Add entity damage and player knockback

Could not find a way to add knockback to entities.  After adding a
velocity to them they will just slide around indefinitely.  Because of
this, knockback is only enabled on players for now.
This commit is contained in:
Elias Åström 2020-04-16 23:05:50 +02:00
parent 77c95fe8c3
commit ca7c8c23c7
2 changed files with 123 additions and 10 deletions

View File

@ -24,16 +24,21 @@ local sphere_shapes = {}
-- Saved node definitions in table using cid-keys for faster look-up.
local node_br = {}
local node_on_blast = {}
local AIR_CID = minetest.get_content_id('air')
-- The step length for the rays (Minecraft uses 0.3)
local STEP_LENGTH = 0.3
-- How many rays to compute entity exposure to explosion
local N_EXPOSURE_RAYS = 16
minetest.after(0, function()
-- Store blast resistance values by content ids to improve performance.
for name, def in pairs(minetest.registered_nodes) do
node_br[minetest.get_content_id(name)] = def._mcl_blast_resistance or 0
node_on_blast[minetest.get_content_id(name)] = def.on_blast
end
end)
@ -203,7 +208,7 @@ local function trace_explode(pos, strength, raydirs, radius, drop_chance)
local data = vm:get_data()
local destroy = {}
-- Trace rays
-- Trace rays for environment destruction
for i = 1, #raydirs do
local rpos_x = pos.x
local rpos_y = pos.y
@ -237,23 +242,126 @@ local function trace_explode(pos, strength, raydirs, radius, drop_chance)
end
if cid ~= AIR_CID then
destroy[hash] = idx
destroy[hash] = idx
end
end
end
-- Entities in radius of explosion
local punch_radius = 2 * strength
local objs = minetest.get_objects_inside_radius(pos, punch_radius)
-- Trace rays for entity damage
for _, obj in pairs(objs) do
-- Object position and direction to explosion center
local opos = obj:get_pos()
if obj:get_luaentity() ~= nil or obj:is_player() then
local collisionbox = nil
if obj:is_player() then
collisionbox = { -0.3, 0.0, -0.3, 0.3, 1.77, 0.3 }
elseif obj:get_luaentity().name then
local def = minetest.registered_entities[obj:get_luaentity().name]
collisionbox = def.collisionbox
end
if collisionbox then
-- Create rays from random points in the collision box
local x1 = collisionbox[1] * 2
local y1 = collisionbox[2] * 2
local z1 = collisionbox[3] * 2
local x2 = collisionbox[4] * 2
local y2 = collisionbox[5] * 2
local z2 = collisionbox[6] * 2
local x_len = math.abs(x2 - x1)
local y_len = math.abs(y2 - y1)
local z_len = math.abs(z2 - z1)
-- Move object position to the center of its bounding box
opos.x = opos.x + x1 + x2
opos.y = opos.y + y1 + y2
opos.z = opos.z + z1 + z2
-- Count number of rays from collision box which are unobstructed
local count = N_EXPOSURE_RAYS
for i = 1, N_EXPOSURE_RAYS do
local rpos_x = opos.x + math.random() * x_len - x_len / 2
local rpos_y = opos.y + math.random() * y_len - y_len / 2
local rpos_z = opos.z + math.random() * z_len - z_len / 2
local rdir_x = pos.x - rpos_x
local rdir_y = pos.y - rpos_y
local rdir_z = pos.z - rpos_z
local rdir_len = math.hypot(rdir_x, math.hypot(rdir_y, rdir_z))
rdir_x = rdir_x / rdir_len
rdir_y = rdir_y / rdir_len
rdir_z = rdir_z / rdir_len
for i=0, rdir_len / STEP_LENGTH do
rpos_x = rpos_x + rdir_x * STEP_LENGTH
rpos_y = rpos_y + rdir_y * STEP_LENGTH
rpos_z = rpos_z + rdir_z * STEP_LENGTH
local npos_x = math.floor(rpos_x + 0.5)
local npos_y = math.floor(rpos_y + 0.5)
local npos_z = math.floor(rpos_z + 0.5)
local idx = (npos_z - emin_z) * zstride + (npos_y - emin_y) * ystride +
npos_x - emin_x + 1
local cid = data[idx]
local br = node_br[cid]
if br ~= 0 then
count = count - 1
break
end
end
end
-- Punch entity with damage depending on explosion exposure and
-- distance to explosion
local exposure = count / N_EXPOSURE_RAYS
local punch_vec = vector.subtract(pos, opos)
local punch_dir = vector.normalize(punch_vec)
local impact = (1 - vector.length(punch_vec) / punch_radius) * exposure
if impact < 0 then
impact = 0
end
local damage = math.floor((impact * impact + impact) * 7 * strength + 1)
obj:punch(obj, nil, { damage_groups = { fleshy = damage } }, punch_dir)
if obj:is_player() then
obj:add_player_velocity(vector.multiply(punch_dir, -exposure * 20))
end
end
end
end
-- Remove destroyed blocks and drop items
for hash, idx in pairs(destroy) do
if math.random() <= drop_chance then
local name = minetest.get_name_from_content_id(data[idx])
local drop = minetest.get_node_drops(name, "")
for _, item in ipairs(drop) do
if type(item) == "string" then
minetest.add_item(get_position_from_hash(hash), item)
end
local do_drop = math.random() <= drop_chance
local on_blast = node_on_blast[data[idx]]
local remove = true
if do_drop or on_blast ~= nil then
local npos = get_position_from_hash(hash)
if on_blast ~= nil then
remove = on_blast(npos, 1.0)
else
local name = minetest.get_name_from_content_id(data[idx])
local drop = minetest.get_node_drops(name, "")
for _, item in ipairs(drop) do
if type(item) == "string" then
minetest.add_item(npos, item)
end
end
end
end
data[idx] = AIR_CID
if remove then
data[idx] = AIR_CID
end
end
-- Log explosion

View File

@ -103,6 +103,11 @@ minetest.register_node("mcl_tnt:tnt", {
_doc_items_usagehelp = S("Place the TNT and ignite it with one of the methods above. Quickly get in safe distance. The TNT will start to be affected by gravity and explodes in 4 seconds."),
groups = { dig_immediate = 3, tnt = 1, enderman_takable=1 },
mesecons = tnt_mesecons,
on_blast = function(pos)
minetest.chat_send_all("on_blast " .. minetest.pos_to_string(pos))
spawn_tnt(pos, "mcl_tnt:tnt")
return true
end,
_on_ignite = function(player, pointed_thing)
tnt.ignite(pointed_thing.under)
return true