From b8ac747ad80bbaffafa9ff12112b42b5bfed7c93 Mon Sep 17 00:00:00 2001
From: oilboi <47129783+oilboi@users.noreply.github.com>
Date: Sat, 4 Jul 2020 19:03:26 -0400
Subject: [PATCH] Add in more advanced rail pathfinding

---
 mods/minecart/init.lua | 127 ++++++++++++++++++++++++-----------------
 1 file changed, 75 insertions(+), 52 deletions(-)

diff --git a/mods/minecart/init.lua b/mods/minecart/init.lua
index e9c806e..b61e24b 100644
--- a/mods/minecart/init.lua
+++ b/mods/minecart/init.lua
@@ -68,68 +68,87 @@ end
 
 local function direction_snap(self)
 	local dir = self.dir
+	local pitch = 0
+	if dir.y == 1 then pitch = math.pi/4 end
+	if dir.y == -1 then pitch = -math.pi/4 end
 	local yaw = minetest.dir_to_yaw(dir)
-	self.object:set_rotation(vector.new(0,yaw,0))
+	self.object:set_rotation(vector.new(pitch,yaw,0))
 end
 
 local function turn_snap(pos,self,dir,dir2)
-	if dir.x ~= 0 and dir2.z ~= 0 then
-		local inertia = math.abs(self.velocity.x)
-		self.velocity = vector.multiply(dir2,inertia)
-		self.dir = dir2
-		self.axis_lock = "z"
-		self.object:set_pos(pos)
-		direction_snap(self)
-		return(true)
-	elseif dir.z ~= 0 and dir2.x ~= 0 then
-		local inertia = math.abs(self.velocity.z)
-		self.velocity = vector.multiply(dir2,inertia)
-		self.dir = dir2
-		self.axis_lock = "x"
-		self.object:set_pos(pos)
-		direction_snap(self)
-		return(true)
+	if self.axis_lock == "x" then
+		if dir.x ~= 0 and dir2.z ~= 0 then
+			local inertia = math.abs(self.velocity.x)
+			self.velocity = vector.multiply(dir2,inertia)
+			self.dir = dir2
+			self.axis_lock = "z"
+			self.object:set_pos(pos)
+			direction_snap(self)
+			return(true)
+		end
+	end
+	if self.axis_lock == "z" then
+		if dir.z ~= 0 and dir2.x ~= 0 then
+			local inertia = math.abs(self.velocity.z)
+			self.velocity = vector.multiply(dir2,inertia)
+			self.dir = dir2
+			self.axis_lock = "x"
+			self.object:set_pos(pos)
+			direction_snap(self)
+			return(true)
+		end
 	end
+	return(false)
 end
 
 local function climb_snap(pos,self,dir,dir2)
-	if dir.x == dir2.x and dir2.y ~= 0 then
-		print(dump(dir2))
-		print("x snapping")
-		local inertia = math.abs(self.velocity.x)
-		self.velocity = vector.multiply(dir2,inertia)
-		self.dir = dir2
-		self.axis_lock = "x"
-		self.object:set_pos(pos)
-		direction_snap(self)
-		return(true)
-	elseif dir.z == dir2.z and dir2.y ~= 0 then
-		local inertia = math.abs(self.velocity.z)
-		self.velocity = vector.multiply(dir2,inertia)
-		self.dir = dir2
-		self.axis_lock = "z"
-		self.object:set_pos(pos)
-		direction_snap(self)
-		return(true)
+	if self.axis_lock == "x" then
+		if dir.x == dir2.x and dir2.y ~= 0 then
+			local inertia = math.abs(self.velocity.x)
+			self.velocity = vector.multiply(dir2,inertia)
+			self.dir = dir2
+			self.axis_lock = "x"
+			self.object:set_pos(pos)
+			direction_snap(self)
+			return(true)
+		end
 	end
+	if self.axis_lock == "z" then
+		if dir.z == dir2.z and dir2.y ~= 0 then
+			local inertia = math.abs(self.velocity.z)
+			self.velocity = vector.multiply(dir2,inertia)
+			self.dir = dir2
+			self.axis_lock = "z"
+			self.object:set_pos(pos)
+			direction_snap(self)
+			return(true)
+		end
+	end
+	return(false)
 end
 
 local function straight_snap(pos,self,dir)
-	if dir.x ~= 0 and pool[minetest.hash_node_position(vector.add(pos,vector.new(dir.x,0,0)))] then
-		self.velocity = vector.new(self.velocity.x,0,0)
-		self.dir = vector.new(dir.x,0,0)
-		self.axis_lock = "x"
-		self.object:set_pos(pos)
-		direction_snap(self)
-		return(true)
-	elseif dir.z ~= 0 and pool[minetest.hash_node_position(vector.add(pos,vector.new(0,0,dir.z)))] then
-		self.velocity = vector.new(0,0,self.velocity.z)
-		self.dir = vector.new(0,0,dir.z)
-		self.axis_lock = "z"
-		self.object:set_pos(pos)
-		direction_snap(self)
-		return(true)
+	if self.axis_lock == "x" then
+		if dir.x ~= 0 and pool[minetest.hash_node_position(vector.add(pos,vector.new(dir.x,0,0)))] then
+			self.velocity = vector.new(self.velocity.x,0,0)
+			self.dir = vector.new(dir.x,0,0)
+			self.axis_lock = "x"
+			self.object:set_pos(pos)
+			direction_snap(self)
+			return(true)
+		end
 	end
+	if self.axis_lock == "z" then
+		if dir.z ~= 0 and pool[minetest.hash_node_position(vector.add(pos,vector.new(0,0,dir.z)))] then
+			self.velocity = vector.new(0,0,self.velocity.z)
+			self.dir = vector.new(0,0,dir.z)
+			self.axis_lock = "z"
+			self.object:set_pos(pos)
+			direction_snap(self)
+			return(true)
+		end
+	end
+	return(false)
 end
 
 local function rail_brain(self,pos)
@@ -143,7 +162,7 @@ local function rail_brain(self,pos)
 
 	local triggered = false
 
-	if dir.x < 0 and pos2.x < pos.x then
+	if     dir.x < 0 and pos2.x < pos.x then
 		triggered = true
 	elseif dir.x > 0 and pos2.x > pos.x then
 		triggered = true
@@ -157,6 +176,7 @@ local function rail_brain(self,pos)
 	if triggered and not pool[minetest.hash_node_position(vector.add(pos,dir))] then
 
 		if straight_snap(pos,self,dir) then
+			print('beraking')
 			return
 		end
 
@@ -167,10 +187,13 @@ local function rail_brain(self,pos)
 			--stop slow down become physical, something
 		else
 			for _,dir2 in pairs(possible_dirs) do
-				if turn_snap(pos,self,dir,dir2) then
+				if climb_snap(pos,self,dir,dir2) then
 					return
 				end
-				if climb_snap(pos,self,dir,dir2) then
+			end
+			
+			for _,dir2 in pairs(possible_dirs) do
+				if turn_snap(pos,self,dir,dir2) then
 					return
 				end
 			end
-- 
2.44.0