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Move code that handles below-rail hoppers to handle_cart_enter, implement timestep-independent cart physics (will need tuning punch, power rail and gravityaccelerations to make game fun)

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teknomunk 2024-03-13 10:28:40 +00:00
parent 0fa067d3ee
commit 0ef0ae6bee
1 changed files with 237 additions and 143 deletions
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380
mods/ENTITIES/mcl_minecarts/init.lua
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@ -21,7 +21,8 @@ local function mcl_log(message)
end end
end end
local function handle_cart_enter(self,pos) local function handle_cart_enter(self, pos, next_dir)
local staticdata = self._staticdata
local node = minetest.get_node(pos) local node = minetest.get_node(pos)
-- Handle track behaviors -- Handle track behaviors
@ -30,11 +31,35 @@ local function handle_cart_enter(self,pos)
node_def._mcl_minecarts_on_enter(pos, cart) node_def._mcl_minecarts_on_enter(pos, cart)
end end
-- check for hopper under the rail
local under_pos = pos - vector.new(0,1,0)
local under_node_name = minetest.get_node(under_pos).name
local under_node_def = minetest.registered_nodes[under_node_name]
if under_node_def._mcl_minecarts_on_enter_above then
under_node_def._mcl_minecarts_on_enter_above(under_pos, cart)
else
local hopper_pulled = false
if DEBUG then print( "under_node_name="..under_node_name..", hopper="..tostring(under_node_def.groups.hopper)) end
if under_node_def and under_node_def.groups.hopper ~= 0 then
hopper_pulled = mcl_hoppers.pull_from_minecart( self, under_pos, self._inv_size or 0 )
if DEBUG then print( "Attempt pull_from_minecart, hopper_pulled="..tostring(hopper_pulled) ) end
if hopper_pulled and next_dir ~= staticdata.dir then
-- If there was an item pulled by a hopper under the rails force the cart to stay put for 1.5 seconds
-- to allow redstone time to process
if hopper_pulled then
staticdata.delay = 1.5
end
end
end
end
-- Handle above-track behaviors (to ensure hoppers can transfer at least one item) -- Handle above-track behaviors (to ensure hoppers can transfer at least one item)
local above_pos = pos + vector.new(0,1,0) local above_pos = pos + vector.new(0,1,0)
local node = minetest.get_node(above_pos) local above_node_name = minetest.get_node(above_pos).name
if node_def._mcl_minecarts_on_enter_below then local above_node_def = minetest.registered_nodes[above_node_name]
node_def._mcl_minecarts_on_enter_below(above_pos, cart) if above_node_def._mcl_minecarts_on_enter_below then
above_node_def._mcl_minecarts_on_enter_below(above_pos, cart)
end end
-- Handle cart-specific behaviors -- Handle cart-specific behaviors
@ -90,88 +115,12 @@ local function update_cart_orientation(self,staticdata)
self.object:set_rotation(rot) self.object:set_rotation(rot)
end end
local function do_movement_step(self, remaining_distance) local function calculate_acceleration(self, staticdata)
local staticdata = self._staticdata
local pos = staticdata.connected_at
if not pos then return remaining_distance end
if staticdata.velocity < 0.1 then return remaining_distance end
local remaining_in_block = 1 - ( staticdata.distance or 0 )
local dinstance = 0
if remaining_in_block > remaining_distance then
distance = remaining_distance
staticdata.distance = ( staticdata.distance or 0 ) + distance
pos = pos + staticdata.dir * staticdata.distance
else
distance = remaining_in_block
staticdata.distance = 0
-- Leave the old node
handle_cart_leave(pos)
-- Anchor at the next node
pos = pos + staticdata.dir
