effects.cc

/*
 *  effects.cc - Special effects.
 *
 *  Copyright (C) 2000-2013  The Exult Team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include "gamewin.h"
#include "gamemap.h"
#include "gameclk.h"
#include "actors.h"
#include "effects.h"
#include "Zombie.h"
#include "dir.h"
#include "chunks.h"
#include "Audio.h"
#include "Gump_manager.h"
#include "game.h"
#include "Gump.h"
#include "egg.h"
#include "shapeinf.h"
#include "ammoinf.h"
#include "weaponinf.h"
#include "ucmachine.h"

#include "SDL_timer.h"

#include "AudioMixer.h"
using namespace Pentagram;

#ifndef UNDER_EMBEDDED_CE
using std::cout;
using std::endl;
using std::rand;
using std::string;
using std::strlen;
#endif

int Cloud::randcnt = 0;
int Lightning_effect::active = 0;

/**
 *  Clean up.
 */

Effects_manager::~Effects_manager() {
	remove_all_effects(false);
}

/**
 *  Add text over a given item.
 *  @param msg      text to add
 *  @param item     Item text ID's, or null.
 */

void Effects_manager::add_text(
    const char *msg,
    Game_object *item
) {
	if (!msg)           // Happens with edited games.
		return;
	// Don't duplicate for item.
	for (Text_effect *each = texts; each; each = each->next)
		if (each->is_text(item))
			return;     // Already have text on this.
	Text_effect *txt = new Text_effect(msg, item);
//	txt->paint(this);        // Draw it.
//	painted = 1;
	add_text_effect(txt);
}

/**
 *  Add a text object at a given spot.
 *  @param msg      text to add
 *  @param x        x coord. on screen.
 *  @param y        y coord. on screen.
 */

void Effects_manager::add_text(
    const char *msg,
    int x, int y
) {
	Text_effect *txt = new Text_effect(msg,
	                                   gwin->get_scrolltx() + x / c_tilesize,
	                                   gwin->get_scrollty() + y / c_tilesize);
	add_text_effect(txt);
}

/**
 *  Add a text object in the center of the screen
 */

void Effects_manager::center_text(
    const char *msg
) {
	remove_text_effects();
	Shape_manager *sman = Shape_manager::get_instance();
	add_text(msg, (gwin->get_width() - sman->get_text_width(0, msg)) / 2,
	         gwin->get_height() / 2);
}

/**
 *  Add an effect at the start of the chain.
 */

void Effects_manager::add_effect(
    Special_effect *effect
) {
	effect->next = effects;     // Insert into chain.
	effect->prev = 0;
	if (effect->next)
		effect->next->prev = effect;
	effects = effect;
}

/**
 *  Add a text effect at the start of the chain.
 */

void Effects_manager::add_text_effect(
    Text_effect *effect
) {
	effect->next = texts;       // Insert into chain.
	effect->prev = 0;
	if (effect->next)
		effect->next->prev = effect;
	texts = effect;
}

/**
 *  Remove a given object's text effect.
 */

void Effects_manager::remove_text_effect(
    Game_object *item       // Item text was added for.
) {
	for (Text_effect *each = texts; each; each = each->next)
		if (each->is_text(item)) {
			// Found it.
			remove_text_effect(each);
			gwin->paint();
			return;
		}
}

/**
 *  Remove a sprite from the chain and delete it.
 */

void Effects_manager::remove_effect(
    Special_effect *effect
) {
	if (effect->in_queue())
		gwin->get_tqueue()->remove(effect);
	if (effect->next)
		effect->next->prev = effect->prev;
	if (effect->prev)
		effect->prev->next = effect->next;
	else                // Head of chain.
		effects = effect->next;
	delete effect;
}

/**
 *  Remove text from the chain and delete it.
 */

void Effects_manager::remove_text_effect(
    Text_effect *txt
) {
	if (txt->in_queue())
		gwin->get_tqueue()->remove(txt);
	if (txt->next)
		txt->next->prev = txt->prev;
	if (txt->prev)
		txt->prev->next = txt->next;
	else                // Head of chain.
		texts = txt->next;
	delete txt;
}

/**
 *  Remove all text items.
 */

void Effects_manager::remove_all_effects(
    bool repaint
) {
	if (!effects && !texts)
		return;
	while (effects)
		remove_effect(effects);
	while (texts)
		remove_text_effect(texts);
	if (repaint)
		gwin->paint();      // Just paint whole screen.
}

/**
 *  Remove text effects.
 */

void Effects_manager::remove_text_effects(
) {
	while (texts)
		remove_text_effect(texts);
	gwin->set_all_dirty();
}

/**
 *  Remove weather effects.
 *  @param  dist    Only remove those from eggs at least this far away.
 */

void Effects_manager::remove_weather_effects(
    int dist
) {
	Actor *main_actor = gwin->get_main_actor();
	Tile_coord apos = main_actor ? main_actor->get_tile()
	                  : Tile_coord(-1, -1, -1);
	Special_effect *each = effects;
	while (each) {
		Special_effect *next = each->next;
		// See if we're far enough away.
		if (each->is_weather() && (!dist ||
		                           reinterpret_cast<Weather_effect *>(each)->out_of_range(apos, dist)))
			remove_effect(each);
		each = next;
	}
	gwin->set_all_dirty();
}

/**
 *  Remove lightning effects.
 */

void Effects_manager::remove_usecode_lightning(
) {
	Special_effect *each = effects;
	while (each) {
		Special_effect *next = each->next;
		// See if we're far enough away.
		Lightning_effect *light = dynamic_cast<Lightning_effect *>(each);
		if (light && light->from_usecode())
			remove_effect(each);
		each = next;
	}
	gwin->set_all_dirty();
}

/**
 *  Find last numbered weather effect added.
 */

int Effects_manager::get_weather(
) {
	Special_effect *each = effects;
	while (each) {
		Special_effect *next = each->next;
		if (each->is_weather()) {
			Weather_effect *weather = reinterpret_cast<Weather_effect *>(each);
			if (weather->get_num() >= 0)
				return weather->get_num();
		}
		each = next;
	}
	return 0;
}

/**
 *  Paint them all.
 */

void Effects_manager::paint(
) {
	for (Special_effect *effect = effects; effect; effect = effect->next)
		effect->paint();
}

/**
 *  Paint all text.
 */

void Effects_manager::paint_text(
) {
	for (Text_effect *txt = texts; txt; txt = txt->next)
		txt->paint();
}

