MuckyFoot-UrbanChaos/fallen/Source/Furn.cpp

//
// Furniture.
//

#include "game.h"
#include "fmatrix.h"
#include "furn.h"
#include "statedef.h"
#include "dirt.h"
#include "mist.h"
#include "hm.h"
#include "interfac.h"
//#include "command.h"
#include "bang.h"
#include	"Sound.h"
#include "pap.h"
#include	"memory.h"

//
// The state functions and the state function table.
//

void FURN_process_normal (Thing *);
void FURN_process_moveing(Thing *);
void FURN_driving        (Thing *);
void FURN_door           (Thing *);



StateFunction FURN_statefunctions[] =
{
	{STATE_INIT,            NULL},
	{STATE_NORMAL,          FURN_process_normal},
	{STATE_COLLISION,       NULL},
	{STATE_ABOUT_TO_REMOVE, NULL},
	{STATE_REMOVE_ME,       NULL},
	{STATE_MOVEING,         FURN_process_moveing},
	{STATE_FDRIVING,        NULL},
	{STATE_FDOOR,			FURN_door}
};



//
// Initialises the furniture structures. If dx == FURN_NULL_DX then
// that furniture structure is unused.
//

#define FURN_NULL_DX (INFINITY)

void init_furniture()
{
	SLONG i;

	for (i = 0; i < MAX_FURNITURE; i++)
	{
		TO_FURNITURE(i)->dx = FURN_NULL_DX;
	}
}


//
// Allocating and decallocating the furniture structues.
//

//
// Allocates a stationary furn structure.
//

Furniture *FURN_alloc_furniture(void)
{
	SLONG i;

	for (i = 0; i < MAX_FURNITURE; i++)
	{
		if (TO_FURNITURE(i)->dx == FURN_NULL_DX)
		{
			Furniture *ans = TO_FURNITURE(i);

			ans->dx     = 0;
			ans->dy     = 0;
			ans->dz     = 0;
			ans->dyaw   = 0;
			ans->dpitch = 0;
			ans->droll  = 0;

			return TO_FURNITURE(i);
		}
	}

	ASSERT(0);

	return NULL;
}

void FURN_dealloc(Furniture *furn)
{
	ASSERT(WITHIN(furn, TO_FURNITURE(0), TO_FURNITURE(MAX_FURNITURE - 1)));

	furn->dx = FURN_NULL_DX;
}


//
// Removes the furniture thing
//

void free_furniture(Thing *p_thing)
{
	//
	// Free the furniture structure, the drawmesh structure and
	// finally the thing structure itself.
	//

	if (p_thing->Genus.Furniture)
	{
		FURN_dealloc(p_thing->Genus.Furniture);
	}

	free_draw_mesh(p_thing->Draw.Mesh);

	free_thing(p_thing);
}


THING_INDEX FURN_create(
		SLONG x,
		SLONG y,
		SLONG z,
		SLONG yaw,
		SLONG pitch,
		SLONG roll,
		SLONG prim)
{
	DrawMesh   *dm;
	THING_INDEX ans = NULL;
	Thing      *p_thing;

	//
	// Get a DrawMesh for this thing.
	//

	dm = alloc_draw_mesh();

	if (dm)
	{
		ans = alloc_primary_thing();

		if (ans)
		{
			p_thing = TO_THING(ans);

			//
			// Initialise the thing.
			//

			p_thing->Class           = CLASS_FURNITURE;
			p_thing->State           = 0;
			p_thing->SubState        = 0;
			p_thing->DrawType        = DT_MESH;
			p_thing->Flags           = 0;
			p_thing->WorldPos.X      = x;
//			p_thing->WorldPos.Y      = calc_height_at(x>>8,z>>8)<<8;
			p_thing->WorldPos.Y      = y;
			p_thing->WorldPos.Z      = z;
			p_thing->Draw.Mesh       = dm;
			p_thing->Genus.Furniture = NULL;

