Make TNT faster by using VoxelManip() for removing nodes.

[red-001]

For testing I changed tnt_radius in minetest.conf to 20. Without my patch an explosion took 6 seconds and with it it took one second.

[paramat]

If people complain you might also want to queue 'on destruct' and 'after destruct' functions, although 'on destruct' is usually called before removing a node so this may have problems.

[kilbith]

Where is i used ? Please ignore it with an underscore.

[red-001]

done

[red-001]

@kilbith done.

[paramat]

Needs input on whether 'on/after destruct' functions should be queued also.

[red-001]

It should be rather easy for mods to use on_blast instead. It could break some mods that are no longer maintained .

[C1ffisme]

This should also help with server-freezing chain reactions. 👍

[paramat]

The possibility of destroying locked chests or protected nodes shoud be considered too.

[tenplus1]

Add something like this to check node and if it's a chest drop all items inside.

if nodename == "default:chest"
or nodename == "3dchest:chest"
or nodename == "bones:bones" then

    local meta = minetest.get_meta(p)
    local inv  = meta:get_inventory()

    for i = 1, inv:get_size("main") do

        local obj = minetest.add_item(pos, inv:get_stack("main", i))

        if obj then

            obj:setvelocity({
                x = math.random(-2, 2),
                y = 7,
                z = math.random(-2, 2)
            })
        end
    end
end

[red-001]

@tenplus1 That's really something mods should handle using the on_blast callback. See #806.

[tenplus1]

red-001: the above code was for default chests in game either using tnt mod or edited for on_blast itself... I agree that user mods should handle drops on their own.

[red-001]

@tenplus1 I would agree minetest game should use on_blast more.
But that should be a different PR.

[paramat]

A dev has said there were reasons the voxelmanip wasn't used for removing nodes, you need to research why, try looking through the files history at previous commits. This PR cannot be merged until that research is done.

[red-001]

@paramat I couldn't find any mention of the reasons in the file history or in the comments on #277 but like you said @ShadowNinja said there where reasons for not using voxelmanip. (link to IRC logs) However at the time of the last major rewrite of TNT the on_blast callback wasn't implanted. The on_blast callback has be implanted almost a year ago 8bc8dd6 on_blast can be used similarly to on_destruct for stopping blocks form being destroyed by TNT. An after_blast callback could be added but mods could also remove the node themselves.

[paramat]

There are lots of changes coming for TNT it seems, and too close to release, sofar is busy with his stuff, so it seems the best thing is to delay TNT changes until after release, then do a thorough rewrite.

[sofar]

I'm counting 6 PRs with related changes. I'm rebasing all of them in a single PR, and making it a master WIP TNT PR that can be used to further improve TNT and comprehensively test all the changes collectively, which is rather cumbersome at this point.

[sofar]

Rebased and folded in to #862