/**
 *  Paint all text.
 */
void Effects_manager::update_dirty_text(
) {
	for (Text_effect *txt = texts; txt; txt = txt->next)
		txt->update_dirty();
}
/**
 *  Some special effects may not need painting.
 */

void Special_effect::paint(
) {
}

/**
 *  Create an animation from the 'sprites.vga' file.
 */

Sprites_effect::Sprites_effect(
    int num,            // Index.
    Tile_coord const &p,    // Position within world.
    int dx, int dy,         // Add to offset for each frame.
    int delay,          // Delay (msecs) before starting.
    int frm,            // Starting frame.
    int rps             // Reps, or <0 to go through frames.
) : sprite(num, frm, SF_SPRITES_VGA), item(0), pos(p),
	xoff(0), yoff(0), deltax(dx), deltay(dy), reps(rps) {
	Game_window *gwin = Game_window::get_instance();
	frames = sprite.get_num_frames();
	// Start.
	gwin->get_tqueue()->add(Game::get_ticks() + delay, this, 0L);
}

/**
 *  Create an animation on an object.
 */

Sprites_effect::Sprites_effect(
    int num,            // Index.
    Game_object *it,        // Item to put effect by.
    int xf, int yf,         // Offset from actor in pixels.
    int dx, int dy,         // Add to offset on each frame.
    int frm,            // Starting frame.
    int rps             // Reps, or <0 to go through frames.
) : sprite(num, frm, SF_SPRITES_VGA), item(it), xoff(xf),
	yoff(yf), deltax(dx), deltay(dy), reps(rps) {
	pos = item->get_tile();
	Game_window *gwin = Game_window::get_instance();
	frames = sprite.get_num_frames();
	// Start immediately.
	gwin->get_tqueue()->add(Game::get_ticks(), this, 0L);
}

/**
 *  Add a dirty rectangle for the current position and frame.
 */

inline void Sprites_effect::add_dirty(
    int frnum
) {
	if (pos.tx == -1 || frnum == -1)
		return;         // Already at destination.
	Shape_frame *shape = sprite.get_shape();
	int lp = pos.tz / 2;

	gwin->add_dirty(gwin->clip_to_win(gwin->get_shape_rect(shape,
	                                  xoff + (pos.tx - lp - gwin->get_scrolltx())*c_tilesize,
	                                  yoff + (pos.ty - lp - gwin->get_scrollty())*c_tilesize
	                                                      ).enlarge((3 * c_tilesize) / 2)));
}

/**
 *  Animation.
 */

void Sprites_effect::handle_event(
    unsigned long curtime,      // Current time of day.
    long udata
) {
	int frame_num = sprite.get_framenum();
	Game_window *gwin = Game_window::get_instance();
	int delay = gwin->get_std_delay();// Delay between frames.  Needs to
	//   match usecode animations.
	if (!reps || (reps < 0 && frame_num == frames)) { // At end?
		// Remove & delete this.
		eman->remove_effect(this);
		gwin->set_all_dirty();
		return;
	}
	add_dirty(frame_num);       // Clear out old.
	gwin->set_painted();
	if (item)           // Following actor?
		pos = item->get_tile();
	xoff += deltax;         // Add deltas.
	yoff += deltay;
	frame_num++;            // Next frame.
	if (reps > 0) {         // Given a count?
		--reps;
		frame_num %= frames;
	}
	add_dirty(frame_num);       // Want to paint new frame.
	sprite.set_frame(frame_num);
	// Add back to queue for next time.
	gwin->get_tqueue()->add(curtime + delay, this, udata);
}

/**
 *  Render.
 */

void Sprites_effect::paint(
) {
	if (sprite.get_framenum() >= frames)
		return;
	int lp = pos.tz / 2;    // Account for lift.
	sprite.paint_shape(
	    xoff + (pos.tx - lp - gwin->get_scrolltx())*c_tilesize - gwin->get_scrolltx_lo(),
	    yoff + (pos.ty - lp - gwin->get_scrollty())*c_tilesize - gwin->get_scrolltx_lo());
}

static inline int get_explosion_shape(
    int weap,
    int proj
) {
	int shp = proj >= 0 ? proj : (weap >= 0 ? weap : 704);
	return ShapeID::get_info(shp).get_explosion_sprite();
}

static inline int get_explosion_sfx(
    int weap,
    int proj
) {
	int shp = proj >= 0 ? proj : (weap >= 0 ? weap : 704);
	return ShapeID::get_info(shp).get_explosion_sfx();
}

/**
 *  Start explosion.
 */

Explosion_effect::Explosion_effect(
    Tile_coord const &p,
    Game_object *exp,
    int delay,          // Delay before starting (msecs).
    int weap,           // Weapon to use for damage calcs., or
    //   -1 for default(704 = powder keg).
    int proj,       // Projectile for e.g., burst arrows, 0 otherwise
    Game_object *att    //who is responsible for the explosion
    //  or 0 for default
    //Different sprites for different explosion types
) : Sprites_effect(get_explosion_shape(weap, proj), p, 0, 0, delay),
	explode(exp), weapon(weap >= 0 ? weap : (proj >= 0 ? proj : 704)),
	projectile(proj), exp_sfx(get_explosion_sfx(weap, proj)),
	attacker(att) {
	//if (exp && exp->get_shapenum() == 704)  // powderkeg
	if (exp && exp->get_info().is_explosive())  // powderkeg
		exp->set_quality(1); // mark as detonating

	if (!attacker || !attacker->as_actor())
		// Blame avatar: if we have no living attacker.
		attacker = gwin->get_main_actor();
}


void Explosion_effect::handle_event(
    unsigned long curtime,      // Current time of day.
    long udata
) {
	int frnum = sprite.get_framenum();
	if (!frnum) {       // Max. volume, with stereo position.
		Audio::get_ptr()->play_sound_effect(exp_sfx, pos, AUDIO_MAX_VOLUME);
	}
	if (frnum == frames / 4) {
		// this was in ~Explosion_effect before
		if (explode && !explode->is_pos_invalid()) {
			Game_window::get_instance()->add_dirty(explode);
			explode->remove_this();
			explode = 0;
		}
		Shape_frame *shape = sprite.get_shape();
		int width = shape->get_width();     //Get the sprite's width
		Game_object_vector vec; // Find objects near explosion.
		Game_object::find_nearby(vec, pos, c_any_shapenum,
		                         width / (2 * c_tilesize), 0);
		for (Game_object_vector::const_iterator it = vec.begin(); it != vec.end(); ++it) {
			Game_object *obj = *it;
			obj->attacked(attacker, weapon, projectile, true);
		}
	}
	Sprites_effect::handle_event(curtime, udata);
}

/**
 *  Get direction in 1/16's starting from North.
 */

inline int Get_dir16(
    Tile_coord &t1,
    Tile_coord &t2
) {
	// Treat as cartesian coords.
	return Get_direction16(t1.ty - t2.ty, t2.tx - t1.tx);
}

/**
 *  Initialize path & add to time queue.
 */

void Projectile_effect::init(
    Tile_coord const &s,            // Source,
    Tile_coord const &d         // Destination.
) {
	no_blocking = false;        // We'll check the ammo & weapon.
	Game_window *gwin = Game_window::get_instance();
	Weapon_info *winfo = ShapeID::get_info(weapon).get_weapon_info();
	if (winfo) {
		no_blocking = no_blocking || winfo->no_blocking();
		if (speed < 0)
			speed = winfo->get_missile_speed();
		autohit = winfo->autohits();
	}
	if (speed < 0)
		speed = 4;
	Ammo_info *ainfo = ShapeID::get_info(projectile_shape).get_ammo_info();
	if (ainfo) {
		no_blocking = no_blocking || ainfo->no_blocking();
		autohit = autohit || ainfo->autohits();
	}
	if (attacker) {         // Try to set start better.
		int dir = target ?
		          attacker->get_direction(target) :
		          attacker->get_direction(d);
		pos = attacker->get_missile_tile(dir);
	} else
		pos = s;            // Get starting position.