staticdata.connected_at = pos
-- Enter the new node
handle_cart_enter(self, pos)
-- check for hopper under the rail
local under_pos = pos - vector.new(0,1,0)
local under_node_name = minetest.get_node(under_pos).name
local under_node_def = minetest.registered_nodes[under_node_name]
local hopper_pulled = false
if DEBUG then print( "under_node_name="..under_node_name..", hopper="..tostring(under_node_def.groups.hopper)) end
if under_node_def and under_node_def.groups.hopper ~= 0 then
hopper_pulled = mcl_hoppers.pull_from_minecart( self, under_pos, self._inv_size or 0 )
if DEBUG then print( "Attempt pull_from_minecart, hopper_pulled="..tostring(hopper_pulled) ) end
end
-- Get the next direction
local next_dir,_ = mcl_minecarts:get_rail_direction(pos, staticdata.dir, nil, nil, staticdata.railtype)
if DEBUG and next_dir ~= staticdata.dir then
print( "Changing direction from "..tostring(staticdata.dir).." to "..tostring(next_dir))
end
-- Handle end of track
if next_dir == staticdata.dir * -1 and ( hopper_pulled or next_dir.y == 0 ) then
if DEBUG then print("Stopping cart at "..tostring(pos)) end
staticdata.velocity = 0
-- If there is a hopper under here, force the cart to stay put for 1.5 seconds
-- to allow redstone time to process
if hopper_pulled then
staticdata.delay = 1.5
end
distance = remaining_distance
end
-- Update cart direction
staticdata.dir = next_dir
end
self.object:move_to(pos)
-- Update cart orientation
update_cart_orientation(self,staticdata)
-- Report distance traveled
return distance
end
local function process_acceleration(self, timestep)
local staticdata = self._staticdata
if not staticdata.connected_at then return end
local acceleration = 0 local acceleration = 0
if DEBUG and staticdata.velocity > 0 then -- Apply friction if moving
print( " acceleration="..tostring(acceleration)..",velocity="..tostring(staticdata.velocity).. if staticdata.velocity > 0 then
",timestep="..tostring(timestep).. acceleration = -friction
",dir="..tostring(staticdata.dir))
end end
local pos = staticdata.connected_at local pos = staticdata.connected_at
@ -188,64 +137,218 @@ local function process_acceleration(self, timestep)
elseif self._fueltime and self._fueltime > 0 then elseif self._fueltime and self._fueltime > 0 then
acceleration = 0.6 acceleration = 0.6
elseif staticdata.velocity >= ( node_def._max_acceleration_velocity or max_vel ) then elseif staticdata.velocity >= ( node_def._max_acceleration_velocity or max_vel ) then
acceleration = 0 -- Standard friction
else else
acceleration = node_def._rail_acceleration or -friction acceleration = node_def._rail_acceleration or acceleration
end end
if math.abs(acceleration) > (friction / 5) then -- Factor in gravity after everything else
local gravity_strength = 9.8 --friction * 5
if staticdata.dir.y < 0 then
acceleration = gravity_strength - friction
elseif staticdata.dir.y > 0 then
acceleration = -gravity_strength + friction
end
return acceleration
end
local function do_movement_step(self, dtime)
local staticdata = self._staticdata
if not staticdata.connected_at then return 0 end
-- Calculate timestep remaiing in this block
local x_0 = staticdata.distance or 0
local remaining_in_block = 1 - x_0
local a = calculate_acceleration(self, staticdata)
local v_0 = staticdata.velocity
if DEBUG and ( v_0 > 0 or a ~= 0 ) then
print( " cart #"..tostring(staticdata.cart_id)..
": a="..tostring(a)..
",v_0="..tostring(v_0)..
",x_0="..tostring(x_0)..
",timestep="..tostring(timestep)..
",dir="..tostring(staticdata.dir)..
",connected_at="..tostring(staticdata.connected_at)..
