nethack/src/nhlsel.c

/* NetHack 3.7	nhlua.c	$NHDT-Date: 1769840272 2026/01/30 22:17:52 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.69 $ */
/*      Copyright (c) 2018 by Pasi Kallinen */
/* NetHack may be freely redistributed.  See license for details. */

#include "hack.h"
#include "sp_lev.h"


struct selectionvar *l_selection_check(lua_State *, int);
staticfn struct selectionvar *l_selection_push_new(lua_State *);

/* lua_CFunction prototypes */
staticfn int l_selection_new(lua_State *);
staticfn int l_selection_clone(lua_State *);
staticfn int l_selection_numpoints(lua_State *);
staticfn int l_selection_getpoint(lua_State *);
staticfn int l_selection_setpoint(lua_State *);
staticfn int l_selection_filter_percent(lua_State *);
staticfn int l_selection_rndcoord(lua_State *);
staticfn int l_selection_room(lua_State *);
staticfn int l_selection_getbounds(lua_State *);
staticfn boolean params_sel_2coords(lua_State *, struct selectionvar **,
                                  coordxy *, coordxy *, coordxy *, coordxy *);
staticfn int l_selection_line(lua_State *);
staticfn int l_selection_randline(lua_State *);
staticfn int l_selection_rect(lua_State *);
staticfn int l_selection_fillrect(lua_State *);
staticfn int l_selection_grow(lua_State *);
staticfn int l_selection_filter_mapchar(lua_State *);
staticfn int l_selection_match(lua_State *);
staticfn int l_selection_flood(lua_State *);
staticfn int l_selection_circle(lua_State *);
staticfn int l_selection_ellipse(lua_State *);
staticfn int l_selection_gradient(lua_State *);
staticfn int l_selection_iterate(lua_State *);
staticfn int l_selection_size_description(lua_State *L);
staticfn int l_selection_gc(lua_State *);
staticfn int l_selection_not(lua_State *);
staticfn int l_selection_and(lua_State *);
staticfn int l_selection_or(lua_State *);
staticfn int l_selection_xor(lua_State *);
/* There doesn't seem to be a point in having a l_selection_add since it would
 * do the same thing as l_selection_or. The addition operator is mapped to
 * l_selection_or. */
staticfn int l_selection_sub(lua_State *);
#if 0
/* the following do not appear to currently be
   used and because they are static, the OSX
   compiler is complaining about them. I've
   if ifdef'd out the prototype here and the
   function body below.
 */
staticfn int l_selection_ipairs(lua_State *);
staticfn struct selectionvar *l_selection_to(lua_State *, int);
#endif

struct selectionvar *
l_selection_check(lua_State *L, int index)
{
    struct selectionvar *sel;

    luaL_checktype(L, index, LUA_TUSERDATA);
    sel = (struct selectionvar *) luaL_checkudata(L, index, "selection");
    if (!sel)
        nhl_error(L, "Selection error");
    return sel;
}

staticfn int
l_selection_gc(lua_State *L)
{
    struct selectionvar *sel = l_selection_check(L, 1);

    if (sel)
        selection_free(sel, FALSE);
    return 0;
}

#if 0
staticfn struct selectionvar *
l_selection_to(lua_State *L, int index)
{
    struct selectionvar *sel
                           = (struct selectionvar *) lua_touserdata(L, index);

    if (!sel)
        nhl_error(L, "Selection error");
    return sel;
}
#endif

/* push a new selection into lua stack, return the selectionvar */
staticfn struct selectionvar *
l_selection_push_new(lua_State *L)
{
    struct selectionvar *tmp = selection_new();
    struct selectionvar *sel
   = (struct selectionvar *) lua_newuserdata(L, sizeof (struct selectionvar));

    luaL_getmetatable(L, "selection");
    lua_setmetatable(L, -2);

    *sel = *tmp;
    sel->map = dupstr(tmp->map);
    selection_free(tmp, TRUE);

    return sel;
}

/* push a copy of selectionvar tmp to lua stack */
void
l_selection_push_copy(lua_State *L, struct selectionvar *tmp)
{
    struct selectionvar *sel
   = (struct selectionvar *) lua_newuserdata(L, sizeof (struct selectionvar));

    luaL_getmetatable(L, "selection");
    lua_setmetatable(L, -2);

    *sel = *tmp;
    sel->map = dupstr(tmp->map);
}


/* local sel = selection.new(); */
staticfn int
l_selection_new(lua_State *L)
{
    (void) l_selection_push_new(L);
    return 1;
}

/* Replace the topmost selection in the stack with a clone of it. */
/* local sel = selection.clone(sel); */
staticfn int
l_selection_clone(lua_State *L)
{
    struct selectionvar *sel = l_selection_check(L, 1);
    struct selectionvar *tmp;

