/*
 * Portions of this file are copyright Rebirth contributors and licensed as
 * described in COPYING.txt.
 * Portions of this file are copyright Parallax Software and licensed
 * according to the Parallax license below.
 * See COPYING.txt for license details.

THE COMPUTER CODE CONTAINED HEREIN IS THE SOLE PROPERTY OF PARALLAX
SOFTWARE CORPORATION ("PARALLAX").  PARALLAX, IN DISTRIBUTING THE CODE TO
END-USERS, AND SUBJECT TO ALL OF THE TERMS AND CONDITIONS HEREIN, GRANTS A
ROYALTY-FREE, PERPETUAL LICENSE TO SUCH END-USERS FOR USE BY SUCH END-USERS
IN USING, DISPLAYING,  AND CREATING DERIVATIVE WORKS THEREOF, SO LONG AS
SUCH USE, DISPLAY OR CREATION IS FOR NON-COMMERCIAL, ROYALTY OR REVENUE
FREE PURPOSES.  IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
CONTAINED HEREIN FOR REVENUE-BEARING PURPOSES.  THE END-USER UNDERSTANDS
AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.
COPYRIGHT 1993-1999 PARALLAX SOFTWARE CORPORATION.  ALL RIGHTS RESERVED.
*/

#include "wall.h"
#include "player.h"
#include "text.h"
#include "fireball.h"
#include "textures.h"
#include "newdemo.h"
#include "multi.h"
#include "gameseq.h"
#include "physfs-serial.h"
#include "gameseg.h"
#include "hudmsg.h"
#include "laser.h"		//	For seeing if a flare is stuck in a wall.
#include "effects.h"

#include "compiler-range_for.h"
#include "partial_range.h"
#include "segiter.h"

//	Special door on boss level which is locked if not in multiplayer...sorry for this awful solution --MK.
#define	BOSS_LOCKED_DOOR_LEVEL	7
#define	BOSS_LOCKED_DOOR_SEG		595
#define	BOSS_LOCKED_DOOR_SIDE	5

namespace dcx {
unsigned Num_walls;							// Number of walls
unsigned Num_wall_anims;
unsigned Num_open_doors;						// Number of open doors
}

namespace dsx {
array<wall, MAX_WALLS> Walls;					// Master walls array
array<wclip, MAX_WALL_ANIMS> WallAnims;		// Wall animations
array<active_door, MAX_DOORS> ActiveDoors;
}
#if defined(DXX_BUILD_DESCENT_II)
#include "collide.h"
namespace dsx {
#define CLOAKING_WALL_TIME f1_0

array<cloaking_wall, MAX_CLOAKING_WALLS> CloakingWalls;
unsigned Num_cloaking_walls;
}
#endif

static std::pair<uint_fast32_t, uint_fast32_t> get_transparency_check_values(const side &side)
{
	if (uint_fast32_t masked_tmap_num2 = side.tmap_num2 & 0x3FFF)
		return {masked_tmap_num2, BM_FLAG_SUPER_TRANSPARENT};
	return {side.tmap_num, BM_FLAG_TRANSPARENT};
}

// This function determines whether the current segment/side is transparent
//		1 = YES
//		0 = NO
static uint_fast32_t check_transparency(const side &side)
{
	auto v = get_transparency_check_values(side);
	return GameBitmaps[Textures[v.first].index].bm_flags & v.second;
}

//-----------------------------------------------------------------
// This function checks whether we can fly through the given side.
//	In other words, whether or not we have a 'doorway'
//	 Flags:
//		WID_FLY_FLAG				1
//		WID_RENDER_FLAG			2
//		WID_RENDPAST_FLAG			4
//	 Return values:
//		WID_WALL						2	// 0/1/0		wall	
//		WID_TRANSPARENT_WALL		6	//	0/1/1		transparent wall
//		WID_ILLUSORY_WALL			3	//	1/1/0		illusory wall
//		WID_TRANSILLUSORY_WALL	7	//	1/1/1		transparent illusory wall
//		WID_NO_WALL					5	//	1/0/1		no wall, can fly through
WALL_IS_DOORWAY_result_t wall_is_doorway(const side &side)
{
	const auto &w = Walls[side.wall_num];
	const auto type = w.type;
	if (type == WALL_OPEN)
		return WID_NO_WALL;

#if defined(DXX_BUILD_DESCENT_II)
	if (unlikely(type == WALL_CLOAKED))
		return WID_CLOAKED_WALL;
#endif

	const auto flags = w.flags;
	if (type == WALL_ILLUSION) {
		if (flags & WALL_ILLUSION_OFF)
			return WID_NO_WALL;
		else {
			if (check_transparency(side))
				return WID_TRANSILLUSORY_WALL;
		 	else
				return WID_ILLUSORY_WALL;
		}
	}

	if (type == WALL_BLASTABLE) {
	 	if (flags & WALL_BLASTED)
			return WID_TRANSILLUSORY_WALL;
		if (check_transparency(side))
			return WID_TRANSPARENT_WALL;
		else
			return WID_WALL;
	}	
	if (unlikely(flags & WALL_DOOR_OPENED))
		return WID_TRANSILLUSORY_WALL;
	if (likely(type == WALL_DOOR) && unlikely(w.state == WALL_DOOR_OPENING))
		return WID_TRANSPARENT_WALL;
// If none of the above flags are set, there is no doorway.
	if (check_transparency(side))
		return WID_TRANSPARENT_WALL;
	else
		return WID_WALL; // There are children behind the door.
}

#ifdef EDITOR
//-----------------------------------------------------------------
// Initializes all the walls (in other words, no special walls)
void wall_init()
{
	Num_walls = 0;
	range_for (auto &w, Walls)
	{
		w.segnum = segment_none;
		w.sidenum = -1;
		w.type = WALL_NORMAL;
		w.flags = 0;
		w.hps = 0;
		w.trigger = -1;
		w.clip_num = -1;
		w.linked_wall = -1;
	}
	Num_open_doors = 0;
#if defined(DXX_BUILD_DESCENT_II)
	Num_cloaking_walls = 0;
#endif

}
#endif

//set the tmap_num or tmap_num2 field for a wall/door
void wall_set_tmap_num(const vsegptridx_t seg,int side,const vsegptridx_t csegp,int cside,int anim_num,int frame_num)
{
	wclip *anim = &WallAnims[anim_num];
	int tmap = anim->frames[frame_num];

	if ( Newdemo_state==ND_STATE_PLAYBACK ) return;

	if (anim->flags & WCF_TMAP1)	{
		if (tmap != seg->sides[side].tmap_num || tmap != csegp->sides[cside].tmap_num)
		{
			seg->sides[side].tmap_num = csegp->sides[cside].tmap_num = tmap;
			if ( Newdemo_state == ND_STATE_RECORDING )
				newdemo_record_wall_set_tmap_num1(seg,side,csegp,cside,tmap);
		}
	} else	{
		Assert(tmap!=0 && seg->sides[side].tmap_num2!=0);
		if (tmap != seg->sides[side].tmap_num2 || tmap != csegp->sides[cside].tmap_num2)
		{
			seg->sides[side].tmap_num2 = csegp->sides[cside].tmap_num2 = tmap;
			if ( Newdemo_state == ND_STATE_RECORDING )
				newdemo_record_wall_set_tmap_num2(seg,side,csegp,cside,tmap);
		}
	}
}


// -------------------------------------------------------------------------------
//when the wall has used all its hitpoints, this will destroy it
static void blast_blastable_wall(const vsegptridx_t seg, int side)
{
	int a, n, cwall_num;

	Assert(seg->sides[side].wall_num != wall_none);

	Walls[seg->sides[side].wall_num].hps = -1;	//say it's blasted

	const auto &&csegp = seg.absolute_sibling(seg->children[side]);
	auto Connectside = find_connect_side(seg, csegp);
	Assert(Connectside != -1);
	cwall_num = csegp->sides[Connectside].wall_num;
	kill_stuck_objects(seg->sides[side].wall_num);
	if (cwall_num > -1)
		kill_stuck_objects(cwall_num);