",distance="..tostring(staticdata.distance)
)
end
-- Not moving
if a == 0 and v_0 == 0 then return 0 end
-- Movement equation with acceleration: x_1 = x_0 + v_0 * t + 0.5 * a * t*t
local timestep
local stops_in_block = false
local inside = v_0 * v_0 + 2 * a * remaining_in_block
if inside < 0 then
-- Would stop or reverse direction inside this block, calculate time to v_1 = 0
timestep = -v_0 / a
stops_in_block = true
elseif a ~= 0 then
-- Setting x_1 = x_0 + remaining_in_block, and solving for t gives:
timestep = ( math.sqrt( v_0 * v_0 + 2 * a * remaining_in_block) - v_0 ) / a
else
timestep = remaining_in_block / v_0
end
-- Truncate timestep to remaining time delta
if timestep > dtime then
timestep = dtime
end
-- Truncate timestep to prevent v_1 from being larger that speed_max
local v_max = mcl_minecarts.speed_max
if v_0 + a * timestep > v_max then
timestep = ( v_max - v_0 ) / a
end
-- Prevent infinite loops
if timestep <= 0 then return 0 end
-- Calculate v_1 taking v_max into account
local v_1 = v_0 + a * timestep
if v_1 > v_max then
v_1 = v_max
elseif v_1 < friction / 5 then
v_1 = 0
end
-- Calculate x_1
local x_1 = x_0 + timestep * v_0 + 0.5 * a * timestep * timestep
-- Update position and velocity of the minecart
staticdata.velocity = v_1
staticdata.distance = x_1
-- Entity movement
local pos = staticdata.connected_at
-- Handle movement to next block, account for loss of precision in calculations
if x_1 >= 0.99 then
staticdata.distance = 0
-- Leave the old node
handle_cart_leave(pos)
-- Anchor at the next node
pos = pos + staticdata.dir
staticdata.connected_at = pos
-- Get the next direction
local next_dir,_ = mcl_minecarts:get_rail_direction(pos, staticdata.dir, nil, nil, staticdata.railtype)
if DEBUG and next_dir ~= staticdata.dir then
print( "Changing direction from "..tostring(staticdata.dir).." to "..tostring(next_dir))
end
-- Enter the new node
handle_cart_enter(self, pos, next_dir)
-- Handle end of track
if next_dir == staticdata.dir * -1 and ( hopper_pulled or next_dir.y == 0 ) then
if DEBUG then print("Stopping cart at end of track at "..tostring(pos)) end
staticdata.velocity = 0
end
-- Update cart direction
staticdata.dir = next_dir
elseif stops_in_block and v_1 < (friction/5) and a <= 0 then
-- Handle direction flip due to gravity
if DEBUG then print("Gravity flipped direction") end
-- Velocity should be zero at this point
staticdata.velocity = 0
-- Complete moving thru this block into the next, reverse direction, and put us back at the same position we were at
local next_dir = -staticdata.dir
pos = pos + staticdata.dir
staticdata.distance = 1 - staticdata.distance
staticdata.connected_at = pos
-- recalculate direction
local next_dir,_ = mcl_minecarts:get_rail_direction(pos + staticdata.dir, next_dir, nil, nil, staticdata.railtype)
staticdata.dir = next_dir
-- Intermediate movement
pos = pos + staticdata.dir * staticdata.distance
else
-- Intermediate movement
pos = pos + staticdata.dir * staticdata.distance
end
self.object:move_to(pos)
-- Update cart orientation
update_cart_orientation(self,staticdata)
-- Debug reporting
if DEBUG and ( v_0 > 0 or v_1 > 0 ) then
print( " cart #"..tostring(staticdata.cart_id)..
": a="..tostring(a)..
",v_0="..tostring(v_0)..
",v_1="..tostring(v_1)..
",x_0="..tostring(x_0)..
",x_1="..tostring(x_1)..
",timestep="..tostring(timestep)..
",dir="..tostring(staticdata.dir)..
",pos="..tostring(pos)..
",connected_at="..tostring(staticdata.connected_at)..
