ref: 350fb1e60c6761d7171df663035846bacc2b8fde
dir: /src/doom/p_mobj.c/
//
// Copyright(C) 1993-1996 Id Software, Inc.
// Copyright(C) 2005-2014 Simon Howard
//
// 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:
// Moving object handling. Spawn functions.
//
#include <stdio.h>
#include "i_system.h"
#include "z_zone.h"
#include "m_random.h"
#include "doomdef.h"
#include "p_local.h"
#include "sounds.h"
#include "st_stuff.h"
#include "hu_stuff.h"
#include "s_sound.h"
#include "doomstat.h"
void G_PlayerReborn (int player);
void P_SpawnMapThing (mapthing_t* mthing);
//
// P_SetMobjState
// Returns true if the mobj is still present.
//
int test;
// Use a heuristic approach to detect infinite state cycles: Count the number
// of times the loop in P_SetMobjState() executes and exit with an error once
// an arbitrary very large limit is reached.
#define MOBJ_CYCLE_LIMIT 1000000
boolean
P_SetMobjState
( mobj_t* mobj,
statenum_t state )
{
state_t* st;
int cycle_counter = 0;
do
{
if (state == S_NULL)
{
mobj->state = (state_t *) S_NULL;
P_RemoveMobj (mobj);
return false;
}
st = &states[state];
mobj->state = st;
mobj->tics = st->tics;
mobj->sprite = st->sprite;
mobj->frame = st->frame;
// Modified handling.
// Call action functions when the state is set
if (st->action.acp1)
st->action.acp1(mobj);
state = st->nextstate;
if (cycle_counter++ > MOBJ_CYCLE_LIMIT)
{
I_Error("P_SetMobjState: Infinite state cycle detected!");
}
} while (!mobj->tics);
return true;
}
//
// P_ExplodeMissile
//
void P_ExplodeMissile (mobj_t* mo)
{
mo->momx = mo->momy = mo->momz = 0;
P_SetMobjState (mo, mobjinfo[mo->type].deathstate);
mo->tics -= P_Random()&3;
if (mo->tics < 1)
mo->tics = 1;
mo->flags &= ~MF_MISSILE;
if (mo->info->deathsound)
S_StartSound (mo, mo->info->deathsound);
}
//
// P_XYMovement
//
#define STOPSPEED 0x1000
#define FRICTION 0xe800
void P_XYMovement (mobj_t* mo)
{
fixed_t ptryx;
fixed_t ptryy;
player_t* player;
fixed_t xmove;
fixed_t ymove;
if (!mo->momx && !mo->momy)
{
if (mo->flags & MF_SKULLFLY)
{
// the skull slammed into something
mo->flags &= ~MF_SKULLFLY;
mo->momx = mo->momy = mo->momz = 0;
P_SetMobjState (mo, mo->info->spawnstate);
}
return;
}
player = mo->player;
if (mo->momx > MAXMOVE)
mo->momx = MAXMOVE;
else if (mo->momx < -MAXMOVE)
mo->momx = -MAXMOVE;
if (mo->momy > MAXMOVE)
mo->momy = MAXMOVE;
else if (mo->momy < -MAXMOVE)
mo->momy = -MAXMOVE;
xmove = mo->momx;
ymove = mo->momy;
do
{
if (xmove > MAXMOVE/2 || ymove > MAXMOVE/2)
{
ptryx = mo->x + xmove/2;
ptryy = mo->y + ymove/2;
xmove >>= 1;
ymove >>= 1;
}
else
{
ptryx = mo->x + xmove;
ptryy = mo->y + ymove;
xmove = ymove = 0;
}
if (!P_TryMove (mo, ptryx, ptryy))
{
// blocked move
if (mo->player)
{ // try to slide along it
P_SlideMove (mo);
}
else if (mo->flags & MF_MISSILE)
{
// explode a missile
if (ceilingline &&
ceilingline->backsector &&
ceilingline->backsector->ceilingpic == skyflatnum)
{
// Hack to prevent missiles exploding
// against the sky.
// Does not handle sky floors.
