p_map.c

Nxdoom真的满好用的

    // this line doesn't block movement
    return true;		
	
    // the line does block movement,
    // see if it is closer than best so far
  isblocking:		
    if (in->frac < bestslidefrac)
    {
	secondslidefrac = bestslidefrac;
	secondslideline = bestslideline;
	bestslidefrac = in->frac;
	bestslideline = li;
    }
	
    return false;	// stop
}



//
// P_SlideMove
// The momx / momy move is bad, so try to slide
// along a wall.
// Find the first line hit, move flush to it,
// and slide along it
//
// This is a kludgy mess.
//
void P_SlideMove (mobj_t* mo)
{
    fixed_t		leadx;
    fixed_t		leady;
    fixed_t		trailx;
    fixed_t		traily;
    fixed_t		newx;
    fixed_t		newy;
    int			hitcount;
		
    slidemo = mo;
    hitcount = 0;
    
  retry:
    if (++hitcount == 3)
	goto stairstep;		// don't loop forever

    
    // trace along the three leading corners
    if (mo->momx > 0)
    {
	leadx = mo->x + mo->radius;
	trailx = mo->x - mo->radius;
    }
    else
    {
	leadx = mo->x - mo->radius;
	trailx = mo->x + mo->radius;
    }
	
    if (mo->momy > 0)
    {
	leady = mo->y + mo->radius;
	traily = mo->y - mo->radius;
    }
    else
    {
	leady = mo->y - mo->radius;
	traily = mo->y + mo->radius;
    }
		
    bestslidefrac = FRACUNIT+1;
	
    P_PathTraverse ( leadx, leady, leadx+mo->momx, leady+mo->momy,
		     PT_ADDLINES, PTR_SlideTraverse );
    P_PathTraverse ( trailx, leady, trailx+mo->momx, leady+mo->momy,
		     PT_ADDLINES, PTR_SlideTraverse );
    P_PathTraverse ( leadx, traily, leadx+mo->momx, traily+mo->momy,
		     PT_ADDLINES, PTR_SlideTraverse );
    
    // move up to the wall
    if (bestslidefrac == FRACUNIT+1)
    {
	// the move most have hit the middle, so stairstep
      stairstep:
	if (!P_TryMove (mo, mo->x, mo->y + mo->momy))
	    P_TryMove (mo, mo->x + mo->momx, mo->y);
	return;
    }

    // fudge a bit to make sure it doesn't hit
    bestslidefrac -= 0x800;	
    if (bestslidefrac > 0)
    {
	newx = FixedMul (mo->momx, bestslidefrac);
	newy = FixedMul (mo->momy, bestslidefrac);
	
	if (!P_TryMove (mo, mo->x+newx, mo->y+newy))
	    goto stairstep;
    }
    
    // Now continue along the wall.
    // First calculate remainder.
    bestslidefrac = FRACUNIT-(bestslidefrac+0x800);
    
    if (bestslidefrac > FRACUNIT)
	bestslidefrac = FRACUNIT;
    
    if (bestslidefrac <= 0)
	return;
    
    tmxmove = FixedMul (mo->momx, bestslidefrac);
    tmymove = FixedMul (mo->momy, bestslidefrac);

    P_HitSlideLine (bestslideline);	// clip the moves

    mo->momx = tmxmove;
    mo->momy = tmymove;
		
    if (!P_TryMove (mo, mo->x+tmxmove, mo->y+tmymove))
    {
	goto retry;
    }
}


//
// P_LineAttack
//
mobj_t*		linetarget;	// who got hit (or NULL)
mobj_t*		shootthing;

// Height if not aiming up or down
// ???: use slope for monsters?
fixed_t		shootz;	

int		la_damage;
fixed_t		attackrange;

fixed_t		aimslope;

// slopes to top and bottom of target
extern fixed_t	topslope;
extern fixed_t	bottomslope;	


