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p_map.c
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p_map.c
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//
// Copyright (C) 1993-1996 Id Software, Inc.
// Copyright (C) 2023-2024 Frenkel Smeijers
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
//
// P_map.c
#include "doomdef.h"
#include "p_local.h"
#include "soundst.h"
/*
===============================================================================
NOTES:
===============================================================================
*/
/*
===============================================================================
mobj_t NOTES
mobj_ts are used to tell the refresh where to draw an image, tell the world simulation when objects are contacted, and tell the sound driver how to position a sound.
The refresh uses the next and prev links to follow lists of things in sectors as they are being drawn. The sprite, frame, and angle elements determine which patch_t is used to draw the sprite if it is visible. The sprite and frame values are allmost allways set from state_t structures. The statescr.exe utility generates the states.h and states.c files that contain the sprite/frame numbers from the statescr.txt source file. The xyz origin point represents a point at the bottom middle of the sprite (between the feet of a biped). This is the default origin position for patch_ts grabbed with lumpy.exe. A walking creature will have its z equal to the floor it is standing on.
The sound code uses the x,y, and subsector fields to do stereo positioning of any sound effited by the mobj_t.
The play simulation uses the blocklinks, x,y,z, radius, height to determine when mobj_ts are touching each other, touching lines in the map, or hit by trace lines (gunshots, lines of sight, etc). The mobj_t->flags element has various bit flags used by the simulation.
Every mobj_t is linked into a single sector based on it's origin coordinates.
The subsector_t is found with R_PointInSubsector(x,y), and the sector_t can be found with subsector->sector. The sector links are only used by the rendering code, the play simulation does not care about them at all.
Any mobj_t that needs to be acted upon be something else in the play world (block movement, be shot, etc) will also need to be linked into the blockmap. If the thing has the MF_NOBLOCK flag set, it will not use the block links. It can still interact with other things, but only as the instigator (missiles will run into other things, but nothing can run into a missile). Each block in the grid is 128*128 units, and knows about every line_t that it contains a piece of, and every interactable mobj_t that has it's origin contained.
A valid mobj_t is a mobj_t that has the proper subsector_t filled in for it's xy coordinates and is linked into the subsector's sector or has the MF_NOSECTOR flag set (the subsector_t needs to be valid even if MF_NOSECTOR is set), and is linked into a blockmap block or has the MF_NOBLOCKMAP flag set. Links should only be modified by the P_[Un]SetThingPosition () functions. Do not change the MF_NO? flags while a thing is valid.
===============================================================================
*/
static fixed_t tmbbox[4];
static mobj_t *tmthing;
static int32_t tmflags;
static fixed_t tmx, tmy;
boolean floatok; // if true, move would be ok if
// within tmfloorz - tmceilingz
fixed_t tmfloorz;
static fixed_t tmceilingz;