    (void) l_selection_new(L);
    tmp = l_selection_check(L, 2);
    if (tmp->map)
        free(tmp->map);
    *tmp = *sel;
    tmp->map = dupstr(sel->map);
    return 1;
}

DISABLE_WARNING_UNREACHABLE_CODE

/* selection.set(sel, x, y); */
/* selection.set(sel, x, y, value); */
/* local sel = selection.set(); */
/* local sel = sel:set(); */
/* local sel = selection.set(sel); */
/* TODO: allow setting multiple coords at once: set({x1,y1},{x2,y2},...); */
staticfn int
l_selection_setpoint(lua_State *L)
{
    struct selectionvar *sel = (struct selectionvar *) 0;
    coordxy x = -1, y = -1;
    int val = 1;
    int argc = lua_gettop(L);
    long crd = 0L;

    if (argc == 0) {
        (void) l_selection_new(L);
    } else if (argc == 1) {
        sel = l_selection_check(L, 1);
    } else if (argc == 2) {
        x = (coordxy) luaL_checkinteger(L, 1);
        y = (coordxy) luaL_checkinteger(L, 2);
        lua_pop(L, 2);
        (void) l_selection_new(L);
        sel = l_selection_check(L, 1);
    } else {
        sel = l_selection_check(L, 1);
        x = (coordxy) luaL_checkinteger(L, 2);
        y = (coordxy) luaL_checkinteger(L, 3);
        val = (int) luaL_optinteger(L, 4, 1);
    }

    if (!sel || !sel->map) {
        nhl_error(L, "Selection setpoint error");
        /*NOTREACHED*/
        return 0;
    }

    if (x == -1 && y == -1)
        crd = SP_COORD_PACK_RANDOM(0);
    else
        crd = SP_COORD_PACK(x,y);
    get_location_coord(&x, &y, ANY_LOC,
                       gc.coder ? gc.coder->croom : NULL, crd);
    selection_setpoint(x, y, sel, val);
    lua_settop(L, 1);
    return 1;
}

/* local numpoints = selection.numpoints(sel); */
staticfn int
l_selection_numpoints(lua_State *L)
{
    struct selectionvar *sel = l_selection_check(L, 1);
    coordxy x, y;
    int ret = 0;
    NhRect rect = cg.zeroNhRect;

    selection_getbounds(sel, &rect);

    for (x = rect.lx; x <= rect.hx; x++)
        for (y = rect.ly; y <= rect.hy; y++)
            if (selection_getpoint(x, y, sel))
                ret++;

    lua_settop(L, 0);
    lua_pushinteger(L, ret);
    return 1;
}

/* local value = selection.get(sel, x, y); */
staticfn int
l_selection_getpoint(lua_State *L)
{
    struct selectionvar *sel = l_selection_check(L, 1);
    coordxy x, y;
    lua_Integer ix, iy;
    int val;
    long crd;

    lua_remove(L, 1); /* sel */
    if (!nhl_get_xy_params(L, &ix, &iy)) {
        nhl_error(L, "l_selection_getpoint: Incorrect params");
        /*NOTREACHED*/
        return 0;
    }
    x = (coordxy) ix;
    y = (coordxy) iy;

    if (x == -1 && y == -1)
        crd = SP_COORD_PACK_RANDOM(0);
    else
        crd = SP_COORD_PACK(x,y);
    get_location_coord(&x, &y, ANY_LOC,
                       gc.coder ? gc.coder->croom : NULL, crd);

    val = selection_getpoint(x, y, sel);
    lua_settop(L, 0);
    lua_pushnumber(L, val);
    return 1;
}

RESTORE_WARNING_UNREACHABLE_CODE

/* local s = selection.negate(sel); */
/* local s = selection.negate(); */
/* local s = sel:negate(); */
staticfn int
l_selection_not(lua_State *L)
{
    int argc = lua_gettop(L);
    struct selectionvar *sel, *sel2;

    if (argc == 0) {
        (void) l_selection_new(L);
        sel = l_selection_check(L, 1);
        selection_clear(sel, 1);
    } else {
        (void) l_selection_check(L, 1);
        (void) l_selection_clone(L);
        sel2 = l_selection_check(L, 2);
        selection_not(sel2);
        lua_remove(L, 1);
    }
    return 1;
}

