nethack/src/light.c

/*	SCCS Id: @(#)light.c	3.3	97/04/10	*/
/* Copyright (c) Dean Luick, 1994					*/
/* NetHack may be freely redistributed.  See license for details.	*/

#include "hack.h"
#include "lev.h"	/* for checking save modes */

/*
 * Mobile light sources.
 *
 * This implementation minimizes memory at the expense of extra
 * recalculations.
 *
 * Light sources are "things" that have a physical position and range.
 * They have a type, which gives us information about them.  Currently
 * they are only attached to objects and monsters.  Note well:  the
 * polymorphed-player handling assumes that both youmonst.m_id and
 * youmonst.mx will always remain 0.
 *
 * Light sources, like timers, either follow game play (RANGE_GLOBAL) or
 * stay on a level (RANGE_LEVEL).  Light sources are unique by their
 * (type, id) pair.  For light sources attached to objects, this id
 * is a pointer to the object.
 *
 * The major working function is do_light_sources(). It is called
 * when the vision system is recreating its "could see" array.  Here
 * we add a flag (TEMP_LIT) to the array for all locations that are lit
 * via a light source.  The bad part of this is that we have to
 * re-calculate the LOS of each light source every time the vision
 * system runs.  Even if the light sources and any topology (vision blocking
 * positions) have not changed.  The good part is that no extra memory
 * is used, plus we don't have to figure out how far the sources have moved,
 * or if the topology has changed.
 *
 * The structure of the save/restore mechanism is amazingly similar to
 * the timer save/restore.  This is because they both have the same
 * principals of having pointers into objects that must be recalculated
 * across saves and restores.
 */

#ifdef OVL3

/* flags */
#define LSF_SHOW	0x1		/* display the light source */
#define LSF_NEEDS_FIXUP	0x2		/* need oid fixup */

static light_source *light_base = 0;

STATIC_DCL void FDECL(write_ls, (int, light_source *));
STATIC_DCL int FDECL(maybe_write_ls, (int, int, BOOLEAN_P));

/* imported from vision.c, for small circles */
extern char circle_data[];
extern char circle_start[];


/* Create a new light source.  */
void
new_light_source(x, y, range, type, id)
    xchar x, y;
    int range, type;
    genericptr_t id;
{
    light_source *ls;

    if (range > MAX_RADIUS || range < 1) {
	impossible("new_light_source:  illegal range %d", range);
	return;
    }

    ls = (light_source *) alloc(sizeof(light_source));

    ls->next = light_base;
    ls->x = x;
    ls->y = y;
    ls->range = range;
    ls->type = type;
    ls->id = id;
    ls->flags = 0;
    light_base = ls;

    vision_full_recalc = 1;	/* make the source show up */
}

/*
 * Delete a light source. This assumes only one light source is attached
 * to an object at a time.
 */
void
del_light_source(type, id)
    int type;
    genericptr_t id;
{
    light_source *curr, *prev;
    genericptr_t tmp_id;

    /* need to be prepared for dealing a with light source which
       has only been partially restored during a level change
       (in particular: chameleon vs prot. from shape changers) */
    switch (type) {
    case LS_OBJECT:	tmp_id = (genericptr_t)(((struct obj *)id)->o_id);
			break;
    case LS_MONSTER:	tmp_id = (genericptr_t)(((struct monst *)id)->m_id);
			break;
    default:		tmp_id = 0;
			break;
    }

    for (prev = 0, curr = light_base; curr; prev = curr, curr = curr->next) {
	if (curr->type != type) continue;
	if (curr->id == ((curr->flags & LSF_NEEDS_FIXUP) ? tmp_id : id)) {
	    if (prev)
		prev->next = curr->next;
	    else
		light_base = curr->next;

	    free((genericptr_t)curr);
	    vision_full_recalc = 1;
	    return;
	}
    }
    impossible("del_light_source: not found type=%d, id=0x%lx", type, (long)id);
}