	//if this is an exploding wall, explode it
	if (WallAnims[Walls[seg->sides[side].wall_num].clip_num].flags & WCF_EXPLODES)
		explode_wall(seg,side);
	else {
		//if not exploding, set final frame, and make door passable
		a = Walls[seg->sides[side].wall_num].clip_num;
		n = WallAnims[a].num_frames;
		wall_set_tmap_num(seg,side,csegp,Connectside,a,n-1);
		Walls[seg->sides[side].wall_num].flags |= WALL_BLASTED;
		if (cwall_num > -1)
			Walls[cwall_num].flags |= WALL_BLASTED;
	}

}


//-----------------------------------------------------------------
// Destroys a blastable wall.
void wall_destroy(const vsegptridx_t seg, int side)
{
	Assert(seg->sides[side].wall_num != wall_none);

	if (Walls[seg->sides[side].wall_num].type == WALL_BLASTABLE)
		blast_blastable_wall( seg, side );
	else
		Error("Hey bub, you are trying to destroy an indestructable wall.");
}

//-----------------------------------------------------------------
// Deteriorate appearance of wall. (Changes bitmap (paste-ons))
void wall_damage(const vsegptridx_t seg, int side, fix damage)
{
	int a, i, n, cwall_num;

	if (seg->sides[side].wall_num == wall_none) {
		return;
	}

	if (Walls[seg->sides[side].wall_num].type != WALL_BLASTABLE)
		return;
	
	if (!(Walls[seg->sides[side].wall_num].flags & WALL_BLASTED) && Walls[seg->sides[side].wall_num].hps >= 0)
		{
		const auto &&csegp = seg.absolute_sibling(seg->children[side]);
		auto Connectside = find_connect_side(seg, csegp);
		Assert(Connectside != -1);
		cwall_num = csegp->sides[Connectside].wall_num;
		Walls[seg->sides[side].wall_num].hps -= damage;
		if (cwall_num > -1)
			Walls[cwall_num].hps -= damage;
			
		a = Walls[seg->sides[side].wall_num].clip_num;
		n = WallAnims[a].num_frames;
		
		if (Walls[seg->sides[side].wall_num].hps < WALL_HPS*1/n) {
			blast_blastable_wall( seg, side );			
			if (Game_mode & GM_MULTI)
				multi_send_door_open(seg, side,Walls[seg->sides[side].wall_num].flags);
		}
		else
			for (i=0;i<n;i++)
				if (Walls[seg->sides[side].wall_num].hps < WALL_HPS*(n-i)/n) {
					wall_set_tmap_num(seg,side,csegp,Connectside,a,i);
				}
		}
}


//-----------------------------------------------------------------
// Opens a door
void wall_open_door(const vsegptridx_t seg, int side)
{
	wall *w;
	active_door *d;
	int cwall_num = -1;
	Assert(seg->sides[side].wall_num != wall_none); 	//Opening door on illegal wall

	auto wall_num = seg->sides[side].wall_num;
	w = &Walls[wall_num];
	//kill_stuck_objects(seg->sides[side].wall_num);

	if ((w->state == WALL_DOOR_OPENING) ||		//already opening
		 (w->state == WALL_DOOR_WAITING))		//open, waiting to close
		return;
#if defined(DXX_BUILD_DESCENT_II)
	if (w->state == WALL_DOOR_OPEN)			//open, & staying open
		return;
#endif

	if (w->state == WALL_DOOR_CLOSING) {		//closing, so reuse door

		int i;
	
		d = NULL;

		for (i=0;i<Num_open_doors;i++) {		//find door

			d = &ActiveDoors[i];
	
			if (d->front_wallnum[0]==wall_num || d->back_wallnum[0]==wall_num ||
				 (d->n_parts==2 && (d->front_wallnum[1]==wall_num || d->back_wallnum[1]==wall_num)))
				break;
		}

		if (i>=Num_open_doors) // likely in demo playback or multiplayer
		{
			d = &ActiveDoors[Num_open_doors];
			d->time = 0;
			Num_open_doors++;
			Assert( Num_open_doors < MAX_DOORS );
		}
		else
		{
			Assert( d!=NULL ); // Get John!

			d->time = WallAnims[w->clip_num].play_time - d->time;

			if (d->time < 0)
				d->time = 0;
		}
	
	}
	else {											//create new door
		Assert(w->state == WALL_DOOR_CLOSED);
		d = &ActiveDoors[Num_open_doors];
		d->time = 0;
		Num_open_doors++;
		Assert( Num_open_doors < MAX_DOORS );
	}


	w->state = WALL_DOOR_OPENING;

	// So that door can't be shot while opening
	const auto &&csegp = vcsegptr(seg->children[side]);
	auto Connectside = find_connect_side(seg, csegp);
	if (Connectside >= 0)
	{
		cwall_num = csegp->sides[Connectside].wall_num;
		if (cwall_num > -1)
		{
			Walls[cwall_num].state = WALL_DOOR_OPENING;
			d->back_wallnum[0] = cwall_num;
		}
		d->front_wallnum[0] = seg->sides[side].wall_num;
	}
	else
		con_printf(CON_URGENT, "Illegal Connectside %i in wall_open_door. Trying to hop over. Please check your level!", side);

	if (Newdemo_state == ND_STATE_RECORDING) {
		newdemo_record_door_opening(seg, side);
	}

	if (w->linked_wall != -1) {
		wall *w2;

		w2		= &Walls[w->linked_wall];

		Assert(w2->linked_wall == seg->sides[side].wall_num);
		//Assert(!(w2->flags & WALL_DOOR_OPENING  ||  w2->flags & WALL_DOOR_OPENED));

		w2->state = WALL_DOOR_OPENING;

		const auto &&seg2 = vcsegptridx(w2->segnum);
		Connectside = find_connect_side(seg2, vcsegptr(seg2->children[w2->sidenum]));
		Assert(Connectside != -1);
		if (cwall_num > -1)
			Walls[cwall_num].state = WALL_DOOR_OPENING;

		d->n_parts = 2;
		d->front_wallnum[1] = w->linked_wall;
		d->back_wallnum[1] = cwall_num;
	}
	else
		d->n_parts = 1;


	if ( Newdemo_state != ND_STATE_PLAYBACK )
	{
		// NOTE THE LINK TO ABOVE!!!!
		const auto cp = compute_center_point_on_side(seg, side );
		if (WallAnims[w->clip_num].open_sound > -1 )
			digi_link_sound_to_pos( WallAnims[w->clip_num].open_sound, seg, side, cp, 0, F1_0 );

	}
}

#if defined(DXX_BUILD_DESCENT_I)
// This function closes the specified door and restores the closed
//  door texture.  This is called when the animation is done
void wall_close_door(int door_num)
{
	int p;
	active_door *d;
	int i;

	d = &ActiveDoors[door_num];

	for (p=0;p<d->n_parts;p++) {
		wall *w;
		int side;
		w = &Walls[d->front_wallnum[p]];

		const auto &&seg = vsegptridx(w->segnum);
		side = w->sidenum;

		Assert(seg->sides[side].wall_num != wall_none);		//Closing door on illegal wall

		const auto &&csegp = seg.absolute_sibling(seg->children[side]);
		auto Connectside = find_connect_side(seg, csegp);
		Assert(Connectside != -1);

		Walls[seg->sides[side].wall_num].state = WALL_DOOR_CLOSED;
		Walls[csegp->sides[Connectside].wall_num].state = WALL_DOOR_CLOSED;

		wall_set_tmap_num(seg,side,csegp,Connectside,w->clip_num,0);

	}

	for (i=door_num;i<Num_open_doors;i++)
		ActiveDoors[i] = ActiveDoors[i+1];

	Num_open_doors--;
}
#endif

#if defined(DXX_BUILD_DESCENT_II)
//-----------------------------------------------------------------
// start the transition from closed -> open wall
void start_wall_cloak(const vsegptridx_t seg, int side)
{
	wall *w;
	cloaking_wall *d;
	int i, cwall_num;

	if ( Newdemo_state==ND_STATE_PLAYBACK ) return;

