Rename to vl_physics

mods/ENTITIES/mcl_item_entity/init.lua

@@ -92,7 +92,6 @@ local function enable_physics(object, luaentity, ignore_check)
 		object:set_properties({
 			physical = true
 		})
-		object:set_acceleration(vector.new(0, -get_gravity(), 0))
 	end
 end
 
@@ -634,62 +633,6 @@ local function push_out_item_stuck_in_solid(self, dtime, p, def, is_in_water)
 	end
 end
 
-local function move_items_in_water (self, p, def, node, is_floating, is_in_water)
-	-- Move item around on flowing liquids; add 'source' check to allow items to continue flowing a bit in the source block of flowing water.
-	if def and not is_floating and (def.liquidtype == "flowing" or def.liquidtype == "source") then
-		self._flowing = true
-
-		--[[ Get flowing direction (function call from flowlib), if there's a liquid.
-        NOTE: According to Qwertymine, flowlib.quickflow is only reliable for liquids with a flowing distance of 7.
-        Luckily, this is exactly what we need if we only care about water, which has this flowing distance. ]]
-		local vec = flowlib.quick_flow(p, node)
-		-- Just to make sure we don't manipulate the speed for no reason
-		if vec.x ~= 0 or vec.y ~= 0 or vec.z ~= 0 then
-			-- Minecraft Wiki: Flowing speed is "about 1.39 meters per second"
-			local f = 1.2
-			-- Set new item moving speed into the direciton of the liquid
-			local newv = vector.multiply(vec, f)
-			-- Swap to acceleration instead of a static speed to better mimic MC mechanics.
-			self.object:set_acceleration(vector.new(newv.x, -0.22, newv.z))
-
-			self.physical_state = true
-			self._flowing = true
-			self.object:set_properties({
-				physical = true
-			})
-			return true
-		end
-		if is_in_water and def.liquidtype == "source" then
-			local cur_vec = self.object:get_velocity()
-			-- apply some acceleration in the opposite direction so it doesn't slide forever
-			local vec = {
-				x = 0 - cur_vec.x * 0.9,
-				y = 3 - cur_vec.y * 0.9,
-				z = 0 - cur_vec.z * 0.9
-			}
-			self.object:set_acceleration(vec)
-			-- slow down the item in water
-			local vel = self.object:get_velocity()
-			if vel.y < 0 then
-				vel.y = vel.y * 0.9
-			end
-			self.object:set_velocity(vel)
-			if self.physical_state ~= false or self._flowing ~= true then
-				self.physical_state = true
-				self._flowing = true
-				self.object:set_properties({
-					physical = true
-				})
-			end
-		end
-	elseif self._flowing == true and not is_in_water and not is_floating then
-		-- Disable flowing physics if not on/in flowing liquid
-		self._flowing = false
-		enable_physics(self.object, self, true)
-		return true
-	end
-end
-
 minetest.register_entity(":__builtin:item", {
 	initial_properties = {
 		hp_max = 1,
@@ -896,7 +839,6 @@ minetest.register_entity(":__builtin:item", {
 
 		self.object:set_armor_groups({ immortal = 1 })
 		-- self.object:set_velocity(vector.new(0, 2, 0))
-		self.object:set_acceleration(vector.new(0, -get_gravity(), 0))
 		self:set_item(self.itemstring)
 	end,
 
@@ -1029,7 +971,7 @@ minetest.register_entity(":__builtin:item", {
 
 		if push_out_item_stuck_in_solid(self, dtime, p, def, is_in_water) then return end
 
-		if move_items_in_water (self, p, def, node, is_floating, is_in_water) then return end
+		vl_physics.apply_entity_environmental_physics(self)
 
