function init()
    DOORS_1_VELOCITY = 1.0
    DOORS_2_VELOCITY = 2.0

    doors1 = FindJoints("door1")
    doors2 = FindJoints("door2")

    local shapes = FindShapes("dcoll")
    for i=1, #shapes do
        local shape = shapes[i]
        SetShapeCollisionFilter(shape, 2, 255-2)
    end

    btn_open = FindShape("open")
    btn_close = FindShape("close")

    state = 0
    stateTime = 0.0

    clickUp = LoadSound("clickup.ogg")
	clickDown = LoadSound("clickdown.ogg")
end

function setState(s)
    state = s
    stateTime = 0.0
end

function timedOut()
    return stateTime > 10.0
end

function tick(dt)

    stateTime = stateTime + dt

    if state == 1 then

        local atTarget = true

        for i=1, #doors1 do
            local joint = doors1[i]
            local min, _ = GetJointLimits(joint)
            local m = GetJointMovement(joint)

            if m > min + 1 and not timedOut() then
                atTarget = false
            end

        end
        for i=1, #doors2 do
            local joint = doors2[i]
            local min, _ = GetJointLimits(joint)
            local m = GetJointMovement(joint)

            if m > min + 1 and not timedOut() then
                atTarget = false
            end
        end

        if atTarget then
            setState(0)
        end

    elseif state == 2 then
        local atTarget = true

        for i=1, #doors1 do
            local joint = doors1[i]
            local _, max = GetJointLimits(joint)
            local m = GetJointMovement(joint)

            if m < max - 4 and not timedOut() then
                atTarget = false
            end

        end
        for i=1, #doors2 do
            local joint = doors2[i]
            local _, max = GetJointLimits(joint)
            local m = GetJointMovement(joint)

            if m < max - 4 and not timedOut() then
                atTarget = false
            end
        end

        if atTarget then
            setState(0)
        end
    end

    if state ~= 0 then
        for i=1, #doors1 do
            local joint = doors1[i]
            local shapes = GetJointShapes(joint)
            for j = 1, #shapes do
                local body = GetShapeBody(shapes[j])
                if IsBodyDynamic(body) then
                    SetBodyActive(body, true)
                end
            end
        end
        for i=1, #doors2 do
            local joint = doors2[i]
            local shapes = GetJointShapes(joint)
            for j = 1, #shapes do
                local body = GetShapeBody(shapes[j])
                if IsBodyDynamic(body) then
                    SetBodyActive(body, true)
                end
            end
        end
    end

    if GetPlayerInteractShape() == btn_close and InputPressed("interact") then
        setState(1)
        PlaySound(clickDown)
        for i=1, #doors1 do
            local joint = doors1[i]
            local min, _ = GetJointLimits(joint)
            SetJointMotorTarget(joint, min, DOORS_1_VELOCITY)
        end
        for i=1, #doors2 do
            local joint = doors2[i]
            local min, _ = GetJointLimits(joint)
            SetJointMotorTarget(joint, min, DOORS_2_VELOCITY)
        end
    elseif GetPlayerInteractShape() == btn_open and InputPressed("interact") then
        setState(2)
        PlaySound(clickUp)
        for i=1, #doors1 do
            local joint = doors1[i]
            local _, max = GetJointLimits(joint)
            SetJointMotorTarget(joint, max, DOORS_1_VELOCITY)
        end
        for i=1, #doors2 do
            local joint = doors2[i]
            local _, max = GetJointLimits(joint)
            SetJointMotorTarget(joint, max, DOORS_2_VELOCITY)
        end
    end

    
end