/* Mark locations that are temporarily lit via mobile light sources. */
void
do_light_sources(cs_rows)
    char **cs_rows;
{
    int x, y, min_x, max_x, max_y, offset;
    char *limits;
    short at_hero_range = 0;
    light_source *ls;
    char *row;

    for (ls = light_base; ls; ls = ls->next) {
	ls->flags &= ~LSF_SHOW;

	/*
	 * Check for moved light sources.  It may be possible to
	 * save some effort if an object has not moved, but not in
	 * the current setup -- we need to recalculate for every
	 * vision recalc.
	 */
	if (ls->type == LS_OBJECT) {
	    if (get_obj_location((struct obj *) ls->id, &ls->x, &ls->y, 0))
		ls->flags |= LSF_SHOW;
	} else if (ls->type == LS_MONSTER) {
	    if (get_mon_location((struct monst *) ls->id, &ls->x, &ls->y, 0))
		ls->flags |= LSF_SHOW;
	}

	/* minor optimization: don't bother with duplicate light sources */
	/* at hero */
	if (ls->x == u.ux && ls->y == u.uy) {
	    if (at_hero_range >= ls->range)
		ls->flags &= ~LSF_SHOW;
	    else
		at_hero_range = ls->range;
	}

	if (ls->flags & LSF_SHOW) {
	    /*
	     * Walk the points in the circle and see if they are
	     * visible from the center.  If so, mark'em.
	     *
	     * Kevin's tests indicated that doing this brute-force
	     * method is faster for radius <= 3 (or so).
	     */
	    limits = circle_ptr(ls->range);
	    if ((max_y = (ls->y + ls->range)) >= ROWNO) max_y = ROWNO-1;
	    if ((y = (ls->y - ls->range)) < 0) y = 0;
	    for (; y <= max_y; y++) {
		row = cs_rows[y];
		offset = limits[abs(y - ls->y)];
		if ((min_x = (ls->x - offset)) < 0) min_x = 0;
		if ((max_x = (ls->x + offset)) >= COLNO) max_x = COLNO-1;

		if (ls->x == u.ux && ls->y == u.uy) {
		    /*
		     * If the light source is located at the hero, then
		     * we can use the COULD_SEE bits already calcualted
		     * by the vision system.  More importantly than
		     * this optimization, is that it allows the vision
		     * system to correct problems with clear_path().
		     * The function clear_path() is a simple LOS
		     * path checker that doesn't go out of its way
		     * make things look "correct".  The vision system
		     * does this.
		     */
		    for (x = min_x; x <= max_x; x++)
			if (row[x] & COULD_SEE)
			    row[x] |= TEMP_LIT;
		} else {
		    for (x = min_x; x <= max_x; x++)
			if ((ls->x == x && ls->y == y)
				|| clear_path((int)ls->x, (int) ls->y, x, y))
			    row[x] |= TEMP_LIT;
		}
	    }
	}
    }
}

/* (mon->mx == 0) implies migrating */
#define mon_is_local(mon)	((mon)->mx > 0)

struct monst *
find_mid(nid, fmflags)
unsigned nid;
unsigned fmflags;
{
	struct monst *mtmp;

	if (!nid)
	    return &youmonst;
	if (fmflags & FM_FMON)
		for (mtmp = fmon; mtmp; mtmp = mtmp->nmon)
		    if (!DEADMONSTER(mtmp) && mtmp->m_id == nid) return mtmp;
	if (fmflags & FM_MIGRATE)
		for (mtmp = migrating_mons; mtmp; mtmp = mtmp->nmon)
	    	    if (mtmp->m_id == nid) return mtmp;
	if (fmflags & FM_MYDOGS)
		for (mtmp = mydogs; mtmp; mtmp = mtmp->nmon)
	    	    if (mtmp->m_id == nid) return mtmp;
	return (struct monst *) 0;
}