//
// PTR_AimTraverse
// Sets linetaget and aimslope when a target is aimed at.
//
boolean
PTR_AimTraverse (intercept_t* in)
{
    line_t*		li;
    mobj_t*		th;
    fixed_t		slope;
    fixed_t		thingtopslope;
    fixed_t		thingbottomslope;
    fixed_t		dist;
		
    if (in->isaline)
    {
	li = in->d.line;
	
	if ( !(li->flags & ML_TWOSIDED) )
	    return false;		// stop
	
	// Crosses a two sided line.
	// A two sided line will restrict
	// the possible target ranges.
	P_LineOpening (li);
	
	if (openbottom >= opentop)
	    return false;		// stop
	
	dist = FixedMul (attackrange, in->frac);

	if (li->frontsector->floorheight != li->backsector->floorheight)
	{
	    slope = FixedDiv (openbottom - shootz , dist);
	    if (slope > bottomslope)
		bottomslope = slope;
	}
		
	if (li->frontsector->ceilingheight != li->backsector->ceilingheight)
	{
	    slope = FixedDiv (opentop - shootz , dist);
	    if (slope < topslope)
		topslope = slope;
	}
		
	if (topslope <= bottomslope)
	    return false;		// stop
			
	return true;			// shot continues
    }
    
    // shoot a thing
    th = in->d.thing;
    if (th == shootthing)
	return true;			// can't shoot self
    
    if (!(th->flags&MF_SHOOTABLE))
	return true;			// corpse or something

    // check angles to see if the thing can be aimed at
    dist = FixedMul (attackrange, in->frac);
    thingtopslope = FixedDiv (th->z+th->height - shootz , dist);

    if (thingtopslope < bottomslope)
	return true;			// shot over the thing

    thingbottomslope = FixedDiv (th->z - shootz, dist);

    if (thingbottomslope > topslope)
	return true;			// shot under the thing
    
    // this thing can be hit!
    if (thingtopslope > topslope)
	thingtopslope = topslope;
    
    if (thingbottomslope < bottomslope)
	thingbottomslope = bottomslope;

    aimslope = (thingtopslope+thingbottomslope)/2;
    linetarget = th;

    return false;			// don't go any farther
}


//
// PTR_ShootTraverse
//
boolean PTR_ShootTraverse (intercept_t* in)
{
    fixed_t		x;
    fixed_t		y;
    fixed_t		z;
    fixed_t		frac;
    
    line_t*		li;
    
    mobj_t*		th;

    fixed_t		slope;
    fixed_t		dist;
    fixed_t		thingtopslope;
    fixed_t		thingbottomslope;
		
    if (in->isaline)
    {
	li = in->d.line;
	
	if (li->special)
	    P_ShootSpecialLine (shootthing, li);

	if ( !(li->flags & ML_TWOSIDED) )
	    goto hitline;
	
	// crosses a two sided line
	P_LineOpening (li);
		
	dist = FixedMul (attackrange, in->frac);

	if (li->frontsector->floorheight != li->backsector->floorheight)
	{
	    slope = FixedDiv (openbottom - shootz , dist);
	    if (slope > aimslope)
		goto hitline;
	}
		
	if (li->frontsector->ceilingheight != li->backsector->ceilingheight)
	{
	    slope = FixedDiv (opentop - shootz , dist);
	    if (slope < aimslope)
		goto hitline;
	}

	// shot continues
	return true;
	
	
	// hit line
      hitline:
	// position a bit closer
	frac = in->frac - FixedDiv (4*FRACUNIT,attackrange);
	x = trace.x + FixedMul (trace.dx, frac);
	y = trace.y + FixedMul (trace.dy, frac);
	z = shootz + FixedMul (aimslope, FixedMul(frac, attackrange));

	if (li->frontsector->ceilingpic == skyflatnum)
	{
	    // don't shoot the sky!
	    if (z > li->frontsector->ceilingheight)
		return false;
	    
	    // it's a sky hack wall
	    if	(li->backsector && li->backsector->ceilingpic == skyflatnum)
		return false;		
	}

	// Spawn bullet puffs.
	P_SpawnPuff (x,y,z);
	
	// don't go any farther
	return false;	
    }
    
    // shoot a thing
    th = in->d.thing;
    if (th == shootthing)
	return true;		// can't shoot self
    
    if (!(th->flags&MF_SHOOTABLE))
	return true;		// corpse or something
		
    // check angles to see if the thing can be aimed at
    dist = FixedMul (attackrange, in->frac);
    thingtopslope = FixedDiv (th->z+th->height - shootz , dist);

    if (thingtopslope < aimslope)
	return true;		// shot over the thing

    thingbottomslope = FixedDiv (th->z - shootz, dist);

    if (thingbottomslope > aimslope)
	return true;		// shot under the thing

    
    // hit thing
    // position a bit closer
    frac = in->frac - FixedDiv (10*FRACUNIT,attackrange);

    x = trace.x + FixedMul (trace.dx, frac);
    y = trace.y + FixedMul (trace.dy, frac);
    z = shootz + FixedMul (aimslope, FixedMul(frac, attackrange));

