Fix typos documentation, add ignore_gravity and liquid_drag options, use vl_projectile.register() for enter pearl, move projectile physics to vl_projectile add hook for future vl_physics support

mods/ITEMS/mcl_bows/arrow.lua

@@ -15,11 +15,6 @@ local STUCK_RECHECK_TIME = 5
 
 local YAW_OFFSET = -math.pi/2
 
-local function dir_to_pitch(dir)
-	local xz = math.abs(dir.x) + math.abs(dir.z)
-	return -math.atan2(-dir.y, xz)
-end
-
 local function random_arrow_positions(positions, placement)
 	if positions == "x" then
 		return math.random(-4, 4)
@@ -123,6 +118,7 @@ local arrow_entity = {
 	textures = {"mcl_bows_arrow.png"},
 	collisionbox = {-0.19, -0.125, -0.19, 0.19, 0.125, 0.19},
 	collide_with_objects = false,
+	liquid_drag = true,
 	_fire_damage_resistant = true,
 
 	_save_fields = {
@@ -348,35 +344,11 @@ local arrow_entity = {
 			self._deflection_cooloff = self._deflection_cooloff - dtime
 		end
 
-		-- TODO: change to use vl_physics
-		-- TODO: move to vl_projectile
-		local def = minetest.registered_nodes[minetest.get_node(pos).name]
-		if def and def.liquidtype ~= "none" then
-			-- Slow down arrow in liquids
-			local v = def.liquid_viscosity or 0
-			self._viscosity = v
-
-			local vpenalty = math.max(0.1, 0.98 - 0.1 * v)
-			local vel = self.object:get_velocity()
-			if math.abs(vel.x) > 0.001 then
-				vel.x = vel.x * vpenalty
-			end
-			if math.abs(vel.z) > 0.001 then
-				vel.z = vel.z * vpenalty
-			end
-			self.object:set_velocity(vel)
-		end
-
 		-- Process as projectile
 		vl_projectile.update_projectile(self, dtime)
 
 		-- Update yaw
 		local vel = self.object:get_velocity()
-		if vel and not self._stuck then
-			local yaw = minetest.dir_to_yaw(vel)+YAW_OFFSET
-			local pitch = dir_to_pitch(vel)
-			self.object:set_rotation(vector.new(0,yaw,pitch))
-		end
 	end,
 
 	-- Force recheck of stuck arrows when punched.

mods/ITEMS/mcl_throwing/ender_pearl.lua

@@ -23,7 +23,7 @@ minetest.register_craftitem("mcl_throwing:ender_pearl", {
 mcl_throwing.register_throwable_object("mcl_throwing:ender_pearl", "mcl_throwing:ender_pearl_entity", 22)
 
 -- Ender pearl entity
-minetest.register_entity("mcl_throwing:ender_pearl_entity",{
+vl_projectile.register("mcl_throwing:ender_pearl_entity",{
 	physical = false,
 	timer=0,
 	textures = {"mcl_throwing_ender_pearl.png"},

mods/ITEMS/vl_projectile/api.md

@@ -10,19 +10,21 @@ Arguments:
 * `def`: Projectile defintion. Supports all fields that standard minetest entities support.
          Must include the field `_vl_projectile` for projectile-specific behaviors. These are the supported
 	    fields:
+  * `ignore_gravity`: if true, the projectile will not be affected by gravity
+  * `liquid_drag`: if true, apply drag from liquid nodes to the projectile
   * `survive_collision`: if this field is `false` or `nil`, the projectile will be removed after a collision.
   * `sticks_in_players`: if true, the projectile will stick into players after colliding with them.
   * `damage_groups`: damage group information to use for `punch()`. May be a function of type `function(projectile, entity_def, projectile_def, obj)`
                      that returns dynamic damange group information.
-  * `allow_punching`: will the projectile punch entities it collieds with. May be a function of type `function(projectile, entity_def, projectile_def, obj)`.
-  * `behaviors`: a list of behavior callbacks that define the projectile's behavior. This mod provides two
-                 behaviors: `vl_projectiles.collides_with_solids`, `vl_projectiles.collides_with_entities` and `vl_projectiles_raycast_collieds_with_entities`
+  * `allow_punching`: will the projectile punch entities it collides with. May be a function of type `function(projectile, entity_def, projectile_def, obj)`.
+  * `behaviors`: a list of behavior callbacks that define the projectile's behavior. This mod provides the following
+                 behaviors: `vl_projectiles.collides_with_solids`, `vl_projectiles.collides_with_entities` and `vl_projectiles_raycast_collides_with_entities`
   * `sounds`: sounds for this projectile. All fields take a table with three parameters corresponding to the
               three parameters for `minetest.play_sound()`. Supported sounds are:
     * `on_collision`: played when no other more specific sound is defined. May be a function of type `function(projectile, entity_def, projectile_def, type, ...)`
     * `on_solid_collision`: played when the projectile collides with a solid node. May be a function of type
         `funciton(projectile, entity_def, projectile_def, type, pos, node, node_def)` with `type = "node"`
-    * `on_entity_collision`: played when the projectile collieds with another entity. May be a function of type
+    * `on_entity_collision`: played when the projectile collides with another entity. May be a function of type
         `function(projectile, entity_def, projectile_def, type, entity)` with `type = "entity"`
  * `on_collide_with_solid`: callback of type `function(projectile, pos, node, node_def)` used when the projectile collides with a solid node. Requires
    `vl_projectile.collides_with_solids` in `behaviors` list.

