From 6193b2630f7f4de51b15220c8230b7700a81a4ec Mon Sep 17 00:00:00 2001
From: teknomunk <teknomunk@protonmail.com>
Date: Sun, 20 Oct 2024 13:31:29 -0500
Subject: [PATCH] Move tracer to vl_projectile

---
 mods/ITEMS/mcl_bows/arrow.lua     | 26 +++++---------------------
 mods/ITEMS/vl_projectile/api.md   |  4 +++-
 mods/ITEMS/vl_projectile/init.lua | 28 ++++++++++++++++++++++++++++
 3 files changed, 36 insertions(+), 22 deletions(-)

diff --git a/mods/ITEMS/mcl_bows/arrow.lua b/mods/ITEMS/mcl_bows/arrow.lua
index 1c4194de0..68c488fc8 100644
--- a/mods/ITEMS/mcl_bows/arrow.lua
+++ b/mods/ITEMS/mcl_bows/arrow.lua
@@ -132,8 +132,13 @@ local arrow_entity = {
 		damage_groups = function(self)
 			return { fleshy = self._damage }
 		end,
+		hide_tracer = function(self)
+			return self._stuck or self._damage < 9 or self._in_player
+		end,
+		tracer_texture = "mobs_mc_arrow_particle.png",
 		behaviors = {
 			vl_projectile.burns,
+			vl_projectile.has_tracer,
 
 			-- Custom arrow behaviors
 			function(self, dtime)
@@ -146,27 +151,6 @@ local arrow_entity = {
 				local pos = self.object:get_pos()
 				self._allow_punch = self._allow_punch or not self._owner or not self._startpos or pos and vector.distance(self._startpos, pos) > 1.5
 
-				-- Add tracer
-				if self._damage >= 9 and self._in_player == false then
-					minetest.add_particlespawner({
-						amount = 20,
-						time = .2,
-						minpos = vector.zero(),
-						maxpos = vector.zero(),
-						minvel = vector.new(-0.1,-0.1,-0.1),
-						maxvel = vector.new(0.1,0.1,0.1),
-						minexptime = 0.5,
-						maxexptime = 0.5,
-						minsize = 2,
-						maxsize = 2,
-						attached = self.object,
-						collisiondetection = false,
-						vertical = false,
-						texture = "mobs_mc_arrow_particle.png",
-						glow = 1,
-					})
-				end
-
 				-- Give the arrows a maximum flight time
 				self._time_in_air = (self._time_in_air or 0) + dtime
 				if self._time_in_air > ARROW_TIMEOUT then
diff --git a/mods/ITEMS/vl_projectile/api.md b/mods/ITEMS/vl_projectile/api.md
index b132546af..942c70685 100644
--- a/mods/ITEMS/vl_projectile/api.md
+++ b/mods/ITEMS/vl_projectile/api.md
@@ -62,9 +62,11 @@ Arguments:
 The projectile API supports specifying the behaviors that a projectile will exhibit. There are several
 standard behaviors provided with the API:
 
-* `vl_projectile.burns`: Projectiles can be set on fire
+* `vl_projectile.burns`: projectile can be set on fire
 * `vl_projectile.collides_with_solids`: handles collisions between projectiles and solid nodes
 * `vl_projectile.collides_with_entities`: handles collisions between projectiles and entities by checking nearby entities
+* `vl_projectile.has_tracer`: projectile will have a tracer trail when thrown/shot. Projectile can define
+   `_vl_projectile.hide_tracer = function(self)` to conditionally hide the tracer.
 * `vl_projectile.raycast_collides_with_entities`: handles collisions between projectils and entities by performing a raycast
    check along the path of movement.
 
diff --git a/mods/ITEMS/vl_projectile/init.lua b/mods/ITEMS/vl_projectile/init.lua
index f8107de3c..db1e15499 100644
--- a/mods/ITEMS/vl_projectile/init.lua
+++ b/mods/ITEMS/vl_projectile/init.lua
@@ -10,6 +10,8 @@ local enable_pvp = minetest.settings:get_bool("enable_pvp")
 
 function mod.projectile_physics(obj, entity_def, v, a)
 	local le = obj:get_luaentity()
+	if not le then return end
+
 	local entity_def = minetest.registered_entities[le.name]
 	local pos = obj:get_pos()
 	if not pos then return end
@@ -203,6 +205,30 @@ function mod.burns(self, dtime, entity_def, projectile_def)
 	end
 end
 
+function mod.has_tracer(self, dtime, entity_def, projectile_def)
+	local hide_tracer = projectile_def.hide_tracer
+	if hide_tracer and hide_tracer(self) then return end
+
+	-- Add tracer
+	minetest.add_particlespawner({
+		amount = 20,
+		time = .2,
+		minpos = vector.zero(),
+		maxpos = vector.zero(),
+		minvel = vector.new(-0.1,-0.1,-0.1),
+		maxvel = vector.new(0.1,0.1,0.1),
+		minexptime = 0.5,
+		maxexptime = 0.5,
+		minsize = 2,
+		maxsize = 2,
+		attached = self.object,
+		collisiondetection = false,
+		vertical = false,
+		texture = projectile_def.tracer_texture or "mobs_mc_arrow_particle.png",
+		glow = 1,
+	})
+end
+
 function mod.collides_with_solids(self, dtime, entity_def, projectile_def)
 	local pos = self.object:get_pos()
 	if not pos then return end
@@ -380,6 +406,8 @@ function mod.raycast_collides_with_entities(self, dtime, entity_def, projectile_
 	local closest_object, closest_distance
 
 	local pos = self.object:get_pos()
+	if not pos then return end
+
 	local arrow_dir = self.object:get_velocity()
 
 	--create a raycast from the arrow based on the velocity of the arrow to deal with lag