float CalculateManipulatedValue(PidParameter* const pid)
{
	const float error = pid->desiredValue - pid->currentValue;
	const float dt = pid->dt;
	const float maxLimitValue = pid->manipulatedValueLimit;
	const float minLimitValue = -maxLimitValue;

	float proportionalTerm = pid->proportionalGain * error;
	float integralTerm = pid->integralTerm + pid->integralGain * error * dt;
	float derivativeTerm = pid->derivativeGain * (error - pid->previousError)
			/ dt;

	//proportionalTerm = BOUNDARY(proportionalTerm, minLimitValue, maxLimitValue);
	integralTerm = BOUNDARY(integralTerm, minLimitValue, maxLimitValue);
	//derivativeTerm = BOUNDARY(derivativeTerm, minLimitValue, maxLimitValue);

	float manipulatedValue = proportionalTerm + integralTerm + derivativeTerm;
	manipulatedValue = BOUNDARY(manipulatedValue, minLimitValue, maxLimitValue);

	//for debuging//
	pid->error = error;
	pid->proportionalTerm = proportionalTerm;
	pid->derivativeTerm = derivativeTerm;
	pid->mainpulatedValue = manipulatedValue;
	////////////////

	pid->integralTerm = integralTerm;
	pid->previousError = error;

	return manipulatedValue;
}
void SetMotorPwmTo(uint16_t id, float motor0, float motor1)
{
	int motor0Pwm = INTEGER(motor0);
	int motor1Pwm = INTEGER(motor1);

	motor0Pwm = BOUNDARY(motor0Pwm, -999, 999);
	motor1Pwm = BOUNDARY(motor1Pwm, -999, 999);

	motor0Pwm = abs(motor0Pwm);
	motor1Pwm = abs(motor1Pwm);

	static uint8_t message[13];

	message[0] = '<';
	message[1] = '0';
	message[2] = 'R';
	message[3] = motor0 > 0 ? '1' : '0';
	message[4] = (motor0Pwm / 100) % 10 + '0';
	message[5] = (motor0Pwm / 10) % 10 + '0';
	message[6] = (motor0Pwm) % 10 + '0';
	message[7] = 'L';
	message[8] = motor1 > 0 ? '1' : '0';
	message[9] = (motor1Pwm / 100) % 10 + '0';
	message[10] = (motor1Pwm / 10) % 10 + '0';
	message[11] = (motor1Pwm) % 10 + '0';
	message[12] = '>';

	if (IsI2c2OnGoing() == TRUE)
		return;
	I2c2WriteRequest(id, message, sizeof(message));
}
Beispiel #3
0
void
end_send_port( int i, int j, int k,
               const grid_t * g ) {
  int port = BOUNDARY( i, j, k), dst = g->bc[port];
  if( dst<0 || dst>=world_size ) return;
  mp_end_send( g->mp, BOUNDARY(i,j,k) );
}
Beispiel #4
0
void
begin_recv_port( int i, int j, int k,
                 int size,
                 const grid_t * g ) {
  int port = BOUNDARY(-i,-j,-k), src = g->bc[port];
  if( src<0 || src>=world_size ) return;
  mp_size_recv_buffer( g->mp, BOUNDARY(-i,-j,-k), size );
  mp_begin_recv( g->mp, port, size, src, BOUNDARY(i,j,k) );
}
Beispiel #5
0
end_recv_port( int i, int j, int k,
               const grid_t * g ) {
  int port = BOUNDARY(-i,-j,-k), src = g->bc[port];
  if( src<0 || src>=world_size ) return NULL;
  mp_end_recv( g->mp, port );
  return mp_recv_buffer( g->mp, port );
}
Beispiel #6
0
void
begin_send_port( int i, int j, int k,
                 int size,
                 const grid_t * g ) {
  int port = BOUNDARY( i, j, k), dst = g->bc[port];
  if( dst<0 || dst>=world_size ) return;
  mp_begin_send( g->mp, port, size, dst, port );
}
Beispiel #7
0
size_send_port( int i, int j, int k,
                int size,
                const grid_t * g ) {
  int port = BOUNDARY( i, j, k), dst = g->bc[port];
  if( dst<0 || dst>=world_size ) return NULL;
  mp_size_send_buffer( g->mp, port, size );
  return mp_send_buffer( g->mp, port );
}
Beispiel #8
0
int BlurEngine::transfer_pixels(pixel_f *src1, 
	pixel_f *src2, 
	pixel_f *src,
	double *radius,
	pixel_f *dest, 
	int size)
{
	int i;
	double sum;

