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Rewrite falling entity to make use of collision info

fixes #4781, fixes #9293
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sfan5 committed May 6, 2020
1 parent b6b80f5 commit 723926a995f8ee0428e4aaa95de37a46354f5249
Showing with 128 additions and 66 deletions.
  1. +128 −66 builtin/game/falling.lua
@@ -30,6 +30,8 @@ local facedir_to_euler = {
{y = math.pi/2, x = math.pi, z = 0}
}

local gravity = tonumber(core.settings:get("movement_gravity")) or 9.81

--
-- Falling stuff
--
@@ -47,6 +49,7 @@ core.register_entity(":__builtin:falling_node", {

node = {},
meta = {},
floats = false,

set_node = function(self, node, meta)
self.node = node
@@ -71,6 +74,11 @@ core.register_entity(":__builtin:falling_node", {
return
end
self.meta = meta

-- Cache whether we're supposed to float on water
self.floats = core.get_item_group(node.name, "float") ~= 0

-- Set entity visuals
if def.drawtype == "torchlike" or def.drawtype == "signlike" then
local textures
if def.tiles and def.tiles[1] then
@@ -113,6 +121,7 @@ core.register_entity(":__builtin:falling_node", {
glow = def.light_source,
})
end

-- Rotate entity
if def.drawtype == "torchlike" then
self.object:set_yaw(math.pi*0.25)
@@ -172,6 +181,7 @@ core.register_entity(":__builtin:falling_node", {

on_activate = function(self, staticdata)
self.object:set_armor_groups({immortal = 1})
self.object:set_acceleration({x = 0, y = -gravity, z = 0})

local ds = core.deserialize(staticdata)
if ds and ds.node then
@@ -183,85 +193,137 @@ core.register_entity(":__builtin:falling_node", {
end
end,

on_step = function(self, dtime)
-- Set gravity
local acceleration = self.object:get_acceleration()
if not vector.equals(acceleration, {x = 0, y = -10, z = 0}) then
self.object:set_acceleration({x = 0, y = -10, z = 0})
try_place = function(self, bcp, bcn)
local bcd = core.registered_nodes[bcn.name]
-- Add levels if dropped on same leveled node
if bcd and bcd.leveled and
bcn.name == self.node.name then
local addlevel = self.node.level
if not addlevel or addlevel <= 0 then
addlevel = bcd.leveled
end
if core.add_node_level(bcp, addlevel) == 0 then
return true
end
end
-- Turn to actual node when colliding with ground, or continue to move
local pos = self.object:get_pos()
-- Position of bottom center point
local bcp = {x = pos.x, y = pos.y - 0.7, z = pos.z}
-- 'bcn' is nil for unloaded nodes
local bcn = core.get_node_or_nil(bcp)
-- Delete on contact with ignore at world edges
if bcn and bcn.name == "ignore" then
self.object:remove()
return

-- Decide if we're replacing the node or placing on top
local np = vector.new(bcp)
if bcd and bcd.buildable_to and
(not self.floats or bcd.liquidtype == "none") then
core.remove_node(bcp)
else
np.y = np.y + 1
end
local bcd = bcn and core.registered_nodes[bcn.name]
if bcn and
(not bcd or bcd.walkable or
(core.get_item_group(self.node.name, "float") ~= 0 and
bcd.liquidtype ~= "none")) then
if bcd and bcd.leveled and
bcn.name == self.node.name then
local addlevel = self.node.level
if not addlevel or addlevel <= 0 then
addlevel = bcd.leveled

-- Check what's here
local n2 = core.get_node(np)
local nd = core.registered_nodes[n2.name]
-- If it's not air or liquid, remove node and replace it with
-- it's drops
if n2.name ~= "air" and (not nd or nd.liquidtype == "none") then
if nd and nd.buildable_to == false then
nd.on_dig(np, n2, nil)
-- If it's still there, it might be protected
if core.get_node(np).name == n2.name then
return false
end
if core.add_node_level(bcp, addlevel) == 0 then
else
core.remove_node(np)
end
end

