399 lines
12 KiB
Lua
399 lines
12 KiB
Lua
--[[
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Explosion API mod for Minetest (adapted to MineClone 2)
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This mod is based on the Minetest explosion API mod, but has been changed
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to have the same explosion mechanics as Minecraft and work with MineClone.
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The computation-intensive parts of the mod has been optimized to allow for
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larger explosions and faster world updating.
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This mod was created by Elias Astrom <ryvnf@riseup.net> and is released
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under the LGPLv2.1 license.
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--]]
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mcl_explosions = {}
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local creative_mode = minetest.settings:get_bool("creative_mode")
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local mod_death_messages = minetest.get_modpath("mcl_death_messages") ~= nil
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local mod_fire = minetest.get_modpath("mcl_fire") ~= nil
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local CONTENT_FIRE = minetest.get_content_id("mcl_fire:fire")
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local S = minetest.get_translator("mcl_explosions")
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-- Saved sphere explosion shapes for various radiuses
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local sphere_shapes = {}
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-- Saved node definitions in table using cid-keys for faster look-up.
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local node_blastres = {}
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local node_on_blast = {}
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local node_walkable = {}
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-- The step length for the rays (Minecraft uses 0.3)
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local STEP_LENGTH = 0.3
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-- How many rays to compute entity exposure to explosion
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local N_EXPOSURE_RAYS = 16
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minetest.register_on_mods_loaded(function()
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-- Store blast resistance values by content ids to improve performance.
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for name, def in pairs(minetest.registered_nodes) do
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local id = minetest.get_content_id(name)
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node_blastres[id] = def._mcl_blast_resistance or 0
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node_on_blast[id] = def.on_blast
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node_walkable[id] = def.walkable
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end
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end)
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-- Compute the rays which make up a sphere with radius. Returns a list of rays
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-- which can be used to trace explosions. This function is not efficient
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-- (especially for larger radiuses), so the generated rays for various radiuses
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-- should be cached and reused.
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--
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-- Should be possible to improve by using a midpoint circle algorithm multiple
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-- times to create the sphere, currently uses more of a brute-force approach.
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local function compute_sphere_rays(radius)
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local rays = {}
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local sphere = {}
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for i=1, 2 do
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for y = -radius, radius do
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for z = -radius, radius do
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for x = -radius, 0, 1 do
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local d = x * x + y * y + z * z
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if d <= radius * radius then
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local pos = { x = x, y = y, z = z }
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sphere[minetest.hash_node_position(pos)] = pos
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break
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end
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end
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end
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end
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end
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for i=1,2 do
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for x = -radius, radius do
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for z = -radius, radius do
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for y = -radius, 0, 1 do
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local d = x * x + y * y + z * z
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if d <= radius * radius then
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local pos = { x = x, y = y, z = z }
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sphere[minetest.hash_node_position(pos)] = pos
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break
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end
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end
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end
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end
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end
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for i=1,2 do
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for x = -radius, radius do
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for y = -radius, radius do
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for z = -radius, 0, 1 do
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local d = x * x + y * y + z * z
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if d <= radius * radius then
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local pos = { x = x, y = y, z = z }
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sphere[minetest.hash_node_position(pos)] = pos
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break
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end
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end
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end
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end
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end
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for _, pos in pairs(sphere) do
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rays[#rays + 1] = vector.normalize(pos)
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end
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return rays
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end
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-- Add particles from explosion
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--
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-- Parameters:
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-- pos - The position of the explosion
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-- radius - The radius of the explosion
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local function add_particles(pos, radius)
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minetest.add_particlespawner({
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amount = 64,
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time = 0.125,
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minpos = pos,
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maxpos = pos,
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minvel = {x = -radius, y = -radius, z = -radius},
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maxvel = {x = radius, y = radius, z = radius},
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minacc = vector.new(),
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maxacc = vector.new(),
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minexptime = 0.5,
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maxexptime = 1.0,
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minsize = radius * 0.5,
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maxsize = radius * 1.0,
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texture = "tnt_smoke.png",
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})
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end
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-- Traces the rays of an explosion, and updates the environment.
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--
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-- Parameters:
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-- pos - Where the rays in the explosion should start from
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-- strength - The strength of each ray
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-- raydirs - The directions for each ray
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-- radius - The maximum distance each ray will go
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-- drop_chance - The chance that destroyed nodes will drop their items
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-- fire - If true, 1/3 of destroyed nodes become fire
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-- puncher - object that punches other objects (optional)
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--
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-- Note that this function has been optimized, it contains code which has been
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-- inlined to avoid function calls and unnecessary table creation. This was
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-- measured to give a significant performance increase.