	Tile_coord dst = d;
	if (target)         // Try to set end better.
		dst = target->get_center_tile();
	else
		dst.tz = pos.tz;
	path = new Zombie();        // Create simple pathfinder.
	// Find path.  Should never fail.
	bool explodes = (winfo && winfo->explodes()) || (ainfo && ainfo->explodes());
	if (explodes && ainfo && ainfo->is_homing())
		path->NewPath(pos, pos, 0); //A bit of a hack, I know...
	else {
		path->NewPath(pos, dst, 0);
		if (attacker) {
			// Getprojectile  out of shooter's volume.
			Block vol = attacker->get_block();
			Tile_coord t;
			bool done;
			while (path->GetNextStep(t, done))
				if (!vol.has_world_point(t.tx, t.ty, t.tz))
					break;
			pos = t;
		}
	}
	int sprite_shape = sprite.get_shapenum();
	set_sprite_shape(sprite_shape);
	// Start after a slight delay.
	gwin->get_tqueue()->add(Game::get_ticks(), this, gwin->get_std_delay() / 2);
}

void Projectile_effect::set_sprite_shape(
    int s
) {
	if (s < 0) {
		skip_render = true;
		sprite.set_shape(s);
		sprite.set_frame(0);
		return;
	}
	sprite.set_shape(s);
	frames = sprite.get_num_frames();
	if (frames >= 24) {     // Use frames 8-23, for direction
		//   going clockwise from North.
		Tile_coord src = path->get_src(), dest = path->get_dest();
		int dir = Get_dir16(src, dest);
		sprite.set_frame(8 + dir);
	}
	//else if (frames == 1 && sprite.get_shapenum() != 704)
	else if (frames == 1 && sprite.get_info().is_explosive())
		sprite.set_frame(0);    // (Don't show powder keg!)
	else
		skip_render = true;     // We just won't show it.
	add_dirty();            // Paint immediately.
}

/**
 *  Create a projectile animation.
 */
Projectile_effect::Projectile_effect(
    Game_object *att,       // Source of spell/attack.
    Game_object *to,        // End here, 'attack' it with shape.
    int weap,           // Weapon (bow, gun, etc.) shape.
    int proj,           // Projectile shape # in 'shapes.vga'.
    int spr,            // Shape to render on-screen or -1 for none.
    int attpts,         // Attack points of projectile.
    int spd             // Projectile speed, or -1 to use default.
) : attacker(att), target(to), weapon(weap), projectile_shape(proj),
	sprite(spr, 0), return_path(false),  skip_render(spr < 0),
	speed(spd), attval(attpts), autohit(false) {
	init(att->get_tile(), to->get_tile());
}

/**
 *  Constructor used by missile eggs & fire_projectile intrinsic.
 */

Projectile_effect::Projectile_effect(
    Game_object *att,       // Source of spell/attack.
    Tile_coord const &d,    // End here.
    int weap,           // Weapon (bow, gun, etc.) shape.
    int proj,           // Projectile shape # in 'shapes.vga'.
    int spr,            // Shape to render on-screen or -1 for none.
    int attpts,         // Attack points of projectile.
    int spd,            // Projectile speed, or -1 to use default.
    bool retpath            // Return of a boomerang.
) : attacker(att), target(0), weapon(weap), projectile_shape(proj),
	sprite(spr, 0), return_path(false), skip_render(spr < 0),
	speed(spd), attval(attpts), autohit(false) {
	init(att->get_tile(), d);
}

/*
 *  Another used by missile eggs and for 'boomerangs'.
 */

Projectile_effect::Projectile_effect(
    Tile_coord const &s,    // Start here.
    Game_object *to,        // End here, 'attack' it with shape.
    int weap,           // Weapon (bow, gun, etc.) shape.
    int proj,           // Projectile shape # in 'shapes.vga'.
    int spr,            // Shape to render on-screen or -1 for none.
    int attpts,         // Attack points of projectile.
    int spd,            // Projectile speed, or -1 to use default.
    bool retpath            // Return of a boomerang.
) : attacker(0), target(to), weapon(weap), projectile_shape(proj),
	sprite(spr, 0), return_path(retpath), skip_render(spr < 0),
	speed(spd), attval(attpts), autohit(false) {
	init(s, to->get_tile());
}

/**
 *  Delete.
 */

Projectile_effect::~Projectile_effect(
) {
	delete path;
}

/**
 *  Add a dirty rectangle for the current position and frame.
 */

inline void Projectile_effect::add_dirty(
) {
	if (skip_render)
		return;
	Shape_frame *shape = sprite.get_shape();
	// Force repaint of prev. position.
	int liftpix = pos.tz * c_tilesize / 2;
	gwin->add_dirty(gwin->clip_to_win(gwin->get_shape_rect(shape,
	                                  (pos.tx - gwin->get_scrolltx())*c_tilesize - liftpix,
	                                  (pos.ty - gwin->get_scrollty())*c_tilesize - liftpix
	                                                      ).enlarge(c_tilesize / 2)));
}

/**
 *  See if something was hit.
 *
 *  @return target hit, or 0.
 */

inline Game_object *Find_target(
    Game_window *gwin,
    Tile_coord pos
) {
	if (pos.tz % 5 == 0)    // On floor?
		pos.tz++;       // Look up 1 tile.
	Tile_coord dest = pos;      // This gets modified.
	if (!Map_chunk::is_blocked(pos, 1, MOVE_FLY, 0) &&
	        dest == pos)
		return (0);
	return Game_object::find_blocking(pos);
}

