Added VelIntercept.

- Uses the same code as Thing_ProjectileIntercept to aim and move the projectile.
  - targ: The actor the caller will aim at.
  - speed: Used for calculating the new angle/pitch and adjusts the speed accordingly. Default is -1 (current speed).
  - aimpitch: If true, aims the pitch in the travelling direction. Default is true.
  - oldvel: If true, does not replace the velocity with the specified speed. Default is false.

- Split the code from Thing_ProjectileIntercept and have that function call VelIntercept.
This commit is contained in:
Major Cooke 2018-09-24 10:59:37 -05:00 committed by Christoph Oelckers
parent 849d110f10
commit 6a8b0df4ba
2 changed files with 83 additions and 50 deletions

View file

@ -163,6 +163,85 @@ bool P_Thing_Move (int tid, AActor *source, int mapspot, bool fog)
return false;
}
// [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.
void VelIntercept(AActor *targ, AActor *mobj, double speed, bool aimpitch = false, bool oldvel = false)
{
if (targ == nullptr || mobj == nullptr) return;
if (speed > 0 && !targ->Vel.isZero())
{
DVector3 aim = mobj->Vec3To(targ);
aim.Z += targ->Height / 2;
// 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.
bool nolead = false;
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;
nolead = !!(targ->Vel.X == 0 && targ->Vel.Y == 0);
}
if (!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);
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
{
mobj->Angles.Yaw = mobj->AngleTo(targ);
mobj->Vel = aim.Resized(speed);
}
}
}
DEFINE_ACTION_FUNCTION(AActor, VelIntercept)
{
PARAM_SELF_PROLOGUE(AActor);
PARAM_OBJECT_NOT_NULL(targ, AActor);
PARAM_FLOAT_DEF(speed);
PARAM_BOOL_DEF(aimpitch);
PARAM_BOOL_DEF(oldvel);
if (speed < 0) speed = self->Speed;
VelIntercept(targ, self, speed, aimpitch, oldvel);
return 0;
}
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)
@ -244,58 +323,11 @@ bool P_Thing_Projectile (int tid, AActor *source, int type, const char *type_nam
}
mobj->target = spot;
if (targ != NULL)
if (targ != nullptr)
{
DVector3 aim = mobj->Vec3To(targ);
aim.Z += targ->Height / 2;
if (leadTarget && speed > 0 && !targ->Vel.isZero())
if (leadTarget)
{
// 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);
VelIntercept(targ, mobj, speed);
}
if (mobj->flags2 & MF2_SEEKERMISSILE)
{

View file

@ -685,6 +685,7 @@ class Actor : Thinker native
native clearscope vector2 Vec2Angle(double length, double angle, bool absolute = false) const;
native clearscope vector2 Vec2Offset(double x, double y, bool absolute = false) const;
native clearscope vector3 Vec2OffsetZ(double x, double y, double atz, bool absolute = false) const;
native void VelIntercept(Actor targ, double speed = -1, bool aimpitch = true, bool oldvel = false);
native void VelFromAngle(double speed = 0, double angle = 0);
native void Vel3DFromAngle(double speed, double angle, double pitch);
native void Thrust(double speed = 0, double angle = 0);