calculate fall time

[Xwad]

Hi. I started creating a new plane bombing script. I created this code that calculates the x,y,z position, where the element (bomb) will fall to.

There is only one problem. It's bugging (the positions are not always correct) and i can't fix it. Any idea? Thx.

 

local face = dxCreateTexture( "crosshair.png" )

function output_bombs()

    local veh = getPedOccupiedVehicle(localPlayer)
    local speed = getElementSpeed(veh, 0)
    local px,py,pz = getElementPosition(veh)
    local rx,ry,rz = getElementRotation(veh)
    local vx,vy,vz = getElementVelocity(veh)
    local ground = getGroundPosition(px,py,pz)
    local height = pz - ground

    local vz = vz * -50

    if vz < 0 then
      vz = vz * -1
    end	

    local time = vz - math.sqrt( vz*vz + height * 19.6 ) / -9.8 -- THAT'S IT

    if time < 0 then
      time = time * -1
    end

    local distanceY = speed * time

    local npx = px + distanceY
    local npy = py + distanceY

    local x,y,z = getPositionFromElementOffset(veh,0,distanceY,0)
    local ground = getGroundPosition(npx,npy,pz)	

    dxDrawImage3D( x,y-10,ground+1, 0,20, face, tocolor( 255,255,255, 255 ), 0, false, x,y,z )		

    dxDrawText ( "height: "..height, 400,100, 0,0, tocolor ( 240,240,240, 255 ), 1.5 )
    dxDrawText ( "speed: "..speed, 400,50, 0,0, tocolor ( 240,240,240, 255 ), 1.5 )
    dxDrawText ( "fall time: "..time, 400,150, 0,0, tocolor ( 240,240,240, 255 ), 1.5 )	
    dxDrawText ( "initial speed: "..vz, 400,250, 0,0, tocolor ( 240,240,240, 255 ), 1.5 )
end

 

Edited October 15, 2019 by Xwad

[Overkillz]

Probably

getTickCount()

Will solve your problem. Just when the "Bomb" reach the point where you want it, get the timer using

local startTick = getTickCount()
--When the bomb reach the point just get the time
local timeVariable = getTickCount() - startTick

Regards.

[Xwad]

But im trying to add a croshair to the ground position where the bomb will fall to. I am using the free fall formula:

local time = vz - math.sqrt( vz*vz + height * 19.6 ) / -9.8

VZ : initial speed of the element when its released from the plane

height : height of the plane (in meters)

and the 19.6 (9.8x2) is the gravitational acceleration.

When i get the time then i can calculate the y distance by multiplicating the time with the planes speed (m/s).

Edited October 16, 2019 by Xwad

[Overkillz]

If you are trying to add a crosshair in the groun. You can use

dxDrawMaterialLine3D()

Read carefully the arguments to draw it correctly.

[Xwad]

No, that's not exactly what i need. I have problems with maths.

Look, i uploaded the script to mediafire!  

https://www.mediafire.com/file/b3xd1n4ws979zgu/crosshair.rar/file

I did not express myself clearly enough so i think the easiest way is if i give you the script so you can test it.

[Xwad]

I fixed some bugs but its still not perfect. idk why.

https://www.mediafire.com/file/frrcxykix48mg29/crosshair.rar/file

[Overkillz]

Im not sure about this, but try to use set as gravity 0.8

Btw, Im not understanding what do you really want.