/* local sel = selection.area(4,5, 40,10) & selection.rect(7,8, 60,14); */
staticfn int
l_selection_and(lua_State *L)
{
    int x, y;
    struct selectionvar *sela = l_selection_check(L, 1);
    struct selectionvar *selb = l_selection_check(L, 2);
    struct selectionvar *selr = l_selection_push_new(L);
    NhRect rect = cg.zeroNhRect;

    rect_bounds(sela->bounds, selb->bounds, &rect);

    for (x = rect.lx; x <= rect.hx; x++)
        for (y = rect.ly; y <= rect.hy; y++) {
            int val = (selection_getpoint(x, y, sela)
                       & selection_getpoint(x, y, selb));

            selection_setpoint(x, y, selr, val);
        }

    lua_remove(L, 1);
    lua_remove(L, 1);
    return 1;
}

/* local sel = selection.area(4,5, 40,10) | selection.rect(7,8, 60,14); */
staticfn int
l_selection_or(lua_State *L)
{
    int x,y;
    struct selectionvar *sela = l_selection_check(L, 1);
    struct selectionvar *selb = l_selection_check(L, 2);
    struct selectionvar *selr = l_selection_push_new(L);
    NhRect rect = cg.zeroNhRect;

    rect_bounds(sela->bounds, selb->bounds, &rect);

    for (x = rect.lx; x <= rect.hx; x++)
        for (y = rect.ly; y <= rect.hy; y++) {
            int val = (selection_getpoint(x, y, sela)
                       | selection_getpoint(x, y, selb));

            selection_setpoint(x, y, selr, val);
        }
    selr->bounds = rect;

    lua_remove(L, 1);
    lua_remove(L, 1);
    return 1;
}

/* local sel = selection.area(4,5, 40,10) ~ selection.rect(7,8, 60,14); */
staticfn int
l_selection_xor(lua_State *L)
{
    int x,y;
    struct selectionvar *sela = l_selection_check(L, 1);
    struct selectionvar *selb = l_selection_check(L, 2);
    struct selectionvar *selr = l_selection_push_new(L);
    NhRect rect = cg.zeroNhRect;

    rect_bounds(sela->bounds, selb->bounds, &rect);

    for (x = rect.lx; x <= rect.hx; x++)
        for (y = rect.ly; y <= rect.hy; y++) {
            int val = (selection_getpoint(x, y, sela)
                       ^ selection_getpoint(x, y, selb));

            selection_setpoint(x, y, selr, val);
        }
    /* this may have created a smaller or irregular selection with
     * bounds_dirty set to true - update its boundaries */
    selection_recalc_bounds(selr);

    lua_remove(L, 1);
    lua_remove(L, 1);
    return 1;
}

/* local sel = selection.area(10,10, 20,20) - selection.area(14,14, 17,17)
 *   - i.e. points that are in A but not in B */
staticfn int
l_selection_sub(lua_State *L)
{
    int x,y;
    struct selectionvar *sela = l_selection_check(L, 1);
    struct selectionvar *selb = l_selection_check(L, 2);
    struct selectionvar *selr = l_selection_push_new(L);
    NhRect rect = cg.zeroNhRect;

    rect_bounds(sela->bounds, selb->bounds, &rect);

    for (x = rect.lx; x <= rect.hx; x++)
        for (y = rect.ly; y <= rect.hy; y++) {
            coordxy a_pt = selection_getpoint(x, y, sela);
            coordxy b_pt = selection_getpoint(x, y, selb);
            int val = (a_pt ^ b_pt) & a_pt;
            selection_setpoint(x, y, selr, val);
        }
    /* this may have created a smaller or irregular selection with
     * bounds_dirty set to true - update its boundaries */
    selection_recalc_bounds(selr);

    lua_remove(L, 1);
    lua_remove(L, 1);
    return 1;
}

/* local s = selection.percentage(sel, 50); */
staticfn int
l_selection_filter_percent(lua_State *L)
{
    int argc = lua_gettop(L);
    struct selectionvar *sel = l_selection_check(L, 1);
    int p = (int) luaL_checkinteger(L, 2);
    struct selectionvar *tmp;

    tmp = selection_filter_percent(sel, p);
    lua_pop(L, argc);
    l_selection_push_copy(L, tmp);
    selection_free(tmp, TRUE);

    return 1;
}

/* local pt = selection.rndcoord(sel); */
/* local pt = selection.rndcoord(sel, 1); */
staticfn int
l_selection_rndcoord(lua_State *L)
{
    struct selectionvar *sel = l_selection_check(L, 1);
    int removeit = (int) luaL_optinteger(L, 2, 0);
    coordxy x = -1, y = -1;
    selection_rndcoord(sel, &x, &y, removeit);
    if (!(x == -1 && y == -1)) {
        update_croom();
        if (gc.coder && gc.coder->croom) {
            x -= gc.coder->croom->lx;
            y -= gc.coder->croom->ly;
        } else {
            x -= gx.xstart;
            y -= gy.ystart;
        }
    }
    lua_settop(L, 0);
    lua_newtable(L);
    nhl_add_table_entry_int(L, "x", x);
    nhl_add_table_entry_int(L, "y", y);
    return 1;
}