			//
			// Initialise the drawmesh info.
			//

			dm->ObjectId = prim;
			dm->Angle    = yaw;
			dm->Tilt     = pitch;
			dm->Roll     = roll;

			//
			// Place on the mapwho.
			//

			add_thing_to_map(p_thing);

			//
			// Put into the normal state.
			//

			set_state_function(p_thing, STATE_NORMAL);
		}
	}

	return ans;
}

THING_INDEX VEHICLE_create(
		SLONG x,
		SLONG y,
		SLONG z,
		SLONG angle,
		SLONG prim)
{
	DrawMesh   *dm;
	THING_INDEX ans = NULL;
	Thing      *p_thing;

	//
	// Get a DrawMesh for this thing.
	//

	dm = alloc_draw_mesh();

	if (dm)
	{
		ans = alloc_primary_thing();

		if (ans)
		{
			p_thing = TO_THING(ans);

			//
			// Initialise the thing.
			//

			p_thing->Class           = CLASS_VEHICLE;
			p_thing->State           = 0;
			p_thing->SubState        = 0;
			p_thing->DrawType        = DT_MESH;
			p_thing->Flags           = 0;
			p_thing->WorldPos.X      = x;
			p_thing->WorldPos.Y      = PAP_calc_height_at(x>>8,z>>8)<<8;
			p_thing->WorldPos.Z      = z;
			p_thing->Draw.Mesh       = dm;
			p_thing->Genus.Furniture = NULL;

			//
			// Initialise the drawmesh info.
			//

			dm->ObjectId = prim;
			dm->Angle    = angle;
			dm->Tilt     = 0; //pitch;
			dm->Roll     = 0; //roll;

			//
			// Place on the mapwho.
			//

			add_thing_to_map(p_thing);

			//
			// Put into the normal state.
			//

//			set_state_function(p_thing, STATE_FDRIVING);
			p_thing->StateFn=NULL;
			p_thing->Genus.Furniture=FURN_alloc_furniture();
		}
	}

	return ans;
}

extern	void scan_walk_triangle(SLONG x0, SLONG y0, SLONG z0,SLONG x1, SLONG y1, SLONG z1,SLONG x2, SLONG y2, SLONG z2,SLONG face);

void	add_walkable_quad(THING_INDEX index,SLONG cx,SLONG cy,SLONG cz,SLONG face)
{
  	SLONG	x[4],y[4],z[4];
	SLONG	c0,p0;
	SLONG	new_face;
	struct PrimFace4 *p_f4,*p_new_f4;

	new_face=next_prim_face4;

	p_new_f4=&prim_faces4[new_face];

	p_f4=&prim_faces4[face];

	p_new_f4->ThingIndex=index;

	//
	// The next four probably arent needed but what the hell
	//

	p_new_f4->DrawFlags=p_f4->DrawFlags;
	p_new_f4->FaceFlags=p_f4->FaceFlags;
	p_new_f4->Type=p_f4->Type;
	p_new_f4->ID=p_f4->ID;

	for(c0=0;c0<4;c0++)
	{
		p0=p_f4->Points[c0];
		p_new_f4->Points[c0]=p0;
		x[c0]=cx+prim_points[p0].X;
		y[c0]=cy+prim_points[p0].Y;
		z[c0]=cz+prim_points[p0].Z;
	}

#ifndef	PSX //scan_walk_triangle
	scan_walk_triangle(x[0],y[0],z[0],x[1],y[1],z[1],x[2],y[2],z[2],new_face);
	scan_walk_triangle(x[1],y[1],z[1],x[3],y[3],z[3],x[2],y[2],z[2],new_face);
#endif

	next_prim_face4++;
}

void	place_walkable_faces_for_prim(THING_INDEX index,SLONG prim)
{
	SLONG	x,y,z;
	SLONG	c0;
	SLONG	sf,ef;
	struct	PrimObject	*p_obj;
	Thing	*p_thing;

	p_thing = TO_THING(index);