P_RemoveMobj (mo);
return;
}
P_ExplodeMissile (mo);
}
else
mo->momx = mo->momy = 0;
}
} while (xmove || ymove);
// slow down
if (player && player->cheats & CF_NOMOMENTUM)
{
// debug option for no sliding at all
mo->momx = mo->momy = 0;
return;
}
if (mo->flags & (MF_MISSILE | MF_SKULLFLY) )
return; // no friction for missiles ever
if (mo->z > mo->floorz)
return; // no friction when airborne
if (mo->flags & MF_CORPSE)
{
// do not stop sliding
// if halfway off a step with some momentum
if (mo->momx > FRACUNIT/4
|| mo->momx < -FRACUNIT/4
|| mo->momy > FRACUNIT/4
|| mo->momy < -FRACUNIT/4)
{
if (mo->floorz != mo->subsector->sector->floorheight)
return;
}
}
if (mo->momx > -STOPSPEED
&& mo->momx < STOPSPEED
&& mo->momy > -STOPSPEED
&& mo->momy < STOPSPEED
&& (!player
|| (player->cmd.forwardmove== 0
&& player->cmd.sidemove == 0 ) ) )
{
// if in a walking frame, stop moving
if ( player&&(unsigned)((player->mo->state - states)- S_PLAY_RUN1) < 4)
P_SetMobjState (player->mo, S_PLAY);
mo->momx = 0;
mo->momy = 0;
}
else
{
mo->momx = FixedMul (mo->momx, FRICTION);
mo->momy = FixedMul (mo->momy, FRICTION);
}
}
//
// P_ZMovement
//
void P_ZMovement (mobj_t* mo)
{
fixed_t dist;
fixed_t delta;
// check for smooth step up
if (mo->player && mo->z < mo->floorz)
{
mo->player->viewheight -= mo->floorz-mo->z;
mo->player->deltaviewheight
= (VIEWHEIGHT - mo->player->viewheight)>>3;
}
// adjust height
mo->z += mo->momz;
if ( mo->flags & MF_FLOAT
&& mo->target)
{
// float down towards target if too close
if ( !(mo->flags & MF_SKULLFLY)
&& !(mo->flags & MF_INFLOAT) )
{
dist = P_AproxDistance (mo->x - mo->target->x,
mo->y - mo->target->y);
delta =(mo->target->z + (mo->height>>1)) - mo->z;
if (delta<0 && dist < -(delta*3) )
mo->z -= FLOATSPEED;
else if (delta>0 && dist < (delta*3) )
mo->z += FLOATSPEED;
}
}
// clip movement
if (mo->z <= mo->floorz)
{
// hit the floor
// Note (id):
// somebody left this after the setting momz to 0,
// kinda useless there.
//
// cph - This was the a bug in the linuxdoom-1.10 source which
// caused it not to sync Doom 2 v1.9 demos. Someone
// added the above comment and moved up the following code. So
// demos would desync in close lost soul fights.
// Note that this only applies to original Doom 1 or Doom2 demos - not
// Final Doom and Ultimate Doom. So we test demo_compatibility *and*
// gamemission. (Note we assume that Doom1 is always Ult Doom, which
// seems to hold for most published demos.)
//
// fraggle - cph got the logic here slightly wrong. There are three
// versions of Doom 1.9:
//
// * The version used in registered doom 1.9 + doom2 - no bounce
// * The version used in ultimate doom - has bounce
// * The version used in final doom - has bounce
//
// So we need to check that this is either retail or commercial
// (but not doom2)
int correct_lost_soul_bounce = gameversion >= exe_ultimate;
if (correct_lost_soul_bounce && mo->flags & MF_SKULLFLY)
{
// the skull slammed into something
mo->momz = -mo->momz;
}
if (mo->momz < 0)
{
if (mo->player
&& mo->momz < -GRAVITY*8)
{
// Squat down.
// Decrease viewheight for a moment
// after hitting the ground (hard),
// and utter appropriate sound.
mo->player->deltaviewheight = mo->momz>>3;
S_StartSound (mo, sfx_oof);
}
mo->momz = 0;
}
mo->z = mo->floorz;
// cph 2001/05/26 -
// See lost soul bouncing comment above. We need this here for bug
// compatibility with original Doom2 v1.9 - if a soul is charging and
// hit by a raising floor this incorrectly reverses its Y momentum.