static fixed_t tmdropoffz;
// keep track of the line that lowers the ceiling, so missiles don't explode
// against sky hack walls
line_t *ceilingline;
// keep track of special lines as they are hit, but don't process them
// until the move is proven valid
#define MAXSPECIALCROSS 8
line_t *spechit[MAXSPECIALCROSS];
int32_t numspechit;
/*
===============================================================================
TELEPORT MOVE
===============================================================================
*/
/*
==================
=
= PIT_StompThing
=
==================
*/
static boolean PIT_StompThing (mobj_t *thing)
{
fixed_t blockdist;
if (!(thing->flags & MF_SHOOTABLE) )
return true;
blockdist = thing->radius + tmthing->radius;
if ( abs(thing->x - tmx) >= blockdist || abs(thing->y - tmy) >= blockdist )
return true; // didn't hit it
if (thing == tmthing)
return true; // don't clip against self
if ( !tmthing->player && gamemap != 30)
return false; // monsters don't stomp things except on boss level
P_DamageMobj (thing, tmthing, tmthing, 10000);
return true;
}
/*
===================
=
= P_TeleportMove
=
===================
*/
boolean P_TeleportMove (mobj_t *thing, fixed_t x, fixed_t y)
{
int32_t xl,xh,yl,yh,bx,by;
subsector_t *newsubsec;
//
// kill anything occupying the position
//
tmthing = thing;
tmflags = thing->flags;
tmx = x;
tmy = y;
tmbbox[BOXTOP] = y + tmthing->radius;
tmbbox[BOXBOTTOM] = y - tmthing->radius;
tmbbox[BOXRIGHT] = x + tmthing->radius;
tmbbox[BOXLEFT] = x - tmthing->radius;
newsubsec = R_PointInSubsector (x,y);
ceilingline = NULL;
//
// the base floor / ceiling is from the subsector that contains the
// point. Any contacted lines the step closer together will adjust them
//
tmfloorz = tmdropoffz = newsubsec->sector->floorheight;
tmceilingz = newsubsec->sector->ceilingheight;
validcount++;
numspechit = 0;
//
// stomp on any things contacted
//
xl = (tmbbox[BOXLEFT] - bmaporgx - MAXRADIUS)>>MAPBLOCKSHIFT;
xh = (tmbbox[BOXRIGHT] - bmaporgx + MAXRADIUS)>>MAPBLOCKSHIFT;
yl = (tmbbox[BOXBOTTOM] - bmaporgy - MAXRADIUS)>>MAPBLOCKSHIFT;
yh = (tmbbox[BOXTOP] - bmaporgy + MAXRADIUS)>>MAPBLOCKSHIFT;
for (bx=xl ; bx<=xh ; bx++)
for (by=yl ; by<=yh ; by++)
if (!P_BlockThingsIterator(bx,by,PIT_StompThing))
return false;
//
// the move is ok, so link the thing into its new position
//
P_UnsetThingPosition (thing);
thing->floorz = tmfloorz;
thing->ceilingz = tmceilingz;
thing->x = x;
thing->y = y;
P_SetThingPosition (thing);
return true;
}
/*
===============================================================================
MOVEMENT ITERATOR FUNCTIONS
===============================================================================
*/
/*
==================
=
= PIT_CheckLine
=
= Adjusts tmfloorz and tmceilingz as lines are contacted
==================
*/
static boolean PIT_CheckLine(line_t *ld)
{
if (tmbbox[BOXRIGHT] <= ld->bbox[BOXLEFT]
|| tmbbox[BOXLEFT] >= ld->bbox[BOXRIGHT]
|| tmbbox[BOXTOP] <= ld->bbox[BOXBOTTOM]
|| tmbbox[BOXBOTTOM] >= ld->bbox[BOXTOP] )
return true;
if (P_BoxOnLineSide(tmbbox, ld) != -1)
return true;
// a line has been hit
/*
=
= The moving thing's destination position will cross the given line.
= If this should not be allowed, return false.
= If the line is special, keep track of it to process later if the move
= is proven ok. NOTE: specials are NOT sorted by order, so two special lines
= that are only 8 pixels apart could be crossed in either order.
