bool P_Thing_Projectile (int tid, AActor *source, int type, const char *type_name, DAngle angle,
double speed, double vspeed, int dest, AActor *forcedest, int gravity, int newtid,
bool leadTarget)
{
int rtn = 0;
PClassActor *kind;
AActor *spot, *mobj, *targ = forcedest;
FActorIterator iterator (tid);
int defflags3;
if (type_name == NULL)
{
kind = P_GetSpawnableType(type);
}
else
{
kind = PClass::FindActor(type_name);
}
if (kind == NULL)
{
return false;
}
// Handle decorate replacements.
kind = kind->GetReplacement();
defflags3 = GetDefaultByType(kind)->flags3;
if ((defflags3 & MF3_ISMONSTER) &&
((dmflags & DF_NO_MONSTERS) || (level.flags2 & LEVEL2_NOMONSTERS)))
return false;
if (tid == 0)
{
spot = source;
}
else
{
spot = iterator.Next();
}
while (spot != NULL)
{
FActorIterator tit (dest);
if (dest == 0 || (targ = tit.Next()))
{
do
{
double z = spot->Z();
if (defflags3 & MF3_FLOORHUGGER)
{
z = ONFLOORZ;
}
else if (defflags3 & MF3_CEILINGHUGGER)
{
z = ONCEILINGZ;
}
else if (z != ONFLOORZ)
{
z -= spot->Floorclip;
}
mobj = Spawn (kind, spot->PosAtZ(z), ALLOW_REPLACE);
if (mobj)
{
mobj->tid = newtid;
mobj->AddToHash ();
P_PlaySpawnSound(mobj, spot);
if (gravity)
{
mobj->flags &= ~MF_NOGRAVITY;
if (!(mobj->flags3 & MF3_ISMONSTER) && gravity == 1)
{
mobj->Gravity = 1./8;
}
}
else
{
mobj->flags |= MF_NOGRAVITY;
}
mobj->target = spot;
if (targ != NULL)
{
DVector3 aim = mobj->Vec3To(targ);
aim.Z += targ->Height / 2;
if (leadTarget && speed > 0 && !targ->Vel.isZero())
{
// Aiming at the target's position some time in the future
// is basically just an application of the law of sines:
// a/sin(A) = b/sin(B)
// Thanks to all those on the notgod phorum for helping me
// with the math. I don't think I would have thought of using
// trig alone had I been left to solve it by myself.
DVector3 tvel = targ->Vel;
if (!(targ->flags & MF_NOGRAVITY) && targ->waterlevel < 3)
{ // If the target is subject to gravity and not underwater,
// assume that it isn't moving vertically. Thanks to gravity,
// even if we did consider the vertical component of the target's
// velocity, we would still miss more often than not.
tvel.Z = 0.0;
if (targ->Vel.X == 0 && targ->Vel.Y == 0)
{
goto nolead;
}
}
double dist = aim.Length();
double targspeed = tvel.Length();
double ydotx = -aim | tvel;
double a = g_acos (clamp (ydotx / targspeed / dist, -1.0, 1.0));
double multiplier = double(pr_leadtarget.Random2())*0.1/255+1.1;
double sinb = -clamp (targspeed*multiplier * g_sin(a) / speed, -1.0, 1.0);
// Use the cross product of two of the triangle's sides to get a
// rotation vector.
DVector3 rv(tvel ^ aim);
// The vector must be normalized.
rv.MakeUnit();
// Now combine the rotation vector with angle b to get a rotation matrix.
DMatrix3x3 rm(rv, g_cos(g_asin(sinb)), sinb);
// And multiply the original aim vector with the matrix to get a
// new aim vector that leads the target.