//
if (!correct_lost_soul_bounce && mo->flags & MF_SKULLFLY)
mo->momz = -mo->momz;
if ( (mo->flags & MF_MISSILE)
&& !(mo->flags & MF_NOCLIP) )
{
P_ExplodeMissile (mo);
return;
}
}
else if (! (mo->flags & MF_NOGRAVITY) )
{
if (mo->momz == 0)
mo->momz = -GRAVITY*2;
else
mo->momz -= GRAVITY;
}
if (mo->z + mo->height > mo->ceilingz)
{
// hit the ceiling
if (mo->momz > 0)
mo->momz = 0;
{
mo->z = mo->ceilingz - mo->height;
}
if (mo->flags & MF_SKULLFLY)
{ // the skull slammed into something
mo->momz = -mo->momz;
}
if ( (mo->flags & MF_MISSILE)
&& !(mo->flags & MF_NOCLIP) )
{
P_ExplodeMissile (mo);
return;
}
}
}
//
// P_NightmareRespawn
//
void
P_NightmareRespawn (mobj_t* mobj)
{
fixed_t x;
fixed_t y;
fixed_t z;
subsector_t* ss;
mobj_t* mo;
mapthing_t* mthing;
x = mobj->spawnpoint.x << FRACBITS;
y = mobj->spawnpoint.y << FRACBITS;
// somthing is occupying it's position?
if (!P_CheckPosition (mobj, x, y) )
return; // no respwan
// spawn a teleport fog at old spot
// because of removal of the body?
mo = P_SpawnMobj (mobj->x,
mobj->y,
mobj->subsector->sector->floorheight , MT_TFOG);
// initiate teleport sound
S_StartSound (mo, sfx_telept);
// spawn a teleport fog at the new spot
ss = R_PointInSubsector (x,y);
mo = P_SpawnMobj (x, y, ss->sector->floorheight , MT_TFOG);
S_StartSound (mo, sfx_telept);
// spawn the new monster
mthing = &mobj->spawnpoint;
// spawn it
if (mobj->info->flags & MF_SPAWNCEILING)
z = ONCEILINGZ;
else
z = ONFLOORZ;
// inherit attributes from deceased one
mo = P_SpawnMobj (x,y,z, mobj->type);
mo->spawnpoint = mobj->spawnpoint;
mo->angle = ANG45 * (mthing->angle/45);
if (mthing->options & MTF_AMBUSH)
mo->flags |= MF_AMBUSH;
mo->reactiontime = 18;
// remove the old monster,
P_RemoveMobj (mobj);
}
//
// P_MobjThinker
//
void P_MobjThinker (mobj_t* mobj)
{
// momentum movement
if (mobj->momx
|| mobj->momy
|| (mobj->flags&MF_SKULLFLY) )
{
P_XYMovement (mobj);
// FIXME: decent NOP/NULL/Nil function pointer please.
if (mobj->thinker.function.acv == (actionf_v) (-1))
return; // mobj was removed
}
if ( (mobj->z != mobj->floorz)
|| mobj->momz )
{
P_ZMovement (mobj);
// FIXME: decent NOP/NULL/Nil function pointer please.