/* local s = selection.room(); */
staticfn int
l_selection_room(lua_State *L)
{
    struct selectionvar *sel;
    int argc = lua_gettop(L);
    struct mkroom *croom = NULL;

    if (argc == 1) {
        int i = luaL_checkinteger(L, -1);

        croom = (i >= 0 && i < svn.nroom) ? &svr.rooms[i] : NULL;
    }

    sel = selection_from_mkroom(croom);

    l_selection_push_copy(L, sel);
    selection_free(sel, TRUE);

    return 1;
}

/* local rect = sel:bounds(); */
staticfn int
l_selection_getbounds(lua_State *L)
{
    struct selectionvar *sel = l_selection_check(L, 1);
    NhRect rect = cg.zeroNhRect;

    selection_getbounds(sel, &rect);
    lua_settop(L, 0);
    lua_newtable(L);
    nhl_add_table_entry_int(L, "lx", rect.lx);
    nhl_add_table_entry_int(L, "ly", rect.ly);
    nhl_add_table_entry_int(L, "hx", rect.hx);
    nhl_add_table_entry_int(L, "hy", rect.hy);
    return 1;
}

/* internal function to get a selection and 4 integer values from lua stack.
   removes the integers from the stack.
   returns TRUE if params are good.
*/
/* function(selection, x1,y1, x2,y2) */
/* selection:function(x1,y1, x2,y2) */
staticfn boolean
params_sel_2coords(lua_State *L, struct selectionvar **sel,
                   coordxy *x1, coordxy *y1, coordxy *x2, coordxy *y2)
{
    int argc = lua_gettop(L);

    if (argc == 4) {
        (void) l_selection_new(L);
        *x1 = (coordxy) luaL_checkinteger(L, 1);
        *y1 = (coordxy) luaL_checkinteger(L, 2);
        *x2 = (coordxy) luaL_checkinteger(L, 3);
        *y2 = (coordxy) luaL_checkinteger(L, 4);
        *sel = l_selection_check(L, 5);
        lua_remove(L, 1);
        lua_remove(L, 1);
        lua_remove(L, 1);
        lua_remove(L, 1);
        return TRUE;
    } else if (argc == 5) {
        *sel = l_selection_check(L, 1);
        *x1 = (coordxy) luaL_checkinteger(L, 2);
        *y1 = (coordxy) luaL_checkinteger(L, 3);
        *x2 = (coordxy) luaL_checkinteger(L, 4);
        *y2 = (coordxy) luaL_checkinteger(L, 5);
        lua_pop(L, 4);
        return TRUE;
    }
    return FALSE;
}

/* local s = selection.line(sel, x1,y1, x2,y2); */
/* local s = selection.line(x1,y1, x2,y2); */
/* s:line(x1,y1, x2,y2); */
staticfn int
l_selection_line(lua_State *L)
{
    struct selectionvar *sel = NULL;
    coordxy x1, y1, x2, y2;

    if (!params_sel_2coords(L, &sel, &x1, &y1, &x2, &y2)) {
        nhl_error(L, "selection.line: illegal arguments");
    }

    get_location_coord(&x1, &y1, ANY_LOC, gc.coder ? gc.coder->croom : NULL,
                       SP_COORD_PACK(x1, y1));
    get_location_coord(&x2, &y2, ANY_LOC, gc.coder ? gc.coder->croom : NULL,
                       SP_COORD_PACK(x2, y2));

    (void) l_selection_clone(L);
    sel = l_selection_check(L, 2);
    selection_do_line(x1,y1,x2,y2, sel);
    return 1;
}

/* local s = selection.rect(sel, x1,y1, x2,y2); */
staticfn int
l_selection_rect(lua_State *L)
{
    struct selectionvar *sel = NULL;
    coordxy x1, y1, x2, y2;

    if (!params_sel_2coords(L, &sel, &x1, &y1, &x2, &y2)) {
        nhl_error(L, "selection.rect: illegal arguments");
    }

    get_location_coord(&x1, &y1, ANY_LOC, gc.coder ? gc.coder->croom : NULL,
                       SP_COORD_PACK(x1, y1));
    get_location_coord(&x2, &y2, ANY_LOC, gc.coder ? gc.coder->croom : NULL,
                       SP_COORD_PACK(x2, y2));

    (void) l_selection_clone(L);
    sel = l_selection_check(L, 2);
    selection_do_line(x1, y1, x2, y1, sel);
    selection_do_line(x1, y1, x1, y2, sel);
    selection_do_line(x2, y1, x2, y2, sel);
    selection_do_line(x1, y2, x2, y2, sel);
    return 1;
}