// printf("BlurEngine::transfer_pixels %d %d %d %d\n", 
// plugin->config.r, 
// plugin->config.g, 
// plugin->config.b, 
// plugin->config.a);

	for(i = 0; i < size; i++)
    {
		sum = src1[i].r + src2[i].r;
		BOUNDARY(sum);
		dest[i].r = sum;

		sum = src1[i].g + src2[i].g;
		BOUNDARY(sum);
		dest[i].g = sum;

		sum = src1[i].b + src2[i].b;
		BOUNDARY(sum);
		dest[i].b = sum;

		sum = src1[i].a + src2[i].a;
		BOUNDARY(sum);
		dest[i].a = sum;

// 		if(radius[i] < 2)
// 		{
// 			double scale = 2.0 - (radius[i] * radius[i] - 2.0);
// 			dest[i].r /= scale;
// 			dest[i].g /= scale;
// 			dest[i].b /= scale;
// 			dest[i].a /= scale;
// 		}
    }
	return 0;
}
Beispiel #9
0
grid_t *
new_grid( void ) {
  grid_t *g;
  int i;
  MALLOC( g, 1 );
  CLEAR( g, 1 );
  for( i=0; i<27; i++ ) g->bc[i] = anti_symmetric_fields;
  g->bc[BOUNDARY(0,0,0)] = world_rank;
  g->mp = new_mp( 27 );
  REGISTER_OBJECT( g, checkpt_grid, restore_grid, NULL );
  return g;
}
Beispiel #10
0
/* Clear all exits for one room */
void clear_room( int x, int y )
{
  int dir, exitx, exity;

  /* Cycle through the four directions */
  for( dir = 0; dir < 4; dir++ )
  {
    /* Find next coord in this direction */
    get_exit_dir( dir, &exitx, &exity, x, y );

    /* If coord is valid, clear it */
    if ( !BOUNDARY( exitx, exity ) ) clear_coord( exitx, exity );
  }
}
Beispiel #11
0
void
partition_periodic_box( grid_t * g,
                        double gx0, double gy0, double gz0,
                        double gx1, double gy1, double gz1,
                        int gnx, int gny, int gnz,
                        int gpx, int gpy, int gpz ) {
  double f;
  int rank, px, py, pz; 

  // Make sure the grid can be setup

  if( !g ) ERROR(( "NULL grid" ));

  if( gpx<1 || gpy<1 || gpz<1 || gpx*gpy*gpz!=world_size )
    ERROR(( "Bad domain decompostion (%ix%ix%i)", gpx, gpy, gpz ));

  if( gnx<1 || gny<1 || gnz<1 || gnx%gpx!=0 || gny%gpy!=0 || gnz%gpz!=0 )
    ERROR(( "Bad resolution (%ix%ix%i) for domain decomposition",
            gnx, gny, gnz, gpx, gpy, gpz ));

