[ACS] Autoaim enabled railgun

[Scotty]

Ed the Bat and I made a little mod that allows railguns to use autoaim!

This works by:

• Firing a 0-damage bullet that is assigned a TID, which uses autoaim.
• Calculating the pitch from which the A_RailAttack needs to be fired based on the player's position and the puff's position.
• Returning the pitch to the call to A_RailAttack on the weapon, which has the RGF_EXPLICITANGLE flag set.

This creates a RailAttack which conforms to the user's autoaim settings.

Other than using this for autoaim, one could create a weapon that uses an angled sprite and shoots an angled RailAttack that hits where the player is aiming.
Provisions for this were started but weren't finished.

There are a couple of known bugs:

• Two bullet chips are created per attack if you allow the weapon to use decals.
• Over long distances, the attack is wildly inaccurate, due to conversion between floating point and fixed point values.

We used a piece of a function found in the ZDoom wiki:
http://zdoom.org/wiki/Distance

If you use this in your mod, credit to us is appreciated but absolutely not mandatory!

Screenshot:

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Download

[Scotty]

The original version of this resource used a feature from the ZDoom's development branch, which was GetActorProperty's APROP_AttackZOffset. A user requested that I make it compatible with the current stable version of ZDoom.

So here it is! If you have a player class that uses a different AttackZOffset, you'll need to account for that when implementing the script. I added in a constant which takes care of that so it's not a big deal, just change the value and recompile.

[Nash]

Nice work, but I wonder what's stopping this from being implemented natively? Seems like something really basic and trivial that it should be addressed at the source level... :S

[Scotty]

Thanks dude! I've wondered that too, it's fairly simple math. Maybe it caused problems or maybe it's to prevent cheap shots in multiplayer.

[Ed the Bat]

Nice work, but I wonder what's stopping this from being implemented natively? Seems like something really basic and trivial that it should be addressed at the source level... :S

I'd been told a couple of times that it would, indeed, be simple to add. But, as you can see, two years later it hasn't happened. Without the help of Epic, I still wouldn't have my armor-piercing gun that honors autoaim.