[ACS] - Making an actor face the player

[FFFF-RRRR]

Good day.

I'm stuck with math here, I'll need help.

There are situations in my project where an actor needs to face the player. (Just by the angle, not the pitch).
I haven't been able to figure out the math. Just setting the angle of the actor to the "inverted" angle of the player (by multiplying it with -1) doesn't produce the right result.

I'm aware of SetActorAngle but I'm unable to figure out how to properly calclate the angle necessary.

Does somebody have an idea how to solve this? Help would be greatly appreciated.

[Sir Robin]

quickest way to "invert" an angle is to add (or subtract) 180

[22alpha22]

Have you tried A_Face with the max_pitch property set to 270?

[Sir Robin]

Yeah I was going to suggest A_Face also but I looked at the wiki and it says Zscript only

[KeksDose]

If you need something that works for any actor given a tid, you can do this:

Code: Select all

// assume that the player is the activator.
int diff_x = GetActorX(0) - GetActorX(thing_tid);
int diff_y = GetActorY(0) - GetActorY(thing_tid);
int ang = VectorAngle(diff_x, diff_y);

ang now has the property that SetActorAngle(thing_tid, ang) will make the thing face the activator. For reference, you can do pitch similarly:

Code: Select all

int diff_z = GetActorZ(0) - GetActorZ(thing_tid);
int vang = VectorAngle(VectorLength(diff_x, diff_y), diff_z);

[FFFF-RRRR]

@KeksDose
That works. Thank you for your help!

quickest way to "invert" an angle is to add (or subtract) 180

That's true. Though I tried it and inverting doesn't do the right thing in this situation.

[KeksDose]

oh yea I forgot to mention! in acs, actor angles are fixed point range, which is 0 to 1.0 with the .0 (1 and 1.0 are not the same here is what I'm saying), so you can reverse angles by adding 0.5.