	Assert(seg->sides[side].wall_num != wall_none); 	//Opening door on illegal wall

	w = &Walls[seg->sides[side].wall_num];

	if (w->type == WALL_OPEN || w->state == WALL_DOOR_CLOAKING)		//already open or cloaking
		return;

	const auto &&csegp = vcsegptr(seg->children[side]);
	auto Connectside = find_connect_side(seg, csegp);
	Assert(Connectside != -1);
	cwall_num = csegp->sides[Connectside].wall_num;

	if (w->state == WALL_DOOR_DECLOAKING) {	//decloaking, so reuse door

		int i;

		d = NULL;

		for (i=0;i<Num_cloaking_walls;i++) {		//find door

			d = &CloakingWalls[i];
	
			if (d->front_wallnum==w-Walls || d->back_wallnum==w-Walls )
				break;
		}

		Assert(i<Num_cloaking_walls);				//didn't find door!
		Assert( d!=NULL ); // Get John!

		d->time = CLOAKING_WALL_TIME - d->time;

	}
	else if (w->state == WALL_DOOR_CLOSED) {	//create new door
		d = &CloakingWalls[Num_cloaking_walls];
		d->time = 0;
		if (Num_cloaking_walls >= MAX_CLOAKING_WALLS) {		//no more!
			Int3();		//ran out of cloaking wall slots
			w->type = WALL_OPEN;
			if (cwall_num > -1)
				Walls[cwall_num].type = WALL_OPEN;
			return;
		}
		Num_cloaking_walls++;
	}
	else {
		Int3();		//unexpected wall state
		return;
	}

	w->state = WALL_DOOR_CLOAKING;
	if (cwall_num > -1)
		Walls[cwall_num].state = WALL_DOOR_CLOAKING;

	d->front_wallnum = seg->sides[side].wall_num;
	d->back_wallnum = cwall_num;
	Assert(w->linked_wall == -1);

	if ( Newdemo_state != ND_STATE_PLAYBACK ) {
		const auto cp = compute_center_point_on_side(seg, side );
		digi_link_sound_to_pos( SOUND_WALL_CLOAK_ON, seg, side, cp, 0, F1_0 );
	}

	for (i=0;i<4;i++) {
		d->front_ls[i] = seg->sides[side].uvls[i].l;
		if (cwall_num > -1)
			d->back_ls[i] = csegp->sides[Connectside].uvls[i].l;
	}
}

//-----------------------------------------------------------------
// start the transition from open -> closed wall
void start_wall_decloak(const vsegptridx_t seg, int side)
{
	wall *w;
	cloaking_wall *d;
	int i, cwall_num;

	if ( Newdemo_state==ND_STATE_PLAYBACK ) return;

	Assert(seg->sides[side].wall_num != wall_none); 	//Opening door on illegal wall

	w = &Walls[seg->sides[side].wall_num];

	if (w->type == WALL_CLOSED || w->state == WALL_DOOR_DECLOAKING)		//already closed or decloaking
		return;

	if (w->state == WALL_DOOR_CLOAKING) {	//cloaking, so reuse door

		int i;

		d = NULL;

		for (i=0;i<Num_cloaking_walls;i++) {		//find door

			d = &CloakingWalls[i];
	
			if (d->front_wallnum==w-Walls || d->back_wallnum==w-Walls )
				break;
		}

		Assert(i<Num_cloaking_walls);				//didn't find door!
		Assert( d!=NULL ); // Get John!

		d->time = CLOAKING_WALL_TIME - d->time;

	}
	else if (w->state == WALL_DOOR_CLOSED) {	//create new door
		d = &CloakingWalls[Num_cloaking_walls];
		d->time = 0;
		if (Num_cloaking_walls >= MAX_CLOAKING_WALLS) {		//no more!
			Int3();		//ran out of cloaking wall slots
			/* what is this _doing_ here?
			w->type = WALL_CLOSED;
			Walls[csegp->sides[Connectside].wall_num].type = WALL_CLOSED;
			*/
			return;
		}
		Num_cloaking_walls++;
	}
	else {
		Int3();		//unexpected wall state
		return;
	}

	w->state = WALL_DOOR_DECLOAKING;

	// So that door can't be shot while opening
	const auto &&csegp = vcsegptr(seg->children[side]);
	auto Connectside = find_connect_side(seg, csegp);
	Assert(Connectside != -1);
	cwall_num = csegp->sides[Connectside].wall_num;
	if (cwall_num > -1)
		Walls[cwall_num].state = WALL_DOOR_DECLOAKING;

	d->front_wallnum = seg->sides[side].wall_num;
	d->back_wallnum = csegp->sides[Connectside].wall_num;
	Assert(w->linked_wall == -1);

	if ( Newdemo_state != ND_STATE_PLAYBACK ) {
		const auto cp = compute_center_point_on_side(seg, side );
		digi_link_sound_to_pos( SOUND_WALL_CLOAK_OFF, seg, side, cp, 0, F1_0 );
	}

	for (i=0;i<4;i++) {
		d->front_ls[i] = seg->sides[side].uvls[i].l;
		if (cwall_num > -1)
			d->back_ls[i] = csegp->sides[Connectside].uvls[i].l;
	}
}
#endif

//-----------------------------------------------------------------
// This function closes the specified door and restores the closed
//  door texture.  This is called when the animation is done
void wall_close_door_num(int door_num)
{
	int p;
	active_door *d;
	int i, cwall_num;

	d = &ActiveDoors[door_num];

	for (p=0;p<d->n_parts;p++) {
		wall *w;
		int side;

		w = &Walls[d->front_wallnum[p]];

		const auto &&seg = vsegptridx(w->segnum);
		side = w->sidenum;

		Assert(seg->sides[side].wall_num != wall_none);		//Closing door on illegal wall

		const auto &&csegp = seg.absolute_sibling(seg->children[side]);
		auto Connectside = find_connect_side(seg, csegp);
		Assert(Connectside != -1);
		cwall_num = csegp->sides[Connectside].wall_num;
		Walls[seg->sides[side].wall_num].state = WALL_DOOR_CLOSED;
		if (cwall_num > -1)
			Walls[cwall_num].state = WALL_DOOR_CLOSED;

		wall_set_tmap_num(seg,side,csegp,Connectside,w->clip_num,0);

	}
	
	for (i=door_num;i<Num_open_doors;i++)
		ActiveDoors[i] = ActiveDoors[i+1];

	Num_open_doors--;

}

static uint8_t check_poke(const vcobjptr_t obj, const vcsegptr_t segnum,int side)
{
	//note: don't let objects with zero size block door
	if (!obj->size)
		return 0;
	return get_seg_masks(obj->pos, segnum, obj->size).sidemask & (1 << side);		//pokes through side!
}

#if defined(DXX_BUILD_DESCENT_I)
//-----------------------------------------------------------------
// Animates and processes the closing of a door.
// Called from the game loop.
void do_door_close(int door_num)
{
	int p;
	active_door *d;
	wall *w;

	Assert(door_num != -1);		//Trying to do_door_open on illegal door

	d = &ActiveDoors[door_num];

	w = &Walls[d->front_wallnum[0]];

	//check for objects in doorway before closing
	if (w->flags & WALL_DOOR_AUTO)
		for (p=0;p<d->n_parts;p++) {
			int side;
			const auto &&seg = vcsegptridx(w->segnum);
			side = w->sidenum;

			const auto &&csegp = vcsegptr(seg->children[side]);
			auto Connectside = find_connect_side(seg, csegp);
			Assert(Connectside != -1);

			//go through each object in each of two segments, and see if
			//it pokes into the connecting seg

			range_for (const auto &&objnum, objects_in(seg))
				if (check_poke(objnum, seg, side))
					return;		//abort!