/**
 *  Animation.
 */

void Projectile_effect::handle_event(
    unsigned long curtime,      // Current time of day.
    long udata
) {
	Game_window *gwin = Game_window::get_instance();
	int delay = gwin->get_std_delay() / 2;
	add_dirty();            // Force repaint of old pos.
	Weapon_info *winf = ShapeID::get_info(weapon).get_weapon_info();
	if (winf && winf->get_rotation_speed()) {
		// The missile rotates (such as axes/boomerangs)
		int new_frame = sprite.get_framenum() + winf->get_rotation_speed();
		sprite.set_frame(new_frame > 23 ? ((new_frame - 8) % 16) + 8 : new_frame);
	}
	bool path_finished = false;
	for (int i = 0; i < speed; i++) {
		// This speeds up the missile.
		path_finished = (path->GetNextStep(pos) == 0) ||    // Get next spot.
		                // If missile egg, detect target.
		                (!target && !no_blocking && (target = Find_target(gwin, pos)) != 0);
		if (path_finished)
			break;
	}
	Ammo_info *ainf = ShapeID::get_info(projectile_shape).get_ammo_info();
	if (path_finished) {
		// Done?
		bool explodes = (winf && winf->explodes()) || (ainf && ainf->explodes());
		if (return_path) {  // Returned a boomerang?
			Ireg_game_object *obj =
			    gmap->create_ireg_object(sprite.get_shapenum(), 0);
			if (!target || !target->add(obj)) {
				obj->set_flag(Obj_flags::okay_to_take);
				obj->set_flag(Obj_flags::is_temporary);
				obj->move(pos.tx, pos.ty, pos.tz, -1);
			}
		} else if (explodes) { // Do this here (don't want to explode
			// returning weapon).
			Tile_coord offset;
			if (target)
				offset = Tile_coord(0, 0, target->get_info().get_3d_height() / 2);
			else
				offset = Tile_coord(0, 0, 0);
			if (ainf && ainf->is_homing())
				eman->add_effect(new Homing_projectile(weapon,
				                                       attacker, target, pos, pos + offset));
			else
				eman->add_effect(new Explosion_effect(pos + offset,
				                                      0, 0, weapon, projectile_shape, attacker));
			target = 0; // Takes care of attack.
		} else {
			// Not teleported away ?
			bool returns = (winf && winf->returns()) || (ainf && ainf->returns());
			bool hit = false;
			if (target && attacker != target &&
			        // Aims for center tile, so check center tile.
			        target->get_center_tile().distance(pos) < 3) {
				hit = autohit || target->try_to_hit(attacker, attval);
				if (hit) {
					target->play_hit_sfx(weapon, true);
					target->attacked(attacker, weapon, projectile_shape, false);
				}
			} else {
				// Hack warning: this exists solely to make Mind Blast (SI)
				// work as it does in the original when you target the
				// avatar with the spell.
				if (winf && winf->get_usecode() > 0)
					ucmachine->call_usecode(winf->get_usecode(), 0,
					                        Usecode_machine::weapon);
			}
			if (returns && attacker &&  // boomerangs
			        attacker->distance(pos) < 50) {
				// not teleported away
				Projectile_effect *proj = new Projectile_effect(
				    pos, attacker, weapon, projectile_shape,
				    sprite.get_shapenum(), attval, speed, true);
				proj->set_speed(speed);
				proj->set_sprite_shape(sprite.get_shapenum());
				eman->add_effect(proj);
			} else {
				// See if we should drop projectile.
				bool drop = false;
				// Seems to match originals quite well.
				if (!winf)
					drop = true;
				else if (ainf) {
					int ammo = winf->get_ammo_consumed(),
					    type = ainf->get_drop_type();
					drop = (ammo >= 0 || ammo == -3) &&
					       (type == Ammo_info::always_drop ||
					        (!hit && type != Ammo_info::never_drop));
				}
				if (drop) {
					Tile_coord dpos = Map_chunk::find_spot(pos, 3,
					                                       sprite.get_shapenum(), 0, 1);
					if (dpos.tx != -1) {
						Game_object *aobj = gmap->create_ireg_object(
						                        sprite.get_shapenum(), 0);
						if (!attacker || attacker->get_flag(Obj_flags::is_temporary))
							aobj->set_flag(Obj_flags::is_temporary);
						aobj->set_flag(Obj_flags::okay_to_take);
						aobj->move(dpos);
					}
				}
			}
		}
		add_dirty();
		skip_render = true;
		eman->remove_effect(this);
		return;
	}
	add_dirty();            // Paint new spot/frame.
	// Add back to queue for next time.
	gwin->get_tqueue()->add(curtime + delay, this, udata);
}

/**
 *  Render.
 */

void Projectile_effect::paint(
) {
	if (skip_render)
		return;
	int liftpix = pos.tz * c_tilesize / 2;
	sprite.paint_shape(
	    (pos.tx - gwin->get_scrolltx())*c_tilesize - liftpix - gwin->get_scrolltx_lo(),
	    (pos.ty - gwin->get_scrollty())*c_tilesize - liftpix - gwin->get_scrollty_lo());
}

/**
 *  Create a 'death vortex' or an 'energy mist'.
 */

Homing_projectile::Homing_projectile(   // A better name is welcome...
    int shnum,              // The projectile shape.
    Game_object *att,       // Who cast the spell.
    Game_object *trg,       // What to aim for.
    Tile_coord const &sp,   // Where to start.
    Tile_coord const &tp    // Target pos, if trg isn't an actor.
) : sprite(ShapeID::get_info(shnum).get_explosion_sprite(), 0, SF_SPRITES_VGA),
	next_damage_time(0), sfx(ShapeID::get_info(shnum).get_explosion_sfx()),
	channel(-1) {
	weapon = shnum;
	attacker = att;
	pos = sp;
	dest = tp;
	target = trg ? trg->as_actor() : 0;
	stationary = target ? false : true; //If true, the sprite will 'park' at dest
	Game_window *gwin = Game_window::get_instance();
	frames = sprite.get_num_frames();
	// Go for 20 seconds.
	stop_time = Game::get_ticks() + 20 * 1000;
	// Start immediately.
	gwin->get_tqueue()->add(Game::get_ticks(), this, 0L);
	channel = Audio::get_ptr()->play_sound_effect(sfx, pos, -1);
}

/**
 *  Add a dirty rectangle for the current position and frame.
 *
 *  @return     Width in pixels.
 */

inline int Homing_projectile::add_dirty(
) {
	Shape_frame *shape = sprite.get_shape();
	int liftpix = pos.tz * c_tilesize / 2;
	gwin->add_dirty(gwin->clip_to_win(gwin->get_shape_rect(shape,
	                                  (pos.tx - gwin->get_scrolltx())*c_tilesize - liftpix,
	                                  (pos.ty - gwin->get_scrollty())*c_tilesize - liftpix
	                                                      ).enlarge(c_tilesize / 2)));
	return shape->get_width();
}

/**
 *  Animation.
 */

void Homing_projectile::handle_event(
    unsigned long curtime,      // Current time of day.
    long udata
) {
	Game_window *gwin = Game_window::get_instance();
	int width = add_dirty();    // Repaint old area.