mods/ITEMS/vl_projectile/init.lua

@@ -1,9 +1,64 @@
 local mod = {}
 vl_projectile = mod
 
+local vl_physics_path = minetest.get_modpath("vl_physics")
+
+local YAW_OFFSET = -math.pi/2
 local GRAVITY = tonumber(minetest.settings:get("movement_gravity"))
 local enable_pvp = minetest.settings:get_bool("enable_pvp")
 
+local function dir_to_pitch(dir)
+	local xz = math.abs(dir.x) + math.abs(dir.z)
+	return -math.atan2(-dir.y, xz)
+end
+
+function mod.projectile_physics(obj, entity_def, v, a)
+	local le = obj:get_luaentity()
+	local entity_def = minetest.registered_entities[le.name]
+	local pos = obj:get_pos()
+	if not pos then return end
+
+	if vl_physics_path then
+		v,a = vl_physics.apply_entity_environmental_physics(obj)
+	else
+		-- Simple physics
+		if not v then v = obj:get_velocity() end
+		if not a then a = vector.zero() end
+
+		if not entity_def.ignore_gravity then
+			a = a + vector.new(0,-GRAVITY,0)
+		end
+
+		if entity_def.liquid_drag then
+			local def = minetest.registered_nodes[minetest.get_node(pos).name]
+			if def and def.liquidtype ~= "none" then
+				-- Slow down arrow in liquids
+				local visc = def.liquid_viscosity or 0
+				le._viscosity = visc
+
+				local vpenalty = math.max(0.1, 0.98 - 0.1 * visc)
+				if math.abs(v.x) > 0.001 then
+					v.x = v.x * vpenalty
+				end
+				if math.abs(v.z) > 0.001 then
+					v.z = v.z * vpenalty
+				end
+			end
+		end
+	end
+
+	-- Pass to entity
+	if v then obj:set_velocity(v) end
+	if a then obj:set_acceleration(a) end
+
+	-- Update projectile yaw to match velocity direction
+	if v and le and not le._stuck then
+		local yaw = minetest.dir_to_yaw(v) + YAW_OFFSET
+		local pitch = dir_to_pitch(v)
+		obj:set_rotation(vector.new(0,yaw,pitch))
+	end
+end
+
 function mod.update_projectile(self, dtime)
 	if self._removed then return end
 
@@ -22,6 +77,8 @@ function mod.update_projectile(self, dtime)
 			return
 		end
 	end
+
+	mod.projectile_physics(self.object, entity_def)
 end
 
 local function no_op()
@@ -300,14 +357,13 @@ function mod.raycast_collides_with_entities(self, dtime, entity_def, projectile_
 end
 
 function mod.create(entity_id, options)
-	local obj = minetest.add_entity(options.pos, entity_id, options.staticdata)
+	local pos = options.pos
+	local obj = minetest.add_entity(pos, entity_id, options.staticdata)
 
-	-- Set initial velocoty and acceleration
-	obj:set_velocity(vector.multiply(options.dir or vector.zero(), options.velocity or 0))
-	obj:set_acceleration(vector.add(
-		vector.multiply(options.dir or vector.zero(), -math.abs(options.drag)),
-		vector.new(0,-GRAVITY,0)
-	))
+	-- Set initial velocity and acceleration
+	local v = vector.multiply(options.dir or vector.zero(), options.velocity or 0)
+	local a = vector.multiply(v, -math.abs(options.drag))
+	mod.projectile_physics(obj, entity_def, v, a)
 
 	-- Update projectile parameters
 	local luaentity = obj:get_luaentity()

mods/ITEMS/vl_projectile/mod.conf

@@ -1,2 +1,3 @@
 name = vl_projectile
 depends = mcl_util
+optional_depends = vl_physics