			range_for (const auto &&objnum, objects_in(csegp))
				if (check_poke(objnum, csegp, Connectside))
					return;		//abort!
		}

	for (p=0;p<d->n_parts;p++) {
		int side;
		fix time_elapsed, time_total, one_frame;
		int i, n;

		w = &Walls[d->front_wallnum[p]];

		const auto &&seg = vsegptridx(w->segnum);
		side = w->sidenum;

		if (seg->sides[side].wall_num == wall_none) {
			return;
		}

		//if here, must be auto door
		Assert(Walls[seg->sides[side].wall_num].flags & WALL_DOOR_AUTO);		

		// Otherwise, close it.
		const auto &&csegp = seg.absolute_sibling(seg->children[side]);
		auto Connectside = find_connect_side(seg, csegp);
		Assert(Connectside != -1);


		if ( Newdemo_state != ND_STATE_PLAYBACK )
			// NOTE THE LINK TO ABOVE!!
			if (p==0)	//only play one sound for linked doors
				if ( d->time==0 )	{		//first time
					const auto cp = compute_center_point_on_side(seg, side );
					if (WallAnims[w->clip_num].close_sound  > -1 )
						digi_link_sound_to_pos( WallAnims[Walls[seg->sides[side].wall_num].clip_num].close_sound, seg, side, cp, 0, F1_0 );
				}

		d->time += FrameTime;

		time_elapsed = d->time;
		n = WallAnims[w->clip_num].num_frames;
		time_total = WallAnims[w->clip_num].play_time;

		one_frame = time_total/n;	

		i = n-time_elapsed/one_frame-1;

		if (i < n/2) {
			Walls[seg->sides[side].wall_num].flags &= ~WALL_DOOR_OPENED;
			Walls[csegp->sides[Connectside].wall_num].flags &= ~WALL_DOOR_OPENED;
		}

		// Animate door.
		if (i > 0) {
			wall_set_tmap_num(seg,side,csegp,Connectside,w->clip_num,i);

			Walls[seg->sides[side].wall_num].state = WALL_DOOR_CLOSING;
			Walls[csegp->sides[Connectside].wall_num].state = WALL_DOOR_CLOSING;

			ActiveDoors[Num_open_doors].time = 0;		//counts up

		} else
			wall_close_door(door_num);
	}
}
#endif

#if defined(DXX_BUILD_DESCENT_II)
static int is_door_side_free(const vcsegptr_t seg, int side)
{
	range_for (const auto &&obj, objects_in(seg))
		if (obj->type!=OBJ_WEAPON && obj->type!=OBJ_FIREBALL && check_poke(obj,seg,side))
			return 0;	//not free
	return 1;
}

//returns true of door in unobjstructed (& thus can close)
static int is_door_free(const vcsegptridx_t seg,int side)
{
	if (!is_door_side_free(seg, side))
		return 0;
	const auto &&csegp = vcsegptr(seg->children[side]);
	auto Connectside = find_connect_side(seg, csegp);
	Assert(Connectside != -1);
	//go through each object in each of two segments, and see if
	//it pokes into the connecting seg
	return is_door_side_free(csegp, Connectside);
}

//-----------------------------------------------------------------
// Closes a door
void wall_close_door(const vsegptridx_t seg, int side)
{
	wall *w;
	active_door *d;
	int wall_num, cwall_num;

	Assert(seg->sides[side].wall_num != wall_none); 	//Opening door on illegal wall

	w = &Walls[seg->sides[side].wall_num];
	wall_num = w - Walls;
	if ((w->state == WALL_DOOR_CLOSING) ||		//already closing
		 (w->state == WALL_DOOR_WAITING)	||		//open, waiting to close
		 (w->state == WALL_DOOR_CLOSED))			//closed
		return;

	if (!is_door_free(seg,side))
		return;

	if (w->state == WALL_DOOR_OPENING) {	//reuse door

		int i;

		d = NULL;

		for (i=0;i<Num_open_doors;i++) {		//find door

			d = &ActiveDoors[i];

			if (d->front_wallnum[0]==wall_num || d->back_wallnum[0]==wall_num ||
				 (d->n_parts==2 && (d->front_wallnum[1]==wall_num || d->back_wallnum[1]==wall_num)))
				break;
		}

		Assert(i<Num_open_doors);				//didn't find door!
		Assert( d!=NULL ); // Get John!

		d->time = WallAnims[w->clip_num].play_time - d->time;

		if (d->time < 0)
			d->time = 0;

	}
	else {											//create new door
		Assert(w->state == WALL_DOOR_OPEN);
		d = &ActiveDoors[Num_open_doors];
		d->time = 0;
		Num_open_doors++;
		Assert( Num_open_doors < MAX_DOORS );
	}

	w->state = WALL_DOOR_CLOSING;

	// So that door can't be shot while opening
	const auto &&csegp = vcsegptr(seg->children[side]);
	auto Connectside = find_connect_side(seg, csegp);
	Assert(Connectside != -1);
	cwall_num = csegp->sides[Connectside].wall_num;
	if (cwall_num > -1)
		Walls[cwall_num].state = WALL_DOOR_CLOSING;

	d->front_wallnum[0] = seg->sides[side].wall_num;
	d->back_wallnum[0] = cwall_num;
	if (Newdemo_state == ND_STATE_RECORDING) {
		newdemo_record_door_opening(seg, side);
	}

	if (w->linked_wall != -1) {
		Int3();		//don't think we ever used linked walls
	}
	else
		d->n_parts = 1;


	if ( Newdemo_state != ND_STATE_PLAYBACK )
	{
		// NOTE THE LINK TO ABOVE!!!!
		const auto cp = compute_center_point_on_side(seg, side );
		if (WallAnims[w->clip_num].open_sound > -1 )
			digi_link_sound_to_pos( WallAnims[w->clip_num].open_sound, seg, side, cp, 0, F1_0 );

	}
}
#endif

//-----------------------------------------------------------------
// Animates opening of a door.
// Called in the game loop.
void do_door_open(int door_num)
{
	int p;
	active_door *d;

// 	Assert(door_num != -1);		//Trying to do_door_open on illegal door
	if (door_num == -1)
		return;

	d = &ActiveDoors[door_num];

	for (p=0;p<d->n_parts;p++) {
		wall *w;
		int side;
		fix time_elapsed, time_total, one_frame;
		int i, n;

		w = &Walls[d->front_wallnum[p]];
		kill_stuck_objects(d->front_wallnum[p]);
		kill_stuck_objects(d->back_wallnum[p]);

		const auto &&seg = vsegptridx(w->segnum);
		side = w->sidenum;

// 		Assert(seg->sides[side].wall_num != -1);		//Trying to do_door_open on illegal wall
		if (seg->sides[side].wall_num == wall_none)
		{
			con_printf(CON_URGENT, "Trying to do_door_open on illegal wall %i. Please check your level!",side);
			continue;
		}

		const auto &&csegp = seg.absolute_sibling(seg->children[side]);
		auto Connectside = find_connect_side(seg, csegp);
		Assert(Connectside != -1);

		d->time += FrameTime;

		time_elapsed = d->time;
		n = WallAnims[w->clip_num].num_frames;
		time_total = WallAnims[w->clip_num].play_time;

		one_frame = time_total/n;	

		i = time_elapsed/one_frame;

		if (i < n)
			wall_set_tmap_num(seg,side,csegp,Connectside,w->clip_num,i);

		if (i> n/2) {
			Walls[seg->sides[side].wall_num].flags |= WALL_DOOR_OPENED;
			Walls[csegp->sides[Connectside].wall_num].flags |= WALL_DOOR_OPENED;
		}

		if (i >= n-1) {
			wall_set_tmap_num(seg,side,csegp,Connectside,w->clip_num,n-1);

			// If our door is not automatic just remove it from the list.
			if (!(Walls[seg->sides[side].wall_num].flags & WALL_DOOR_AUTO)) {
				for (i=door_num;i<Num_open_doors;i++)
					ActiveDoors[i] = ActiveDoors[i+1];
				Num_open_doors--;
#if defined(DXX_BUILD_DESCENT_II)
				Walls[seg->sides[side].wall_num].state = WALL_DOOR_OPEN;
				Walls[csegp->sides[Connectside].wall_num].state = WALL_DOOR_OPEN;
#endif
			}
			else {