/* local s = selection.fillrect(sel, x1,y1, x2,y2); */
/* local s = selection.fillrect(x1,y1, x2,y2); */
/* s:fillrect(x1,y1, x2,y2); */
/* selection.area(x1,y1, x2,y2); */
staticfn int
l_selection_fillrect(lua_State *L)
{
    struct selectionvar *sel = NULL;
    int y;
    coordxy x1, y1, x2, y2;

    if (!params_sel_2coords(L, &sel, &x1, &y1, &x2, &y2)) {
        nhl_error(L, "selection.fillrect: illegal arguments");
    }

    get_location_coord(&x1, &y1, ANY_LOC, gc.coder ? gc.coder->croom : NULL,
                       SP_COORD_PACK(x1, y1));
    get_location_coord(&x2, &y2, ANY_LOC, gc.coder ? gc.coder->croom : NULL,
                       SP_COORD_PACK(x2, y2));

    (void) l_selection_clone(L);
    sel = l_selection_check(L, 2);
    if (x1 == x2) {
        for (y = y1; y <= y2; y++)
            selection_setpoint(x1, y, sel, 1);
    } else {
        for (y = y1; y <= y2; y++)
            selection_do_line(x1, y, x2, y, sel);
    }
    return 1;
}

/* local s = selection.randline(sel, x1,y1, x2,y2, roughness); */
/* local s = selection.randline(x1,y1, x2,y2, roughness); */
/* TODO: selection.randline(x1,y1, x2,y2, roughness); */
/* TODO: selection.randline({x1,y1}, {x2,y2}, roughness); */
staticfn int
l_selection_randline(lua_State *L)
{
    int argc = lua_gettop(L);
    struct selectionvar *sel;
    coordxy x1 = 0, y1 = 0, x2 = 0, y2 = 0;
    int roughness = 7;

    if (argc == 6) {
        (void) l_selection_check(L, 1);
        x1 = (coordxy) luaL_checkinteger(L, 2);
        y1 = (coordxy) luaL_checkinteger(L, 3);
        x2 = (coordxy) luaL_checkinteger(L, 4);
        y2 = (coordxy) luaL_checkinteger(L, 5);
        roughness = (int) luaL_checkinteger(L, 6);
        lua_pop(L, 5);
    } else if (argc == 5 && lua_type(L, 1) == LUA_TNUMBER) {
        x1 = (coordxy) luaL_checkinteger(L, 1);
        y1 = (coordxy) luaL_checkinteger(L, 2);
        x2 = (coordxy) luaL_checkinteger(L, 3);
        y2 = (coordxy) luaL_checkinteger(L, 4);
        roughness = (int) luaL_checkinteger(L, 5);
        lua_pop(L, 5);
        (void) l_selection_new(L);
        (void) l_selection_check(L, 1);
    }

    get_location_coord(&x1, &y1, ANY_LOC, gc.coder ? gc.coder->croom : NULL,
                       SP_COORD_PACK(x1, y1));
    get_location_coord(&x2, &y2, ANY_LOC, gc.coder ? gc.coder->croom : NULL,
                       SP_COORD_PACK(x2, y2));

    (void) l_selection_clone(L);
    sel = l_selection_check(L, 2);
    selection_do_randline(x1, y1, x2, y2, roughness, 12, sel);
    return 1;
}

/* local s = selection.grow(sel); */
/* local s = selection.grow(sel, "north"); */
staticfn int
l_selection_grow(lua_State *L)
{
    static const char *const growdirs[] = {
        "all", "random", "north", "west", "east", "south", NULL
    };
    static const int growdirs2i[] = {
        W_ANY, W_RANDOM, W_NORTH, W_WEST, W_EAST, W_SOUTH, 0
    };
    struct selectionvar *sel;
    int dir, argc = lua_gettop(L);

    (void) l_selection_check(L, 1);
    dir = growdirs2i[luaL_checkoption(L, 2, "all", growdirs)];

    if (argc == 2)
        lua_pop(L, 1); /* get rid of growdir */

    (void) l_selection_clone(L);
    sel = l_selection_check(L, 2);
    selection_do_grow(sel, dir);
    return 1;
}