	x=p_thing->WorldPos.X>>8;
	y=p_thing->WorldPos.Y>>8;
	z=p_thing->WorldPos.Z>>8;

	p_obj=&prim_objects[prim];

	sf=p_obj->StartFace4;
	ef=p_obj->EndFace4;

	for(c0=sf;c0<ef;c0++)
	{
		if(prim_faces4[c0].DrawFlags&POLY_FLAG_WALKABLE)
		{
			//
			// In the game we use FaceFlags for the walkable flag,
			// not the drawflags...
			//

			prim_faces4[c0].FaceFlags |= FACE_FLAG_WALKABLE;	// !!!

			add_walkable_quad(index,x,y,z,c0);
		}
	}
}

//
// for each furniture thing, scan for walkable faces, copy them, then index them to the thing
//

void	FURN_add_walkable(void)
{
	THING_INDEX	current_thing;
	Thing	*p_thing;
	
	current_thing	=	PRIMARY_USED;
	while(current_thing)
	{
		p_thing			=	TO_THING(current_thing);

		if(p_thing->Class==CLASS_FURNITURE)
		{
			place_walkable_faces_for_prim(current_thing,p_thing->Draw.Mesh->ObjectId);
		}

		current_thing	=	p_thing->LinkChild;
	}
}


void FURN_push(
		THING_INDEX thing,
		SLONG x1, SLONG y1, SLONG z1,
		SLONG x2, SLONG y2, SLONG z2)
{
	SLONG dx;
	SLONG dy;
	SLONG dz;

	SLONG cx;
	SLONG cy;
	SLONG cz;

	SLONG qx;
	SLONG qy;
	SLONG qz;

	SLONG nx;
	SLONG ny;
	SLONG nz;

	SLONG dyaw;
	SLONG dpitch;
	SLONG droll;

	SLONG matrix[9];

	PrimInfo *inf;

	Thing     *p_thing = TO_THING(thing);
	DrawMesh  *dm      = p_thing->Draw.Mesh;
	Furniture *furn    = p_thing->Genus.Furniture;

	//
	// Make sure that this is a furniture thing.
	//

	ASSERT(p_thing->Class == CLASS_FURNITURE);

	if (furn == NULL)
	{
		//
		// This furniture thing is currently stationary.
		//

		furn = p_thing->Genus.Furniture = FURN_alloc_furniture();

		//
		// Start it moving.
		//

		set_state_function(p_thing, STATE_MOVEING);
	}

	ASSERT(WITHIN(dm,   TO_DRAW_MESH(0), TO_DRAW_MESH(MAX_DRAW_MESHES - 1)));
	ASSERT(WITHIN(furn, TO_FURNITURE(0), TO_FURNITURE(MAX_FURNITURE   - 1)));

	//
	// Find the centre of gravity of the prim.
	//

	inf = get_prim_info(dm->ObjectId);

	//
	// Find the rotation matrix of the prim.
	//

	FMATRIX_calc(
		matrix,
		dm->Angle,
		dm->Tilt,
		dm->Roll);

	//
	// The weight and moment of inertia shifts.
	//

	#define FURN_SHIFT_WEIGHT 12
	#define FURN_SHIFT_YAW    10
	#define FURN_SHIFT_PITCH  10
	#define FURN_SHIFT_ROLL   10

	//
	// Add the force to the velocity of the object.
	//

	dx = x2 - x1;
	dy = y2 - y1;
	dz = z2 - z1;

	furn->dx += dx << FURN_SHIFT_WEIGHT;
	furn->dy += dy << FURN_SHIFT_WEIGHT;
	furn->dz += dz << FURN_SHIFT_WEIGHT;

	//
	// Rotate the vector into prim space.
	//

	x1 -= p_thing->WorldPos.X>>8;
	y1 -= p_thing->WorldPos.Y>>8;
	z1 -= p_thing->WorldPos.Z>>8;

	x2 -= p_thing->WorldPos.X>>8;
	y2 -= p_thing->WorldPos.Y>>8;
	z2 -= p_thing->WorldPos.Z>>8;