 		-- If node is not registered or node is walkably solid and resting on nodebox
 		local nn = minetest.get_node(vector.offset(p, 0, -0.5, 0)).name

mods/ENTITIES/mcl_item_entity/mod.conf

@@ -1,4 +1,4 @@
 name = mcl_item_entity
 author = PilzAdam
 description = Dropped items will be attracted to the player like a magnet.
-depends = flowlib, mcl_enchanting
+depends = vl_physics, mcl_enchanting

mods/ENTITIES/mcl_mobs/api.lua

@@ -395,7 +395,8 @@ local function on_step_work (self, dtime)
 	local player_in_active_range = self:player_in_active_range()
 	self:check_suspend(player_in_active_range)
 
-	self:check_water_flow()
+	-- Handle environmental physics
+	vl_physics.apply_entity_environmental_physics(self)
 
 	if not self._jumping_cliff then
 		self._can_jump_cliff = self:can_jump_cliff()

mods/ENTITIES/mcl_mobs/mod.conf

@@ -2,4 +2,4 @@ name = mcl_mobs
 author = PilzAdam
 description = Adds a mob API for mods to add animals or monsters, etc.
 depends = mcl_particles
-optional_depends = mcl_weather, mcl_explosions, mcl_hunger, mcl_worlds, invisibility, lucky_block, cmi, doc_identifier, mcl_armor, mcl_portals, mcl_experience, mcl_sculk
+optional_depends = mcl_weather, mcl_explosions, mcl_hunger, mcl_worlds, invisibility, lucky_block, cmi, doc_identifier, mcl_armor, mcl_portals, mcl_experience, mcl_sculk, vl_physics

mods/ENTITIES/mcl_mobs/physics.lua

@@ -1026,43 +1026,7 @@ function mob_class:falling(pos)
 end
 
 function mob_class:check_water_flow()
-	-- Add water flowing for mobs from mcl_item_entity
-	local p, node, nn, def
-	p = self.object:get_pos()
-	node = minetest.get_node_or_nil(p)
-	if node then
-		nn = node.name
-		def = minetest.registered_nodes[nn]
-	end
-
-	-- Move item around on flowing liquids
-	if def and def.liquidtype == "flowing" then
-
-		--[[ Get flowing direction (function call from flowlib), if there's a liquid.
-		NOTE: According to Qwertymine, flowlib.quickflow is only reliable for liquids with a flowing distance of 7.
-		Luckily, this is exactly what we need if we only care about water, which has this flowing distance. ]]
-		local vec = flowlib.quick_flow(p, node)
-		-- Just to make sure we don't manipulate the speed for no reason
-		if vec.x ~= 0 or vec.y ~= 0 or vec.z ~= 0 then
-			-- Minecraft Wiki: Flowing speed is "about 1.39 meters per second"
-			local f = 1.39
-			-- Set new item moving speed into the direciton of the liquid
-			local newv = vector.multiply(vec, f)
-			self.object:set_acceleration({x = 0, y = 0, z = 0})
-			self.object:set_velocity({x = newv.x, y = -0.22, z = newv.z})
-
-			self.physical_state = true
-			self._flowing = true
-			self.object:set_properties({
-				physical = true
-			})
-			return
-		end
-	elseif self._flowing == true then
-		-- Disable flowing physics if not on/in flowing liquid
-		self._flowing = false
-		return
-	end
+	-- Deprecated. Do nothing
 end
 
 function mob_class:check_dying()

