Hello,


I have scripted a simple turret that can shoot at arbitrary targets.
The turret itself can only be rotated about the Z axis (pan). Its barrel can only be rotatet about the Y axis (tilt).

The script works fine as long as the turret is located on a plane floor.
However if it is standing on a wall or a ceiling it doesn't work anymore.

I know how to rotate the turret about its local axes; what i don't know is:
How do I calculate the direction vector accordingly, so that the turret can be rotated to its target (while being arbitrary oriented)?


Any help is appreciated.

Maybe you could post the code you created for turning the turret around his own axis combined with the rotation part of the turret relative to the target.
The error could be occuring within the code for turning the model around his own axis, you never know

Thanks in progress

Frazzle

Here is the code:

Code:

---

define barrel_handle, skill1;

action ent_turret
{
	my.barrel_handle = handle(ent_create("turret_barrel.mdl", my.x, NULL));
	
	while(my) {
		
		you = ptr_for_handle(my.barrel_handle);
		
		var  vec_to_ent[3];
		var  ang_to_ent[3];
		
		// get the direction vector turret->camera and its angles
		vec_diff(vec_to_ent, camera.x, my.x); 
		vec_to_angle(ang_to_ent, vec_to_ent); 
		
		// first rotate the turret's body
		ang_rotate(my.pan, vector(ang(ang_to_ent.pan - my.pan),0,0));
	
	        // now rotate the barrel
		vec_set(you.pan, my.pan);
		ang_rotate(you.pan, vector(0,ang(ang_to_ent.tilt - you.tilt),0));
		
		
		
		wait(1);	
	}	
}

---

As you can see, the calculations of the code above will not work with arbitrary orientations.
However, I have no idea what has to be changed to get it working.

Maybe try to modify the following lines :

Code:

---

var speed = 0.5; // play with 0.5
// first rotate the turret's body
//ang_rotate(my.pan, vector(ang(ang_to_ent.pan - my.pan),0,0));
my.pan += ang(ang_to_ent.x-my.pan) * speed * time_step;

//now rotate the barrel
//vec_set(you.pan, my.pan);
//ang_rotate(you.pan, vector(0,ang(ang_to_ent.tilt - you.tilt),0));


my.tilt += ang(ang_to_ent.y-my.tilt) * speed  * time_step;

..alright, I've had this problem as well, but I don't think I ever fixed it

Basically, what you have to do is convert the angles from world space to object space (we already knew this). You do that by rotating the angle by the inverse of the objects angle...

With vectors, this is really easy. But with angles... not so much. Here's as example using a vector:

Code:

---

Function iRotate(&_vec, &_ang)
{
    vec_set(temp, _ang);     // Store the angle in temp
    vec_inverse(temp);       // Invert the angle
    vec_rotate(_vec, temp);  // Rotate the vector
}

---

You can either try rotating the offset vector for the target before getting the direction, or, apply the same concept to the direction after you've found it. Hope I explained this well

Well in theory, this is what Guitar proposed:

Code:

---

  
vec_set(temp,vector(entity.pan,0,0));     // Store the angle in temp    
vec_inverse(temp);       // Invert the angle    
ang_rotate(entity.pan,temp);  // Rotate the angle

---

Ang_add wouldn't help since it's used for adjusting angles relative to the world axis AFAIK

Cheers

Frazzle

...IDK, I haven't tried it out yet (I'm hoping I'll have time soon), but I think if you rotate the offset first, then it will work better. Hard to explain:

var offset[3];
vec_diff(offset, you.x, my.x);
vec_iRotate(offset, my.pan);

...the offset variable should now have the "local difference", instead of world. So now:

vec_to_angle(temp, offset);

...temp now holds the angle it should point in relative to the model.

c_rotate(..., temp, ... + USE_AXISR);

...I don't know, something like that. I never really use c_rotate().


Of course all of this is just theory, and I'll just have to test it later

Seems logic but I don't get why you set you.x if you need to calculate the origin of my ??

Btw, didn't you mean :

Code:

---

  
vec_rotate(offset, my.pan);

---

Thanks in progress

Frazzle

Thanks, I have tried to implement your suggestions into my code. However I didn't have much success in doing so.

Standing on a plane the turret is still working fine.
But when its angles are changed (e.g. tilt or roll) it aims at a wrong location.

Nevertheless I think this is the right approach.

This is the code:

Code:

---

define barrel_handle, skill1;

action ent_turret
{
	my.barrel_handle = handle(ent_create("turret_barrel.mdl", my.x, NULL));
	
	while(my) {
		
		you = ptr_for_handle(my.barrel_handle);
		
		var  vec_to_ent[3];
		var  ang_to_ent[3];

                vec_diff(vec_to_ent, camera.x, my.x); // direction vector
		
		vec_set(temp, my.pan);         // Store the angle in temp
                vec_inverse(temp);             // Invert the angle
                vec_rotate(vec_to_ent, temp);  // Rotate the vector
      
		vec_to_angle(ang_to_ent, vec_to_ent); // angle of direction vector

		// first rotate the turret's body
		ang_rotate(my.pan, vector(ang_to_ent.pan,0,0));
		
                // now rotate the barrel
		vec_set(you.pan, my.pan);
		ang_rotate(you.pan, vector(0,ang_to_ent.tilt,0));
		
		
		
		wait(1);	
	}	
}

---

FenrisWolf has it right. Apparently I was wrong though. As soon as I find some time, I'll test it out...