/* local s = selection.filter_mapchar(sel, mapchar, lit); */
staticfn int
l_selection_filter_mapchar(lua_State *L)
{
    int argc = lua_gettop(L);
    struct selectionvar *sel = l_selection_check(L, 1);
    char *mapchr = dupstr(luaL_checkstring(L, 2));
    coordxy typ = check_mapchr(mapchr);
    int lit = (int) luaL_optinteger(L, 3, -2); /* TODO: special lit values */
    struct selectionvar *tmp;

    if (typ == INVALID_TYPE)
        nhl_error(L, "Erroneous map char");

    tmp = selection_filter_mapchar(sel, typ, lit);
    lua_pop(L, argc);
    l_selection_push_copy(L, tmp);
    selection_free(tmp, TRUE);

    if (mapchr)
        free(mapchr);

    return 1;
}

/* local s = selection.match([[...]]); */
staticfn int
l_selection_match(lua_State *L)
{
    int argc = lua_gettop(L);
    struct selectionvar *sel = (struct selectionvar *) 0;
    struct mapfragment *mf = (struct mapfragment *) 0;
    int x, y;

    if (argc == 1) {
        const char *err;
        char *mapstr = dupstr(luaL_checkstring(L, 1));
        lua_pop(L, 1);
        (void) l_selection_new(L);
        sel = l_selection_check(L, 1);

        mf = mapfrag_fromstr(mapstr);
        free(mapstr);

        if ((err = mapfrag_error(mf)) != NULL) {
            nhl_error(L, err);
            /*NOTREACHED*/
        }

    } else {
        nhl_error(L, "wrong parameters");
        /*NOTREACHED*/
    }

    for (y = 0; y <= sel->hei; y++)
        for (x = 1; x < sel->wid; x++)
            selection_setpoint(x, y, sel, mapfrag_match(mf, x,y) ? 1 : 0);

    /* unless the (0, 1) coordinate is a match, this would wind up with a
       selection with lx=COLNO, hx=0, etc, so fix the boundaries */
    selection_recalc_bounds(sel);

    mapfrag_free(&mf);

    return 1;
}


/* local s = selection.floodfill(x,y); */
/* local s = selection.floodfill(x,y, diagonals); */
staticfn int
l_selection_flood(lua_State *L)
{
    int argc = lua_gettop(L);
    struct selectionvar *sel = (struct selectionvar *) 0;
    coordxy x = 0, y = 0;
    boolean diagonals = FALSE;

    if (argc == 2 || argc == 3) {
        x = (coordxy) luaL_checkinteger(L, 1);
        y = (coordxy) luaL_checkinteger(L, 2);
        if (argc == 3)
            diagonals = lua_toboolean(L, 3);
        lua_pop(L, argc);
        (void) l_selection_new(L);
        sel = l_selection_check(L, 1);
    } else {
        nhl_error(L, "wrong parameters");
        /*NOTREACHED*/
    }

    get_location_coord(&x, &y, ANY_LOC, gc.coder ? gc.coder->croom : NULL,
                       SP_COORD_PACK(x, y));

    if (isok(x, y)) {
        set_floodfillchk_match_under(levl[x][y].typ);
        selection_floodfill(sel, x, y, diagonals);
    }
    return 1;
}


/* local s = selection.circle(x,y, radius); */
/* local s = selection.circle(x, y, radius, filled); */
/* local s = selection.circle(sel, x, y, radius); */
/* local s = selection.circle(sel, x, y, radius, filled); */
staticfn int
l_selection_circle(lua_State *L)
{
    int argc = lua_gettop(L);
    struct selectionvar *sel = (struct selectionvar *) 0;
    coordxy x = 0, y = 0;
    int r = 0, filled = 0;

    if (argc == 3) {
        x = (coordxy) luaL_checkinteger(L, 1);
        y = (coordxy) luaL_checkinteger(L, 2);
        r = (int) luaL_checkinteger(L, 3);
        lua_pop(L, 3);
        (void) l_selection_new(L);
        sel = l_selection_check(L, 1);
        filled = 0;
    } else if (argc == 4 && lua_type(L, 1) == LUA_TNUMBER) {
        x = (coordxy) luaL_checkinteger(L, 1);
        y = (coordxy) luaL_checkinteger(L, 2);
        r = (int) luaL_checkinteger(L, 3);
        filled = (int) luaL_checkinteger(L, 4); /* TODO: boolean*/
        lua_pop(L, 4);
        (void) l_selection_new(L);
        sel = l_selection_check(L, 1);
    } else if (argc == 4 || argc == 5) {
        sel = l_selection_check(L, 1);
        x = (coordxy) luaL_checkinteger(L, 2);
        y = (coordxy) luaL_checkinteger(L, 3);
        r = (int) luaL_checkinteger(L, 4);
        filled = (int) luaL_optinteger(L, 5, 0); /* TODO: boolean */
    } else {
        nhl_error(L, "wrong parameters");
        /*NOTREACHED*/
    }

    get_location_coord(&x, &y, ANY_LOC, gc.coder ? gc.coder->croom : NULL,
                       SP_COORD_PACK(x, y));

    selection_do_ellipse(sel, x, y, r, r, !filled);