	FMATRIX_MUL(matrix, x1, y1, z2);
	FMATRIX_MUL(matrix, x2, y2, z2);

	dx = x2 - x1;
	dy = y2 - y1;
	dz = z2 - z1;

	//
	// Find the torque around the y, x and z axis.
	//

	//
	// The force on yaw is the torque around the y-axis.
	// Consider the (x,z) plane and find the perpendicular
	// distance of the 2d force line from the origin.  We
	// need the normal of the line, n, and a point on the
	// line q.
	//

	nx =  dz;
	nz = -dx;

	qx =  x1;
	qz =  z1;

	dyaw = nx * qx + nz * qz;

	//
	// Pitch is about the x-axis.
	//

	nz =  dy;
	ny = -dz;

	qz =  z1;
	qy =  y1;

	dpitch = nz * qz + ny * qy;

	//
	// Roll is about the z-axis.
	//

	dx =  dy;
	dy = -dx;

	qx =  x1;
	qz =  y1;

	droll = nx * qx + ny * qy;

	furn->dyaw   += dyaw   << FURN_SHIFT_YAW;
	furn->dpitch += dpitch << FURN_SHIFT_PITCH;
	furn->droll  += droll  << FURN_SHIFT_ROLL;
}


void FURN_process_normal(Thing *p_thing)
{
	SLONG x1;
	SLONG x2;
	SLONG z1;
	SLONG z2;

	ASSERT(WITHIN(p_thing, TO_THING(1), TO_THING(MAX_THINGS - 1)));

	DrawMesh *dm = p_thing->Draw.Mesh;

	//
	// Make sure that this is a furniture thing and everything is valid.
	//

	ASSERT(
		p_thing->Class == CLASS_FURNITURE ||
		p_thing->Class == CLASS_VEHICLE);
	ASSERT(WITHIN(dm, TO_DRAW_MESH(0), TO_DRAW_MESH(MAX_DRAW_MESHES - 1)));

	if (dm->Hm != 255)
	{
		SLONG dx;
		SLONG dz;

		SLONG mx;
		SLONG mz;	    

		SLONG mid_x;
		SLONG mid_z;

		SLONG v_list;
		SLONG i_vect;

		SLONG overndist;
		SLONG num_slides;
		SLONG last_slide;

		CollisionVect *p_vect;

		//
		// Move the object to the positon of the hypermatter object.
		//
		
		{
			SLONG mx;
			SLONG my;
			SLONG mz;
			SLONG myaw;
			SLONG mpitch;
			SLONG mroll;

			HM_find_mesh_pos(dm->Hm,
				&mx,
				&my,
				&mz,
				&myaw,
				&mpitch,
				&mroll);

			myaw   &= 2047;
			mpitch &= 2047;
			mroll  &= 2047;

			GameCoord new_pos;
			
			new_pos.X = mx << 8;
			new_pos.Y = my << 8;
			new_pos.Z = mz << 8;

			move_thing_on_map(p_thing, &new_pos);

			dm->Angle = myaw;
			dm->Tilt  = mpitch;
			dm->Roll  = mroll;
		}

		//
		// Sort out which colvects the hypermatter should collide with.
		//

		HM_colvect_clear(dm->Hm);
		
		//
		// Look for nearby colvects.
		//

		#define FURN_COL_RADIUS (1024)

		x1 = (p_thing->WorldPos.X >> 8) - FURN_COL_RADIUS >> ELE_SHIFT;
		z1 = (p_thing->WorldPos.Z >> 8) - FURN_COL_RADIUS >> ELE_SHIFT;

		x2 = (p_thing->WorldPos.X >> 8) + FURN_COL_RADIUS >> ELE_SHIFT;
		z2 = (p_thing->WorldPos.Z >> 8) + FURN_COL_RADIUS >> ELE_SHIFT;