	if ((target && !target->is_dead()) || stationary) {
		//Move to target/destination if needed
		Tile_coord tpos = stationary ? dest : target->get_tile();
		int deltax = tpos.tx - pos.tx, deltay = tpos.ty - pos.ty,
		    deltaz = tpos.tz +
		             (stationary ? 0 : target->get_info().get_3d_height() / 2) - pos.tz;
		int absx = deltax >= 0 ? deltax : -deltax;
		int absy = deltay >= 0 ? deltay : -deltay;
		int absz = deltaz >= 0 ? deltaz : -deltaz;
		uint32 dist = absx * absx + absy * absy + absz * absz;
		if (dist > 1) {
			if (deltax)
				pos.tx += deltax / absx;
			if (deltay)
				pos.ty += deltay / absy;
			if (deltaz)
				pos.tz += deltaz / absz;
		}
	} else {
		//The target has been killed; find another one
		Actor_vector npcs;  // Find NPC's.
		Game_object::find_nearby_actors(npcs, pos, -1, 30);
		Actor *nearest = 0;
		uint32 bestdist = 100000;
		for (Actor_vector::const_iterator it = npcs.begin();
		        it != npcs.end(); ++it) {
			Actor *npc = *it;
			if (!npc->is_in_party() && !npc->is_dead() &&
			        (npc->get_effective_alignment() >= Actor::evil)) {
				Tile_coord npos = npc->get_tile();
				int dx = npos.tx - pos.tx, dy = npos.ty - pos.ty, dz = npos.tz - pos.tz;
				uint32 dist = dx * dx + dy * dy + dz * dz;
				if (dist < bestdist) {
					bestdist = dist;
					nearest = npc;
				}
			}
		}
		target = nearest;
	}
	if (curtime > next_damage_time) { // Time to cause damage.
		// Do it every second.
		next_damage_time = curtime + 1000;
		Actor_vector npcs;  // Find NPC's.
		Game_object::find_nearby_actors(npcs, pos, -1, width / (2 * c_tilesize));
		for (Actor_vector::const_iterator it = npcs.begin();
		        it != npcs.end(); ++it) {
			Actor *npc = *it;
			if (!npc->is_in_party())
				//Still powerful, but no longer overkill...
				//also makes the enemy react, which is good
				npc->attacked(attacker, weapon, weapon, true);
		}
	}
	sprite.set_frame((sprite.get_framenum() + 1) % frames);

	add_dirty();            // Paint new.
	if (curtime < stop_time) {  // Keep going?
		gwin->get_tqueue()->add(curtime + 100, this, udata);
		if (channel < 0)
			return;
		channel = Audio::get_ptr()->update_sound_effect(channel, pos);
	} else {
		if (channel >= 0) {
			AudioMixer::get_instance()->stopSample(channel);
			channel = -1;
		}
		gwin->set_all_dirty();
		eman->remove_effect(this);
	}
}

/**
 *  Render.
 */

void Homing_projectile::paint(
) {
	int liftpix = pos.tz * c_tilesize / 2;
	sprite.paint_shape(
	    (pos.tx - gwin->get_scrolltx())*c_tilesize - liftpix - gwin->get_scrolltx_lo(),
	    (pos.ty - gwin->get_scrollty())*c_tilesize - liftpix - gwin->get_scrollty_lo());
}

/**
 *  Figure text position.
 */

Rectangle Text_effect::Figure_text_pos() {
	Game_window *gwin = Game_window::get_instance();
	if (item) {
		Gump_manager *gumpman = gwin->get_gump_man();
		// See if it's in a gump.
		Gump *gump = gumpman->find_gump(item);
		if (gump)
			return gump->get_shape_rect(item);
		else {
			Game_object *outer = item->get_outermost();
			if (!outer->get_chunk()) return pos;
			Rectangle r = gwin->get_shape_rect(outer);
			r.x -= gwin->get_scrolltx_lo();
			r.y -= gwin->get_scrollty_lo();
			return r;
		}
	} else {
		int x, y;
		gwin->get_shape_location(tpos, x, y);
		return Rectangle(x, y, c_tilesize, c_tilesize);
	}
}

/**
 *  Add dirty rectangle for current position.
 */

void Text_effect::add_dirty(
) {
	Game_window *gwin = Game_window::get_instance();
	// Repaint slightly bigger rectangle.
	Rectangle rect(pos.x - c_tilesize,
	               pos.y - c_tilesize,
	               width + 2 * c_tilesize, height + 2 * c_tilesize);
	gwin->add_dirty(gwin->clip_to_win(rect));
}

/**
 *  Initialize.
 */

void Text_effect::init(
) {
	set_always(true);       // Always execute in time queue, even
	//   when paused.
	Game_window *gwin = Game_window::get_instance();
	width = 8 + sman->get_text_width(0, msg.c_str());
	height = 8 + sman->get_text_height(0);
	add_dirty();            // Force first paint.
	// Start immediately.
	gwin->get_tqueue()->add(Game::get_ticks(), this, 0L);
	if (msg[0] == '@')
		msg[0] = '"';
	int len = msg.size();
	if (msg[len - 1] == '@')
		msg[len - 1] = '"';
}

/**
 *  Create a text effect for a given object.
 */

Text_effect::Text_effect(
    const string &m,        // A copy is made.
    Game_object *it         // Item text is on, or null.
) : msg(m), item(it), pos(Figure_text_pos()), num_ticks(0) {
	init();
}

/**
 *  Create a text object.
 */

Text_effect::Text_effect(
    const string &m,        // A copy is made.
    int t_x, int t_y        // Abs. tile coords.
) : msg(m), item(0), tpos(t_x, t_y, 0), pos(Figure_text_pos()), num_ticks(0) {
	init();
}

/**
 *
 */

void Text_effect::handle_event(
    unsigned long curtime,      // Current time of day.
    long udata          // Ignored.
) {
	Game_window *gwin = Game_window::get_instance();
	if (++num_ticks == 10) {    // About 1-2 seconds.
		// All done.
		add_dirty();
		eman->remove_text_effect(this);
		return;
	}
	// Back into queue.
	gwin->get_tqueue()->add(Game::get_ticks() + gwin->get_std_delay(),
	                        this, 0L);

	update_dirty();
}

/**
 *  Reposition if necessary.
 */

void Text_effect::update_dirty(
) {
	// See if moved.
	Rectangle npos = Figure_text_pos();
	if (npos == pos)        // No change?
		return;
	add_dirty();            // Force repaint of old area.
	pos = npos;         // Then set to repaint new.
	add_dirty();
}

/**
 *  Render.
 */

void Text_effect::paint(
) {
	const char *ptr = msg.c_str();
	int len = strlen(ptr);
	sman->paint_text(0, ptr, len,
	                 pos.x,
	                 pos.y);
}

