KOS wait until facing = prograde

[thekapm]

I'm trying to lock steering to ship:prograde/retrograde, and then wait until facing = prograde. The problem is that the facing will never actually be equal to prograde or retrograde when locked like that, so the ship sits on the direction infinitely.

I want this script to be universal regardless of how long it takes a ship to turn.

My code looks like this:

lock steering to ship:prograde.

wait until ship:facing = ship:prograde.

 

[Crzyrndm]

Not sure what KOS syntax is, but the operation you're looking for is a vector dot product

Assuming the vectors are normalised. ie. length of 1:

• 1.0 == perfect alignment
• 0 == perpendicular (90 degrees)
• -1.0 == perfect opposition
• >0.999 = <2.5 degrees of seperation
• More generically: cos^-1(result) = angle

Edited October 9, 2016 by Crzyrndm

[Chabadarl]

I use this function :

function waitAngle{
  parameter vector.
  lock steering to vector.
  wait until vang(ship:facing:forevector,vector) <2.
}

In your case you only need : wait until vang(ship:facing:forevector,prograde) < 2.

vang calculate the angle between two vectors. Facing is a direction, that's why you need to use  ship:facing:forevector. (see kOS documentation for more explanation).

I find that 2° is generally  good enough, but you can use whatever threshold you want.

 

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Edit: If you want to use the vector dot product as suggested above by @Crzyrndm. Here we go :

wait until vdot(ship:facing:forevector,prograde) > 0.999.

If it doesnt work check if the prograde and facing are unatary vector. If not, you need to multiply 0.999 by their magnitudes.

 

Edited October 8, 2016 by Chabadarl

[thekapm]

That is a lot easier than what I finally came up with. Here is what I did:

declare function pcheck
{
	set a to ship:prograde:pitch.
	set b to ship:prograde:yaw.
	set c to ship:prograde:roll.
	lock steering to R(a,b,c).
	WAIT UNTIL (ship:facing:pitch >= (round(a) - 5) AND ship:facing:roll >= (round(c) - 5)) AND (ship:facing:pitch <= (round(a) + 5) AND ship:facing:roll round(c) + 5)).
}

I had found out that the pitch and roll, when rounded, stay the same for prograde and retrograde. So I made it wait until they were equal. Then after the function in my code I added a lock steering to ship:prograde, because by then they were close enough that it could throttle without spinning all over the place.

[sebseb7]

1st:
when lock steering for a burn, you usually don't need to roll, this can be done by:
lock steering to lookdirup(MYVECTOR, ship:facing:topvector).

2nd:
you can then burn a long as the angle is low enough
lock throttle_ to nextnode:burnvector:mag*mass)/(maxthrust+0.01)*1.5.
lock throttle to min( vectorangle(MYVECTOR,ship:facing:vector)*-1+2 ,throttle_).