",distance="..tostring(staticdata.distance)
)
end
-- Report the amount of time processed
return dtime - timestep
--[[
---Process acceleration
local pos = staticdata.connected_at
-- Apply acceleleration
if math.abs(acceleration) > 0 then
-- Apply simple acceleration
staticdata.velocity = ( staticdata.velocity or 0 ) + acceleration * timestep staticdata.velocity = ( staticdata.velocity or 0 ) + acceleration * timestep
-- Apply friction to resist direction of velocity
if staticdata.velocity > 0 then
staticdata.velocity = ( staticdata.velocity ) - friction * timestep
-- Velocity flip due to friction should stop movement
if staticdata.velocity < 0 then
if DEBUG then print("Friction stopped minecart") end
staticdata.velocity = 0
end
else
end
if staticdata.velocity > max_vel then if staticdata.velocity > max_vel then
staticdata.velocity = max_vel staticdata.velocity = max_vel
elseif staticdata.velocity < (friction/5) then elseif staticdata.velocity < (friction/5) then
if DEBUG then print("Stopping cart at "..tostring(pos)) end
staticdata.velocity = 0 staticdata.velocity = 0
end end
end end
-- Factor in gravity after everything else
local gravity_accel = 0
local gravity_strength = friction + 0.2
if staticdata.dir.y < 0 then
gravity_accel = gravity_strength
elseif staticdata.dir.y > 0 then
gravity_accel = -gravity_strength
end
if DEBUG and gravity_accel ~= 0 then
print("gravity_accel="..tostring(gravity_accel))
end
if gravity_accel ~= 0 then
staticdata.velocity = (staticdata.velocity or 0) + gravity_accel
if staticdata.velocity < 0 then
if DEBUG then
print("Gravity flipped direction")
end
-- Complete moving thru this block into the next, reverse direction, and put us back at the same position we were at
staticdata.velocity = staticdata.velocity * -1
next_dir = -staticdata.dir
pos = pos + staticdata.dir
staticdata.distance = 1 - staticdata.distance
staticdata.connected_at = pos
local next_dir,_ = mcl_minecarts:get_rail_direction(pos + staticdata.dir, next_dir, nil, nil, staticdata.railtype)
staticdata.dir = next_dir
update_cart_orientation(self,staticdata)
end
end
-- Force the cart to stop if moving slowly enough -- Force the cart to stop if moving slowly enough
if (staticdata.velocity or 0) < 0.1 then if (staticdata.velocity or 0) < (friction/5) then
staticdata.velocity = 0 staticdata.velocity = 0
end end
if DEBUG and staticdata.velocity > 0 then
print( " acceleration="..tostring(acceleration)..",velocity="..tostring(staticdata.velocity).. -- Handle movement
",timestep="..tostring(timestep).. local pos = staticdata.connected_at
",dir="..tostring(staticdata.dir))
end if not pos then return remaining_distance end
if staticdata.velocity < 0.1 then return remaining_distance end
-- Report distance traveled
return distance
]]--
end end
local function do_movement( self, dtime ) local function do_movement( self, dtime )
local staticdata = self._staticdata local staticdata = self._staticdata
@ -262,25 +365,11 @@ local function do_movement( self, dtime )
staticdata.velocity = initial_velocity staticdata.velocity = initial_velocity
end end
-- Break long movements into fixed-size steps so that -- Break long movements at block boundaries to make it
-- it is impossible to jump across gaps due to server lag -- it impossible to jump across gaps due to server lag
-- causing large timesteps -- causing large timesteps
local total_distance = dtime * ( staticdata.velocity or 0 ) while dtime > 0 do
local remaining_distance = total_distance dtime = do_movement_step(self, dtime)
process_acceleration(self,dtime * max_step_distance / total_distance)
-- Skip processing stopped railcarts
if not staticdata.velocity or math.abs(staticdata.velocity) < (friction/5) then
return
end
while remaining_distance > 0.1 do
local step_distance = do_movement_step(self, remaining_distance)
if step_distance > 0.1 then
process_acceleration(self, dtime * step_distance / total_distance)
end
remaining_distance = remaining_distance - step_distance
end end
-- Clear punched flag now that movement for this step has been completed -- Clear punched flag now that movement for this step has been completed
@ -457,6 +546,7 @@ local function make_staticdata( railtype, connected_at, dir )
distance = 0, distance = 0,
velocity = 0, velocity = 0,
dir = vector.new(dir), dir = vector.new(dir),
cart_id = math.random(1,1000000000),
} }
end end
@ -641,6 +731,10 @@ local function register_entity(entity_id, def)
function cart:on_step(dtime) function cart:on_step(dtime)
hopper_take_item(self, dtime) hopper_take_item(self, dtime)
local staticdata = self._staticdata local staticdata = self._staticdata
-- Make sure all carts have an ID to isolate them
staticdata.cart_id = staticdata.cart_id or math.random(1,1000000000)
if not staticdata then if not staticdata then
staticdata = make_staticdata() staticdata = make_staticdata()
self._staticdata = staticdata self._staticdata = staticdata