mods/ENVIRONMENT/vl_physics/api.lua

@@ -0,0 +1,62 @@
+local mod = vl_physics
+
+local registered_environment_effects = {}
+
+function mod.register_environment_effect(effect)
+	local list = registered_environment_effects
+	list[#list + 1] = effect
+end
+
+function mod.get_environment_effect(pos, vel, staticdata, mass, entity)
+	local v = vector.zero()
+	local a = vector.zero()
+
+	-- Accumulate all enviornmental effects
+	for _,effect in ipairs(registered_environment_effects) do
+		local dv,da = effect(pos, vel, staticdata, entity)
+		if dv then
+			v = v + dv
+		end
+		if da then
+			a = a + da
+		end
+	end
+
+	-- Disable small effects
+	if vector.length(v) < 0.01 then v = nil end
+	if vector.length(a) < 0.01 then a = nil end
+
+	return v,a
+end
+
+local DEFAULT_ENTITY_PHYSICS = {
+	mass = 1,
+}
+function mod.apply_entity_environmental_physics(self, data)
+	data = data or {}
+
+	local physics = self._vl_physics or DEFAULT_ENTITY_PHYSICS
+	local mass = physics.mass or DEFAULT_ENTITY_PHYSICS.mass
+
+	local pos = self.object:get_pos()
+	local vel = self.object:get_velocity()
+	local new_velocity,new_acceleration = vl_physics.get_environment_effect(pos, vel, data, mass, self)
+
+	--if new_velocity then print("new_velocity="..tostring(new_velocity)) end
+	--if new_acceleration then print("new_acceleration="..tostring(new_acceleration)) end
+
+	-- Update entity states
+	self._flowing = data.flowing
+
+	-- Apply environmental effects if there are any
+	if new_velocity or new_acceleration then
+		if new_acceleration then self.object:set_acceleration(new_acceleration) end
+		if new_velocity then self.object:set_velocity(new_velocity) end
+
+		self.physical_state = true
+		self._flowing = true
+		self.object:set_properties({
+			physical = true
+		})
+	end
+end

mods/ENVIRONMENT/vl_physics/init.lua

@@ -0,0 +1,100 @@
+local modname = minetest.get_current_modname()
+local modpath = minetest.get_modpath(modname)
+local mod = {}
+vl_physics = mod
+
+dofile(modpath.."/api.lua")
+
+-- Flowing water
+-- TODO: move to Flowlib
+local FLOW_SPEED = 1.39
+local BOUANCY = 3
+mod.register_environment_effect(function(pos, vel, staticdata, entity)
+	-- Get the node and node definition
+	local node = minetest.get_node_or_nil(pos); if not node then return end
+	local nodedef = minetest.registered_nodes[node.name]; if not nodedef then return end
+
+	-- Make sure we are in a liquid before continuing
+	local is_flowing = (nodedef.liquidtype == "flowing")
+	staticdata.flowing = is_flowing
+	if not is_flowing then return end
+
+	-- Get liquid flow direction
+	local vec = vector.multiply(flowlib.quick_flow(pos, node), FLOW_SPEED)
+	return vector.new(vec.x, -0.22, vec.z),nil -- TODO: move bouancy velocity out of here
+end)
+
+-- Simple gravity and bouancy
+mod.register_environment_effect(function(pos, vel, staticdata, entity)
+	-- Get the node and node definition
+	local node = minetest.get_node_or_nil(pos);
+	local nodedef = nil
+	if node then nodedef = minetest.registered_nodes[node.name] end
+
+	if nodedef and nodedef.liquidtype == "source" then -- TODO: make this apply to flowing liquids as well
+		-- TODO: make this not apply to fish
+		--print("entity="..dump(entity))
+
+		-- Apply decceleration and bouancy if the entity moved from flowing water to
+		-- stationary water
+		return nil,vector.new(
+			0 - vel.x * 0.9,
+			BOUANCY - vel.y * 0.9,
+			0 - vel.z * 0.9
+		)
+	else
+		local gravity = tonumber(minetest.settings:get("movement_gravity")) or 9.81
+		return nil,vector.new(0,-gravity,0)
+	end
+end)
+
+-- Node effects
+local DEFAULT_NODE_PHYSICS = {
+	friction = 0.9
+}
+local function apply_node_physics(node, vel, staticdata, entity)
+	local node_def = minetest.registered_nodes[node.name] or {}
+	local node_physics = node_def._vl_physics or DEFAULT_NODE_PHYSICS
+
+	local node_physics_effect = node_physics.effect
+	if node_physics_effect then
+		return node_physics_effect(pos, vel, staticdata)
+	end
+
+	-- Default behavior
+	local accel = vector.zero()
+
+	-- Friction
+	if node.name ~= "air" then
+		local friction_scale = node_physics.friction
+		accel = accel + vel * -friction_scale
+	end
+
+	return vector.zero(), accel
+end
+mod.register_environment_effect(function(pos, vel, staticdata, entity)
+	local a = vector.zero()
+	local v = vector.zero()
+
+	-- Apply node physics for the node we are inside of
+	local pos1_r = vector.round(pos)
+	local node1 = minetest.get_node(pos1_r)
+	local v1,a1 = apply_node_physics(node1, vel, staticdata, entity)
+	v = v + v1
+	a = a + a1
+
+	-- TODO: only apply when touching under_node
+	local pos2_r = vector.offset(pos1_r,0,-1,0)
+	local node2 = minetest.get_node(pos2_r)
+	local v2,a2 = apply_node_physics(node2, vel, staticdata, entity)
+	v = v + v2
+	a = a + a2
+
+	-- Male speeds of less than 1/100 block/second count as zero
+	if vector.length(v) < 0.01 then
+		v = nil
+	end
+
+	return v,a
+end)
+

