drift script

[DakiLLa]

hi. I want to make not too much difficult code for drift. I tryed to make it with marker, for begin. And i have two questions: how to calculate numbers of "getVehicleTurnVelocity" like 400 not 0.00456789...e" ? example from wiki gives only decimal value..

And how to sum all picked up values from turnVelocity when player is in marker?

This code gives me result when player only hits marker.

function onMarkerHit ( thePlayer, matchingDimension ) 
    if source == marker then 
        local vehicle = getPlayerOccupiedVehicle ( thePlayer ) 
        if ( not vehicle ) then 
            outputChatBox ( "You need to be in a vehicle to activate this marker!", thePlayer, 255, 0, 0 ) 
        else 
            local x, y, z = getVehicleTurnVelocity ( vehicle ) 
            actualturn = ( x^2 + y^2 + z^2)^(0.5)  
            outputChatBox ( "Your current turn velocity: " .. actualturn .. " points.", thePlayer, 0, 255, 0 ) 
        end 
   end 
end 
addEventHandler ( "onMarkerHit", marker, onMarkerHit ) 
  

[DefiniteIntegral]

I am not certain, but I think turn velocity is measured in radians per second. Can someone confirm this?

Drift is about a bit more than turn velocity. You should take rotation, velocity and speed into account also. Trigonometry, vectors and dot products are your friend. Getting a really accurate measurement of drift in MTA might be difficult though, since I don't think there is a way to get the coordinates of the center of the front and back axles.

So yeah a good drift measurement is difficult if you don't know some math. If you want an simple one you should be able to do that pretty easily.

Just set some parameters for min and max speed and turn velocity, and come up with an arbitrary score.

eg

  
  
minspeed = 0.1  
maxspeed = 1.5 
minturnspeed = math.rad(1)  
maxturnspeed = math.rad(45)  
  
maxscore = 10.0  -- Score when drifting at maximum speed and turn velocity 
  
  
function someFunction(vehicle) 
  
local vx, vy, vz = getElementVelocity(vehicle) 
local rx, ry, rz = getVehicleRotation(vehicle) 
local rvx, rvy, rvz = getVehicleTurnVelocity(vehicle) 
  
local speed = math.sqrt(vx*vx + vy*vy + vz*vz) 
  
local score = 0 
  
local onGround = isVehicleOnGround(vehicle) -- this wont work for monster truck 
local upright =((rx >= 0 and rx <= 90) or (rx >= 270 and rx <= 360)) and ((ry >= 0 and ry <= 90) or (ry >= 270 and ry <= 360)) -- Don't score upside down vehicle 
  
-- only score if on ground and upright 
if onGround == true and upright == true then 
  
-- only score if above minimum speed and turn speed limits 
-- Only take vehicles Z rotation into account since it is vehicle relative 
if speed >= minspeed and rvz >= minturnspeed then 
  
-- cap speeds at maximum. This allows scoring above max speed, capped at max rate. 
if speed > maxspeed then 
speed = maxspeed 
end 
  
if turnspeed > maxturnspeed then 
turnspeed = maxturnspeed 
end 
  
-- add score 
local speedRatio = (speed - minspeed) / (maxspeed - minspeed) -- Get speed and turn speed ratio 
local turnSpeedRatio = (rvz - minturnspeed) / (maxturnspeed - minturnspeed) 
  
local scoreScalar = speedRatio * turnSpeedRatio -- Multiply ratios to find combined ratio.  
score = maxscore * scoreScalar -- Scale max score by combined speed ratio 
  
end 
  
end 
  
return score 
  
end 
  
  
  

.. or something like that. I just came up with that off the top of my head, there are probably mistakes.

As for your marker issue... you could use the server events onMarkerHit and onMarkerLeave to start/stop a timer to accumulate score. Or, you could just have an infinitely repeating timer so drifting can be scored constantly.

[DakiLLa]

hm, if i will use onClientRender for this, but i think it will not get a result there is some server functions. I dont know what i need to use, onMarkerHit and Leave - wrong ways to activate this script i think..somebody help i really need this script working nice!