track player

[Wisin]

hi, i made a track script that allows the player to track another player and a label will appear at screen with the meters he is from you, all working fine but i want to make like "Robot is approximately 50 north from you" my question is, how i make that "north" or "south"?

thanks in advance.

[dzek (varez)]

you need all directions (W E N S) or just N S ? if Y of "robot" > Y of player - north, else - south.

[Wisin]

thats my question, can you give me a little example of what i need to make?

[dzek (varez)]

i asked you if you need only N/S or all directions?... you didnt answer

[Wisin]

oh sorry i didn't readed it all, all directions.

[dzek (varez)]

you need to get distance 2d between player and robot, "virtually create" point C placed your distance length to north ( so X of player, Y + distance),

count the angle PLAYER, C, ROBOT (trigonometry, search wikipedia), now if robot X < player X - add 180 to result.

you will get direction (azimuth). now if its:

0-45 or 315-360 == north

45-135 == east

135-225 = south

225 - 315 = west

edit: function to count angle between 3 points:

  
function getAngleBetweenPoints2D(ax,ay,bx,by,cx,cy) 
    local AB = { ax-bx, ay-by } 
    local BC = { cx-bx, cy-by } 
    local AB_ = getDistanceBetweenPoints2D(ax,ay,bx,by) 
    local BC_ = getDistanceBetweenPoints2D(bx,by,cx,cy) 
    local iloczynSkalarny = AB[1]*BC[1] + AB[2]*BC[2] 
    local tmp = iloczynSkalarny/(AB_*BC_) 
    local kat = math.acos(tmp) 
    local degrees = kat*180/(22/7) 
    --outputChatBox("deg "..degrees) 
    return degrees 
end 
-- note: in my script there was angle invertion on return (180-degrees) - not sure if you should use it or not, as i dont remember it exactly 
  

[Wisin]

i made this but keeps returning "north" and "east"

x, y, z = getElementPosition ( ped ) 
x2, y2, z2 = getElementPosition ( player ) 
distance = getDistanceBetweenPoints2D ( x, y, x2, y2 ) 
local newvalue = math.floor ( distance ) 
local loc = getAngleBetweenPoints2D(x,y,x2,y2,x,y2) 
if loc < 45 then 
loca = "north" 
elseif loc < 135 then 
loca = "east" 
elseif loc < 225 then 
loca = "south" 
elseif loc < 315 then 
loca = "west" 

[dzek (varez)]

you didnt read carefully..

try this one, should work, but im not a math god, also this was written in browser..

  
local px,py,pz = getElementPosition(player) 
local rx, ry, rz = getElementPosition(bot) 
local distanceBetweenPlayerAndBot = getDistanceBetweenElements2D(px,py,rx,ry) 
local cx = px 
local cy = py+distanceBetweenPlayerAndBot 
local angle = getAngleBetweenPoints2D(px,py,cx,cy,rx,ry) 
if rxif (angle >= 0 and angle < 45) or (angle > 315 and angle <= 360) then 
  direction = "north" 
elseif (angle>45 and angle <= 135) then 
  direction = "east" 
elseif (angle>135 and angle <= 225) then 
  direction = "south" 
elseif (angle>225 and angle <= 315) then 
  direction = "west" 
end 
  

[Wisin]

dosn't works makes this error: attempt to call global 'getDistanceBetweenElements2D' (a nil value), at line: local distanceBetweenPlayerAndBot = getDistanceBetweenElements2D(px,py,rx,ry)

[dzek (varez)]

maybe try doing something by yourself?

i told you it was written in browser - the only thing you had to do is open wiki and see my mistake.

it's: getDistanceBetweenPoints2D

...

[Wisin]

thank you, its working

[dzek (varez)]

are directions ok? or just script is not broking? im wondering if i did everything right as i suck at maths

[Wisin]

i walk around the bot and it sets to south,west,north etc

[dzek (varez)]

are the directions correct? not inverted or just random?

[Wisin]

lets hope they are correct, i don't know how to test that.

[dzek (varez)]

lol, just go to the north from the bot and check if it is saying "south"? same for other directions..

[Wisin]

yes directions are correct i checked and they're right thanks again.

[dzek (varez)]

your welcome, im happy that math thing done by me actually worked