RedOnion

The code for this example is:

Random=native.UnityEngine.Random

function selfDestruct(part)
    local childParts=part.children
    for i=childParts.count-1,0,-1 do
        selfDestruct(childParts[i])
    end
    part.explode()
    sleep(Random.Range(0,10))
end

selfDestruct(ship.parts[0])

This example explodes all the parts of the ship, starting from the the leaf parts.

First we use native to get UnityEngine’s Random class.

Random=native.UnityEngine.Random

In KSP, a Vessel has a collection of parts arranged in a tree-like fashion. The list of parts can also be viewed as a list, rather than a tree, which is what Vessel.parts, or ship.parts returns. But they are also connected to each other in a tree-structure, with each part having a list of children.

To take advantage of this structure, we define a recursive function that will navigate the tree of parts and destroy leaf parts (parts that have no children) first. Recursion is very convenient for tree structures.

function selfDestruct(part)
    local childParts=part.children
    for i=childParts.count-1,0,-1 do
        selfDestruct(childParts[i])
    end
    part.explode()
    sleep(Random.Range(0,10))
end

The zeroth element of the parts list is the root of the parts tree.

So

selfDestruct(ship.parts[0])

calls the recursive function on the root part.

Then we go through a loop calling selfDestruct recursively on all the children of that part. We’re treating the children as each being a subtree. If a part has no children, childParts.count-1 will be -1, and this loop never runs because it would be a loop from i=-1 to zero going backwards but -1 is already less than zero.

for i=childParts.count-1,0,-1 do
    selfDestruct(childParts[i])
end

After the loop, this part is guaranteed to have had all it’s children and their children (etc) exploded.

So we can call explode on this part itself.

part.explode()

And then go to sleep a little bit to put a delay before exploding the next part.

sleep(Random.Range(0,10))

This may be confusing, but the first time we get to this point in the recursive function is actually after selfDestruct was called with a part that has no children. At that point the parent of the current part is waiting in a loop for it’s children (including this part) to be destroyed. So this delay happens before the next child in that loop or the parent part explodes.