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local function trace_explode(pos, strength, raydirs, radius, drop_chance, fire, puncher)
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local vm = minetest.get_voxel_manip()
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local emin, emax = vm:read_from_map(vector.subtract(pos, radius),
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vector.add(pos, radius))
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local emin_x = emin.x
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local emin_y = emin.y
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local emin_z = emin.z
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local ystride = (emax.x - emin_x + 1)
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local zstride = ystride * (emax.y - emin_y + 1)
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local pos_x = pos.x
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local pos_y = pos.y
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local pos_z = pos.z
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local area = VoxelArea:new {
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MinEdge = emin,
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MaxEdge = emax
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}
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local data = vm:get_data()
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local destroy = {}
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-- Trace rays for environment destruction
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for i = 1, #raydirs do
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local rpos_x = pos.x
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local rpos_y = pos.y
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local rpos_z = pos.z
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local rdir_x = raydirs[i].x
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local rdir_y = raydirs[i].y
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local rdir_z = raydirs[i].z
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local rstr = (0.7 + math.random() * 0.6) * strength
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for r = 0, math.ceil(radius * (1.0 / STEP_LENGTH)) do
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local npos_x = math.floor(rpos_x + 0.5)
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local npos_y = math.floor(rpos_y + 0.5)
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local npos_z = math.floor(rpos_z + 0.5)
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local idx = (npos_z - emin_z) * zstride + (npos_y - emin_y) * ystride +
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npos_x - emin_x + 1
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local cid = data[idx]
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local br = node_blastres[cid]
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local hash = minetest.hash_node_position({x=npos_x, y=npos_y, z=npos_z})
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rpos_x = rpos_x + STEP_LENGTH * rdir_x
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rpos_y = rpos_y + STEP_LENGTH * rdir_y
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rpos_z = rpos_z + STEP_LENGTH * rdir_z
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rstr = rstr - 0.75 * STEP_LENGTH - (br + 0.3) * STEP_LENGTH
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if rstr <= 0 then
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break
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end
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if cid ~= minetest.CONTENT_AIR then
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destroy[hash] = idx
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end
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end
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end
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-- Entities in radius of explosion
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local punch_radius = 2 * strength
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local objs = minetest.get_objects_inside_radius(pos, punch_radius)
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-- Trace rays for entity damage
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for _, obj in pairs(objs) do
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local ent = obj:get_luaentity()
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-- Ignore items to lower lag
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if obj:is_player() or (ent and ent.name ~= '__builtin.item') then
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local opos = obj:get_pos()
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local collisionbox = nil
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if obj:is_player() then
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collisionbox = { -0.3, 0.0, -0.3, 0.3, 1.77, 0.3 }
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elseif ent.name then
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local def = minetest.registered_entities[ent.name]
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collisionbox = def.collisionbox
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end
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if collisionbox then
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-- Create rays from random points in the collision box
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local x1 = collisionbox[1] * 2
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local y1 = collisionbox[2] * 2
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local z1 = collisionbox[3] * 2
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local x2 = collisionbox[4] * 2
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local y2 = collisionbox[5] * 2
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local z2 = collisionbox[6] * 2
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local x_len = math.abs(x2 - x1)
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local y_len = math.abs(y2 - y1)
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local z_len = math.abs(z2 - z1)
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-- Move object position to the center of its bounding box
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opos.x = opos.x + x1 + x2
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opos.y = opos.y + y1 + y2
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opos.z = opos.z + z1 + z2
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-- Count number of rays from collision box which are unobstructed
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local count = N_EXPOSURE_RAYS
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for i = 1, N_EXPOSURE_RAYS do
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local rpos_x = opos.x + math.random() * x_len - x_len / 2
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local rpos_y = opos.y + math.random() * y_len - y_len / 2
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local rpos_z = opos.z + math.random() * z_len - z_len / 2
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local rdir_x = pos.x - rpos_x
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local rdir_y = pos.y - rpos_y
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local rdir_z = pos.z - rpos_z
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local rdir_len = math.hypot(rdir_x, math.hypot(rdir_y, rdir_z))
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rdir_x = rdir_x / rdir_len
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rdir_y = rdir_y / rdir_len
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rdir_z = rdir_z / rdir_len
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for i=0, rdir_len / STEP_LENGTH do
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rpos_x = rpos_x + rdir_x * STEP_LENGTH
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rpos_y = rpos_y + rdir_y * STEP_LENGTH
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rpos_z = rpos_z + rdir_z * STEP_LENGTH
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local npos_x = math.floor(rpos_x + 0.5)
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local npos_y = math.floor(rpos_y + 0.5)
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local npos_z = math.floor(rpos_z + 0.5)
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local idx = (npos_z - emin_z) * zstride + (npos_y - emin_y) * ystride +
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npos_x - emin_x + 1
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local cid = data[idx]
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local walkable = node_walkable[cid]
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if walkable then
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count = count - 1
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break
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end
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end
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end
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-- Punch entity with damage depending on explosion exposure and