		SATURATE(x1, 0, MAP_WIDTH  - 1);
		SATURATE(x2, 0, MAP_WIDTH  - 1);

		SATURATE(z1, 0, MAP_HEIGHT - 1);
		SATURATE(z2, 0, MAP_HEIGHT - 1);

		for (mx = x1; mx <= x2; mx++)
		for (mz = z1; mz <= z2; mz++)
		{
			v_list = MAP2(mx,mz).ColVectHead;

			while(v_list)
			{
				ASSERT(WITHIN(v_list,                            0, next_col_vect_link - 1));
				ASSERT(WITHIN(col_vects_links[v_list].VectIndex, 0, next_col_vect      - 1));

				i_vect =  col_vects_links[v_list].VectIndex;
				p_vect = &col_vects[i_vect];

				if (p_vect->Y[0] != PAP_calc_height_at(p_vect->X[0], p_vect->Z[0]))
				{
					//
					// Only consider colvects on the ground.
					//
				}
				else
				{
					HM_colvect_add(
						dm->Hm,
						p_vect->X[0], p_vect->Z[0],
						p_vect->X[1], p_vect->Z[1]);
				}
				
				v_list = col_vects_links[v_list].Next;
			}	
		}

		if (abs(dm->Tilt) < 256)
		{
			if (HM_stationary(dm->Hm))
			{
				MSG_add("Hm is at a standstill");

				HM_destroy(dm->Hm);

				dm->Hm = 255;

				if (p_thing->Genus.Furniture)
				{
					p_thing->Genus.Furniture->RAngle    = dm->Angle;
					p_thing->Genus.Furniture->Wheel     = 0;
					p_thing->Genus.Furniture->OverSteer = 0;
					p_thing->Velocity                   = 0;

					set_state_function(p_thing, STATE_FDRIVING);
				}
			}
		}
	}
}

void FURN_process_moveing(Thing *p_thing)
{
	ASSERT(WITHIN(p_thing, TO_THING(1), TO_THING(MAX_THINGS - 1)));

	DrawMesh  *dm   = p_thing->Draw.Mesh;
	Furniture *furn = p_thing->Genus.Furniture;

	//
	// Make sure that this is a furniture thing and everything is valid.
	//

	ASSERT(p_thing->Class == CLASS_FURNITURE);
	ASSERT(WITHIN(dm,   TO_DRAW_MESH(0), TO_DRAW_MESH(MAX_DRAW_MESHES - 1)));
	ASSERT(WITHIN(furn, TO_FURNITURE(0), TO_FURNITURE(MAX_FURNITURE   - 1)));

	//
	// Move it.
	//

	GameCoord new_pos;

	new_pos.X = p_thing->WorldPos.X + (furn->dx >> 8);
	new_pos.Y = p_thing->WorldPos.Y + (furn->dy >> 8);
	new_pos.Z = p_thing->WorldPos.Z + (furn->dz >> 8);

	//
	// Rotate it.
	//

	dm->Angle += furn->dyaw   >> 16;
	dm->Tilt  += furn->dpitch >> 16;
	dm->Roll  += furn->droll  >> 16;

	move_thing_on_map(p_thing, &new_pos);
}



SLONG FURN_slide_along(
		THING_INDEX thing,
		SLONG  x1, SLONG  y1, SLONG  z1,
		SLONG *x2, SLONG *y2, SLONG *z2,
		SLONG  radius,
		SLONG  dont_slide)
{
	Thing *p_thing = TO_THING(thing);

	ASSERT(WITHIN(p_thing, TO_THING(1), TO_THING(MAX_THINGS - 1)));
	ASSERT(p_thing->Class == CLASS_FURNITURE||p_thing->Class == CLASS_VEHICLE);

	SLONG tx1, tz1;
	SLONG tx2, tz2;

	SLONG rx1, rz1;
	SLONG rx2, rz2;

	SLONG y_bot;
	SLONG y_top;