    lua_settop(L, 1);
    return 1;
}

/* local s = selection.ellipse(x, y, radius1, radius2); */
/* local s = selection.ellipse(x, y, radius1, radius2, filled); */
/* local s = selection.ellipse(sel, x, y, radius1, radius2); */
/* local s = selection.ellipse(sel, x, y, radius1, radius2, filled); */
staticfn int
l_selection_ellipse(lua_State *L)
{
    int argc = lua_gettop(L);
    struct selectionvar *sel = (struct selectionvar *) 0;
    coordxy x = 0, y = 0;
    int r1 = 0, r2 = 0, filled = 0;

    if (argc == 4) {
        x = (coordxy) luaL_checkinteger(L, 1);
        y = (coordxy) luaL_checkinteger(L, 2);
        r1 = (int) luaL_checkinteger(L, 3);
        r2 = (int) luaL_checkinteger(L, 4);
        lua_pop(L, 4);
        (void) l_selection_new(L);
        sel = l_selection_check(L, 1);
        filled = 0;
    } else if (argc == 5 && lua_type(L, 1) == LUA_TNUMBER) {
        x = (coordxy) luaL_checkinteger(L, 1);
        y = (coordxy) luaL_checkinteger(L, 2);
        r1 = (int) luaL_checkinteger(L, 3);
        r2 = (int) luaL_checkinteger(L, 4);
        filled = (int) luaL_optinteger(L, 5, 0); /* TODO: boolean */
        lua_pop(L, 5);
        (void) l_selection_new(L);
        sel = l_selection_check(L, 1);
    } else if (argc == 5 || argc == 6) {
        sel = l_selection_check(L, 1);
        x = (coordxy) luaL_checkinteger(L, 2);
        y = (coordxy) luaL_checkinteger(L, 3);
        r1 = (int) luaL_checkinteger(L, 4);
        r2 = (int) luaL_checkinteger(L, 5);
        filled = (int) luaL_optinteger(L, 6, 0); /* TODO: boolean */
    } else {
        nhl_error(L, "wrong parameters");
        /*NOTREACHED*/
    }

    get_location_coord(&x, &y, ANY_LOC, gc.coder ? gc.coder->croom : NULL,
                       SP_COORD_PACK(x, y));

    selection_do_ellipse(sel, x, y, r1, r2, !filled);

    lua_settop(L, 1);
    return 1;
}

/* Gradients are versatile enough, with so many independently optional
 * arguments, that it doesn't seem helpful to provide a non-table form with
 * non-obvious argument order. */
/* selection.gradient({ type = "radial", x = 3, y = 5, x2 = 10, y2 = 12,
 *                      mindist = 4, maxdist = 10, limited = false });    */
staticfn int
l_selection_gradient(lua_State *L)
{
    int argc = lua_gettop(L);
    struct selectionvar *sel = (struct selectionvar *) 0;
    /* if x2 and y2 aren't set, the gradient has a single center point of x,y;
     * if they are set, the gradient is centered on a (x,y) to (x2,y2) line */
    coordxy x = 0, y = 0, x2 = -1, y2 = -1;
    /* points are always added within mindist of the center; the chance for a
     * point between mindist and maxdist to be added to the selection starts
     * at 100% at mindist and decreases linearly to 0% at maxdist */
    coordxy mindist = 0, maxdist = 0;
    long type = 0;
    static const char *const gradtypes[] = {
        "radial", "square", NULL
    };
    static const int gradtypes2i[] = {
        SEL_GRADIENT_RADIAL, SEL_GRADIENT_SQUARE, -1
    };

    if (argc == 1 && lua_type(L, 1) == LUA_TTABLE) {
        lcheck_param_table(L);
        type = gradtypes2i[get_table_option(L, "type", "radial", gradtypes)];
        x = (coordxy) get_table_int(L, "x");
        y = (coordxy) get_table_int(L, "y");
        x2 = (coordxy) get_table_int_opt(L, "x2", -1);
        y2 = (coordxy) get_table_int_opt(L, "y2", -1);
        cvt_to_abscoord(&x, &y);
        cvt_to_abscoord(&x2, &y2);
        /* maxdist is required because there's no obvious default value for
         * it, whereas mindist has an obvious default of 0 */
        maxdist = get_table_int(L, "maxdist");
        mindist = get_table_int_opt(L, "mindist", 0);

        lua_pop(L, 1);
        (void) l_selection_new(L);
        sel = l_selection_check(L, 1);
    } else {
        nhl_error(L, "selection.gradient requires table argument");
        /* NOTREACHED */
    }

    /* someone might conceivably want to draw a gradient somewhere off-map. So
     * the only coordinate that's "illegal" for that is (-1,-1).
     * If a level designer really needs to draw a gradient line using that
     * coordinate, they can do so by setting regular x and y to -1. */
    if (x2 == -1 && y2 == -1) {
        x2 = x;
        y2 = y;
    }

    selection_do_gradient(sel, x, y, x2, y2, type, mindist, maxdist);
    lua_settop(L, 1);
    return 1;
}

