AI Pursuit Behavior

I am trying some logic to allow ai to go after a target and calculate the position they will be in the future. Then turning the wheel to the new target position. The problem is that I don't get the correct results back. I am using the information from this website about pursuit and evade behaviors. https://gamedevelopment.tutsplus.co...ing-behaviors-pursuit-and-evade--gamedev-2946

Here is what I have come up with so far.


**********************************************************************************************************
--aiVel2Target and aiTimetoTarget come from the ai.lua file.
--vdata is the ai vehicle data
--tdata is the target vehicle data


local aiVel2Target = vec3(vdata.vel):dot((tdata.pos - vdata.pos):normalized())
local aiTimeToTarget = (tdata.pos - vdata.pos):length() / (aiVel2Target + 1e-30)

--pursuit logic from gamedevelopment.com
local futurePos = tdata.pos + (tdata.vel * aiTimeToTarget)

targetVec = (futurePos - vdata.pos):normalized()

print(aiVel2Target)
print(aiTimeToTarget)
print(futurePos)
print(targetVec)

print(dirDiff)

--calculate a new steering wheel position for the ai
local dirDiff2 = math.asin(dirVec.x * targetVec.y - dirVec.y * targetVec.x)

if dirDiff2 > 0 or dirDiff2 < 0 then
dirDiff = dirDiff2
print(dirDiff2.."new diff")
end

********************************************************************************************************
Results
230.81024|A|GELua.print|vec3(-0.36776748664375,-0.92991523141565,0.002176728948314)
230.81029|A|GELua.print|-0.075835180804463
230.81032|A|GELua.print|-473.2302927265
230.81035|A|GELua.print|vec3(824.26627325285,3063.0274744736,72.979271442529)
230.81038|A|GELua.print|vec3(0.21071781268679,0.97754466518054,-0.0021049925328699)
230.81040|A|GELua.print|-1.498599470887
230.81042|A|GELua.print|1.3350355973452new diff