  // Setup basic variables
  RANK_TO_INDEX( world_rank, px,py,pz );

  g->dx = (gx1-gx0)/(double)gnx;
  g->dy = (gy1-gy0)/(double)gny;
  g->dz = (gz1-gz0)/(double)gnz;
  g->dV = ((gx1-gx0)/(double)gnx)*
          ((gy1-gy0)/(double)gny)*
          ((gz1-gz0)/(double)gnz);

  g->rdx =  (double)gnx/(gx1-gx0);
  g->rdy =  (double)gny/(gy1-gy0);
  g->rdz =  (double)gnz/(gz1-gz0);
  g->r8V = ((double)gnx/(gx1-gx0))*
           ((double)gny/(gy1-gy0))*
           ((double)gnz/(gz1-gz0))*0.125;

  f = (double) px   /(double)gpx; g->x0 = gx0*(1-f) + gx1*f;
  f = (double) py   /(double)gpy; g->y0 = gy0*(1-f) + gy1*f;
  f = (double) pz   /(double)gpz; g->z0 = gz0*(1-f) + gz1*f;

  f = (double)(px+1)/(double)gpx; g->x1 = gx0*(1-f) + gx1*f;
  f = (double)(py+1)/(double)gpy; g->y1 = gy0*(1-f) + gy1*f;
  f = (double)(pz+1)/(double)gpz; g->z1 = gz0*(1-f) + gz1*f;

  // Size the local grid
  size_grid(g,gnx/gpx,gny/gpy,gnz/gpz);

  // Join the grid to neighbors
  INDEX_TO_RANK(px-1,py,  pz,  rank); join_grid(g,BOUNDARY(-1, 0, 0),rank);
  INDEX_TO_RANK(px,  py-1,pz,  rank); join_grid(g,BOUNDARY( 0,-1, 0),rank);
  INDEX_TO_RANK(px,  py,  pz-1,rank); join_grid(g,BOUNDARY( 0, 0,-1),rank);
  INDEX_TO_RANK(px+1,py,  pz,  rank); join_grid(g,BOUNDARY( 1, 0, 0),rank);
  INDEX_TO_RANK(px,  py+1,pz,  rank); join_grid(g,BOUNDARY( 0, 1, 0),rank);
  INDEX_TO_RANK(px,  py,  pz+1,rank); join_grid(g,BOUNDARY( 0, 0, 1),rank);
}
Beispiel #12
0
/*
 * rexmit: is the specified segment a retransmit?
 *   returns: number of retransmitted bytes in segment, 0 if not a rexmit
 *            *pout_order to to TRUE if segment is out of order
 */
int
rexmit (tcb * ptcb, seqnum seq, seglen len, Bool * pout_order,
        u_short this_ip_id)
{
  seqspace *sspace = ptcb->ss;
  seqnum seq_last = seq + len - 1;
  quadrant *pquad;
  int rexlen = 0;

  /* unless told otherwise, it's IN order */
  *pout_order = FALSE;


  /* see which quadrant it starts in */
  pquad = whichquad (sspace, seq);

  /* add the new segment into the segment database */
  if (BOUNDARY (seq, seq_last))
    {
      /* lives in two different quadrants (can't be > 2) */
      seqnum seq1, seq2;
      u_long len1, len2;

      /* in first quadrant */
      seq1 = seq;
      len1 = LAST_SEQ (QUADNUM (seq1)) - seq1 + 1;
      rexlen = addseg (ptcb, pquad, seq1, len1, pout_order, this_ip_id);

      /* in second quadrant */
      seq2 = FIRST_SEQ (QUADNUM (seq_last));
      len2 = len - len1;
      rexlen +=
        addseg (ptcb, pquad->next, seq2, len2, pout_order, this_ip_id);
    }
  else
    {
      rexlen = addseg (ptcb, pquad, seq, len, pout_order, this_ip_id);
    }

  return (rexlen);
}
void MotorControlProcess()
{
	if (isOnTimeForMotorControlProcess == FALSE)
		return;
	else
		isOnTimeForMotorControlProcess = FALSE;