*/
if (!ld->backsector)
return false; // one sided line
if (!(tmthing->flags & MF_MISSILE) )
{
if ( ld->flags & ML_BLOCKING )
return false; // explicitly blocking everything
if ( !tmthing->player && ld->flags & ML_BLOCKMONSTERS )
return false; // block monsters only
}
P_LineOpening (ld); // set openrange, opentop, openbottom
// adjust floor / ceiling heights
if (opentop < tmceilingz)
{
tmceilingz = opentop;
ceilingline = ld;
}
if (openbottom > tmfloorz)
tmfloorz = openbottom;
if (lowfloor < tmdropoffz)
tmdropoffz = lowfloor;
if (ld->special)
{ // if contacted a special line, add it to the list
spechit[numspechit] = ld;
numspechit++;
}
return true;
}
/*
==================
=
= PIT_CheckThing
=
==================
*/
static boolean PIT_CheckThing (mobj_t *thing)
{
fixed_t blockdist;
boolean solid;
int32_t damage;
if (!(thing->flags & (MF_SOLID|MF_SPECIAL|MF_SHOOTABLE) ))
return true;
blockdist = thing->radius+tmthing->radius;
if (abs(thing->x-tmx) >= blockdist || abs(thing->y-tmy) >= blockdist)
{ // didn't hit thing
return true;
}
// don't clip against self
if (thing == tmthing)
return true;
//
// check for skulls slamming into things
//
if (tmthing->flags & MF_SKULLFLY)
{
damage = ((P_Random()%8)+1)*tmthing->info->damage;
P_DamageMobj (thing, tmthing, tmthing, damage);
tmthing->flags &= ~MF_SKULLFLY;
tmthing->momx = tmthing->momy = tmthing->momz = 0;
P_SetMobjState (tmthing, tmthing->info->spawnstate);
return false; // stop moving
}
//
// missiles can hit other things
//
if (tmthing->flags & MF_MISSILE)
{
// see if it went over / under
if (tmthing->z > thing->z + thing->height)
return true; // overhead
if (tmthing->z+tmthing->height < thing->z)
return true; // underneath
if (tmthing->target && (tmthing->target->type == thing->type ||
(tmthing->target->type == MT_KNIGHT && thing->type == MT_BRUISER)||
(tmthing->target->type == MT_BRUISER && thing->type == MT_KNIGHT) ) )
{ // Don't hit same species as originator
if (thing == tmthing->target)
return true;
if (thing->type != MT_PLAYER)
return false; // explode, but do no damage
// let players missile other players
}
if (! (thing->flags&MF_SHOOTABLE) )
return !(thing->flags & MF_SOLID); // didn't do any damage
// damage / explode
damage = ((P_Random()%8)+1)*tmthing->info->damage;
P_DamageMobj (thing, tmthing, tmthing->target, damage);
return false; // don't traverse any more
}
//
// check for special pickup
//
if (thing->flags & MF_SPECIAL)
{
solid = thing->flags&MF_SOLID;
if (tmflags&MF_PICKUP)
P_TouchSpecialThing (thing, tmthing); // can remove thing
return !solid;
}
return !(thing->flags & MF_SOLID);
}
/*
===============================================================================
MOVEMENT CLIPPING
===============================================================================
*/
/*
==================
=
= P_CheckPosition
=
= This is purely informative, nothing is modified (except things picked up)
in:
a mobj_t (can be valid or invalid)
a position to be checked (doesn't need to be related to the mobj_t->x,y)
during:
special things are touched if MF_PICKUP
early out on solid lines?
out:
newsubsec
floorz
ceilingz
tmdropoffz the lowest point contacted (monsters won't move to a dropoff)
speciallines[]
numspeciallines
==================
*/
boolean P_CheckPosition (mobj_t *thing, fixed_t x, fixed_t y)
{
int32_t xl,xh,yl,yh,bx,by;
subsector_t *newsubsec;
tmthing = thing;
tmflags = thing->flags;
tmx = x;