    // Spawn bullet puffs or blod spots,
    // depending on target type.
    if (in->d.thing->flags & MF_NOBLOOD)
	P_SpawnPuff (x,y,z);
    else
	P_SpawnBlood (x,y,z, la_damage);

    if (la_damage)
	P_DamageMobj (th, shootthing, shootthing, la_damage);

    // don't go any farther
    return false;
	
}


//
// P_AimLineAttack
//
fixed_t
P_AimLineAttack
( mobj_t*	t1,
  angle_t	angle,
  fixed_t	distance )
{
    fixed_t	x2;
    fixed_t	y2;
	
    angle >>= ANGLETOFINESHIFT;
    shootthing = t1;
    
    x2 = t1->x + (distance>>FRACBITS)*finecosine[angle];
    y2 = t1->y + (distance>>FRACBITS)*finesine[angle];
    shootz = t1->z + (t1->height>>1) + 8*FRACUNIT;

    // can't shoot outside view angles
    topslope = 100*FRACUNIT/160;	
    bottomslope = -100*FRACUNIT/160;
    
    attackrange = distance;
    linetarget = NULL;
	
    P_PathTraverse ( t1->x, t1->y,
		     x2, y2,
		     PT_ADDLINES|PT_ADDTHINGS,
		     PTR_AimTraverse );
		
    if (linetarget)
	return aimslope;

    return 0;
}
 

//
// P_LineAttack
// If damage == 0, it is just a test trace
// that will leave linetarget set.
//
void
P_LineAttack
( mobj_t*	t1,
  angle_t	angle,
  fixed_t	distance,
  fixed_t	slope,
  int		damage )
{
    fixed_t	x2;
    fixed_t	y2;
	
    angle >>= ANGLETOFINESHIFT;
    shootthing = t1;
    la_damage = damage;
    x2 = t1->x + (distance>>FRACBITS)*finecosine[angle];
    y2 = t1->y + (distance>>FRACBITS)*finesine[angle];
    shootz = t1->z + (t1->height>>1) + 8*FRACUNIT;
    attackrange = distance;
    aimslope = slope;
		
    P_PathTraverse ( t1->x, t1->y,
		     x2, y2,
		     PT_ADDLINES|PT_ADDTHINGS,
		     PTR_ShootTraverse );
}
 


//
// USE LINES
//
mobj_t*		usething;

boolean	PTR_UseTraverse (intercept_t* in)
{
    int		side;
	
    if (!in->d.line->special)
    {
	P_LineOpening (in->d.line);
	if (openrange <= 0)
	{
	    S_StartSound (usething, sfx_noway);
	    
	    // can't use through a wall
	    return false;	
	}
	// not a special line, but keep checking
	return true ;		
    }
	
    side = 0;
    if (P_PointOnLineSide (usething->x, usething->y, in->d.line) == 1)
	side = 1;
    
    //	return false;		// don't use back side
	
    P_UseSpecialLine (usething, in->d.line, side);

    // can't use for than one special line in a row
    return false;
}


//
// P_UseLines
// Looks for special lines in front of the player to activate.
//
void P_UseLines (player_t*	player) 
{
    int		angle;
    fixed_t	x1;
    fixed_t	y1;
    fixed_t	x2;
    fixed_t	y2;
	
    usething = player->mo;
		
    angle = player->mo->angle >> ANGLETOFINESHIFT;

    x1 = player->mo->x;
    y1 = player->mo->y;
    x2 = x1 + (USERANGE>>FRACBITS)*finecosine[angle];
    y2 = y1 + (USERANGE>>FRACBITS)*finesine[angle];
	
    P_PathTraverse ( x1, y1, x2, y2, PT_ADDLINES, PTR_UseTraverse );
}


//
// RADIUS ATTACK
//
mobj_t*		bombsource;
mobj_t*		bombspot;
int		bombdamage;


