Finding distance

[LilWhiteMouse]

I'm trying to setup a script that monitors a minotaurfriend actor, and execute a script if he get's to far from the player. It doesn't work though, I tend to end up with negative distances. So what do I need to change so it does? FYI, I don't think I ever learned how to determine distance in three dimensions, I had to make a guess. Is that my error?

Code: Select all

script 52 (void) {
int PX, PY, PZ;
int MX, MY, MZ;
int Dist, Roam;
Roam = 1024;
while (1)
	{
//Get player location
Thing_ChangeTID(0, 255);
PX = GetActorX(255)/65536;
PY = GetActorY(255)/65536;
PZ = GetActorZ(255)/65536;
//Get monoceros location
MX = GetActorX(304)/65536;
MY = GetActorY(304)/65536;
MZ = GetActorZ(304)/65536;
Dist = ((PX - MX)^2 + (PY - MY)^2 + (PZ - MZ)^2)^(1/2);
print (d:Dist);//display distance test
if (Dist > Roam){ACS_Execute(53, 0);}//Respawns Monoceros near player
delay (const:35);
	}
}

[Graf Zahl]

The problem is that the '^' operator is not doing what you think. In C and ACS it's an exclusive or. And don't forget that (1/2) is 0 in integer arithmetics.

To get the square you have to actually write (PX - MX)*(PX - MX).
An operator that calculates a square root doesn't exist.
It's actually not necessary to calculate the square root. You can as well calculate the square of the distance and then compare that to the square of Roam:

Code: Select all

Dist = (PX - MX)*(PX - MX) + (PY - MY)*(PY - MY) + (PZ - MZ)*(PZ - MZ); 
if (Dist > Roam*Roam)

This is most likely the only efficient way to do this in ACS.

[LilWhiteMouse]

Thanks, it's working now.

[Eevee]

Doesn't ACS have **? I'm.. pretty sure C does, but I can never keep the power operators straight between languages. o.-

[Graf Zahl]

C doesn't and ACS does neither. Honestly, in a simple scripting language a power operator is rarely needed. When do you need a power greater than 2?

[Eevee]

oh, right, C has pow(). PERL has **. Dammit.

I assumed ACS would because I keep thinking anything in Perl will work in C for some odd reason nevermind.

[cccp_leha]

Well, I guess that when "C" was stripped to "ACS", they tok out pow() as well because Hexen didn't have the 1337 functions to get actorX/Y/Z.