	float manipulatedValues[CONTROL_MOTOR_COUNT] =
	{ 0.0f, 0.0f };
	int64_t currentEcnoderValues[CONTROL_MOTOR_COUNT] =
	{ motorEncoders[0].encoderCount, motorEncoders[1].encoderCount };

	int i;
	for (i = 0; i < CONTROL_MOTOR_COUNT; i++)
	{
		const float controlDesiredValue =
				motorControlTypes[i].controlDeisredValue;
		const float dt = motorControlTypes[i].pid.dt;
		const float acceleration =
				motorControlTypes[i].velocityParameter.acceleration;
		const float maxVelocity =
				motorControlTypes[i].velocityParameter.maximumVelocity;
		const float velocityUnit = acceleration * dt;
		const float pulsePerRotation = motorControlTypes[i].pulsePerRotation;
		const float currentVelocity = (currentEcnoderValues[i]
				- motorControlTypes[i].previousEncoder) * 360.0f
				/ (pulsePerRotation * dt); //degree/s
		const float averageVelocity = CalculateMovingAverage(
				&motorControlTypes[i].movingAverageVelocitySamples,
				currentVelocity); //degree/s
		const uint32_t time = motorControlTypes[i].time;

		switch (motorControlTypes[i].controlMode)
		{
		case CONTROL_VELOCITY:
		{
			float startVelocity = motorControlTypes[i].startVelocity;
			uint32_t desiredTime = motorControlTypes[i].desiredTime;

			if (time == 0)
			{
				startVelocity = averageVelocity;
				desiredTime = fabsf(controlDesiredValue - startVelocity)
						/ acceleration / dt;

				motorControlTypes[i].startVelocity = startVelocity;
				motorControlTypes[i].desiredTime = desiredTime;
			}

			float acceledDesiredVelocity = 0.0f;
			if (time < desiredTime)
			{
				acceledDesiredVelocity = startVelocity
						+ (controlDesiredValue - startVelocity > 0 ? 1.0 : -1.0)
								* velocityUnit * time;
			}
			else
			{
				acceledDesiredVelocity = controlDesiredValue;
			}

			motorControlTypes[i].pid.desiredValue = acceledDesiredVelocity;
			motorControlTypes[i].pid.currentValue = averageVelocity;
			manipulatedValues[i] = CalculateManipulatedValue(
					&motorControlTypes[i].pid);
		}
			break;
		case CONTROL_POSITION:
		{
			const float currentPosition = currentEcnoderValues[i] * 360.0f
					/ pulsePerRotation;

			const float positionError = controlDesiredValue - currentPosition;
			const float absOfPositionError = fabsf(positionError);
			const float positionErrorSign = positionError > 0.0f ? 1.0f : -1.0f;

			uint32_t desiredTime = motorControlTypes[i].desiredTime;
			float acceledDesiredVelocity = 0.0f;
			if (time > desiredTime)
			{
				acceledDesiredVelocity =
						absOfPositionError
								< motorControlTypes[i].positionErrorLimit ?
								0.0 :
								positionErrorSign
										* sqrtf(
												2 * acceleration
														* absOfPositionError);
				acceledDesiredVelocity =
						BOUNDARY(acceledDesiredVelocity, -maxVelocity, maxVelocity);
			}
			else
			{
				float startVelocity = motorControlTypes[i].startVelocity;

				if (time == 0)
				{
					const float desiredVelocity = positionErrorSign
							* maxVelocity;

					startVelocity =
							BOUNDARY(averageVelocity, -maxVelocity, maxVelocity);

					uint32_t startAreaDistance = fabsf(
							(desiredVelocity - startVelocity)
									* (desiredVelocity + startVelocity)
									/ (2 * acceleration));
					uint32_t endAreaDistance = desiredVelocity * desiredVelocity
							/ (2 * acceleration);