	SLONG sin_yaw;
	SLONG cos_yaw;

	SLONG minx;
	SLONG minz;
	SLONG maxx;
	SLONG maxz;

	SLONG matrix[4];

	PrimInfo *pi;
	DrawMesh *dm    = p_thing->Draw.Mesh;
	Furniture *furn = p_thing->Genus.Furniture;

	x1>>=8;
	y1>>=8;
	z1>>=8;

	*x2=(*x2)>>8;
	*y2=(*y2)>>8;
	*z2=(*z2)>>8;

	//
	// The prim info...
	//

	pi = get_prim_info(dm->ObjectId);

	//
	// Is the 'y' range ok?
	//

	#define FURN_UNDERNEATH 32

	y_bot = (p_thing->WorldPos.Y>>8) + pi->miny - FURN_UNDERNEATH;
	y_top = (p_thing->WorldPos.Y>>8) + pi->maxy;
	
	if (WITHIN(y1, y_bot, y_top))
	{
		//
		// Rotates the movement vector into the space of the furniture.
		// We assume that the pitch of the furniture is negligible.
		//

		SLONG useangle;

		useangle  = -dm->Angle;
		useangle &=  2047;

		sin_yaw = SIN(useangle);
		cos_yaw = COS(useangle);

		matrix[0] =  cos_yaw;
		matrix[1] =  sin_yaw;
		matrix[2] = -sin_yaw;
		matrix[3] =  cos_yaw;

		//
		// Rotate the positions.
		//
		
		tx1 =  x1 - (p_thing->WorldPos.X>>8);
		tz1 =  z1 - (p_thing->WorldPos.Z>>8);

		tx2 = *x2 - (p_thing->WorldPos.X>>8);
		tz2 = *z2 - (p_thing->WorldPos.Z>>8);

		rx1 = MUL64(tx1, matrix[0]) + MUL64(tz1, matrix[1]);
		rz1 = MUL64(tx1, matrix[2]) + MUL64(tz1, matrix[3]);

		rx2 = MUL64(tx2, matrix[0]) + MUL64(tz2, matrix[1]);
		rz2 = MUL64(tx2, matrix[2]) + MUL64(tz2, matrix[3]);

		//
		// The bounding box.
		//

		minx = pi->minx - radius;
		minz = pi->minz - radius;

		maxx = pi->maxx + radius;
		maxz = pi->maxz + radius;

		//
		// Do we collide?
		//

		if (rx2 > maxx ||
			rx2 < minx ||
			rz2 > maxz ||
			rz2 < minz)
		{
			//
			// We don't collide with the bounding box.
			//

			*x2 <<= 8;
			*y2 <<= 8;
			*z2 <<= 8;

			return FALSE;	// FALSE => Still moving.
		}

		if (p_thing->State == STATE_FDOOR)
		{
			//
			// Set the door rotating.
			//

			if (rz1 < 0)
			{
				furn->dyaw -= 3;
			}
			else
			{
				furn->dyaw += 3;
			}
		}

		if (dont_slide)
		{
			//
			// We aren't allowed to slide, and we can't go into the
			// furniture, so we have to stay still.
			//

			*x2 = x1 << 8;
			*y2 = y1 << 8;
			*z2 = z1 << 8;

			return TRUE; // TRUE => No more movement.
		}
		else
		{
			//
			// Slide to the nearest point to the edge of the box.
			//

			SLONG dminx;
			SLONG dminz;
			SLONG dmaxx;
			SLONG dmaxz;

			SLONG best;
			SLONG best_x;
			SLONG best_z;

			dminx = rx2 - minx;
			dmaxx = maxx - rx2;

			dminz = rz2 - minz;
			dmaxz = maxz - rz2;

			best   = dminx;
			best_x = minx - 1;
			best_z = rz2;
			
			if (dmaxx < best)
			{
				best   = dmaxx;
				best_x = maxx - 1;
				best_z = rz2;
			}

			if (dminz < best)
			{
				best   = dminz;
				best_x = rx2;
				best_z = minz - 1;
			}

			if (dmaxz < best)
			{
				best   = dmaxz;
				best_x = rx2;
				best_z = maxz + 1;
			}