/**
 *  Init. a weather effect.
 */

Weather_effect::Weather_effect(
    int duration,           // Length in game minutes.
    int delay,          // Delay before starting.
    int n,              // Weather number.
    Game_object *egg        // Egg that started it, or null.
) : num(n) {
	Game_window *gwin = Game_window::get_instance();
	if (egg)
		eggloc = egg->get_tile();
	else
		eggloc = Tile_coord(-1, -1, -1);
	stop_time = Game::get_ticks() + delay + duration * gwin->get_std_delay() * ticks_per_minute;
	// Start immediately.
	gwin->get_tqueue()->add(Game::get_ticks() + delay, this, 0L);
}

/**
 *  Are we far enough away from this to cancel it?
 *  @param  avpos   Avatar's position.
 *  @param  dist    Distance in tiles to cancel at.
 */

int Weather_effect::out_of_range(
    Tile_coord &avpos,
    int dist
) {
	if (eggloc.tx == -1)        // Not created by an egg?
		return 0;
	return eggloc.distance(avpos) >= dist;
}

Fog_effect::~Fog_effect() {
	gclock->set_fog(false);
}

void Fog_effect::handle_event(unsigned long curtime, long udata) {
	if (start) {
		start = false;
		// Nothing more to do but end.
		gwin->get_tqueue()->add(stop_time, this, udata);
		gclock->set_fog(true);
	} else              // Must be time to stop.
		eman->remove_effect(this);
}

/*
 *  A generic raindrop/snowflake/magic sparkle particle:
 */
class Particle : public ShapeID {
	long ax, ay;            // Coords. where drawn in abs. pixels.
	bool forward;
public:
	Particle()
		: ShapeID(0, -1, SF_SPRITES_VGA), ax(-1), ay(-1), forward(true)
	{  }
	// Move to next position.
	void move(long dx, long dy) {
		ax = dx;
		ay = dy;
	}
	long get_ax() const {
		return ax;
	}
	long get_ay() const {
		return ay;
	}
	bool get_forward() const {
		return forward;
	}
	void toggle_forward() {
		forward = !forward;
	}
};

class Particledrop {
protected:
	virtual void do_move(Particle &drop, int x, int y, int w, int h,
	                     int ascrollx, int ascrolly)
	{  }
public:
	virtual ~Particledrop() {  }
	void move
	(
	    Particle &drop,
	    int scrolltx, int scrollty,
	    int w, int h
	) {
		int frame = drop.get_framenum();
		uint32 ascrollx = scrolltx * static_cast<uint32>(c_tilesize),
		       ascrolly = scrollty * static_cast<uint32>(c_tilesize);
		int ax = drop.get_ax(), ay = drop.get_ay();
		int x = ax - ascrollx, y = ay - ascrolly;
		// Still on screen?  Restore pix.
		if (frame >= 0 && x >= 0 && y >= 0 && x < w && y < h) {
			Game_window *gwin = Game_window::get_instance();
			gwin->add_dirty(gwin->clip_to_win(gwin->get_shape_rect(
			                                      drop.get_shape(), x, y).enlarge(c_tilesize / 2)));
		}
		do_move(drop, x, y, w, h, ascrollx, ascrolly);
	}
	void paint
	(
	    Particle &drop,
	    int scrolltx, int scrollty,
	    int w, int h
	) {
		uint32 ascrollx = scrolltx * static_cast<uint32>(c_tilesize),
		       ascrolly = scrollty * static_cast<uint32>(c_tilesize);
		int ax = drop.get_ax(), ay = drop.get_ay();
		int x = ax - ascrollx, y = ay - ascrolly;
		// Still on screen?  Restore pix.
		if (x >= 0 && y >= 0 && x < w && y < h) {
			Game_window *gwin = Game_window::get_instance();
			drop.paint_shape(x, y);
			gwin->add_dirty(gwin->clip_to_win(gwin->get_shape_rect(
			                                      drop.get_shape(), x, y).enlarge(c_tilesize / 2)));
		}
	}
};

template<int fra0, int fraN, bool randomize>
static inline void set_frame(Particle &drop) {
	int frame = drop.get_framenum();
	if (frame < 0) {
		if (randomize) {
			int dir = rand() % 2;
			if (dir)
				drop.toggle_forward();
			frame = fra0 + rand() % (fraN - fra0) + dir;
		} else
			frame = fra0;
	} else if (drop.get_forward()) {
		if (++frame == fraN)
			drop.toggle_forward();
	} else if (--frame == fra0)
		drop.toggle_forward();
	drop.set_frame(frame);
}


template<int fra0, int fraN, int delta, bool randomize>
class Basicdrop : public Particledrop {
protected:
	virtual void do_move(Particle &drop, int x, int y, int w, int h,
	                     int ascrollx, int ascrolly) {
		set_frame<fra0, fraN, randomize>(drop);
		// Time to restart?
		if (x < 0 || x >= w || y < 0 || y >= h) {
			int r = rand();
			drop.move(ascrollx + r % (w - w / 8), ascrolly + r % (h - h / 4));
		} else              // Next spot.
			drop.move(drop.get_ax() + delta, drop.get_ay() + delta);
	}
};

// This looks slightly cooler:
//typedef Basicdrop< 3, 6, 6, false> Raindrop;
typedef Basicdrop< 3, 7, 6, false> Raindrop;
typedef Basicdrop<13, 20, 1, false> Snowflake;
typedef Basicdrop<21, 27, 12, true > Sparkle;

/*
 *  Raining.
 */
#define MAXDROPS 200
template<typename Functor>
class Rain_effect : public Weather_effect {
protected:
	Particle drops[MAXDROPS];   // Drops moving down the screen.
	int num_drops;          // # to actually use.
	bool gradual;
	Functor do_drop;            // Controls how drops move.
	void change_ndrops(unsigned long curtime) {
		if (!gradual)
			return;
		if ((curtime > stop_time - 2500) && num_drops) {
			// End gradually.
			num_drops -= (rand() % 15);
			if (num_drops < 0)
				num_drops = 0;
		} else if (gradual && curtime < stop_time) { // Keep going?
			// Start gradually.
			if (num_drops < MAXDROPS)
				num_drops += (rand() % 5);
			if (num_drops > MAXDROPS)
				num_drops = MAXDROPS;
		}
	}
public:
	Rain_effect(int duration, int delay = 0,
	            int ndrops = MAXDROPS, int n = -1, Game_object *egg = 0)
		: Weather_effect(duration, delay, n, egg),
		  num_drops(ndrops), gradual(ndrops == 0)
	{  }
	// Execute when due.
	virtual void handle_event
	(
	    unsigned long curtime,      // Current time of day.
	    long udata
	) {
		Game_window *gwin = Game_window::get_instance();