if (mobj->thinker.function.acv == (actionf_v) (-1))
return; // mobj was removed
}
// cycle through states,
// calling action functions at transitions
if (mobj->tics != -1)
{
mobj->tics--;
// you can cycle through multiple states in a tic
if (!mobj->tics)
if (!P_SetMobjState (mobj, mobj->state->nextstate) )
return; // freed itself
}
else
{
// check for nightmare respawn
if (! (mobj->flags & MF_COUNTKILL) )
return;
if (!respawnmonsters)
return;
mobj->movecount++;
if (mobj->movecount < 12*TICRATE)
return;
if ( leveltime&31 )
return;
if (P_Random () > 4)
return;
P_NightmareRespawn (mobj);
}
}
//
// P_SpawnMobj
//
mobj_t*
P_SpawnMobj
( fixed_t x,
fixed_t y,
fixed_t z,
mobjtype_t type )
{
mobj_t* mobj;
state_t* st;
mobjinfo_t* info;
mobj = Z_Malloc (sizeof(*mobj), PU_LEVEL, NULL);
memset (mobj, 0, sizeof (*mobj));
info = &mobjinfo[type];
mobj->type = type;
mobj->info = info;
mobj->x = x;
mobj->y = y;
mobj->radius = info->radius;
mobj->height = info->height;
mobj->flags = info->flags;
mobj->health = info->spawnhealth;
if (gameskill != sk_nightmare)
mobj->reactiontime = info->reactiontime;
mobj->lastlook = P_Random () % MAXPLAYERS;
// do not set the state with P_SetMobjState,
// because action routines can not be called yet
st = &states[info->spawnstate];
mobj->state = st;
mobj->tics = st->tics;
mobj->sprite = st->sprite;
mobj->frame = st->frame;
// set subsector and/or block links
P_SetThingPosition (mobj);
mobj->floorz = mobj->subsector->sector->floorheight;
mobj->ceilingz = mobj->subsector->sector->ceilingheight;
if (z == ONFLOORZ)
mobj->z = mobj->floorz;
else if (z == ONCEILINGZ)
mobj->z = mobj->ceilingz - mobj->info->height;
else
mobj->z = z;
mobj->thinker.function.acp1 = (actionf_p1)P_MobjThinker;
P_AddThinker (&mobj->thinker);
return mobj;
}
//
// P_RemoveMobj
//
mapthing_t itemrespawnque[ITEMQUESIZE];
int itemrespawntime[ITEMQUESIZE];
int iquehead;
int iquetail;
void P_RemoveMobj (mobj_t* mobj)
{
if ((mobj->flags & MF_SPECIAL)
&& !(mobj->flags & MF_DROPPED)
&& (mobj->type != MT_INV)
&& (mobj->type != MT_INS))
{
itemrespawnque[iquehead] = mobj->spawnpoint;
itemrespawntime[iquehead] = leveltime;
iquehead = (iquehead+1)&(ITEMQUESIZE-1);
// lose one off the end?
if (iquehead == iquetail)
iquetail = (iquetail+1)&(ITEMQUESIZE-1);
}
// unlink from sector and block lists
P_UnsetThingPosition (mobj);
// stop any playing sound
S_StopSound (mobj);
// free block
P_RemoveThinker ((thinker_t*)mobj);
}
//
// P_RespawnSpecials
//
void P_RespawnSpecials (void)
{
fixed_t x;
fixed_t y;
fixed_t z;
subsector_t* ss;
mobj_t* mo;
mapthing_t* mthing;
int i;
// only respawn items in deathmatch
if (deathmatch != 2)
return; //
// nothing left to respawn?
if (iquehead == iquetail)
return;
// wait at least 30 seconds
if (leveltime - itemrespawntime[iquetail] < 30*TICRATE)
return;
mthing = &itemrespawnque[iquetail];
x = mthing->x << FRACBITS;
y = mthing->y << FRACBITS;
// spawn a teleport fog at the new spot
ss = R_PointInSubsector (x,y);
mo = P_SpawnMobj (x, y, ss->sector->floorheight , MT_IFOG);
S_StartSound (mo, sfx_itmbk);
// find which type to spawn
for (i=0 ; i< NUMMOBJTYPES ; i++)
{
if (mthing->type == mobjinfo[i].doomednum)
break;
}
if (i >= NUMMOBJTYPES)
{
I_Error("P_RespawnSpecials: Failed to find mobj type with doomednum "
"%d when respawning thing. This would cause a buffer overrun "
"in vanilla Doom", mthing->type);
}
// spawn it
if (mobjinfo[i].flags & MF_SPAWNCEILING)
z = ONCEILINGZ;
else
z = ONFLOORZ;
mo = P_SpawnMobj (x,y,z, i);
mo->spawnpoint = *mthing;
mo->angle = ANG45 * (mthing->angle/45);
// pull it from the que
iquetail = (iquetail+1)&(ITEMQUESIZE-1);
}
//
// P_SpawnPlayer
// Called when a player is spawned on the level.
// Most of the player structure stays unchanged
// between levels.
