Is it possible to make 3D monsters turn around smoothly?

[PixelWAD]

I am using MD3 model files for my monsters. However, when they are chasing the player, they tend to turn 45 degrees spontanously. Is it possible to apply smooth motion to that?

[Rachael]

I don't know if it's possible or not, but if I were to do it I'd just create a second actor that incrementally follows the first so that the movement appears to be smooth.

[Graf Zahl]

... just ...

Shame on you!

[Rachael]

Yeah yeah, I know, that word never does justice to anything. It's just simply overused. So unjustifiably, too.

[PixelWAD]

I have added "just" to my actor code and it works perfectly! /s

If you could at least provide me with a mod name that uses such functionality, i would love to have a look.

[Caligari87]

I don't believe there are any existing mods that do this. I did see a tech demo of the technique a while back but I can't recall who or where it was posted.

Here's what I would do: Create your monster as normal, but have it spawn an invisible "chaser" monster when it first spawns. The invisible monster just uses A_Chase to follow the player as normal. Your real monster then, instead of using A_Chase, simply looks at the invisible monster (giving you smooth rotation) and adds velocity in the direction of the invisible monster (giving you smooth movement). For the latter, I recommend a damped-spring formula applied to the appropriate X/Y/Z velocities.

Keep in mind this will require use of pointers and may need some additional manual logic for attack states. If you're not yet comfortable with ZScript this might be a little advanced and will require a bit of tweaking and experimentation to get working properly. There are likely other ways to accomplish this without the invisible chasing monster, but then you'd basically need to write a custom chase function.

[Graf Zahl]

The main problem here will be that even if you get it to look right, monsters can only move in the 8 cardinal directions, unless you write your own monster AI. Writing your own A_Chase which can do more with the angle isn't really that hard: Store the angle, call A_Chase, compare angle and make adjustments.

[Caligari87]

I suggest this method mainly because it's pretty easy to understand what's happening (at least in my mind) and the code would be a fairly simple extrapolation from the stock behaviors. Obviously if you have the know-how then coding a new chase function is trivial, but in this case the OP probably needs something a little less conceptually abstract. The nice part about my idea is that the looser the "real" monster follows the "chaser", the smoother and more averaged-out the movement becomes. Unfortunately this means it'd also be possible to get stuck or separated from the chaser, in which case some special handling would be necessary.