DVector3 aimvec = rm * aim;
// And make the projectile follow that vector at the desired speed.
mobj->Vel = aimvec * (speed / dist);
mobj->AngleFromVel();
}
else
{
nolead:
mobj->Angles.Yaw = mobj->AngleTo(targ);
mobj->Vel = aim.Resized (speed);
}
if (mobj->flags2 & MF2_SEEKERMISSILE)
{
mobj->tracer = targ;
}
}
else
{
mobj->Angles.Yaw = angle;
mobj->VelFromAngle(speed);
mobj->Vel.Z = vspeed;
}
// Set the missile's speed to reflect the speed it was spawned at.
if (mobj->flags & MF_MISSILE)
{
mobj->Speed = mobj->VelToSpeed();
}
// Hugger missiles don't have any vertical velocity
if (mobj->flags3 & (MF3_FLOORHUGGER|MF3_CEILINGHUGGER))
{
mobj->Vel.Z = 0;
}
if (mobj->flags & MF_SPECIAL)
{
mobj->flags |= MF_DROPPED;
}
if (mobj->flags & MF_MISSILE)
{
if (P_CheckMissileSpawn (mobj, spot->radius))
{
rtn = true;
}
}
else if (!P_TestMobjLocation (mobj))
{
// If this is a monster, subtract it from the total monster
// count, because it already added to it during spawning.
mobj->ClearCounters();
mobj->Destroy ();
}
else
{
// It spawned fine.
rtn = 1;
}
}
} while (dest != 0 && (targ = tit.Next()));
}
spot = iterator.Next();
}
return rtn != 0;
}
// [MC] Was part of P_Thing_Projectile, now its own function for use in ZScript.
// Aims mobj at targ based on speed and targ's velocity.
static void VelIntercept(AActor *targ, AActor *mobj, double speed, bool aimpitch = false, bool oldvel = false, bool leadtarget = true)
{
if (targ == nullptr || mobj == nullptr) return;
DVector3 aim = mobj->Vec3To(targ);
aim.Z += targ->Height / 2;
if (leadtarget && speed > 0 && !targ->Vel.isZero())
{
// Aiming at the target's position some time in the future
// is basically just an application of the law of sines:
// a/sin(A) = b/sin(B)
// Thanks to all those on the notgod phorum for helping me
// with the math. I don't think I would have thought of using
// trig alone had I been left to solve it by myself.
DVector3 tvel = targ->Vel;
if (!(targ->flags & MF_NOGRAVITY) && targ->waterlevel < 3)
{ // If the target is subject to gravity and not underwater,
// assume that it isn't moving vertically. Thanks to gravity,
// even if we did consider the vertical component of the target's
// velocity, we would still miss more often than not.
tvel.Z = 0.0;
if (targ->Vel.X == 0 && targ->Vel.Y == 0)
{
InterceptDefaultAim(mobj, targ, aim, speed);
return;
}
}
double dist = aim.Length();
double targspeed = tvel.Length();
double ydotx = -aim | tvel;
double a = g_acos(clamp(ydotx / targspeed / dist, -1.0, 1.0));
double multiplier = double(pr_leadtarget.Random2())*0.1 / 255 + 1.1;
double sinb = -clamp(targspeed*multiplier * g_sin(a) / speed, -1.0, 1.0);
DVector3 prevel = mobj->Vel;
// Use the cross product of two of the triangle's sides to get a
// rotation vector.
DVector3 rv(tvel ^ aim);
// The vector must be normalized.
rv.MakeUnit();
// Now combine the rotation vector with angle b to get a rotation matrix.
DMatrix3x3 rm(rv, g_cos(g_asin(sinb)), sinb);
// And multiply the original aim vector with the matrix to get a
// new aim vector that leads the target.
DVector3 aimvec = rm * aim;
// And make the projectile follow that vector at the desired speed.
mobj->Vel = aimvec * (speed / dist);
mobj->AngleFromVel();
if (oldvel)
{
mobj->Vel = prevel;
}
if (aimpitch) // [MC] Ripped right out of A_FaceMovementDirection
{
const DVector2 velocity = mobj->Vel.XY();
mobj->Angles.Pitch = -VecToAngle(velocity.Length(), mobj->Vel.Z);
}
}
else
{
InterceptDefaultAim(mobj, targ, aim, speed);
}
}