sticking entities to players

[Boss429]

Hey all. I was dabbling a bit in QuakeC trying to make an entity to stick to the player.
Its suppose to be a vehicle that sicks to you when you touch it (simulating you getting in the car) and then lets you drive off...
The sticking part works until your car touches a wall and then the car kind of falls off your player model.

Here's my code:

Code: Select all

void() car_touch;

void() item_vehi =
{
   self.touch = car_touch;
   setmodel(self, "models/car.mdl");
   setsize (self, '0 0 0', '32 32 56');
   StartItem ();
};

void() car_touch =
{
   if (other.classname != "player") //monsters can't drive
      return;

   //self.solid = SOLID_NOT; //make the item not solid
      self.origin = other.origin;
      if ( (self.velocity == VEC_ORIGIN) )
         self.avelocity = VEC_ORIGIN;
   sv_friction = sv_friction * .5;
   sv_stopspeed = sv_stopspeed * 4;
   
};

I tried to remedy this by using the self.solid = SOLID_NOT; line as you can see, but this just made the player drop the entity instantly.
Is there a quick fix for this?
Any help is appreciated.

[r00k]

well off the top of my head, you can set the car's .think function and .nextthink = time + 0.05
and update the car's origin to the player's origin 20 times per sec.

Code: Select all

void() drive_me_crazy =
{
   if (self.movetarget)
   {
      setorigin(self, self.movetarget.origin);
      self.angles = self.movetarget.v_angle;
      self.v_angle = self.movetarget.v_angle;
      self.fixangle = TRUE;

      self.nextthink = time + 0.05;   
   }
};

void() car_touch =
{
   if (other.classname != "player") //monsters can't drive
      return;
   self.movetarget = other;
   self.think = drive_me_crazy;
   self.nextthink = time + 0.05;   
};


of course you also must create some code to release ownership of the car after they get out...

[Error]

if you are using the Darkplaces engine, you can simply use movetype_follow

[Boss429]

Error, thanks for point that out. But how duth one use this movetype_follow?

Here's what I tried:

Code: Select all

void() car_touch;

void() item_vehi =
{
   self.touch = car_touch;
   setmodel(self, "models/car.mdl");
   setsize (self, '0 0 0', '32 32 56');
   self.movetype = MOVETYPE_FOLLOW;
   StartItem ();
};

void() car_touch =
{
   if (other.classname != "player") //monsters can't drive
      return;

   //self.solid = SOLID_NOT; //make the item not solid
        self.aiment = other;
   sv_friction = sv_friction * .5;
   sv_stopspeed = sv_stopspeed * 4;
   
};

am I missing something?

[Spike]

esentually:

Code: Select all

void() movetype_follow_think =
{
 makevectors(self.aiment.angles);
 self.origin = self.aiment.origin + v_forward*self.view_ofs_x +  v_right*self.view_ofs_y + v_up*self.view_ofs_z;
 self.angles = self.v_angle + self.aiment.angles;
};


that is, put the following ent view_ofs units away from the followed origin based on the followed's angles.
you can rotate the followed ent around the owner by changing punchangle too.
or something like that.

note that movetype_follow can be a frame behind, depending on spawn sequence. it is not practically usable on player entities.

[Boss429]

Thanks for the heads up Spike.
I tried your method r00k and it worked great for the most part.
.nextthink = time + 0.05 was too slow so I changed it to .nextthink = time;
Thanks for the help.

[r00k]

maybe try time + 0.001 atleast..

[Urre]

r00k: why? Without nextthink = time; TWIG wouldn't work, for example. Or is it a QW mod we're talking about here, I've heard QW doesn't like entities thinking every frame...

[MauveBib]

r00k: nexthink = time is essentially for this sort of thing, as it means it updates every frame. It won't get stuck in a loop if that's what you're worried about, it just means it updates every frame.

Of course depending on entity order the sticking entity may end up one frame behind, which is a problem I'm having in DiD2.

Any solutions? Other than md3 tagging...

[Wazat]

Mauve: Well, instead of having each individual piece think independently, you can instead have the main core entity do the thinking, and it updates everything all at once (i.e. in its .think or in player post think). When it moves or turns etc, it updates its child pieces. The example below has a parts list as a linked list (instead of a .entity for each possible part):

Code: Select all

// position/angle has changed.  Update all pieces following me
head = self.attachedPart;
while(head != world) {
  head.origin = self.origin + v_forward * head.view_ofs_x + v_right * head.view_ofs.y + v_up * head.view_ofs.z;
  // also do angles, etc

  head = head.attachedPart;
}


Or use MOVETYPE_FOLLOW in DP or another supporting engine, which should presumably keep them fairly effectively attached (not sure how clean it is).

[MauveBib]

wazat: not a bad idea, I'll give it a go. MOVETYPE_FOLLOW has the same issue as .think, it is sometimes a frame behind depending on entity order.