kOS-Kerbcast Addon

A kOS addon for kerbcast. It lets a kerboscript running on a vessel's own CPU enumerate that vessel's kerbcast cameras and control them: set field of view, pan steerable mounts, and target-track a moving point.

Requirements

• kerbcast (the camera mod itself)
• kOS

Install both alongside this addon.

API

Everything hangs off ADDONS:KERBCAST.

Each camera has:

:BORESIGHT and :POSITION let a script steer the vessel to hold a target the mount alone can't reach: rotate the craft so :BORESIGHT lines up with TARGET:POSITION - cam:POSITION, optionally with a steerable mount fine-tracking on top.

Sets are clamped to each camera's limits, and pan/aim sets are ignored on cameras that cannot pan. FOV and pan ease toward their targets rather than snapping, so writing a value every tick tracks smoothly.

Example

// List the cameras and their capabilities.
FOR c IN ADDONS:KERBCAST:CAMERAS {
  PRINT c:NAME + " (fov " + ROUND(c:FOV,0) + ", pan " + c:SUPPORTSPAN + ")".
}

// Zoom the first zoom-capable camera in.
FOR c IN ADDONS:KERBCAST:CAMERAS {
  IF c:SUPPORTSZOOM { SET c:FOV TO c:FOVMIN + 5. BREAK. }
}

// Track the current target with a steerable mount, then stop.
FOR c IN ADDONS:KERBCAST:CAMERAS {
  IF c:SUPPORTSPAN AND HASTARGET {
    SET c:AIM TO { RETURN TARGET:POSITION. }.  // re-evaluated each tick
    WAIT 10.
    c:STOPAIM().                               // stop tracking, hold last angle
    BREAK.
  }
}

The :AIM callback is the intended way to follow something: it is a recalculating source, so as the target and vessel move, the mount keeps pointing at it. :LOOKAT(v) is the one-shot equivalent for a fixed point.

Run continuous :AIM tracking from a program, not the terminal. A kOS callback ({ ... }) lives only as long as the context that created it, and typing LOCK STEERING / UNLOCK STEERING at the interpreter can leave the CPU in a state where scheduled callbacks (:AIM tracking included) quietly stop running. This is a kOS quirk, not something the addon can prevent. If tracking goes unresponsive, REBOOT. the CPU to clear it. Putting your script in a .ks file and running it with RUN avoids the problem entirely: the callback lives for the whole run, and steering stays out of the interpreter. Setting :AIM to a plain vector, or using :LOOKAT(v), is a one-shot and is not affected.

Demo: track a target with the whole craft

:BORESIGHT and :POSITION let the vessel help point a camera, so even a fixed camera can hold a moving target. This rotates the hull so the camera's boresight stays on the target; if the camera is also steerable, its mount fine-tracks on top, so vessel and camera move together. Needs a target set and enough control authority (reaction wheels / RCS) to turn the craft.

IF NOT HASTARGET {
  PRINT "Set a target first.".
} ELSE {
  SET cam TO ADDONS:KERBCAST:CAMERAS[0].   // the camera to keep on target

  // Camera pointing relative to the hull. Constant for a fixed mount, so
  // capture it once; the vessel then carries the camera onto the target.
  SET mount TO SHIP:FACING:INVERSE * LOOKDIRUP(cam:BORESIGHT, SHIP:FACING:TOPVECTOR).

  // Attitude that puts the camera's boresight on the target, recomputed live.
  LOCK aimDir TO LOOKDIRUP(TARGET:POSITION - cam:POSITION, SHIP:UP:FOREVECTOR).
  LOCK STEERING TO aimDir * mount:INVERSE.

  // If the camera can pan, let the mount fine-track too (camera + vessel).
  IF cam:SUPPORTSPAN { SET cam:AIM TO { RETURN TARGET:POSITION. }. }

  PRINT "Tracking " + TARGET:NAME + " with the vessel.".
  WAIT 30.

  IF cam:SUPPORTSPAN { cam:STOPAIM(). }
  UNLOCK STEERING.
  PRINT "Done.".
}

On the stream the target stays framed while the craft slews to follow it; with a steerable camera the mount makes the fine corrections and the hull handles the coarse rotation.

Licence

KerbcastKos is GPL-3.0-only because it links kOS (GPLv3). This is separate from kerbcast's own CC BY-NC-SA licence; see NOTICE-KOS.txt. The full licence text is in LICENSE.