//
void P_SpawnPlayer (mapthing_t* mthing)
{
player_t* p;
fixed_t x;
fixed_t y;
fixed_t z;
mobj_t* mobj;
int i;
if (mthing->type == 0)
{
return;
}
// not playing?
if (!playeringame[mthing->type-1])
return;
p = &players[mthing->type-1];
if (p->playerstate == PST_REBORN)
G_PlayerReborn (mthing->type-1);
x = mthing->x << FRACBITS;
y = mthing->y << FRACBITS;
z = ONFLOORZ;
mobj = P_SpawnMobj (x,y,z, MT_PLAYER);
// set color translations for player sprites
if (mthing->type > 1)
mobj->flags |= (mthing->type-1)<<MF_TRANSSHIFT;
mobj->angle = ANG45 * (mthing->angle/45);
mobj->player = p;
mobj->health = p->health;
p->mo = mobj;
p->playerstate = PST_LIVE;
p->refire = 0;
p->message = NULL;
p->damagecount = 0;
p->bonuscount = 0;
p->extralight = 0;
p->fixedcolormap = 0;
p->viewheight = VIEWHEIGHT;
// setup gun psprite
P_SetupPsprites (p);
// give all cards in death match mode
if (deathmatch)
for (i=0 ; i<NUMCARDS ; i++)
p->cards[i] = true;
if (mthing->type-1 == consoleplayer)
{
// wake up the status bar
ST_Start ();
// wake up the heads up text
HU_Start ();
}
}
//
// P_SpawnMapThing
// The fields of the mapthing should
// already be in host byte order.
//
void P_SpawnMapThing (mapthing_t* mthing)
{
int i;
int bit;
mobj_t* mobj;
fixed_t x;
fixed_t y;
fixed_t z;
// count deathmatch start positions
if (mthing->type == 11)
{
if (deathmatch_p < &deathmatchstarts[10])
{
memcpy (deathmatch_p, mthing, sizeof(*mthing));
deathmatch_p++;
}
return;
}
if (mthing->type <= 0)
{
// Thing type 0 is actually "player -1 start".
// For some reason, Vanilla Doom accepts/ignores this.
return;
}
// check for players specially
if (mthing->type <= 4)
{
// save spots for respawning in network games
playerstarts[mthing->type-1] = *mthing;
playerstartsingame[mthing->type-1] = true;
if (!deathmatch)
P_SpawnPlayer (mthing);
return;
}
// check for appropriate skill level
if (!netgame && (mthing->options & 16) )
return;
if (gameskill == sk_baby)
bit = 1;
else if (gameskill == sk_nightmare)
bit = 4;
else
bit = 1<<(gameskill-1);
if (!(mthing->options & bit) )
return;
// find which type to spawn
for (i=0 ; i< NUMMOBJTYPES ; i++)
if (mthing->type == mobjinfo[i].doomednum)
break;
if (i==NUMMOBJTYPES)
I_Error ("P_SpawnMapThing: Unknown type %i at (%i, %i)",
mthing->type,
mthing->x, mthing->y);
// don't spawn keycards and players in deathmatch
if (deathmatch && mobjinfo[i].flags & MF_NOTDMATCH)
return;
// don't spawn any monsters if -nomonsters
if (nomonsters
&& ( i == MT_SKULL
|| (mobjinfo[i].flags & MF_COUNTKILL)) )
{
return;
}
// spawn it
x = mthing->x << FRACBITS;
y = mthing->y << FRACBITS;
if (mobjinfo[i].flags & MF_SPAWNCEILING)
z = ONCEILINGZ;
else
z = ONFLOORZ;
mobj = P_SpawnMobj (x,y,z, i);
mobj->spawnpoint = *mthing;
if (mobj->tics > 0)
mobj->tics = 1 + (P_Random () % mobj->tics);
if (mobj->flags & MF_COUNTKILL)
totalkills++;
if (mobj->flags & MF_COUNTITEM)
totalitems++;
mobj->angle = ANG45 * (mthing->angle/45);
if (mthing->options & MTF_AMBUSH)
mobj->flags |= MF_AMBUSH;
}
//
// GAME SPAWN FUNCTIONS
//
//
// P_SpawnPuff
//
void
P_SpawnPuff
( fixed_t x,
fixed_t y,
fixed_t z )
{
mobj_t* th;
z += (P_SubRandom() << 10);
th = P_SpawnMobj (x,y,z, MT_PUFF);
th->momz = FRACUNIT;
th->tics -= P_Random()&3;
if (th->tics < 1)
th->tics = 1;
// don't make punches spark on the wall
if (attackrange == MELEERANGE)
P_SetMobjState (th, S_PUFF3);
}
//
// P_SpawnBlood
//
void
P_SpawnBlood
( fixed_t x,
fixed_t y,
fixed_t z,
int damage )
{
mobj_t* th;
z += (P_SubRandom() << 10);
th = P_SpawnMobj (x,y,z, MT_BLOOD);
th->momz = FRACUNIT*2;
th->tics -= P_Random()&3;
if (th->tics < 1)
th->tics = 1;
if (damage <= 12 && damage >= 9)
P_SetMobjState (th,S_BLOOD2);
else if (damage < 9)
P_SetMobjState (th,S_BLOOD3);
}
//
// P_CheckMissileSpawn
// Moves the missile forward a bit
// and possibly explodes it right there.