DISABLE_WARNING_UNREACHABLE_CODE

/* sel:iterate(function(x,y) ... end);
 * The x, y coordinates passed to the function are map- or room-relative
 * rather than absolute, unless there has been no previous map or room
 * defined.
 */
staticfn int
l_selection_iterate(lua_State *L)
{
    int argc = lua_gettop(L);
    struct selectionvar *sel = (struct selectionvar *) 0;
    int x, y;
    NhRect rect = cg.zeroNhRect;

    if (argc == 2 && lua_type(L, 2) == LUA_TFUNCTION) {
        sel = l_selection_check(L, 1);
        selection_getbounds(sel, &rect);
        for (y = rect.ly; y <= rect.hy; y++) {
            for (x = max(1,rect.lx); x <= rect.hx; x++)
                if (selection_getpoint(x, y, sel)) {
                    coordxy tmpx = x, tmpy = y;
                    cvt_to_relcoord(&tmpx, &tmpy);
                    lua_pushvalue(L, 2);
                    lua_pushinteger(L, tmpx);
                    lua_pushinteger(L, tmpy);
                    if (nhl_pcall_handle(L, 2, 0, "l_selection_iterate",
                                         NHLpa_impossible)) {
                        /* abort loops to prevent possible error cascade */
                        goto out;
                    }
                }
            lua_gc(L, LUA_GCCOLLECT, 0);
        }
    } else {
        nhl_error(L, "wrong parameters");
        /*NOTREACHED*/
    }
 out:
    return 0;
}

/* local txt = sel:describe_size(); */
/* gives a textual description of the selection size */
staticfn int
l_selection_size_description(lua_State *L)
{
    int argc = lua_gettop(L);

    if (argc == 1) {
        struct selectionvar *sel = l_selection_check(L, 1);
        char buf[BUFSZ];

        lua_pushstring(L, selection_size_description(sel, buf));
        return 1;
    } else {
        nhl_error(L, "wrong parameters");
        /*NOTREACHED*/
    }
    return 0;
}

RESTORE_WARNING_UNREACHABLE_CODE

static const struct luaL_Reg l_selection_methods[] = {
    { "new", l_selection_new },
    { "clone", l_selection_clone },
    { "get", l_selection_getpoint },
    { "set", l_selection_setpoint },
    { "numpoints", l_selection_numpoints },
    { "negate", l_selection_not },
    { "percentage", l_selection_filter_percent },
    { "rndcoord", l_selection_rndcoord },
    { "line", l_selection_line },
    { "randline", l_selection_randline },
    { "rect", l_selection_rect },
    { "fillrect", l_selection_fillrect },
    { "area", l_selection_fillrect },
    { "grow", l_selection_grow },
    { "filter_mapchar", l_selection_filter_mapchar },
    { "match", l_selection_match },
    { "floodfill", l_selection_flood },
    { "circle", l_selection_circle },
    { "ellipse", l_selection_ellipse },
    { "gradient", l_selection_gradient },
    { "iterate", l_selection_iterate },
    { "bounds", l_selection_getbounds },
    { "room", l_selection_room },
    { "describe_size", l_selection_size_description },
    { NULL, NULL }
};

static const luaL_Reg l_selection_meta[] = {
    { "__gc", l_selection_gc },
    { "__unm", l_selection_not },
    { "__band", l_selection_and },
    { "__bor", l_selection_or },
    { "__bxor", l_selection_xor },
    { "__bnot", l_selection_not },
    { "__add", l_selection_or }, /* this aliases + to be the same as | */
    { "__sub", l_selection_sub },
    /* TODO: http://lua-users.org/wiki/MetatableEvents
       { "__ipairs", l_selection_ipairs },
    */
    { NULL, NULL }
};

int
l_selection_register(lua_State *L)
{
    /* Table of instance methods and static methods. */
    luaL_newlib(L, l_selection_methods);

    /* metatable = { __name = "selection", __gc = l_selection_gc } */
    luaL_newmetatable(L, "selection");
    luaL_setfuncs(L, l_selection_meta, 0);

    /* metatable.__index points at the selection method table. */
    lua_pushvalue(L, -2);
    lua_setfield(L, -2, "__index");

    /* Don't let lua code mess with the real metatable.
       Instead offer a fake one that only contains __gc. */
    luaL_newlib(L, l_selection_meta);
    lua_setfield(L, -2, "__metatable");

    /* We don't need the metatable anymore. It's safe in the
       Lua registry for use by luaL_setmetatable. */
    lua_pop(L, 1);

    /* global selection = the method table we created at the start */
    lua_setglobal(L, "selection");

    return 0;
}