			//
			// We have to un-rotate the points. The inverse of the
			// matrix is its transpose.
			//

			SWAP(matrix[1], matrix[2]);

			*x2 = MUL64(best_x, matrix[0]) + MUL64(best_z, matrix[1]);
			*z2 = MUL64(best_x, matrix[2]) + MUL64(best_z, matrix[3]);

			*x2 += p_thing->WorldPos.X>>8;
			*z2 += p_thing->WorldPos.Z>>8;

			*x2 <<= 8;
			*y2 <<= 8;
			*z2 <<= 8;

			return TRUE;	// bumped the car
		}
	}

	*x2 <<= 8;
	*y2 <<= 8;
	*z2 <<= 8;

	return FALSE; // FALSE => Still moving.	 //didnt bump car
}


void FURN_hypermatterise(THING_INDEX thing)
{
	SLONG dx;
	SLONG dy;
	SLONG dz;

	Thing    *p_thing = TO_THING(thing);
	DrawMesh *dm      = p_thing->Draw.Mesh;
	Furniture *furn   = p_thing->Genus.Furniture;

	HM_Primgrid *hpg = HM_get_primgrid(dm->ObjectId);

	if (furn != NULL)
	{
		dx = -(SIN(furn->RAngle)*p_thing->Velocity)>>8;
		dz = -(COS(furn->RAngle)*p_thing->Velocity)>>8;

		dx = (dx*TICK_RATIO)>>(TICK_SHIFT);
		dz = (dz*TICK_RATIO)>>(TICK_SHIFT);

		dx >>= 16;
		dz >>= 16;

		dy = 2;
	}
	else
	{
		dx = 0;
		dy = 0;
		dz = 0;
	}

	SLONG pointx[5] = {0, 0x5300, 0xa600, 0x10000};
	SLONG pointy[5] = {0, 0x5300, 0xa600, 0x10000};
	SLONG pointz[5] = {0, 0x5300, 0xa600, 0x10000};



	UBYTE hm_index   = HM_create(
							dm->ObjectId,
							p_thing->WorldPos.X >> 8,
							p_thing->WorldPos.Y >> 8,
							p_thing->WorldPos.Z >> 8,

							dm->Angle,
							0,//dm->Roll,
							0,//dm->Tilt,

							dx,	// Velocity...
						 	dy,
						    dz,

							hpg->x_res,
							hpg->y_res,
							hpg->z_res,
							hpg->x_point,
							hpg->y_point,
							hpg->z_point,

							/*

							4,//hpg->x_res,
							4,//hpg->y_res,
							4,//hpg->z_res,
							pointx,//hpg->x_point,
							pointy,//hpg->y_point,
							pointz,//hpg->z_point,

							*/

							hpg->x_dgrav,
							hpg->y_dgrav,
							hpg->z_dgrav,

							0.010F,		// elasticity
							0.950F,		// bounciness
							0.850F,		// friction
							0.997F);	// damping
	
	if (hm_index != HM_NO_MORE_OBJECTS)
	{
		dm->Hm = hm_index;

		//
		// Stop the car obeying commands and being driven...
		//

		if (furn)
		{
			furn->Flags   &= ~FLAG_FURN_DRIVING;
			furn->Command  =  0;
		}

		set_state_function(p_thing, STATE_NORMAL);
	}
}






void FURN_turn_into_door(
		THING_INDEX furniture_thing,
		UWORD       closed_angle,
		UWORD		ajar,
		UBYTE		am_i_locked)
{
	Thing    *p_thing = TO_THING(furniture_thing);
	DrawMesh *dm      = p_thing->Draw.Mesh;
	Furniture *furn;