-- Create node
local def = core.registered_nodes[self.node.name]
if def then
core.add_node(np, self.node)
if self.meta then
core.get_meta(np):from_table(self.meta)
end
if def.sounds and def.sounds.place then
core.sound_play(def.sounds.place, {pos = np}, true)
end
end
core.check_for_falling(np)
return true
end,

on_step = function(self, dtime, moveresult)
-- Fallback code since collision detection can't tell us
-- about liquids (which do not collide)
if self.floats then
local pos = self.object:get_pos()

local bcp = vector.round({x = pos.x, y = pos.y - 0.7, z = pos.z})
local bcn = core.get_node(bcp)

local bcd = core.registered_nodes[bcn.name]
if bcd and bcd.liquidtype ~= "none" then
if self:try_place(bcp, bcn) then
self.object:remove()
return
end
elseif bcd and bcd.buildable_to and
(core.get_item_group(self.node.name, "float") == 0 or
bcd.liquidtype == "none") then
core.remove_node(bcp)
return
end
local np = {x = bcp.x, y = bcp.y + 1, z = bcp.z}
-- Check what's here
local n2 = core.get_node(np)
local nd = core.registered_nodes[n2.name]
-- If it's not air or liquid, remove node and replace it with
-- it's drops
if n2.name ~= "air" and (not nd or nd.liquidtype == "none") then
core.remove_node(np)
if nd and nd.buildable_to == false then
-- Add dropped items
local drops = core.get_node_drops(n2, "")
for _, dropped_item in pairs(drops) do
core.add_item(np, dropped_item)
end
end
-- Run script hook
for _, callback in pairs(core.registered_on_dignodes) do
callback(np, n2)
end
end
-- Create node and remove entity
local def = core.registered_nodes[self.node.name]
if def then
core.add_node(np, self.node)
if self.meta then
local meta = core.get_meta(np)
meta:from_table(self.meta)
end
if def.sounds and def.sounds.place then
core.sound_play(def.sounds.place, {pos = np}, true)
end

assert(moveresult)
if not moveresult.collides then
return -- Nothing to do :)
end

local bcp, bcn
if moveresult.touching_ground then
for _, info in ipairs(moveresult.collisions) do
if info.axis == "y" then
bcp = info.node_pos
bcn = core.get_node(bcp)
break
end
end
end

if not bcp then
-- We're colliding with something, but not the ground. Irrelevant to us.
return
elseif bcn.name == "ignore" then
-- Delete on contact with ignore at world edges
self.object:remove()
core.check_for_falling(np)
return
end
local vel = self.object:get_velocity()
if vector.equals(vel, {x = 0, y = 0, z = 0}) then
local npos = self.object:get_pos()
self.object:set_pos(vector.round(npos))

local failure = false

local pos = self.object:get_pos()
local distance = vector.apply(vector.subtract(pos, bcp), math.abs)
if distance.x >= 1 or distance.z >= 1 then
-- We're colliding with some part of a node that's sticking out
-- Since we don't want to visually teleport, drop as item
failure = true
elseif distance.y >= 2 then
-- Doors consist of a hidden top node and a bottom node that is
-- the actual door. Despite the top node being solid, the moveresult
-- almost always indicates collision with the bottom node.
-- Compensate for this by checking the top node
bcp.y = bcp.y + 1
bcn = core.get_node(bcp)
local def = core.registered_nodes[bcn.name]
if not (def and def.walkable) then
failure = true -- This is unexpected, fail
end
end

-- Try to actually place ourselves
if not failure then
failure = not self:try_place(bcp, bcn)
end

if failure then
local drops = core.get_node_drops(self.node, "")
for _, item in pairs(drops) do
core.add_item(pos, item)
end
end
self.object:remove()
end
})

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