argument for func
*/
static void
view_from(
coordxy srow, coordxy scol,
seenV **loc_cs_rows,
coordxy *left_most, coordxy *right_most,
int range,
void (*func)(coordxy, coordxy, genericptr_t),
genericptr_t arg)
{
register int i; /* loop counter */
seenV *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 */
const coordxy *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 = (coordxy *) 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);
}
}
/*===== 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(
coordxy scol, coordxy srow,
int range,
void (*func)(coordxy, coordxy, 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, (seenV **) 0, (coordxy *) 0, (coordxy *) 0,
range, func, arg);
} else {
register int x;
int y, min_x, max_x, max_y, offset;
const coordxy *limits;
boolean override_vision;
/* vision doesn't pass through water or clouds, detection should
[this probably ought to be an arg supplied by our caller...] */
override_vision =
(Is_waterlevel(&u.uz) || Is_airlevel(&u.uz)) && detecting(func);
if (range > MAX_RADIUS || range < 1)
panic("do_clear_area: illegal range %d", range);
if (gv.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[v_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) || override_vision)
(*func)(x, y, arg);
}
}
}
/* bitmask indicating ways mon is seen; extracted from lookat(pager.c) */
unsigned
howmonseen(struct monst *mon)
{
boolean useemon = (boolean) canseemon(mon);
int xraydist = (u.xray_range < 0) ? -1 : (u.xray_range * u.xray_range);
unsigned how_seen = 0; /* result */
/* normal vision;
cansee is true for both normal and astral vision,
but couldsee it not true for astral vision */
if ((mon->wormno ? worm_known(mon) : (cansee(mon->mx, mon->my)
&& couldsee(mon->mx, mon->my)))
&& mon_visible(mon) && !mon->minvis)
how_seen |= MONSEEN_NORMAL;
/* see invisible */
if (useemon && mon->minvis)
how_seen |= MONSEEN_SEEINVIS;
/* infravision */
if ((!mon->minvis || See_invisible) && see_with_infrared(mon))
how_seen |= MONSEEN_INFRAVIS;
/* telepathy */
if (tp_sensemon(mon))
how_seen |= MONSEEN_TELEPAT;
/* xray */
if (useemon && xraydist > 0 && mdistu(mon) <= xraydist)
how_seen |= MONSEEN_XRAYVIS;
/* extended detection */
if (Detect_monsters)
how_seen |= MONSEEN_DETECT;
/* class-/type-specific warning */
if (MATCH_WARN_OF_MON(mon))
how_seen |= MONSEEN_WARNMON;
return how_seen;
}
/*vision.c*/
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