Fix minor bugs

1 files changed, 8 insertions, 0 deletions

diff --git a/advtrains/trainlogic.lua b/advtrains/trainlogic.lua
index 4b76deb..7e9a613 100644
--- a/advtrains/trainlogic.lua
+++ b/advtrains/trainlogic.lua
@@ -428,25 +428,33 @@ function advtrains.train_step_b(id, train, dtime)
 	local v0 = train.velocity
 	local v1 = a*dtime+v0
 	v1 = math.min(v1, (train.max_speed or 10))
+	v1 = math.max(v1, 0)
 	local s
 	if a == 0 then s = v1*dtime
 	else s = (v1*v1 - v0*v0)/2/a
 	end
+	train.ctrl.lzb = nil
 	if lzblimit.velocity and lzblimit.velocity < train.velocity then
 		tmp_lever = lzblimit.lever
 		while (lzbmap[tmp_lever].t > dtime) do
 			tmp_lever = tmp_lever - 1
 		end
+		train.ctrl.lzb = tmp_lever
 		a = advtrains.get_acceleration(train, tmp_lever)
 		v0 = lzbmap[tmp_lever].v
 		t = dtime - lzbmap[tmp_lever].t
 		v1 = a*t+v0
 		v1 = math.min(v1, (train.max_speed or 10))
+		v1 = math.max(v1, 0)
 		s = lzbmap[tmp_lever].i - train.index
 		if a == 0 then s = s + v1*t
 		else s = s + (v1*v1-v0*v0)/2/a
 		end
 	end
+	-- FIX: calculate the average acceleration, as if it is static, to avoid
+	-- weird wagon positions
+	-- Since v0 might have been changed, we should use train.velocity instead.
+	a = (v1 - train.velocity)/dtime
 	--- 4b. Move train and update train properties ---
 	local pdist = train.path_dist[math.floor(train.index)] or 1
 	local distance = s / pdist