		// Gradual start/end.
		change_ndrops(curtime);

		if (!gwin->is_main_actor_inside() &&
		        !gumpman->showing_gumps(true)) {
			// Don't show rain inside buildings!
			Image_window8 *win = gwin->get_win();
			int w = win->get_game_width(), h = win->get_game_height();
			// Get transform table.
			int scrolltx = gwin->get_scrolltx(),
			    scrollty = gwin->get_scrollty();
			// Move drops.
			for (int i = 0; i < num_drops; i++)
				do_drop.move(drops[i], scrolltx, scrollty, w, h);
			gwin->set_painted();
		}
		if (curtime >= stop_time) {
			gwin->set_all_dirty();
			eman->remove_effect(this);
			return;
		}
		gwin->get_tqueue()->add(curtime + 100, this, udata);
	}
	// Render.
	virtual void paint
	(
	) {
		if (gwin->is_main_actor_inside())
			return;         // Inside.
		// Get transform table.
		int scrolltx = gwin->get_scrolltx(),
		    scrollty = gwin->get_scrollty();
		Image_window8 *win = gwin->get_win();
		int w = win->get_game_width(), h = win->get_game_height();
		for (int i = 0; i < num_drops; i++)
			do_drop.paint(drops[i], scrolltx, scrollty, w, h);
		gwin->set_painted();
	}
};

/**
 *  End of lightning.
 */

Lightning_effect::~Lightning_effect(
) {
	if (flashing)           // Be sure palette is restored.
		Game_window::get_instance()->get_clock()->set_palette();
}

/**
 *  Lightning.
 */

void Lightning_effect::handle_event(
    unsigned long curtime,      // Current time of day.
    long udata
) {
	Game_window *gwin = Game_window::get_instance();
	int r = rand();         // Get a random #.
	int delay = 100;        // Delay for next time.
	if (flashing) {         // Just turned white?  Restore.
		gclock->set_palette();
		flashing = false;
		active = false;
		if (curtime >= stop_time) {
			// Time to stop.
			eman->remove_effect(this);
			return;
		}
		if (r % 50 == 0)    // Occassionally flash again.
			delay = (1 + r % 7) * 40;
		else            // Otherwise, wait several secs.
			delay = (4000 + r % 3000);
	} else if ((fromusecode || !gwin->is_in_dungeon()) && !active) { // Time to flash.
		// Play thunder.
		Audio::get_ptr()->play_sound_effect(Audio::game_sfx(62));
		active = true;
		flashing = true;
		gwin->get_pal()->set(PALETTE_LIGHTNING);
		delay = (1 + r % 2) * 25;
	}
	gwin->get_tqueue()->add(curtime + delay, this, udata);
}

/**
 *  Start a storm.
 */

Storm_effect::Storm_effect(
    int duration,           // In game minutes.
    int delay,          // In msecs.
    Game_object *egg        // Egg that caused it, or null.
) : Weather_effect(duration, delay, 2, egg), start(true) {
	// Start raining soon.
	eman->add_effect(new Clouds_effect(duration + 1, delay));
	int rain_delay = 20 + rand() % 1000;
	eman->add_effect(new Rain_effect<Raindrop>(duration + 2, rain_delay, 0));
	int lightning_delay = rain_delay + rand() % 500;
	eman->add_effect(new Lightning_effect(duration - 2, lightning_delay));
}

/**
 *  Start/end of storm.
 */
void Storm_effect::handle_event(
    unsigned long curtime,      // Current time of day.
    long udata
) {
	Game_window *gwin = Game_window::get_instance();
	if (start) {
		start = false;
		// Nothing more to do but end.
		gwin->get_tqueue()->add(stop_time, this, udata);
	} else              // Must be time to stop.
		eman->remove_effect(this);
}

/**
 *  Start a snowstorm.
 */

Snowstorm_effect::Snowstorm_effect(
    int duration,           // In game minutes.
    int delay,          // In msecs.
    Game_object *egg        // Egg that caused it, or null.
) : Weather_effect(duration, delay, 1, egg), start(true) {
	// Start snowing soon.
	eman->add_effect(new Clouds_effect(duration + 1, delay));
	eman->add_effect(new Rain_effect<Snowflake>(duration + 2, 20 + rand() % 1000, 0));
}

/**
 *  Start/end of snowstorm.
 */
void Snowstorm_effect::handle_event(
    unsigned long curtime,      // Current time of day.
    long udata
) {
	Game_window *gwin = Game_window::get_instance();
	if (start) {
		start = false;
		// Nothing more to do but end.
		gwin->get_tqueue()->add(stop_time, this, udata);
	} else              // Must be time to stop.
		eman->remove_effect(this);
}

/**
 *  Start anti magic storm.
 */

Sparkle_effect::Sparkle_effect(
    int duration,           // In game minutes.
    int delay,          // In msecs.
    Game_object *egg        // Egg that caused it, or null.
) : Weather_effect(duration, delay, 3, egg), start(true) {
	// Start snowing soon.
	eman->add_effect(new Rain_effect<Sparkle>(duration, delay, MAXDROPS / 10, 3));
}

/**
 *  Sparkles (in Ambrosia and generators).
 */

void Sparkle_effect::handle_event(
    unsigned long curtime,      // Current time of day.
    long udata
) {
	Game_window *gwin = Game_window::get_instance();
	if (start) {
		start = false;
		// Nothing more to do but end.
		gwin->get_tqueue()->add(stop_time, this, udata);
	} else              // Must be time to stop.
		eman->remove_effect(this);
}

/**
 *  Create a cloud.
 */

const int CLOUD = 2;        // Shape #.

Cloud::Cloud(
    short dx, short dy      // Deltas for movement.
) : cloud(CLOUD, 0, SF_SPRITES_VGA), wx(0), wy(0), deltax(dx), deltay(dy), count(-1) {
	Game_window *gwin = Game_window::get_instance();
	// Get abs. values.
	int adx = deltax > 0 ? deltax : -deltax;
	int ady = deltay > 0 ? deltay : -deltay;
	if (adx < ady)
		max_count = 2 * gwin->get_height() / ady;
	else
		max_count = 2 * gwin->get_width() / adx;
	start_time = 0;
}

/**
 *  Set starting screen position according to direction.
 */

void Cloud::set_start_pos(
    Shape_frame *shape,
    int w, int h,           // Dims. of window.
    int &x, int &y          // Screen pos. returned.
) {
	if (!deltax) {          // Special cases first.
		x = rand() % w;
		y = deltay > 0 ? -shape->get_ybelow() :
		    h + shape->get_yabove();
		return;
	}
	if (!deltay) {
		y = rand() % h;
		x = deltax > 0 ? -shape->get_xright() : w + shape->get_xleft();
		return;
	}
	int halfp = w + h;      // 1/2 perimeter.
	int r = rand() % halfp;     // Start on one of two sides.
	if (r > h) {        // Start on top/bottom.
		x = r - h;
		y = deltay > 0 ? -shape->get_ybelow() :
		    h + shape->get_yabove();
		return;
	}
	y = r;              // On left or right side.
	if (deltax > 0)         // Going right?
		x = -shape->get_xright();
	else                // Going left?
		x = w + shape->get_xleft();
}