/* Save all light sources of the given range. */
void
save_light_sources(fd, mode, range)
    int fd, mode, range;
{
    int count, actual, is_global;
    light_source **prev, *curr;

    if (perform_bwrite(mode)) {
	count = maybe_write_ls(fd, range, FALSE);
	bwrite(fd, (genericptr_t) &count, sizeof count);
	actual = maybe_write_ls(fd, range, TRUE);
	if (actual != count)
	    panic("counted %d light sources, wrote %d! [range=%d]",
		  count, actual, range);
    }

    if (release_data(mode)) {
	for (prev = &light_base; (curr = *prev) != 0; ) {
	    if (!curr->id) {
		impossible("save_light_sources: no id! [range=%d]", range);
		is_global = 0;
	    } else
	    switch (curr->type) {
	    case LS_OBJECT:
		is_global = !obj_is_local((struct obj *)curr->id);
		break;
	    case LS_MONSTER:
		is_global = !mon_is_local((struct monst *)curr->id);
		break;
	    default:
		is_global = 0;
		impossible("save_light_sources: bad type (%d) [range=%d]",
			   curr->type, range);
		break;
	    }
	    /* if global and not doing local, or vice versa, remove it */
	    if (is_global ^ (range == RANGE_LEVEL)) {
		*prev = curr->next;
		free((genericptr_t)curr);
	    } else {
		prev = &(*prev)->next;
	    }
	}
    }
}

/*
 * Pull in the structures from disk, but don't recalculate the object
 * pointers.
 */
void
restore_light_sources(fd)
    int fd;
{
    int count;
    light_source *ls;

    /* restore elements */
    mread(fd, (genericptr_t) &count, sizeof count);

    while (count-- > 0) {
	ls = (light_source *) alloc(sizeof(light_source));
	mread(fd, (genericptr_t) ls, sizeof(light_source));
	ls->next = light_base;
	light_base = ls;
    }
}

/* Relink all lights that are so marked. */
void
relink_light_sources(ghostly)
    boolean ghostly;
{
    char which;
    unsigned nid;
    light_source *ls;

    for (ls = light_base; ls; ls = ls->next) {
	if (ls->flags & LSF_NEEDS_FIXUP) {
	    if (ls->type == LS_OBJECT || ls->type == LS_MONSTER) {
		if (ghostly) {
		    if (!lookup_id_mapping((unsigned)ls->id, &nid))
			impossible("relink_light_sources: no id mapping");
		} else
		    nid = (unsigned) ls->id;
		if (ls->type == LS_OBJECT) {
		    which = 'o';
		    ls->id = (genericptr_t) find_oid(nid);
		} else {
		    which = 'm';
		    ls->id = (genericptr_t) find_mid(nid, FM_EVERYWHERE);
		}
		if (!ls->id)
		    impossible("relink_light_sources: cant find %c_id %d",
			       which, nid);
	    } else
		impossible("relink_light_sources: bad type (%d)", ls->type);

	    ls->flags &= ~LSF_NEEDS_FIXUP;
	}
    }
}

/*
 * Part of the light source save routine.  Count up the number of light
 * sources that would be written.  If write_it is true, actually write
 * the light source out.
 */
STATIC_OVL int
maybe_write_ls(fd, range, write_it)
    int fd, range;
    boolean write_it;
{
    int count = 0, is_global;
    light_source *ls;

    for (ls = light_base; ls; ls = ls->next) {
	if (!ls->id) {
	    impossible("maybe_write_ls: no id! [range=%d]", range);
	    continue;
	}
	switch (ls->type) {
	case LS_OBJECT:
	    is_global = !obj_is_local((struct obj *)ls->id);
	    break;
	case LS_MONSTER:
	    is_global = !mon_is_local((struct monst *)ls->id);
	    break;
	default:
	    is_global = 0;
	    impossible("maybe_write_ls: bad type (%d) [range=%d]",
		       ls->type, range);
	    break;
	}
	/* if global and not doing local, or vice versa, count it */
	if (is_global ^ (range == RANGE_LEVEL)) {
	    count++;
	    if (write_it) write_ls(fd, ls);
	}
    }

    return count;
}

/* Write a light source structure to disk. */
STATIC_OVL void
write_ls(fd, ls)
    int fd;
    light_source *ls;
{
    genericptr_t arg_save;
    struct obj *otmp;
    struct monst *mtmp;

