Train scripting

Help and Feedback Scripting Support
#1

I’ve been trying to make a functioning train. While I understand how to use spinning wheels to achieve forward momentum, those are more physics-intensive than BodyVelocity.

What I don’t understand is how to use BodyVelocity. The only free model available in Studio is (https://www.roblox.com/library/3111261455/Body-velocity-train-base-WORKING), may or may not be leaked; apparently made by yyrebrblx.

My main issue is generally being confused with how to make this. I have tried to search, but I can’t really find anything… Nothing I can find anywhere generally helps with this.

Anything helps!

The thing I need most is someone to explain to me how the code works; and/or point me to a good scripting tutorial for Lua

Here’s the code:

bin = script.Parent
eng = { }
st = bin.VehicleSeat
msp = script.MaximumSpeed.Value
st.MaxSpeed = msp
mrs = script.MaximumReverseSpeed.Value --> Maximum Reverse Speed
spt = script.SpeedPerThrottle.Value --> Speed Per Throttle. This is how much each notch on the throttle changes
mxt = math.ceil(msp / spt) --> This is the maximum throttle
crt = 0 --> Current throttle
csd = 0 --> Current speed
cdr = 0 --> Current direction
drive = false --> Is the train driving. False = not driving, true = driving
plr = nil --> This will change to the current driver
DirTable = {"Reverse", "Neutral", "Foward"}
TrtStp = 0 --> This is used so there is a second or 2 gap in between changing the throttle.

function GetEngines() --> This finds all the engines in the train and then puts them into the table 'eng'
	for _, a in pairs(bin:GetChildren()) do
		if (a.Name == "Engine") then
			--if a:findFirstChild("BodyVelocity") then
				local bv = script.BodyVelocity:Clone()
				bv.Parent = a
				eng[#eng + 1] = a
			--end
		end
	end
end 

function GetDirString() return DirTable[cdr + 2]; end

function GetSpeedString(a)
	if (a < 0) then return "-"..a.."" end
	return msp
end

function GetPlayer()
	local a = st.SeatWeld.Part1
	if a then
		local p = game.Players:findFirstChild(a.Parent.Name)
		if p then
			return p
		end
	end
	return false
end

function GetHint(p)
	-- local a = p:findFirstChild("TrainDriveHint")
	local a = p.PlayerGui:findFirstChild("TrainDriveGui")
	if a then return a; end
	return
end

wait(1)
GetEngines()

h = script.TrainDriveGui:Clone()
h.TextDisplay.Text = "Direction: "..GetDirString().." - Throttle: "..crt.."/"..mxt.." - Speed: "..GetSpeedString(csd).."/"..GetSpeedString(mrs)
h2 = h:Clone();

st.ChildAdded:connect(function () 
	drive = true 
	--[[local cam = script.Cam:Clone()
	cam.Disabled = false
	if GetPlayer() then
		cam.Parent = GetPlayer().Backpack
	end]]
end)

st.ChildRemoved:connect(function () 
	drive = false
	if GetHint(plr) then 
		GetHint(plr).Parent = nil 
		h = script.TrainDriveGui:Clone()
		h2 = h:Clone()
	end
end)

while true do
	wait(0.05)
	if drive then
		local p = GetPlayer()
		if p then
			plr = p 
			local gh = GetHint(p)
			if not gh then h2.Parent = p.PlayerGui end
			local h2 = GetHint(p)
			--Now to calculate the current throttle
			local trt, dir = st.Steer, st.Throttle
			if (TrtStp > 0) then
				TrtStp = TrtStp - 0.5
			else
				if (trt == -1) then
					if (crt > 0) then crt = crt - 1; TrtStp = 1; end
				elseif(trt == 1) then
					if (crt < mxt) then crt = crt + 1; TrtStp = 1; end
				end
			end
			--Throttle calculated, now get the direction
			cdr = cdr + dir
			if (cdr > 1) then cdr = 1 end
			if (cdr < -1) then cdr = -1 end
			--Direction done, now work out the speed			
			if (crt == 0) then
				if (csd < 0) then
					if (csd + 0.5 > 0) then
						csd = 0
					else
						csd = csd + 0.5
					end
				elseif (csd > 0) then
					if (csd - 0.5 < 0) then
						csd = 0
					else
						csd = csd - 0.5
					end
				end					
			end
			if (crt > 0) then
				if (cdr == -1) then
					if (csd - (crt / 10) < (spt * crt) * -1) then 
						csd = (spt * crt) * -1
					else
						csd = csd - (crt / 10)
					end
					csd = csd - (crt / 10)
					if (csd < (spt * crt) * -1) then csd = csd + 0.5 end
					if (csd < (mrs * -1)) then csd = mrs  * -1 end
					if (csd > 0) then csd = csd * -1 end
				elseif (cdr == 1) then
					if (csd + (crt / 10) > spt * crt) then 
						csd = spt * crt
					else
						csd = csd + (crt / 10)
					end
					if (csd > spt * crt) then csd = csd - 0.5 end
					if (csd > msp) then csd = msp end
					if (csd < 0) then csd = csd * -1 end
				end
			end
			for _, a in pairs(eng) do
				a.BodyVelocity.velocity = a.CFrame.lookVector * csd
			end
			h2.TextDisplay.Text = "Direction: "..GetDirString().." - Throttle: "..crt.."/"..mxt.." - Speed: "..csd.."/"..GetSpeedString(mrs)..""
		end
	end
end

Thanks!
-0rcaa

2 Likes