tmy = y;
tmbbox[BOXTOP] = y + tmthing->radius;
tmbbox[BOXBOTTOM] = y - tmthing->radius;
tmbbox[BOXRIGHT] = x + tmthing->radius;
tmbbox[BOXLEFT] = x - tmthing->radius;
newsubsec = R_PointInSubsector (x,y);
ceilingline = NULL;
//
// the base floor / ceiling is from the subsector that contains the
// point. Any contacted lines the step closer together will adjust them
//
tmfloorz = tmdropoffz = newsubsec->sector->floorheight;
tmceilingz = newsubsec->sector->ceilingheight;
validcount++;
numspechit = 0;
if ( tmflags & MF_NOCLIP )
return true;
//
// check things first, possibly picking things up
// the bounding box is extended by MAXRADIUS because mobj_ts are grouped
// into mapblocks based on their origin point, and can overlap into adjacent
// blocks by up to MAXRADIUS units
//
xl = (tmbbox[BOXLEFT] - bmaporgx - MAXRADIUS)>>MAPBLOCKSHIFT;
xh = (tmbbox[BOXRIGHT] - bmaporgx + MAXRADIUS)>>MAPBLOCKSHIFT;
yl = (tmbbox[BOXBOTTOM] - bmaporgy - MAXRADIUS)>>MAPBLOCKSHIFT;
yh = (tmbbox[BOXTOP] - bmaporgy + MAXRADIUS)>>MAPBLOCKSHIFT;
for (bx=xl ; bx<=xh ; bx++)
for (by=yl ; by<=yh ; by++)
if (!P_BlockThingsIterator(bx,by,PIT_CheckThing))
return false;
//
// check lines
//
xl = (tmbbox[BOXLEFT] - bmaporgx)>>MAPBLOCKSHIFT;
xh = (tmbbox[BOXRIGHT] - bmaporgx)>>MAPBLOCKSHIFT;
yl = (tmbbox[BOXBOTTOM] - bmaporgy)>>MAPBLOCKSHIFT;
yh = (tmbbox[BOXTOP] - bmaporgy)>>MAPBLOCKSHIFT;
for (bx=xl ; bx<=xh ; bx++)
for (by=yl ; by<=yh ; by++)
if (!P_BlockLinesIterator (bx,by,PIT_CheckLine))
return false;
return true;
}
/*
===================
=
= P_TryMove
=
= Attempt to move to a new position, crossing special lines
=
===================
*/
boolean P_TryMove (mobj_t *thing, fixed_t x, fixed_t y)
{
fixed_t oldx, oldy;
int32_t side, oldside;
line_t *ld;
floatok = false;
if (!P_CheckPosition (thing, x, y))
return false; // solid wall or thing
if ( !(thing->flags & MF_NOCLIP) )
{
if (tmceilingz - tmfloorz < thing->height)
return false; // doesn't fit
floatok = true;
if (tmceilingz - thing->z < thing->height)
return false; // mobj must lower itself to fit
if (tmfloorz - thing->z > 24*FRACUNIT )
return false; // too big a step up
if ( !(thing->flags&(MF_DROPOFF|MF_FLOAT))
&& tmfloorz - tmdropoffz > 24*FRACUNIT )
return false; // don't stand over a dropoff
}
//
// the move is ok, so link the thing into its new position
//
P_UnsetThingPosition (thing);
oldx = thing->x;
oldy = thing->y;
thing->floorz = tmfloorz;
thing->ceilingz = tmceilingz;
thing->x = x;
thing->y = y;
P_SetThingPosition (thing);
//
// if any special lines were hit, do the effect
//
if (!(thing->flags & MF_NOCLIP))
while (numspechit--)
{
// see if the line was crossed
ld = spechit[numspechit];
side = P_PointOnLineSide (thing->x, thing->y, ld);
oldside = P_PointOnLineSide (oldx, oldy, ld);
if (side != oldside)
{
if (ld->special)
P_CrossSpecialLine (ld-lines, oldside, thing);
}
}
return true;
}
/*
==================
=
= P_ThingHeightClip
=
= Takes a valid thing and adjusts the thing->floorz, thing->ceilingz,
= anf possibly thing->z
=
= This is called for all nearby monsters whenever a sector changes height
=
= If the thing doesn't fit, the z will be set to the lowest value and
= false will be returned
==================
*/
static boolean P_ThingHeightClip (mobj_t *thing)
{
boolean onfloor;
onfloor = (thing->z == thing->floorz);
P_CheckPosition (thing, thing->x, thing->y);
// what about stranding a monster partially off an edge?