    if (ls->type == LS_OBJECT || ls->type == LS_MONSTER) {
	if (ls->flags & LSF_NEEDS_FIXUP)
	    bwrite(fd, (genericptr_t)ls, sizeof(light_source));
	else {
	    /* replace object pointer with id for write, then put back */
	    arg_save = ls->id;
	    if (ls->type == LS_OBJECT) {
		otmp = (struct obj *)ls->id;
		ls->id = (genericptr_t)otmp->o_id;
#ifdef DEBUG
		if (find_oid((unsigned)ls->id) != otmp)
		    panic("write_ls: can't find obj #%u!", (unsigned)ls->id);
#endif
	    } else { /* ls->type == LS_MONSTER */
		mtmp = (struct monst *)ls->id;
		ls->id = (genericptr_t)mtmp->m_id;
#ifdef DEBUG
		if (find_mid((unsigned)ls->id, FM_EVERYWHERE) != mtmp)
		    panic("write_ls: can't find mon #%u!", (unsigned)ls->id);
#endif
	    }
	    ls->flags |= LSF_NEEDS_FIXUP;
	    bwrite(fd, (genericptr_t)ls, sizeof(light_source));
	    ls->id = arg_save;
	    ls->flags &= ~LSF_NEEDS_FIXUP;
	}
    } else {
	impossible("write_ls: bad type (%d)", ls->type);
    }
}

/* Change light source's ID from src to dest. */
void
obj_move_light_source(src, dest)
    struct obj *src, *dest;
{
    light_source *ls;

    for (ls = light_base; ls; ls = ls->next)
	if (ls->type == LS_OBJECT && ls->id == (genericptr_t) src)
	    ls->id = (genericptr_t) dest;
    src->lamplit = 0;
    dest->lamplit = 1;
}

/* return true if there exist any light sources */
boolean
any_light_source()
{
    return light_base != (light_source *) 0;
}

/*
 * Snuff an object light source if at (x,y).  This currently works
 * only for burning light sources.
 */
void
snuff_light_source(x, y)
    int x, y;
{
    light_source *ls;
    struct obj *obj;

    for (ls = light_base; ls; ls = ls->next)
	/*
	Is this position check valid??? Can I assume that the positions
	will always be correct because the objects would have been
	updated with the last vision update?  [Is that recent enough???]
	*/
	if (ls->type == LS_OBJECT && ls->x == x && ls->y == y) {
	    obj = (struct obj *) ls->id;
	    if (obj_is_burning(obj)) {
		/* The only way to snuff Sunsword is to unwield it.  Darkness
		 * scrolls won't affect it.  (If we got here because it was
		 * dropped or thrown inside a monster, this won't matter anyway
		 * because it will go out when dropped.)
		 */
		if (artifact_light(obj)) continue;
		end_burn(obj, obj->otyp != MAGIC_LAMP);
		/*
		 * The current ls element has just been removed (and
		 * ls->next is now invalid).  Return assuming that there
		 * is only one light source attached to each object.
		 */
		return;
	    }
	}
}

/* Return TRUE if object sheds any light at all. */
boolean
obj_sheds_light(obj)
    struct obj *obj;
{
    /* so far, only burning objects shed light */
    return obj_is_burning(obj);
}

/* Return TRUE if sheds light AND will be snuffed by end_burn(). */
boolean
obj_is_burning(obj)
    struct obj *obj;
{
    return (obj->lamplit &&
		(  obj->otyp == MAGIC_LAMP
		|| obj->otyp == BRASS_LANTERN
		|| obj->otyp == OIL_LAMP
		|| obj->otyp == CANDELABRUM_OF_INVOCATION
		|| obj->otyp == TALLOW_CANDLE
		|| obj->otyp == WAX_CANDLE
		|| obj->otyp == POT_OIL
		|| artifact_light(obj)));
}

