e2_applytorque.txt

--@name E2 ApplyTorque
--@author legokidlogan
--@server

--[[
    - A tool for easily and stably rotating unfrozen entities.
--]]


torqueStrength = torqueStrength or 100
torqueStabilization = torqueStabilization or 30


local mClamp = math.clamp
local mAbs = math.abs

function clampVec( v )
    return Vector(
        mClamp( v.x, -100000000, 100000000 ),
        mClamp( v.y, -100000000, 100000000 ),
        mClamp( v.z, -100000000, 100000000 )
    )
end

-- e2's version of the applyTorque() function, ripped from wiremod
function e2ApplyTorque( ent, torque )
    if torque == Vector( 0, 0, 0 ) then return end

    torque = clampVec( torque )

    local phys = ent:getPhysicsObject()
    local torqueamount = torque:getLength()

    -- Convert torque from local to world axis
    torque = phys:localToWorld( torque ) - phys:getPos()

    -- Find two vectors perpendicular to the torque axis
    local off = Vector( 0, 0, 0 )

    if mAbs( torque.x ) > torqueamount * 0.1 or mAbs( torque.z ) > torqueamount * 0.1 then
        off = Vector( -torque.z, 0, torque.x )
    else
        off = Vector( -torque.y, torque.x, 0 )
    end

    off = off:getNormalized() * torqueamount * 0.5

    local dir = ( torque:cross( off ) ):getNormalized()

    dir = clampVec( dir )
    off = clampVec( off )

    phys:applyForceOffset( dir, off )
    phys:applyForceOffset( dir * -1, off * -1 )
end

-- If called frequently via think/timer, this will stably rotate ent to the angle desAng using torque.
function torqueAlign( ent, desAng, overrideStrength, overrideStabilization )
    local CQ = ent:getAngles():getQuaternion()
    local TQ = desAng:getQuaternion()
    local Q = TQ / CQ
    local Torque = ent:worldToLocal( Q:getRotationVector() + ent:getPos() )

    e2ApplyTorque( ent, ( Torque * ( overrideStrength or torqueStrength ) - ent:getAngleVelocity() * ( overrideStabilization or torqueStabilization ) ) * ent:getInertia() )
end