				Walls[seg->sides[side].wall_num].state = WALL_DOOR_WAITING;
				Walls[csegp->sides[Connectside].wall_num].state = WALL_DOOR_WAITING;

				ActiveDoors[Num_open_doors].time = 0;	//counts up
			}
		}

	}

}

#if defined(DXX_BUILD_DESCENT_II)
//-----------------------------------------------------------------
// Animates and processes the closing of a door.
// Called from the game loop.
void do_door_close(int door_num)
{
	int p;
	active_door *d;
	wall *w;

	Assert(door_num != -1);		//Trying to do_door_open on illegal door

	d = &ActiveDoors[door_num];

	w = &Walls[d->front_wallnum[0]];

	const auto &&wsegp = vsegptridx(w->segnum);

	//check for objects in doorway before closing
	if (w->flags & WALL_DOOR_AUTO)
		if (!is_door_free(wsegp, w->sidenum)) {
			digi_kill_sound_linked_to_segment(w->segnum,w->sidenum,-1);
			wall_open_door(wsegp, w->sidenum);		//re-open door
			return;
		}

	for (p=0;p<d->n_parts;p++) {
		wall *w;
		int side;
		fix time_elapsed, time_total, one_frame;
		int i, n;

		w = &Walls[d->front_wallnum[p]];

		const auto &seg = wsegp;
		side = w->sidenum;

		if (seg->sides[side].wall_num == wall_none) {
			return;
		}

		//if here, must be auto door
//		Assert(Walls[seg->sides[side].wall_num].flags & WALL_DOOR_AUTO);		
//don't assert here, because now we have triggers to close non-auto doors

		// Otherwise, close it.
		const auto &&csegp = seg.absolute_sibling(seg->children[side]);
		auto Connectside = find_connect_side(seg, csegp);
		Assert(Connectside != -1);


		if ( Newdemo_state != ND_STATE_PLAYBACK )
			// NOTE THE LINK TO ABOVE!!
			if (p==0)	//only play one sound for linked doors
				if ( d->time==0 )	{		//first time
					const auto cp = compute_center_point_on_side(seg, side );
					if (WallAnims[w->clip_num].close_sound  > -1 )
						digi_link_sound_to_pos( WallAnims[Walls[seg->sides[side].wall_num].clip_num].close_sound, seg, side, cp, 0, F1_0 );
				}

		d->time += FrameTime;

		time_elapsed = d->time;
		n = WallAnims[w->clip_num].num_frames;
		time_total = WallAnims[w->clip_num].play_time;

		one_frame = time_total/n;	

		i = n-time_elapsed/one_frame-1;

		if (i < n/2) {
			Walls[seg->sides[side].wall_num].flags &= ~WALL_DOOR_OPENED;
			Walls[csegp->sides[Connectside].wall_num].flags &= ~WALL_DOOR_OPENED;
		}

		// Animate door.
		if (i > 0) {
			wall_set_tmap_num(seg,side,csegp,Connectside,w->clip_num,i);

			Walls[seg->sides[side].wall_num].state = WALL_DOOR_CLOSING;
			Walls[csegp->sides[Connectside].wall_num].state = WALL_DOOR_CLOSING;

			ActiveDoors[Num_open_doors].time = 0;		//counts up

		} else
			wall_close_door_num(door_num);
	}
}
#endif


//-----------------------------------------------------------------
// Turns off an illusionary wall (This will be used primarily for
//  wall switches or triggers that can turn on/off illusionary walls.)
void wall_illusion_off(const vsegptridx_t seg, int side)
{
	const auto &&csegp = vcsegptr(seg->children[side]);
	auto cside = find_connect_side(seg, csegp);
	Assert(cside != -1);

	if (seg->sides[side].wall_num == wall_none) {
		return;
	}

	Walls[seg->sides[side].wall_num].flags |= WALL_ILLUSION_OFF;
	Walls[csegp->sides[cside].wall_num].flags |= WALL_ILLUSION_OFF;

#if defined(DXX_BUILD_DESCENT_II)
	kill_stuck_objects(seg->sides[side].wall_num);
	kill_stuck_objects(csegp->sides[cside].wall_num);
#endif
}

//-----------------------------------------------------------------
// Turns on an illusionary wall (This will be used primarily for
//  wall switches or triggers that can turn on/off illusionary walls.)
void wall_illusion_on(const vsegptridx_t seg, int side)
{
	const auto &&csegp = vcsegptr(seg->children[side]);
	auto cside = find_connect_side(seg, csegp);
	Assert(cside != -1);

	if (seg->sides[side].wall_num == wall_none) {
		return;
	}

	Walls[seg->sides[side].wall_num].flags &= ~WALL_ILLUSION_OFF;
	Walls[csegp->sides[cside].wall_num].flags &= ~WALL_ILLUSION_OFF;
}

//	-----------------------------------------------------------------------------
//	Allowed to open the normally locked special boss door if in multiplayer mode.
static int special_boss_opening_allowed(segnum_t segnum, int sidenum)
{
	if (Game_mode & GM_MULTI)
		return (Current_level_num == BOSS_LOCKED_DOOR_LEVEL) && (segnum == BOSS_LOCKED_DOOR_SEG) && (sidenum == BOSS_LOCKED_DOOR_SIDE);
	else
		return 0;
}

//-----------------------------------------------------------------
// Determines what happens when a wall is shot
//returns info about wall.  see wall.h for codes
//obj is the object that hit...either a weapon or the player himself
//playernum is the number the player who hit the wall or fired the weapon,
//or -1 if a robot fired the weapon
wall_hit_process_t wall_hit_process(const vsegptridx_t seg, int side, fix damage, int playernum, const vobjptr_t obj)
{
	wall	*w;
	fix	show_message;

	// If it is not a "wall" then just return.
	if ( seg->sides[side].wall_num == wall_none )
		return wall_hit_process_t::WHP_NOT_SPECIAL;

	w = &Walls[seg->sides[side].wall_num];

	if ( Newdemo_state == ND_STATE_RECORDING )
		newdemo_record_wall_hit_process( seg, side, damage, playernum );

	if (w->type == WALL_BLASTABLE) {
#if defined(DXX_BUILD_DESCENT_II)
		if (obj->ctype.laser_info.parent_type == OBJ_PLAYER)
#endif
			wall_damage(seg, side, damage);
		return wall_hit_process_t::WHP_BLASTABLE;
	}

	if (playernum != Player_num)	//return if was robot fire
		return wall_hit_process_t::WHP_NOT_SPECIAL;

	Assert( playernum > -1 );
	
	//	Determine whether player is moving forward.  If not, don't say negative
	//	messages because he probably didn't intentionally hit the door.
	if (obj->type == OBJ_PLAYER)
		show_message = (vm_vec_dot(obj->orient.fvec, obj->mtype.phys_info.velocity) > 0);
#if defined(DXX_BUILD_DESCENT_II)
	else if (obj->type == OBJ_ROBOT)
		show_message = 0;
	else if ((obj->type == OBJ_WEAPON) && (obj->ctype.laser_info.parent_type == OBJ_ROBOT))
		show_message = 0;
#endif
	else
		show_message = 1;

