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p_map.c
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//
// Copyright (C) 1993-1996 Id Software, Inc.
// Copyright (C) 2016-2017 Alexey Khokholov (Nuke.YKT)
//
// 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.
//
// DESCRIPTION:
// Movement, collision handling.
// Shooting and aiming.
//
#include <stdlib.h>
#include "m_misc.h"
#include "i_system.h"
#include "doomdef.h"
#include "p_local.h"
#include "s_sound.h"
// State.
#include "doomstat.h"
#include "r_state.h"
// Data.
#include "sounds.h"
fixed_t tmbbox[4];
mobj_t* tmthing;
int tmflags;
fixed_t tmx;
fixed_t tmy;
// If "floatok" true, move would be ok
// if within "tmfloorz - tmceilingz".
boolean floatok;
fixed_t tmfloorz;
fixed_t tmceilingz;
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];
int numspechit;
//
// TELEPORT MOVE
//
//
// PIT_StompThing
//
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 )
{
// didn't hit it
return true;
}
// don't clip against self
if (thing == tmthing)
return true;
// monsters don't stomp things except on boss level
if ( !tmthing->player && gamemap != 30)
return false;
P_DamageMobj (thing, tmthing, tmthing, 10000);
return true;
}
//
// P_TeleportMove
//
boolean
P_TeleportMove
( mobj_t* thing,
fixed_t x,
fixed_t y )
{
int xl;
int xh;
int yl;
int yh;
int bx;
int 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
//
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
}
// set openrange, opentop, openbottom
P_LineOpening (ld);
// adjust floor / ceiling heights
if (opentop < tmceilingz)
{
tmceilingz = opentop;
ceilingline = ld;
}
if (openbottom > tmfloorz)
tmfloorz = openbottom;
if (lowfloor < tmdropoffz)
tmdropoffz = lowfloor;
// if contacted a special line, add it to the list
if (ld->special)
{
spechit[numspechit] = ld;
numspechit++;
}
return true;
}
//
// PIT_CheckThing
//
boolean PIT_CheckThing (mobj_t* thing)
{
fixed_t blockdist;
boolean solid;
int 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 it
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)
{
// Explode, but do no damage.
// Let players missile other players.
return false;
}
}
if (! (thing->flags & MF_SHOOTABLE) )
{
// didn't do any damage
return !(thing->flags & MF_SOLID);
}
// damage / explode
damage = ((P_Random()%8)+1)*tmthing->info->damage;
P_DamageMobj (thing, tmthing, tmthing->target, damage);
// don't traverse any more
return false;
}
// check for special pickup
if (thing->flags & MF_SPECIAL)
{
solid = thing->flags&MF_SOLID;
if (tmflags&MF_PICKUP)
{
// can remove thing
P_TouchSpecialThing (thing, tmthing);
}
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 )
{
int xl;
int xh;
int yl;
int yh;
int bx;
int 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 unless MF_TELEPORT is set.
//
boolean
P_TryMove
( mobj_t* thing,
fixed_t x,
fixed_t y )
{
fixed_t oldx;
fixed_t oldy;
int side;
int 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 ( !(thing->flags&MF_TELEPORT)
&&tmceilingz - thing->z < thing->height)
return false; // mobj must lower itself to fit
if ( !(thing->flags&MF_TELEPORT)
&& 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_TELEPORT|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, and 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.
//
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;
}
if (thing->ceilingz - thing->floorz < thing->height)
return false;
return true;
}
//
// SLIDE MOVE
// Allows the player to slide along any angled walls.
//
fixed_t bestslidefrac;
fixed_t secondslidefrac;
line_t* bestslideline;
line_t* secondslideline;
mobj_t* slidemo;
fixed_t tmxmove;
fixed_t tmymove;
//
// P_HitSlideLine
// Adjusts the xmove / ymove
// so that the next move will slide along the wall.
//
void P_HitSlideLine (line_t* ld)
{
int side;
angle_t lineangle;
angle_t moveangle;
angle_t deltaangle;
fixed_t movelen;
fixed_t 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
//
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))
{
// don't hit the back side
return true;
}
goto isblocking;
}
// set openrange, opentop, openbottom
P_LineOpening (li);
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
// 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);