thing->floorz = tmfloorz;
thing->ceilingz = tmceilingz;
if (onfloor)
// walking monsters rise and fall with the floor
thing->z = thing->floorz;
else
{ // don't adjust a floating monster unless forced to
if (thing->z+thing->height > thing->ceilingz)
thing->z = thing->ceilingz - thing->height;
}
return thing->ceilingz - thing->floorz >= thing->height;
}
/*
==============================================================================
SLIDE MOVE
Allows the player to slide along any angled walls
==============================================================================
*/
static fixed_t bestslidefrac, secondslidefrac;
static line_t *bestslideline, *secondslideline;
static mobj_t *slidemo;
static fixed_t tmxmove, tmymove;
/*
==================
=
= P_HitSlideLine
=
= Adjusts the xmove / ymove so that the next move will slide along the wall
==================
*/
static void P_HitSlideLine (line_t *ld)
{
int32_t side;
angle_t lineangle, moveangle, deltaangle;
fixed_t movelen, newlen;
if (ld->slopetype == ST_HORIZONTAL)
{
tmymove = 0;
return;
}
if (ld->slopetype == ST_VERTICAL)
{
tmxmove = 0;
return;
}
side = P_PointOnLineSide (slidemo->x, slidemo->y, ld);
lineangle = R_PointToAngle2 (0,0, ld->dx, ld->dy);
if (side == 1)
lineangle += ANG180;
moveangle = R_PointToAngle2 (0,0, tmxmove, tmymove);
deltaangle = moveangle-lineangle;
if (deltaangle > ANG180)
deltaangle += ANG180;
// I_Error ("SlideLine: ang>ANG180");
lineangle >>= ANGLETOFINESHIFT;
deltaangle >>= ANGLETOFINESHIFT;
movelen = P_AproxDistance (tmxmove, tmymove);
newlen = FixedMul (movelen, finecosine[deltaangle]);
tmxmove = FixedMul (newlen, finecosine[lineangle]);
tmymove = FixedMul (newlen, finesine[lineangle]);
}
/*
==============
=
= PTR_SlideTraverse
=
==============
*/
static boolean PTR_SlideTraverse (intercept_t *in)
{
line_t *li;
if (!in->isaline)
I_Error ("PTR_SlideTraverse: not a line?");
li = in->d.line;
if ( ! (li->flags & ML_TWOSIDED) )
{
if (P_PointOnLineSide (slidemo->x, slidemo->y, li))
return true; // don't hit the back side
goto isblocking;
}
P_LineOpening (li); // set openrange, opentop, openbottom
if (openrange < slidemo->height)
goto isblocking; // doesn't fit
if (opentop - slidemo->z < slidemo->height)
goto isblocking; // mobj is too high
if (openbottom - slidemo->z > 24*FRACUNIT )
goto isblocking; // too big a step up
return true; // this line doesn't block movement
// 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, leady;
fixed_t trailx, traily;
fixed_t newx, newy;
int32_t 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;
}
bestslidefrac -= 0x800; // fudge a bit to make sure it doesn't hit
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
//
bestslidefrac = FRACUNIT-(bestslidefrac+0x800); // remainder
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)
static mobj_t *shootthing;
static fixed_t shootz; // height if not aiming up or down
// ???: use slope for monsters?
static int32_t la_damage;
fixed_t attackrange;
static fixed_t aimslope;
extern fixed_t topslope, bottomslope; // slopes to top and bottom of target
/*
===============================================================================
=
= PTR_AimTraverse
=
= Sets linetaget and aimslope when a target is aimed at
===============================================================================
*/
static boolean PTR_AimTraverse (intercept_t *in)
{
line_t *li;
mobj_t *th;
fixed_t slope, thingtopslope, 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;
}
return topslope > bottomslope;
}
//
// 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
=
==============================================================================
*/
static boolean PTR_ShootTraverse (intercept_t *in)
{
fixed_t x,y,z;
fixed_t frac;
line_t *li;
mobj_t *th;
fixed_t slope;
fixed_t dist;
fixed_t thingtopslope, 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;
}
return true; // shot continues
//
// 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)
{
if (z > li->frontsector->ceilingheight)
return false; // don't shoot the sky!
if (li->backsector && li->backsector->ceilingpic == skyflatnum)
return false; // it's a sky hack wall
}
P_SpawnPuff (x,y,z);
return false; // don't go any farther
}
//
// 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);
return false; // don't go any farther
}
/*
=================
=
= P_AimLineAttack
=
=================
*/
fixed_t P_AimLineAttack (mobj_t *t1, angle_t angle, fixed_t distance)
{
fixed_t x2, 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;
topslope = 100*FRACUNIT/160; // can't shoot outside view angles
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;
}