/**
 *  Move cloud
 */

inline void Cloud::next(
    Game_window *gwin,      // Game window.
    unsigned long curtime,      // Current time of day.
    int w, int h            // Dims. of window.
) {
	if (curtime < start_time)
		return;         // Not yet.
	// Get top-left world pos.
	long scrollx = gwin->get_scrolltx() * c_tilesize;
	long scrolly = gwin->get_scrollty() * c_tilesize;
	Shape_frame *shape = cloud.get_shape();
	gwin->add_dirty(gwin->clip_to_win(gwin->get_shape_rect(
	                                      shape, wx - scrollx, wy - scrolly).enlarge(c_tilesize / 2)));
	if (count <= 0) {       // Time to restart?
		// Set start time randomly.
		start_time = curtime + 2000 * randcnt + rand() % 2000;
		randcnt = (randcnt + 1) % 4;
		start_time = Game::get_ticks() + 2000 * randcnt + rand() % 500;
		count = max_count;
		cloud.set_frame(rand() % cloud.get_num_frames());
		int x, y;       // Get screen pos.
		set_start_pos(shape, w, h, x, y);
		wx = x + scrollx;
		wy = y + scrolly;
	} else {
		wx += deltax;
		wy += deltay;
		count--;
	}
	gwin->add_dirty(gwin->clip_to_win(gwin->get_shape_rect(
	                                      shape, wx - scrollx, wy - scrolly).enlarge(c_tilesize / 2)));
}

/**
 *  Paint cloud.
 */

void Cloud::paint(
) {
	Game_window *gwin = Game_window::get_instance();
	if (count > 0)          // Might not have been started.
		cloud.paint_shape(
		    wx - gwin->get_scrolltx()*c_tilesize - gwin->get_scrolltx_lo(),
		    wy - gwin->get_scrollty()*c_tilesize - gwin->get_scrollty_lo());
}

/**
 *  Create a few clouds to float across the screen.
 */

Clouds_effect::Clouds_effect(
    int duration,           // In game minutes.
    int delay,          // In msecs.
    Game_object *egg,       // Egg that caused it, or null.
    int n
) : Weather_effect(duration, delay, n, egg), overcast(n != 6) {
	Game_clock *gclock = Game_window::get_instance()->get_clock();
	if (overcast)
		gclock->set_overcast(true);
	else
		gclock->set_overcast(false);

	num_clouds = 2 + rand() % 5; // Pick #.
	if (overcast)
		num_clouds += rand() % 2;
	clouds = new Cloud *[num_clouds];
	// Figure wind direction.
	int dx = rand() % 5 - 2;
	int dy = rand() % 5 - 2;
	if (!dx && !dy) {
		dx = 1 + rand() % 2;
		dy = 1 - rand() % 3;
	}
	for (int i = 0; i < num_clouds; i++) {
		// Modify speed of some.
		int deltax = dx, deltay = dy;
		if (rand() % 2 == 0) {
			deltax += deltax / 2;
			deltay += deltay / 2;
		}
		clouds[i] = new Cloud(deltax, deltay);
	}
}

/**
 *  Cloud drift.
 */

void Clouds_effect::handle_event(
    unsigned long curtime,      // Current time of day.
    long udata
) {
	const int delay = 100;
	Game_window *gwin = Game_window::get_instance();
	if (curtime >= stop_time) {
		// Time to stop.
		eman->remove_effect(this);
		gwin->set_all_dirty();
		return;
	}
	int w = gwin->get_width(), h = gwin->get_height();
	for (int i = 0; i < num_clouds; i++)
		clouds[i]->next(gwin, curtime, w, h);
	gwin->get_tqueue()->add(curtime + delay, this, udata);
}

/**
 *  Render.
 */

void Clouds_effect::paint(
) {
	if (!gwin->is_main_actor_inside())
		for (int i = 0; i < num_clouds; i++)
			clouds[i]->paint();
}

/**
 *  Destructor.
 */

Clouds_effect::~Clouds_effect() {
	delete [] clouds;
	if (overcast)
		Game_window::get_instance()->get_clock()->set_overcast(false);
}

/**
 *  Shake the screen.
 */

void Earthquake::handle_event(
    unsigned long curtime,      // Current time of day.
    long udata
) {
	static int eqsoundonce;

	if (eqsoundonce != 1) {
		eqsoundonce = 1;
		// Play earthquake SFX once
		Audio::get_ptr()->play_sound_effect(Audio::game_sfx(60));
	}

	Game_window *gwin = Game_window::get_instance();
	Image_window *win = gwin->get_win();
	int w = win->get_game_width(), h = win->get_game_height();
	int sx = 0, sy = 0;
	int dx = rand() % 9 - 4;
	int dy = rand() % 9 - 4;
	if (dx > 0)
		w -= dx;
	else {
		w += dx;
		sx -= dx;
		dx = 0;
	}
	if (dy > 0)
		h -= dy;
	else {
		h += dy;
		sy -= dy;
		dy = 0;
	}
	win->copy(sx, sy, w, h, dx, dy);
	gwin->set_painted();
	gwin->show();
	// Shake back.
	win->copy(dx, dy, w, h, sx, sy);
	if (++i < len)          // More to do?  Put back in queue.
		gwin->get_tqueue()->add(curtime + 100, this, udata);
	else {
		eqsoundonce = 0;
		delete this;
	}

}

/**
 *  Create a fire field that will last for about 4 seconds.
 */

Fire_field_effect::Fire_field_effect(
    Tile_coord const &t         // Where to create it.
) {
	field = gmap->create_ireg_object(895, 0);
	field->set_flag(Obj_flags::is_temporary);
	field->move(t.tx, t.ty, t.tz);
	gwin->get_tqueue()->add(Game::get_ticks() + 3000 + rand() % 2000, this,
	                        0L);
}

/**
 *  Remove the field.
 */

void Fire_field_effect::handle_event(
    unsigned long curtime,      // Current time of day.
    long udata
) {
	int frnum = field->get_framenum();
	if (frnum == 0) {       // All done?
		field->remove_this();
		eman->remove_effect(this);
	} else {
		if (frnum > 3) {    // Starting to wind down?
			field->as_egg()->stop_animation();
			frnum = 3;
		} else
			frnum--;
		gwin->add_dirty(field);
		field->set_frame(frnum);
		gwin->get_tqueue()->add(curtime + gwin->get_std_delay(),
		                        this, udata);
	}
}