Cuberite Forum

maybe I can not wait this plugin:D:D

Greetings,

This is a very useful plug-in and I thank you for creating it. However, would it be possible to include protection from Mob damage in your protected area with this plug-in? I have managed to protect my spawn but am worried about mischievous types luring in a few creepers and exploding my grand temple...

Darth.

This is not currently possible, the explosion API is missing. An approximation would be possible but it would not be 100% effective.

Maybe use the OnExploding hook, create a new bounding box that represents that area, and return true if it is in the expanded box? (Expanded to make sure explosions don't happen inside or near the area)

The problem is in MCS's implementation of explosions. It doesn't use the Vanilla's ray model, but instead a custom, inferior one. The hook then provides no means of actually determining what blocks are affected by the explosion, only an approximation via the relative ExplosionSize parameter.

So, the implementation should be rewritten in order to use a predictable ray model? Then using Lua, you could get a table of blocks that are affected, iterate through that, then stop any individual blocks from moving under certain conditions using a hook? Or maybe a hook that goes like HOOK_BLOCK_DISPLACED that is triggered per block or something like that?

I like the first variant more - a single hook call providing all the data. That would require a new class, though - array of block coords and blocktypes / metas, and bindings for that class, so that the hook could add or remove individual blocks being blown up.

So, something like:

class cBlockToEntityData
{
    public:
        Vector3i Position;
        int GetBlockType(); // returns E_BLOCK type
        int GetMetaData(); // returns E_META data
        cBlockInfo GetBlockInfo(); // returns a cBlockInfo
        // Excuse my lack of knowledge of the internals of MCServer...
}

Then the Lua bindings would send table full of these:

function OnExploding(World, ExplosionSize, CanCauseFire, X, Y, Z, Source, SourceData, AffectedBlocks)
    -- AffectedBlocks is a table full of cBlockToEntityData
    for n, k in pairs(AffectedBlocks) do
        if k:GetBlockType() == E_BLOCK_DIRT then
            table.remove(AffectedBlocks, n)
        end
    end
    -- send the modified table to the server to be processed
end

Rather than pushing the entire table to Lua and back, it'd be better to wrap the array into an object, cBlockArray:

function OnExploding(World, ExplosionSize, CanCauseFire, X, Y, Z, Source, SourceData, AffectedBlocks)
    assert(tolua.type(AffectedBlocks) == "cBlockArray")  -- It is an object with its own operations

    -- Example: do NOT explode dirt:
    for n = AffectedBlocks.GetCount() - 1, 0, -1 do  -- count from GetCount() - 1 down to 0
        if (AffectedBlock:GetBlockType(n) == E_BLOCK_DIRT) then  -- Get the n-th block's type
            AffectedBlocks.Remove(n)
        end
    end
    return false
end

Ah, that's also a good idea. Saves a bit of overhead, especially when you decide to go crazy with WorldEdit and set off 100000+ TNT.