/* copy the light source(s) attachted to src, and attach it/them to dest */
void
obj_split_light_source(src, dest)
    struct obj *src, *dest;
{
    light_source *ls, *new_ls;

    for (ls = light_base; ls; ls = ls->next)
	if (ls->type == LS_OBJECT && ls->id == (genericptr_t) src) {
	    /*
	     * Insert the new source at beginning of list.  This will
	     * never interfere us walking down the list - we are already
	     * past the insertion point.
	     */
	    new_ls = (light_source *) alloc(sizeof(light_source));
	    *new_ls = *ls;
	    if (Is_candle(src)) {
		/* split candles may emit less light than original group */
		ls->range = candle_light_range(src);
		new_ls->range = candle_light_range(dest);
		vision_full_recalc = 1;	/* in case range changed */
	    }
	    new_ls->id = (genericptr_t) dest;
	    new_ls->next = light_base;
	    light_base = new_ls;
	    dest->lamplit = 1;		/* now an active light source */
	}
}

/* light source `src' has been folded into light source `dest';
   used for merging lit candles and adding candle(s) to lit candelabrum */
void
obj_merge_light_sources(src, dest)
struct obj *src, *dest;
{
    light_source *ls;

    /* src == dest implies adding to candelabrum */
    if (src != dest) end_burn(src, TRUE);		/* extinguish candles */

    for (ls = light_base; ls; ls = ls->next)
	if (ls->type == LS_OBJECT && ls->id == (genericptr_t) dest) {
	    ls->range = candle_light_range(dest);
	    vision_full_recalc = 1;	/* in case range changed */
	    break;
	}
}

/* Candlelight is proportional to the number of candles;
   minimum range is 2 rather than 1 for playability. */
int
candle_light_range(obj)
struct obj *obj;
{
    int radius;

    if (obj->otyp == CANDELABRUM_OF_INVOCATION) {
	/*
	 *	The special candelabrum emits more light than the
	 *	corresponding number of candles would.
	 *	 1..3 candles, range 2 (minimum range);
	 *	 4..6 candles, range 3 (normal lamp range);
	 *	    7 candles, range 4 (bright).
	 */
	radius = (obj->spe < 4) ? 2 : (obj->spe < 7) ? 3 : 4;
    } else if (Is_candle(obj)) {
	/*
	 *	Range is incremented by powers of 7 so that it will take
	 *	wizard mode quantities of candles to get more light than
	 *	from a lamp, without imposing an arbitrary limit.
	 *	 1..6   candles, range 2;
	 *	 7..48  candles, range 3;
	 *	49..342 candles, range 4; &c.
	 */
	long n = obj->quan;

	radius = 1;	/* always incremented at least once */
	do {
	    radius++;
	    n /= 7L;
	} while (n > 0L);
    } else {
	/* we're only called for lit candelabrum or candles */
     /* impossible("candlelight for %d?", obj->otyp); */
	radius = 3;		/* lamp's value */
    }
    return radius;
}

#ifdef WIZARD
extern char *FDECL(fmt_ptr, (const genericptr, char *));  /* from alloc.c */

int
wiz_light_sources()
{
    winid win;
    char buf[BUFSZ], arg_address[20];
    light_source *ls;

    win = create_nhwindow(NHW_MENU);	/* corner text window */
    if (win == WIN_ERR) return 0;

    Sprintf(buf, "Mobile light sources: hero @ (%2d,%2d)", u.ux, u.uy);
    putstr(win, 0, buf);
    putstr(win, 0, "");

    if (light_base) {
	putstr(win, 0, "location range flags  type    id");
	putstr(win, 0, "-------- ----- ------ ----  -------");
	for (ls = light_base; ls; ls = ls->next) {
	    Sprintf(buf, "  %2d,%2d   %2d   0x%04x  %s  %s",
		ls->x, ls->y, ls->range, ls->flags,
		(ls->type == LS_OBJECT ? "obj" :
		 ls->type == LS_MONSTER ?
		    (mon_is_local((struct monst *)ls->id) ? "mon" :
		     ((struct monst *)ls->id == &youmonst) ? "you" :
		     "<m>") :		/* migrating monster */
		 "???"),
		fmt_ptr(ls->id, arg_address));
	    putstr(win, 0, buf);
	}
    } else
	putstr(win, 0, "<none>");


    display_nhwindow(win, FALSE);
    destroy_nhwindow(win);

    return 0;
}

#endif /* WIZARD */

#endif /* OVL3 */

/*light.c*/