From c1398b52cca1f3166db288f96279c3007562e321 Mon Sep 17 00:00:00 2001
From: teknomunk <teknomunk@protonmail.com>
Date: Tue, 23 Apr 2024 16:34:39 +0000
Subject: [PATCH] Stop carts from reversing when they stop, make stopped carts
 try to start moving in the direction the player is facing

---
 mods/ENTITIES/mcl_minecarts/carts.lua    |  2 ++
 mods/ENTITIES/mcl_minecarts/movement.lua | 28 +++++++++++++++---------
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/mods/ENTITIES/mcl_minecarts/carts.lua b/mods/ENTITIES/mcl_minecarts/carts.lua
index 6e4b9a528..ed19690d7 100644
--- a/mods/ENTITIES/mcl_minecarts/carts.lua
+++ b/mods/ENTITIES/mcl_minecarts/carts.lua
@@ -21,6 +21,7 @@ assert(handle_cart_enter)
 -- Constants
 local max_step_distance = 0.5
 local MINECART_MAX_HP = 4
+local TWO_OVER_PI = 2 / math.pi
 
 local function detach_driver(self)
 	local staticdata = self._staticdata
@@ -244,6 +245,7 @@ function DEFAULT_CART_DEF:on_step(dtime)
 			local controls = {}
 			if ctrl.up then controls.forward = now_time end
 			if ctrl.down then controls.brake = now_time end
+			controls.look = math.round(player:get_look_horizontal() * TWO_OVER_PI) % 4
 			staticdata.controls = controls
 		end
 
diff --git a/mods/ENTITIES/mcl_minecarts/movement.lua b/mods/ENTITIES/mcl_minecarts/movement.lua
index 2499bddc4..e4e682508 100644
--- a/mods/ENTITIES/mcl_minecarts/movement.lua
+++ b/mods/ENTITIES/mcl_minecarts/movement.lua
@@ -38,6 +38,16 @@ local function try_detach_minecart(staticdata)
 	end
 end
 
+local function reverse_direction(staticdata)
+	if staticdata.behind or staticdata.ahead then
+		reverse_train(staticdata)
+		return
+	end
+
+	mod.reverse_cart_direction(staticdata)
+end
+
+
 --[[
 	Array of hooks { {u,v,w}, name }
 	Actual position is pos + u * dir + v * right + w * up
@@ -248,6 +258,13 @@ local function calculate_acceleration(staticdata)
 	local time_active = minetest.get_gametime() - 0.25
 
 	if (ctrl.forward or 0) > time_active then
+		if staticdata.velocity == 0 then
+			local look_dir = minetest.facedir_to_dir(ctrl.look or 0)
+			local dot = vector.dot(staticdata.dir, look_dir)
+			if dot < 0 then
+				reverse_direction(staticdata)
+			end
+		end
 		acceleration = 4
 	elseif (ctrl.brake or 0) > time_active then
 		acceleration = -1.5
@@ -270,15 +287,6 @@ local function calculate_acceleration(staticdata)
 	return acceleration
 end
 
-local function reverse_direction(staticdata)
-	if staticdata.behind or staticdata.ahead then
-		reverse_train(staticdata)
-		return
-	end
-
-	mod.reverse_cart_direction(staticdata)
-end
-
 local function do_movement_step(staticdata, dtime)
 	if not staticdata.connected_at then return 0 end
 
@@ -405,7 +413,7 @@ local function do_movement_step(staticdata, dtime)
 
 		-- Update cart direction
 		staticdata.dir = next_dir
-	elseif stops_in_block and v_1 < (FRICTION/5) and a <= 0 then
+	elseif stops_in_block and v_1 < (FRICTION/5) and a <= 0 and staticdata.dir.y > 0 then
 		-- Handle direction flip due to gravity
 		if DEBUG then mcl_debug("Gravity flipped direction") end