	/* Set key_color only after the type matches, since TXT_* are macros
	 * that trigger a load from memory.  Use operator,() to suppress the
	 * truth test on the second branch since the compiler cannot prove
	 * that the loaded value will always be non-null.
	 */
	const char *key_color;
	if (
		(w->keys == KEY_BLUE && (key_color = TXT_BLUE, true)) ||
		(w->keys == KEY_GOLD && (key_color = TXT_YELLOW, true)) ||
		(w->keys == KEY_RED && (key_color = TXT_RED, true))
	)
	{
		const auto &objp = get_local_plrobj();
		const auto &player_info = objp.ctype.player_info;
		if (!(player_info.powerup_flags & static_cast<PLAYER_FLAG>(w->keys)))
		{
			static_assert(KEY_BLUE == static_cast<unsigned>(PLAYER_FLAGS_BLUE_KEY), "BLUE key flag mismatch");
			static_assert(KEY_GOLD == static_cast<unsigned>(PLAYER_FLAGS_GOLD_KEY), "GOLD key flag mismatch");
			static_assert(KEY_RED == static_cast<unsigned>(PLAYER_FLAGS_RED_KEY), "RED key flag mismatch");
				if (show_message)
					HUD_init_message(HM_DEFAULT, "%s %s",key_color,TXT_ACCESS_DENIED);
			return wall_hit_process_t::WHP_NO_KEY;
		}
	}

	if (w->type == WALL_DOOR)
	{
		if ((w->flags & WALL_DOOR_LOCKED ) && !(special_boss_opening_allowed(seg, side)) ) {
				if (show_message)
					HUD_init_message_literal(HM_DEFAULT, TXT_CANT_OPEN_DOOR);
			return wall_hit_process_t::WHP_NO_KEY;
		}
		else {
			if (w->state != WALL_DOOR_OPENING)
			{
				wall_open_door(seg, side);
				if (Game_mode & GM_MULTI)
				{
					int flags;
#if defined(DXX_BUILD_DESCENT_I)
					flags = 0;
#elif defined(DXX_BUILD_DESCENT_II)
					flags = w->flags;
#endif
					multi_send_door_open(seg, side,flags);
				}
			}
			return wall_hit_process_t::WHP_DOOR;
			
		}
	}
	return wall_hit_process_t::WHP_NOT_SPECIAL;		//default is treat like normal wall
}

//-----------------------------------------------------------------
// Opens doors/destroys wall/shuts off triggers.
void wall_toggle(const vsegptridx_t segp, unsigned side)
{
	if (side >= MAX_SIDES_PER_SEGMENT)
	{
#ifndef NDEBUG
		Warning("Can't toggle side %u of segment %d (%u)!\n", side, static_cast<segnum_t>(segp), Highest_segment_index);
#endif
		return;
	}
	auto wall_num = segp->sides[side].wall_num;
	if (wall_num == wall_none) {
		return;
	}

	if ( Newdemo_state == ND_STATE_RECORDING )
		newdemo_record_wall_toggle(segp, side);

	if (Walls[wall_num].type == WALL_BLASTABLE)
		wall_destroy(segp, side);

	if ((Walls[wall_num].type == WALL_DOOR) && (Walls[wall_num].state == WALL_DOOR_CLOSED))
		wall_open_door(segp, side);
}


//-----------------------------------------------------------------
// Tidy up Walls array for load/save purposes.
void reset_walls()
{
	range_for (auto &w, partial_range(Walls, Num_walls, MAX_WALLS))
	{
		w.type = WALL_NORMAL;
		w.flags = 0;
		w.hps = 0;
		w.trigger = -1;
		w.clip_num = -1;
		}
}

#if defined(DXX_BUILD_DESCENT_II)
static void do_cloaking_wall_frame(int cloaking_wall_num)
{
	cloaking_wall *d;
	wall *wfront,*wback;
	sbyte old_cloak; // for demo recording

	if ( Newdemo_state==ND_STATE_PLAYBACK ) return;

	d = &CloakingWalls[cloaking_wall_num];
	wfront = &Walls[d->front_wallnum];
	wback = NULL;
	if (d->back_wallnum > -1)
		wback = &Walls[d->back_wallnum];

	old_cloak = wfront->cloak_value;

	d->time += FrameTime;

	if (d->time > CLOAKING_WALL_TIME) {
		int i;

		wfront->type = WALL_OPEN;
		wfront->state = WALL_DOOR_CLOSED;		//why closed? why not?
		if (wback) {
			wback->type = WALL_OPEN;
			wback->state = WALL_DOOR_CLOSED;		//why closed? why not?
		}

		for (i=cloaking_wall_num;i<Num_cloaking_walls;i++)
			CloakingWalls[i] = CloakingWalls[i+1];
		Num_cloaking_walls--;

	}
	else if (d->time > CLOAKING_WALL_TIME/2) {
		int old_type=wfront->type;

		wfront->cloak_value = ((d->time - CLOAKING_WALL_TIME/2) * (GR_FADE_LEVELS-2)) / (CLOAKING_WALL_TIME/2);
		if (wback)
			wback->cloak_value = wfront->cloak_value;

		if (old_type != WALL_CLOAKED) {		//just switched
			int i;

			wfront->type = WALL_CLOAKED;
			if (wback)
				wback->type = WALL_CLOAKED;

			for (i=0;i<4;i++) {
				Segments[wfront->segnum].sides[wfront->sidenum].uvls[i].l = d->front_ls[i];
				if (wback)
					Segments[wback->segnum].sides[wback->sidenum].uvls[i].l = d->back_ls[i];
			}
		}
	}
	else {		//fading out
		fix light_scale;
		int i;

		light_scale = fixdiv(CLOAKING_WALL_TIME/2-d->time,CLOAKING_WALL_TIME/2);

		for (i=0;i<4;i++) {
			Segments[wfront->segnum].sides[wfront->sidenum].uvls[i].l = fixmul(d->front_ls[i],light_scale);
			if (wback)
				Segments[wback->segnum].sides[wback->sidenum].uvls[i].l = fixmul(d->back_ls[i],light_scale);
		}
	}

	// check if the actual cloak_value changed in this frame to prevent redundant recordings and wasted bytes
	if ( Newdemo_state == ND_STATE_RECORDING && (wfront->cloak_value != old_cloak || d->time == FrameTime) )
		newdemo_record_cloaking_wall(d->front_wallnum, d->back_wallnum, wfront->type, wfront->state, wfront->cloak_value, Segments[wfront->segnum].sides[wfront->sidenum].uvls[0].l, Segments[wfront->segnum].sides[wfront->sidenum].uvls[1].l, Segments[wfront->segnum].sides[wfront->sidenum].uvls[2].l, Segments[wfront->segnum].sides[wfront->sidenum].uvls[3].l);

}

static void do_decloaking_wall_frame(int cloaking_wall_num)
{
	cloaking_wall *d;
	wall *wfront,*wback;
	sbyte old_cloak; // for demo recording

	if ( Newdemo_state==ND_STATE_PLAYBACK ) return;

	d = &CloakingWalls[cloaking_wall_num];
	wfront = &Walls[d->front_wallnum];
	wback = NULL;
	if (d->back_wallnum > -1)
		wback = &Walls[d->back_wallnum];

	old_cloak = wfront->cloak_value;

	d->time += FrameTime;

	if (d->time > CLOAKING_WALL_TIME) {
		int i;

		wfront->state = WALL_DOOR_CLOSED;
		if (wback)
			wback->state = WALL_DOOR_CLOSED;

		for (i=0;i<4;i++) {
			Segments[wfront->segnum].sides[wfront->sidenum].uvls[i].l = d->front_ls[i];
			if (wback)
				Segments[wback->segnum].sides[wback->sidenum].uvls[i].l = d->back_ls[i];
		}

		for (i=cloaking_wall_num;i<Num_cloaking_walls;i++)
			CloakingWalls[i] = CloakingWalls[i+1];
		Num_cloaking_walls--;

	}
	else if (d->time > CLOAKING_WALL_TIME/2) {		//fading in
		fix light_scale;
		int i;

		wfront->type = wback->type = WALL_CLOSED;

		light_scale = fixdiv(d->time-CLOAKING_WALL_TIME/2,CLOAKING_WALL_TIME/2);

		for (i=0;i<4;i++) {
			Segments[wfront->segnum].sides[wfront->sidenum].uvls[i].l = fixmul(d->front_ls[i],light_scale);
			if (wback)
			Segments[wback->segnum].sides[wback->sidenum].uvls[i].l = fixmul(d->back_ls[i],light_scale);
		}
	}
	else {		//cloaking in
		wfront->cloak_value = ((CLOAKING_WALL_TIME/2 - d->time) * (GR_FADE_LEVELS-2)) / (CLOAKING_WALL_TIME/2);
		wfront->type = WALL_CLOAKED;
		if (wback) {
			wback->cloak_value = wfront->cloak_value;
			wback->type = WALL_CLOAKED;
		}
	}