//
// PIT_RadiusAttack
// "bombsource" is the creature
// that caused the explosion at "bombspot".
//
boolean PIT_RadiusAttack (mobj_t* thing)
{
    fixed_t	dx;
    fixed_t	dy;
    fixed_t	dist;
	
    if (!(thing->flags & MF_SHOOTABLE) )
	return true;

    // Boss spider and cyborg
    // take no damage from concussion.
    if (thing->type == MT_CYBORG
	|| thing->type == MT_SPIDER)
	return true;	
		
    dx = abs(thing->x - bombspot->x);
    dy = abs(thing->y - bombspot->y);
    
    dist = dx>dy ? dx : dy;
    dist = (dist - thing->radius) >> FRACBITS;

    if (dist < 0)
	dist = 0;

    if (dist >= bombdamage)
	return true;	// out of range

    if ( P_CheckSight (thing, bombspot) )
    {
	// must be in direct path
	P_DamageMobj (thing, bombspot, bombsource, bombdamage - dist);
    }
    
    return true;
}


//
// P_RadiusAttack
// Source is the creature that caused the explosion at spot.
//
void
P_RadiusAttack
( mobj_t*	spot,
  mobj_t*	source,
  int		damage )
{
    int		x;
    int		y;
    
    int		xl;
    int		xh;
    int		yl;
    int		yh;
    
    fixed_t	dist;
	
    dist = (damage+MAXRADIUS)<<FRACBITS;
    yh = (spot->y + dist - bmaporgy)>>MAPBLOCKSHIFT;
    yl = (spot->y - dist - bmaporgy)>>MAPBLOCKSHIFT;
    xh = (spot->x + dist - bmaporgx)>>MAPBLOCKSHIFT;
    xl = (spot->x - dist - bmaporgx)>>MAPBLOCKSHIFT;
    bombspot = spot;
    bombsource = source;
    bombdamage = damage;
	
    for (y=yl ; y<=yh ; y++)
	for (x=xl ; x<=xh ; x++)
	    P_BlockThingsIterator (x, y, PIT_RadiusAttack );
}



//
// SECTOR HEIGHT CHANGING
// After modifying a sectors floor or ceiling height,
// call this routine to adjust the positions
// of all things that touch the sector.
//
// If anything doesn't fit anymore, true will be returned.
// If crunch is true, they will take damage
//  as they are being crushed.
// If Crunch is false, you should set the sector height back
//  the way it was and call P_ChangeSector again
//  to undo the changes.
//
boolean		crushchange;
boolean		nofit;


//
// PIT_ChangeSector
//
boolean PIT_ChangeSector (mobj_t*	thing)
{
    mobj_t*	mo;
	
    if (P_ThingHeightClip (thing))
    {
	// keep checking
	return true;
    }
    

    // crunch bodies to giblets
    if (thing->health <= 0)
    {
	P_SetMobjState (thing, S_GIBS);

	thing->flags &= ~MF_SOLID;
	thing->height = 0;
	thing->radius = 0;

	// keep checking
	return true;		
    }

    // crunch dropped items
    if (thing->flags & MF_DROPPED)
    {
	P_RemoveMobj (thing);
	
	// keep checking
	return true;		
    }

    if (! (thing->flags & MF_SHOOTABLE) )
    {
	// assume it is bloody gibs or something
	return true;			
    }
    
    nofit = true;

    if (crushchange && !(leveltime&3) )
    {
	P_DamageMobj(thing,NULL,NULL,10);

	// spray blood in a random direction
	mo = P_SpawnMobj (thing->x,
			  thing->y,
			  thing->z + thing->height/2, MT_BLOOD);
	
	mo->momx = (P_Random() - P_Random ())<<12;
	mo->momy = (P_Random() - P_Random ())<<12;
    }

    // keep checking (crush other things)	
    return true;	
}



//
// P_ChangeSector
//
boolean
P_ChangeSector
( sector_t*	sector,
  boolean	crunch )
{
    int		x;
    int		y;
	
    nofit = false;
    crushchange = crunch;
	
    // re-check heights for all things near the moving sector
    for (x=sector->blockbox[BOXLEFT] ; x<= sector->blockbox[BOXRIGHT] ; x++)
	for (y=sector->blockbox[BOXBOTTOM];y<= sector->blockbox[BOXTOP] ; y++)
	    P_BlockThingsIterator (x, y, PIT_ChangeSector);
	
	
    return nofit;
}