	//
	// Allocate the furniture structure.
	//

	furn = p_thing->Genus.Furniture = FURN_alloc_furniture();

	furn->dyaw         = 0;
	furn->closed_angle = closed_angle;
	furn->ajar         = ajar;

	if (am_i_locked)
	{
		p_thing->Flags |=  FLAGS_LOCKED;
	}
	else
	{
		p_thing->Flags &= ~FLAGS_LOCKED;
	}

	set_state_function(p_thing, STATE_FDOOR);
	
}

void FURN_door(Thing *p_thing)
{
	DrawMesh  *dm   = p_thing->Draw.Mesh;
	Furniture *furn = p_thing->Genus.Furniture;

	SLONG min_angle;
	SLONG max_angle;

	dm->Angle += furn->dyaw;
	dm->Angle &= 2047;

	furn->dyaw -= SIGN(furn->dyaw);
}

SLONG FURN_avoid(
		THING_INDEX thing,
		SLONG x1, SLONG y1, SLONG z1,
		SLONG x2, SLONG y2, SLONG z2)
{
	Thing *p_thing = TO_THING(thing);

	SLONG x;
	SLONG y;
	SLONG z;

	SLONG dx;
	SLONG dy;
	SLONG dz;

	SLONG da;
	SLONG db;

	SLONG dist;
	SLONG dist1;
	SLONG dist2;

	SLONG fx;
	SLONG fz;

	SLONG px1;
	SLONG pz1;
	SLONG px2;
	SLONG pz2;

	SLONG furn_radius;

	PrimInfo *pi = get_prim_info(p_thing->Draw.Mesh->ObjectId);

	x1 >>= 8;
	y1 >>= 8;
	z1 >>= 8;

	x2 >>= 8;
	y2 >>= 8;
	z2 >>= 8;

	//
	// Lengthen the movement vector...
	//

	dx = x2 - x1 << 3;
	dy = y2 - y1 << 3;
	dz = z2 - z1 << 3;

	x2 = x1 + dx;
	y2 = y1 + dy;
	z2 = z1 + dz;

	#define FURN_AVOID_LOOK_EXTRA 0x40

	if (p_thing->Draw.Mesh->ObjectId < 5 ||
		p_thing->Draw.Mesh->ObjectId == 55)
	{
		//
		// A lampost.
		//

		furn_radius = 0x40 + FURN_AVOID_LOOK_EXTRA;
	}
	else
	{
		furn_radius = pi->radius + FURN_AVOID_LOOK_EXTRA;
	}

	fx = p_thing->WorldPos.X >> 8;
	fz = p_thing->WorldPos.Z >> 8;

	dx = fx - x1;
	dz = fz - z1;

	//
	// Normalise dx,dz to the radius of the furniture.
	//

	dist = QDIST2(abs(dx),abs(dz));

	if (dist == 0) {dist = 1;}

	dx = dx * furn_radius / dist;
	dz = dz * furn_radius / dist;

	px1 = fx + (-dz);
	pz1 = fz + (+dx);

	px2 = fx - (-dz);
	pz2 = fz - (+dx);

	SLONG roomy1 = there_is_a_los(fx, y1, fz, px1, y2, pz1);
	SLONG roomy2 = there_is_a_los(fx, y1, fz, px2, y2, pz2);

	if (roomy1 ^ roomy2)
	{
		//
		// Turn towards the side of the prim we can go around.
		//

		if (roomy1)
		{
			return -1;
		}
		else
		{
			return +1;
		}
	}
	else
	{
		//
		// Turn towards the nearest side of the prim to where you are going.
		//

		dx = abs(px1 - x2);
		dz = abs(pz1 - z2);

		dist1 = QDIST2(dx,dz);

		dx = abs(px2 - x2);
		dz = abs(pz2 - z2);

		dist2 = QDIST2(dx,dz);

		if (dist1 < dist2)
		{
			return -1;
		}
		else
		{
			return +1;
		}
	}
}