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-- distance to explosion
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local exposure = count / N_EXPOSURE_RAYS
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local punch_vec = vector.subtract(opos, pos)
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local punch_dir = vector.normalize(punch_vec)
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local impact = (1 - vector.length(punch_vec) / punch_radius) * exposure
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if impact < 0 then
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impact = 0
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end
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local damage = math.floor((impact * impact + impact) * 7 * strength + 1)
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if mod_death_messages and obj:is_player() then
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mcl_death_messages.player_damage(obj, S("@1 was caught in an explosion.", obj:get_player_name()))
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end
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local source = puncher
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if not source then
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source = obj
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end
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obj:punch(source, 10, { damage_groups = { full_punch_interval = 1,
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fleshy = damage, knockback = impact * 20.0 } }, punch_dir)
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if obj:is_player() then
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obj:add_player_velocity(vector.multiply(punch_dir, impact * 20))
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elseif ent.tnt_knockback then
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obj:add_velocity(vector.multiply(punch_dir, impact * 20))
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end
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end
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end
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end
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local airs, fires = {}, {}
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-- Remove destroyed blocks and drop items
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for hash, idx in pairs(destroy) do
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local do_drop = not creative_mode and math.random() <= drop_chance
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local on_blast = node_on_blast[data[idx]]
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local remove = true
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if do_drop or on_blast ~= nil then
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local npos = minetest.get_position_from_hash(hash)
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if on_blast ~= nil then
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on_blast(npos, 1.0)
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remove = false
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else
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local name = minetest.get_name_from_content_id(data[idx])
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local drop = minetest.get_node_drops(name, "")
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for _, item in ipairs(drop) do
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if type(item) ~= "string" then
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item = item:get_name() .. item:get_count()
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end
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minetest.add_item(npos, item)
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end
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end
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end
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if remove then
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if mod_fire and fire and math.random(1, 3) == 1 then
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table.insert(fires, minetest.get_position_from_hash(hash))
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else
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table.insert(airs, minetest.get_position_from_hash(hash))
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end
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end
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end
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-- We use bulk_set_node instead of LVM because we want to have on_destruct and
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-- on_construct being called
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if #airs > 0 then
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minetest.bulk_set_node(airs, {name="air"})
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end
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if #fires > 0 then
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minetest.bulk_set_node(fires, {name="mcl_fire:fire"})
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end
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-- Update falling nodes
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for a=1, #airs do
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local p = airs[a]
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minetest.check_for_falling({x=p.x, y=p.y+1, z=p.z})
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end
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for f=1, #fires do
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local p = fires[f]
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minetest.check_for_falling({x=p.x, y=p.y+1, z=p.z})
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end
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-- Log explosion
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minetest.log('action', 'Explosion at ' .. minetest.pos_to_string(pos) ..
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' with strength ' .. strength .. ' and radius ' .. radius)
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end
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-- Create an explosion with strength at pos.
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--
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-- Parameters:
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-- pos - The position where the explosion originates from
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-- strength - The blast strength of the explosion (a TNT explosion uses 4)
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-- info - Table containing information about explosion.
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-- puncher - object that is reported as source of punches/damage (optional)
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--
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-- Values in info:
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-- drop_chance - If specified becomes the drop chance of all nodes in the
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-- explosion (defaults to 1.0 / strength)
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-- no_sound - If true then the explosion will not play a sound
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-- no_particle - If true then the explosion will not create particles
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-- fire - If true, 1/3 nodes become fire (default: false)
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function mcl_explosions.explode(pos, strength, info, puncher)
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-- The maximum blast radius (in the air)
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local radius = math.ceil(1.3 * strength / (0.3 * 0.75) * 0.3)
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if not sphere_shapes[radius] then
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sphere_shapes[radius] = compute_sphere_rays(radius)
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end
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local shape = sphere_shapes[radius]
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trace_explode(pos, strength, shape, radius, (info and info.drop_chance) or 1 / strength, info.fire == true, puncher)
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if not (info and info.no_sound) then
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add_particles(pos, radius)
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end
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if not (info and info.no_particle) then
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minetest.sound_play("tnt_explode", {
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pos = pos, gain = 1.0,
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max_hear_distance = strength * 16
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}, true)
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end
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end
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