	// check if the actual cloak_value changed in this frame to prevent redundant recordings and wasted bytes
	if ( Newdemo_state == ND_STATE_RECORDING && (wfront->cloak_value != old_cloak || d->time == FrameTime) )
		newdemo_record_cloaking_wall(d->front_wallnum, d->back_wallnum, wfront->type, wfront->state, wfront->cloak_value, Segments[wfront->segnum].sides[wfront->sidenum].uvls[0].l, Segments[wfront->segnum].sides[wfront->sidenum].uvls[1].l, Segments[wfront->segnum].sides[wfront->sidenum].uvls[2].l, Segments[wfront->segnum].sides[wfront->sidenum].uvls[3].l);

}
#endif

void wall_frame_process()
{
	int i;

	for (i=0;i<Num_open_doors;i++) {
		active_door *d;
		wall *w;

		d = &ActiveDoors[i];
		w = &Walls[d->front_wallnum[0]];

		if (w->state == WALL_DOOR_OPENING)
			do_door_open(i);
		else if (w->state == WALL_DOOR_CLOSING)
			do_door_close(i);
		else if (w->state == WALL_DOOR_WAITING) {
			d->time += FrameTime;

			// set flags to fix occasional netgame problem where door is waiting to close but open flag isn't set
			w->flags |= WALL_DOOR_OPENED;
			if (d->back_wallnum[0] > -1)
				Walls[d->back_wallnum[0]].flags |= WALL_DOOR_OPENED;

			if (d->time > DOOR_WAIT_TIME)
#if defined(DXX_BUILD_DESCENT_II)
				if (is_door_free(vcsegptridx(w->segnum), w->sidenum))
#endif
				{
					w->state = WALL_DOOR_CLOSING;
					d->time = 0;
				}
		}
#if defined(DXX_BUILD_DESCENT_II)
		else if (w->state == WALL_DOOR_CLOSED || w->state == WALL_DOOR_OPEN) {
			//this shouldn't happen.  if the wall is in one of these states,
			//there shouldn't be an activedoor entry for it.  So we'll kill
			//the activedoor entry.  Tres simple.
			int t;
			Int3();		//a bad thing has happened, but I'll try to fix it up
			for (t=i;t<Num_open_doors;t++)
				ActiveDoors[t] = ActiveDoors[t+1];
			Num_open_doors--;
		}
#endif
	}

#if defined(DXX_BUILD_DESCENT_II)
	for (i=0;i<Num_cloaking_walls;i++) {
		cloaking_wall *d;
		wall *w;

		d = &CloakingWalls[i];
		w = &Walls[d->front_wallnum];

		if (w->state == WALL_DOOR_CLOAKING)
			do_cloaking_wall_frame(i);
		else if (w->state == WALL_DOOR_DECLOAKING)
			do_decloaking_wall_frame(i);
#ifdef _DEBUG
		else
			Int3();	//unexpected wall state
#endif
	}
#endif
}

static unsigned Num_stuck_objects;
static array<stuckobj, MAX_STUCK_OBJECTS> Stuck_objects;

//	An object got stuck in a door (like a flare).
//	Add global entry.
void add_stuck_object(const vobjptridx_t objp, const vsegptr_t segp, int sidenum)
{
	const auto wallnum = segp->sides[sidenum].wall_num;
	if (wallnum != wall_none)
	{
		if (Walls[wallnum].flags & WALL_BLASTED)
			objp->flags |= OF_SHOULD_BE_DEAD;
		range_for (auto &i, Stuck_objects)
		{
			if (i.wallnum == -1) {
				i.wallnum = wallnum;
				i.objnum = objp;
				i.signature = objp->signature;
				Num_stuck_objects++;
				break;
			}
		}
	}
}

#if defined(DXX_BUILD_DESCENT_I)
//	--------------------------------------------------------------------------------------------------
//	Look at the list of stuck objects, clean up in case an object has gone away, but not been removed here.
//	Removes up to one/frame.
void remove_obsolete_stuck_objects(void)
{
	int	objnum;

	objnum = d_tick_count % MAX_STUCK_OBJECTS;

	if (Stuck_objects[objnum].wallnum != -1)
		if ((Stuck_objects[objnum].wallnum == 0) || (vcobjptr(Stuck_objects[objnum].objnum)->signature != Stuck_objects[objnum].signature))
		{
			Num_stuck_objects--;
			Stuck_objects[objnum].wallnum = -1;
		}
}
#endif

#if defined(DXX_BUILD_DESCENT_II)
//	--------------------------------------------------------------------------------------------------
//	Look at the list of stuck objects, clean up in case an object has gone away, but not been removed here.
//	Removes up to one/frame.
void remove_obsolete_stuck_objects(void)
{
	int	objnum;

	//	Safety and efficiency code.  If no stuck objects, should never get inside the IF, but this is faster.
	if (!Num_stuck_objects)
		return;

	objnum = d_tick_count % MAX_STUCK_OBJECTS;

	if (Stuck_objects[objnum].wallnum != -1)
		if ((Walls[Stuck_objects[objnum].wallnum].state != WALL_DOOR_CLOSED) || (vcobjptr(Stuck_objects[objnum].objnum)->signature != Stuck_objects[objnum].signature)) {
			Num_stuck_objects--;
			vobjptr(Stuck_objects[objnum].objnum)->lifeleft = F1_0/8;
			Stuck_objects[objnum].wallnum = -1;
		}

}
#endif

//	----------------------------------------------------------------------------------------------------
//	Door with wall index wallnum is opening, kill all objects stuck in it.
void kill_stuck_objects(int wallnum)
{
	int	i;

	if (wallnum < 0 || Num_stuck_objects == 0) {
		return;
	}

	Num_stuck_objects=0;

	for (i=0; i<MAX_STUCK_OBJECTS; i++)
		if (Stuck_objects[i].wallnum == wallnum) {
			const auto &&objp = vobjptr(Stuck_objects[i].objnum);
			if (objp->type == OBJ_WEAPON) {
#if defined(DXX_BUILD_DESCENT_I)
#define DXX_WEAPON_LIFELEFT	F1_0/4
#elif defined(DXX_BUILD_DESCENT_II)
#define DXX_WEAPON_LIFELEFT	F1_0/8
#endif
				objp->lifeleft = DXX_WEAPON_LIFELEFT;
			}
			Stuck_objects[i].wallnum = -1;
		} else if (Stuck_objects[i].wallnum != -1) {
			Num_stuck_objects++;
		}
	//	Ok, this is awful, but we need to do things whenever a door opens/closes/disappears, etc.
#if defined(DXX_BUILD_DESCENT_II)
	flush_fcd_cache();
#endif

}

#if defined(DXX_BUILD_DESCENT_II)
// -----------------------------------------------------------------------------------
// Initialize stuck objects array.  Called at start of level
void init_stuck_objects(void)
{
	range_for (auto &i, Stuck_objects)
		i.wallnum = -1;
	Num_stuck_objects = 0;
}

// -----------------------------------------------------------------------------------
// Clear out all stuck objects.  Called for a new ship
void clear_stuck_objects(void)
{
	range_for (auto &i, Stuck_objects)
	{
		if (i.wallnum != -1) {
			const auto &&objp = vobjptr(i.objnum);
			if (objp->type == OBJ_WEAPON && get_weapon_id(objp) == weapon_id_type::FLARE_ID)
				objp->lifeleft = F1_0/8;

			i.wallnum = -1;
			Num_stuck_objects--;
		}
	}

	Assert(Num_stuck_objects == 0);

}

// -----------------------------------------------------------------------------------
#define	MAX_BLAST_GLASS_DEPTH	5

static void bng_process_segment(const vobjptr_t objp, fix damage, const vsegptridx_t segp, int depth, visited_segment_bitarray_t &visited)
{
	int	i, sidenum;

	if (depth > MAX_BLAST_GLASS_DEPTH)
		return;

	depth++;

	for (sidenum=0; sidenum<MAX_SIDES_PER_SEGMENT; sidenum++) {
		int			tm;
		fix			dist;