mods/ENVIRONMENT/vl_physics/mod.conf

@@ -0,0 +1,4 @@
+name = vl_physics
+author = teknomunk
+description = Environmental physics
+depends = flowlib

mods/HUD/mcl_experience/orb.lua

@@ -109,42 +109,7 @@ local function xp_step(self, dtime)
 	end
 
 	-- Slide on slippery nodes
-	vel = self.object:get_velocity()
-	def = node and minetest.registered_nodes[node.name]
-	is_moving = (def and not def.walkable) or
-		vel.x ~= 0 or vel.y ~= 0 or vel.z ~= 0
-	is_slippery = false
-
-	if def and def.walkable then
-		slippery = minetest.get_item_group(node.name, "slippery")
-		is_slippery = slippery ~= 0
-		if is_slippery and (math.abs(vel.x) > 0.2 or math.abs(vel.z) > 0.2) then
-			-- Horizontal deceleration
-			slip_factor = 4.0 / (slippery + 4)
-			self.object:set_acceleration({
-				x = -vel.x * slip_factor,
-				y = 0,
-				z = -vel.z * slip_factor
-			})
-		elseif vel.y == 0 then
-			is_moving = false
-		end
-	end
-
-	if self.moving_state == is_moving and self.slippery_state == is_slippery then
-		-- Do not update anything until the moving state changes
-		return
-	end
-
-	self.moving_state = is_moving
-	self.slippery_state = is_slippery
-
-	if is_moving then
-		self.object:set_acceleration(gravity)
-	else
-		self.object:set_acceleration({x = 0, y = 0, z = 0})
-		self.object:set_velocity({x = 0, y = 0, z = 0})
-	end
+	vl_physics.apply_entity_environmental_physics(self)
 end
 
 minetest.register_entity("mcl_experience:orb", {

mods/ITEMS/mcl_core/nodes_base.lua

@@ -907,6 +907,9 @@ minetest.register_node("mcl_core:ice", {
 	_mcl_blast_resistance = 0.5,
 	_mcl_hardness = 0.5,
 	_mcl_silk_touch_drop = true,
+	_vl_physics = {
+		friction = 0.4,
+	},
 })
 
 minetest.register_node("mcl_core:packed_ice", {
@@ -921,6 +924,9 @@ minetest.register_node("mcl_core:packed_ice", {
 	_mcl_blast_resistance = 0.5,
 	_mcl_hardness = 0.5,
 	_mcl_silk_touch_drop = true,
+	_vl_physics = {
+		friction = 0.15,
+	},
 })
 
 -- Frosted Ice (4 nodes)