					if (absOfPositionError
							< startAreaDistance + endAreaDistance)
					{
						float desiredFloatTime =
								fabsf(
										(-2 * startVelocity
												+ sqrtf(
														2 * startVelocity
																* startVelocity
																+ 4
																		* acceleration
																		* absOfPositionError))
												/ (2 * acceleration) / dt);
						desiredTime = INTEGER(desiredFloatTime);
					}
					else
					{
						float desiredFloatTime = fabsf(
								desiredVelocity - startVelocity) / acceleration
								/ dt;
						desiredTime = INTEGER(desiredFloatTime);
					}

					motorControlTypes[i].startVelocity = startVelocity;
					motorControlTypes[i].desiredTime = desiredTime;
				}

				acceledDesiredVelocity = startVelocity
						+ positionErrorSign * velocityUnit * time;
			}

			motorControlTypes[i].pid.desiredValue = acceledDesiredVelocity;
			motorControlTypes[i].pid.currentValue = averageVelocity;
			manipulatedValues[i] = CalculateManipulatedValue(
					&motorControlTypes[i].pid);
		}
			break;
		case CONTROL_PID_TUNING:
		{
			motorControlTypes[i].pid.desiredValue = controlDesiredValue;
			motorControlTypes[i].pid.currentValue = currentVelocity;
			manipulatedValues[i] = CalculateManipulatedValue(
					&motorControlTypes[i].pid);
		}
			break;
		default:
			manipulatedValues[i] = 0.0f;
			break;
		}

		if (motorControlTypes[i].time != 0xFFFFFFFF)
			motorControlTypes[i].time += 1;
		motorControlTypes[i].previousEncoder = currentEcnoderValues[i];
		motorControlTypes[i].averageVelocity = averageVelocity;
	}

	//manipulatedValues[0] = -100;

	SetMotorPwmTo(NT_S_DCDM1210_0_I2C_ADRESS, manipulatedValues[0],
			manipulatedValues[1]);
	//SetMotorPwmTo(0x08, manipulatedValues[2], manipulatedValues[3]);
}
Beispiel #14
0
/* This function is recursive, ie it calls itself */
void map_exits( CHAR_DATA * ch, ROOM_INDEX_DATA * pRoom, int x, int y, int depth )
{
	static char map_chars[11] = "|-|-UD/\\\\/";
	int door;
	int exitx = 0, exity = 0;
	int roomx = 0, roomy = 0;
	EXIT_DATA *pExit;

	/*
	 * Setup this coord as a room - Change any symbols that can't be displayed here 
	 */
	dmap[x][y].sector = pRoom->sector_type;
	switch ( pRoom->sector_type )
	{
		case SECT_INSIDE:
			dmap[x][y].tegn = 'O';
			dmap[x][y].sector = -1;
			break;

		case SECT_CITY:
			dmap[x][y].tegn = ':';
			break;

		case SECT_FIELD:
		case SECT_FOREST:
		case SECT_HILLS:
			dmap[x][y].tegn = '*';
			break;

		case SECT_MOUNTAIN:
			dmap[x][y].tegn = '@';
			break;

		case SECT_WATER_SWIM:
		case SECT_WATER_NOSWIM:
			dmap[x][y].tegn = '=';
			break;

		case SECT_AIR:
			dmap[x][y].tegn = '~';
			break;

		case SECT_DESERT:
			dmap[x][y].tegn = '+';
			break;

		default:
			dmap[x][y].tegn = 'O';
			dmap[x][y].sector = -1;
			bug( "%s: Bad sector type (%d) in room %d.", __FUNCTION__, pRoom->sector_type, pRoom->vnum );
			break;
	}

	dmap[x][y].vnum = pRoom->vnum;
	dmap[x][y].depth = depth;
//   dmap[x][y].info = pRoom->room_flags;
	dmap[x][y].can_see = room_is_dark( pRoom );

	/*
	 * Limit recursion 
	 */
	if ( depth > MAXDEPTH )
		return;