		//	Process only walls which have glass.
		if ((tm=segp->sides[sidenum].tmap_num2) != 0) {
			int	ec, db;

			tm &= 0x3fff;			//tm without flags

			if ((((ec=TmapInfo[tm].eclip_num)!=-1) && ((db=Effects[ec].dest_bm_num)!=-1 && !(Effects[ec].flags&EF_ONE_SHOT))) ||	(ec==-1 && (TmapInfo[tm].destroyed!=-1))) {
				const auto pnt = compute_center_point_on_side(segp, sidenum);
				dist = vm_vec_dist_quick(pnt, objp->pos);
				if (dist < damage/2) {
					dist = find_connected_distance(pnt, segp, objp->pos, segp.absolute_sibling(objp->segnum), MAX_BLAST_GLASS_DEPTH, WID_RENDPAST_FLAG);
					if ((dist > 0) && (dist < damage/2))
						check_effect_blowup(segp, sidenum, pnt, vcobjptr(objp->ctype.laser_info.parent_num)->ctype.laser_info, 1, 0);
				}
			}
		}
	}

	for (i=0; i<MAX_SIDES_PER_SEGMENT; i++) {
		auto segnum = segp->children[i];

		if (segnum != segment_none) {
			if (!visited[segnum]) {
				if (WALL_IS_DOORWAY(segp, i) & WID_FLY_FLAG) {
					visited[segnum] = true;
					bng_process_segment(objp, damage, segp.absolute_sibling(segnum), depth, visited);
				}
			}
		}
	}
}

// -----------------------------------------------------------------------------------
//	objp is going to detonate
//	blast nearby monitors, lights, maybe other things
void blast_nearby_glass(const vobjptr_t objp, fix damage)
{
	visited_segment_bitarray_t visited;

	visited[objp->segnum] = true;
	bng_process_segment(objp, damage, vsegptridx(objp->segnum), 0, visited);
}

struct d1wclip
{
	wclip *wc;
	d1wclip(wclip &w) : wc(&w) {}
};

DEFINE_SERIAL_UDT_TO_MESSAGE(d1wclip, dwc, (dwc.wc->play_time, dwc.wc->num_frames, dwc.wc->d1_frames, dwc.wc->open_sound, dwc.wc->close_sound, dwc.wc->flags, dwc.wc->filename, serial::pad<1>()));
ASSERT_SERIAL_UDT_MESSAGE_SIZE(d1wclip, 26 + (sizeof(int16_t) * MAX_CLIP_FRAMES_D1));
#endif

DEFINE_SERIAL_UDT_TO_MESSAGE(wclip, wc, (wc.play_time, wc.num_frames, wc.frames, wc.open_sound, wc.close_sound, wc.flags, wc.filename, serial::pad<1>()));
ASSERT_SERIAL_UDT_MESSAGE_SIZE(wclip, 26 + (sizeof(int16_t) * MAX_CLIP_FRAMES));

/*
 * reads a wclip structure from a PHYSFS_file
 */
void wclip_read(PHYSFS_file *fp, wclip &wc)
{
	PHYSFSX_serialize_read(fp, wc);
}

#if 0
void wclip_write(PHYSFS_file *fp, const wclip &wc)
{
	PHYSFSX_serialize_write(fp, wc);
}
#endif

struct wrap_v16_wall
{
	const wall *w;
	wrap_v16_wall(const wall &t) : w(&t) {}
};

#define _SERIAL_UDT_WALL_V16_MEMBERS(P)	(P type, P flags, P hps, P trigger, P clip_num, P keys)

DEFINE_SERIAL_UDT_TO_MESSAGE(v16_wall, w, _SERIAL_UDT_WALL_V16_MEMBERS(w.));
DEFINE_SERIAL_UDT_TO_MESSAGE(wrap_v16_wall, w, _SERIAL_UDT_WALL_V16_MEMBERS(w.w->));
ASSERT_SERIAL_UDT_MESSAGE_SIZE(wrap_v16_wall, 9);

/*
 * reads a v16_wall structure from a PHYSFS_file
 */
void v16_wall_read(PHYSFS_file *fp, v16_wall &w)
{
	PHYSFSX_serialize_read(fp, w);
}

struct wrap_v19_wall
{
	const wall *w;
	wrap_v19_wall(const wall &t) : w(&t) {}
};

DEFINE_SERIAL_UDT_TO_MESSAGE(v19_wall, w, (w.segnum, serial::pad<2>(), w.sidenum, w.type, w.flags, w.hps, w.trigger, w.clip_num, w.keys, w.linked_wall));
DEFINE_SERIAL_UDT_TO_MESSAGE(wrap_v19_wall, w, (w.w->segnum, serial::pad<2>(), w.w->sidenum, serial::pad<3>(), w.w->type, w.w->flags, w.w->hps, w.w->trigger, w.w->clip_num, w.w->keys, w.w->linked_wall, serial::pad<2>()));
ASSERT_SERIAL_UDT_MESSAGE_SIZE(v19_wall, 21);
ASSERT_SERIAL_UDT_MESSAGE_SIZE(wrap_v19_wall, 21);

/*
 * reads a v19_wall structure from a PHYSFS_file
 */
void v19_wall_read(PHYSFS_file *fp, v19_wall &w)
{
	PHYSFSX_serialize_read(fp, w);
}

#if defined(DXX_BUILD_DESCENT_I)
#define _SERIAL_UDT_WALL_D2X_MEMBERS	serial::pad<2>()
#elif defined(DXX_BUILD_DESCENT_II)
#define _SERIAL_UDT_WALL_D2X_MEMBERS	w.controlling_trigger, w.cloak_value
#endif
DEFINE_SERIAL_UDT_TO_MESSAGE(wall, w, (w.segnum, serial::pad<2>(), w.sidenum, serial::pad<3>(), w.hps, w.linked_wall, serial::pad<2>(), w.type, w.flags, w.state, w.trigger, w.clip_num, w.keys, _SERIAL_UDT_WALL_D2X_MEMBERS));
ASSERT_SERIAL_UDT_MESSAGE_SIZE(wall, 24);

/*
 * reads a wall structure from a PHYSFS_file
 */
void wall_read(PHYSFS_file *fp, wall &w)
{
	PHYSFSX_serialize_read(fp, w);
}

DEFINE_SERIAL_UDT_TO_MESSAGE(active_door, d, (d.n_parts, d.front_wallnum, d.back_wallnum, d.time));
ASSERT_SERIAL_UDT_MESSAGE_SIZE(active_door, 16);

/*
 * reads an active_door structure from a PHYSFS_file
 */
void active_door_read(PHYSFS_file *fp, active_door &ad)
{
	PHYSFSX_serialize_read(fp, ad);
}

void active_door_write(PHYSFS_file *fp, const active_door &ad)
{
	PHYSFSX_serialize_write(fp, ad);
}

void wall_write(PHYSFS_file *fp, const wall &w, short version)
{
	if (version <= 16)
		PHYSFSX_serialize_write<wrap_v16_wall>(fp, w);
	else if (version <= 19)
		PHYSFSX_serialize_write<wrap_v19_wall>(fp, w);
	else
		PHYSFSX_serialize_write(fp, w);
}

#if defined(DXX_BUILD_DESCENT_II)
DEFINE_SERIAL_UDT_TO_MESSAGE(cloaking_wall, cw, (cw.front_wallnum, cw.back_wallnum, cw.front_ls, cw.back_ls, cw.time));
ASSERT_SERIAL_UDT_MESSAGE_SIZE(cloaking_wall, 40);

void cloaking_wall_read(cloaking_wall &cw, PHYSFS_file *fp)
{
	PHYSFSX_serialize_read(fp, cw);
}

void cloaking_wall_write(const cloaking_wall &cw, PHYSFS_file *fp)
{
	PHYSFSX_serialize_write(fp, cw);
}
#endif