//
void P_CheckMissileSpawn (mobj_t* th)
{
th->tics -= P_Random()&3;
if (th->tics < 1)
th->tics = 1;
// move a little forward so an angle can
// be computed if it immediately explodes
th->x += (th->momx>>1);
th->y += (th->momy>>1);
th->z += (th->momz>>1);
if (!P_TryMove (th, th->x, th->y))
P_ExplodeMissile (th);
}
// Certain functions assume that a mobj_t pointer is non-NULL,
// causing a crash in some situations where it is NULL. Vanilla
// Doom did not crash because of the lack of proper memory
// protection. This function substitutes NULL pointers for
// pointers to a dummy mobj, to avoid a crash.
mobj_t *P_SubstNullMobj(mobj_t *mobj)
{
if (mobj == NULL)
{
static mobj_t dummy_mobj;
dummy_mobj.x = 0;
dummy_mobj.y = 0;
dummy_mobj.z = 0;
dummy_mobj.flags = 0;
mobj = &dummy_mobj;
}
return mobj;
}
//
// P_SpawnMissile
//
mobj_t*
P_SpawnMissile
( mobj_t* source,
mobj_t* dest,
mobjtype_t type )
{
mobj_t* th;
angle_t an;
int dist;
th = P_SpawnMobj (source->x,
source->y,
source->z + 4*8*FRACUNIT, type);
if (th->info->seesound)
S_StartSound (th, th->info->seesound);
th->target = source; // where it came from
an = R_PointToAngle2 (source->x, source->y, dest->x, dest->y);
// fuzzy player
if (dest->flags & MF_SHADOW)
an += P_SubRandom() << 20;
th->angle = an;
an >>= ANGLETOFINESHIFT;
th->momx = FixedMul (th->info->speed, finecosine[an]);
th->momy = FixedMul (th->info->speed, finesine[an]);
dist = P_AproxDistance (dest->x - source->x, dest->y - source->y);
dist = dist / th->info->speed;
if (dist < 1)
dist = 1;
th->momz = (dest->z - source->z) / dist;
P_CheckMissileSpawn (th);
return th;
}
//
// P_SpawnPlayerMissile
// Tries to aim at a nearby monster
//
void
P_SpawnPlayerMissile
( mobj_t* source,
mobjtype_t type )
{
mobj_t* th;
angle_t an;
fixed_t x;
fixed_t y;
fixed_t z;
fixed_t slope;
// see which target is to be aimed at
an = source->angle;
slope = P_AimLineAttack (source, an, 16*64*FRACUNIT);
if (!linetarget)
{
an += 1<<26;
slope = P_AimLineAttack (source, an, 16*64*FRACUNIT);
if (!linetarget)
{
an -= 2<<26;
slope = P_AimLineAttack (source, an, 16*64*FRACUNIT);
}
if (!linetarget)
{
an = source->angle;
slope = 0;
}
}
x = source->x;
y = source->y;
z = source->z + 4*8*FRACUNIT;
th = P_SpawnMobj (x,y,z, type);
if (th->info->seesound)
S_StartSound (th, th->info->seesound);
th->target = source;
th->angle = an;
th->momx = FixedMul( th->info->speed,
finecosine[an>>ANGLETOFINESHIFT]);
th->momy = FixedMul( th->info->speed,
finesine[an>>ANGLETOFINESHIFT]);
th->momz = FixedMul( th->info->speed, slope);
P_CheckMissileSpawn (th);
}