	/*
	 * This room is done, deal with it's exits 
	 */
	for ( door = 0; door < 10; ++door )
	{
		/*
		 * Skip if there is no exit in this direction 
		 */
		if ( !( pExit = get_exit( pRoom, door ) ) )
			continue;

		/*
		 * Skip up and down until I can figure out a good way to display it 
		 */
		if ( door == 4 || door == 5 )
			continue;

		/*
		 * Get the coords for the next exit and room in this direction 
		 */
		get_exit_dir( door, &exitx, &exity, x, y );
		get_exit_dir( door, &roomx, &roomy, exitx, exity );

		/*
		 * Skip if coords fall outside map 
		 */
		if ( BOUNDARY( exitx, exity ) || BOUNDARY( roomx, roomy ) )
			continue;

		/*
		 * Skip if there is no room beyond this exit 
		 */
		if ( !pExit->to_room )
			continue;

		/*
		 * Ensure there are no clashes with previously defined rooms 
		 */
		if ( ( dmap[roomx][roomy].vnum != 0 ) && ( dmap[roomx][roomy].vnum != pExit->to_room->vnum ) )
		{
			/*
			 * Use the new room if the depth is higher 
			 */
			if ( dmap[roomx][roomy].depth <= depth )
				continue;

			/*
			 * It is so clear the old room 
			 */
			clear_room( roomx, roomy );
		}

		/*
		 * No exits at MAXDEPTH 
		 */
		if ( depth == MAXDEPTH )
			continue;

		/*
		 * No need for exits that are already mapped 
		 */
		if ( dmap[exitx][exity].depth > 0 )
			continue;

		/*
		 * Fill in exit 
		 */
		dmap[exitx][exity].depth = depth;
		dmap[exitx][exity].vnum = pExit->to_room->vnum;
//      dmap[exitx][exity].info = pExit->exit_info;
		dmap[exitx][exity].tegn = map_chars[door];
		dmap[exitx][exity].sector = -1;

		/*
		 * More to do? If so we recurse 
		 */
		if ( depth < MAXDEPTH && ( ( dmap[roomx][roomy].vnum == pExit->to_room->vnum ) || ( dmap[roomx][roomy].vnum == 0 ) ) )
		{
			/*
			 * Depth increases by one each time 
			 */
			map_exits( ch, pExit->to_room, roomx, roomy, depth + 1 );
		}
	}
}
Beispiel #15
0
void
partition_absorbing_box( grid_t * g,
                         double gx0, double gy0, double gz0,
                         double gx1, double gy1, double gz1,
                         int gnx, int gny, int gnz,
                         int gpx, int gpy, int gpz,
                         int pbc ) {
  int px, py, pz; 

  partition_periodic_box( g,
                          gx0, gy0, gz0,
                          gx1, gy1, gz1,
                          gnx, gny, gnz,
                          gpx, gpy, gpz );

  // Override periodic boundary conditions

  RANK_TO_INDEX( world_rank, px,py,pz );

  if( px==0 && gnx>1 ) { 
    set_fbc(g,BOUNDARY(-1,0,0),absorb_fields);
    set_pbc(g,BOUNDARY(-1,0,0),pbc);
  } 

  if( px==gpx-1 && gnx>1 ) {
    set_fbc(g,BOUNDARY( 1,0,0),absorb_fields);
    set_pbc(g,BOUNDARY( 1,0,0),pbc);
  }

  if( py==0 && gny>1 ) { 
    set_fbc(g,BOUNDARY(0,-1,0),absorb_fields);
    set_pbc(g,BOUNDARY(0,-1,0),pbc);
  } 

  if( py==gpy-1 && gny>1 ) {
    set_fbc(g,BOUNDARY(0, 1,0),absorb_fields);
    set_pbc(g,BOUNDARY(0, 1,0),pbc);
  }

  if( pz==0 && gnz>1 ) { 
    set_fbc(g,BOUNDARY(0,0,-1),absorb_fields);
    set_pbc(g,BOUNDARY(0,0,-1),pbc);
  } 

  if( pz==gpz-1 && gnz>1 ) {
    set_fbc(g,BOUNDARY(0,0, 1),absorb_fields);
    set_pbc(g,BOUNDARY(0,0, 1),pbc);
  }
}
Beispiel #16
0
/* This function is recursive, ie it calls itself */
void map_exits(CHAR_DATA *ch, ROOM_INDEX_DATA *pRoom, int x, int y, int depth)
{
  static char map_chars [4] = "|-|-";
  int door;
  int exitx = 0, exity = 0;
  int roomx = 0, roomy = 0;
  char buf[200]; // bugs
  EXIT_DATA *pExit;

  /* Setup this coord as a room */
  switch(pRoom->sector_type)
  {
    case SECT_CITY:
    case SECT_INSIDE:
    case SECT_UNUSED:
      map[x][y].tegn = 'O';
      break;
    case SECT_FIELD:
    case SECT_FOREST:
    case SECT_HILLS:
      map[x][y].tegn = '*';
      break;
    case SECT_MOUNTAIN:
      map[x][y].tegn = '@';
      break;
    case SECT_WATER_SWIM:
    case SECT_WATER_NOSWIM:
      map[x][y].tegn = '=';
      break;
    case SECT_AIR:
      map[x][y].tegn = '~';
      break;
    case SECT_DESERT:
      map[x][y].tegn = '+';
      break;
    default:
      map[x][y].tegn = 'O';
      xprintf(buf, "Map_exits: Bad sector type (%d) in room %d.",
        pRoom->sector_type, pRoom->vnum);
      bug(buf, 0);
      break;
  }
  map[x][y].vnum = pRoom->vnum;
  map[x][y].depth = depth;
  map[x][y].info = pRoom->room_flags;
  map[x][y].can_see = room_is_dark( pRoom );

  /* Limit recursion */
  if ( depth > MAXDEPTH ) return;

  /* This room is done, deal with it's exits */
  for( door = 0; door < 4; door++ )
  {
    /* Skip if there is no exit in this direction */
    if ( ( pExit = pRoom->exit[door] ) == NULL ) continue;

    /* Get the coords for the next exit and room in this direction */
    get_exit_dir( door, &exitx, &exity, x, y );
    get_exit_dir( door, &roomx, &roomy, exitx, exity );

    /* Skip if coords fall outside map */
    if ( BOUNDARY( exitx, exity ) || BOUNDARY( roomx, roomy )) continue;

    /* Skip if there is no room beyond this exit */
    if ( pExit->to_room == NULL ) continue;

    /* Ensure there are no clashes with previously defined rooms */
    if ( ( map[roomx][roomy].vnum != 0 ) &&
         ( map[roomx][roomy].vnum != pExit->to_room->vnum ))
    {
      /* Use the new room if the depth is higher */
      if ( map[roomx][roomy].depth <= depth ) continue;

      /* It is so clear the old room */
      clear_room( roomx, roomy );
    }

    /* No exits at MAXDEPTH */
    if ( depth == MAXDEPTH ) continue;

    /* No need for exits that are already mapped */
    if ( map[exitx][exity].depth > 0 ) continue;

    /* Fill in exit */
    map[exitx][exity].depth = depth;
    map[exitx][exity].vnum = pExit->to_room->vnum;
    map[exitx][exity].info = pExit->exit_info;
    map[exitx][exity].tegn = map_chars[door];

    /* More to do? If so we recurse */
    if ( ( depth < MAXDEPTH ) &&
       ( ( map[roomx][roomy].vnum == pExit->to_room->vnum ) ||
         ( map[roomx][roomy].vnum == 0 ) ) )
    {
      /* Depth increases by one each time */
      map_exits( ch, pExit->to_room, roomx, roomy, depth + 1 );
    }
  }
}