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isLineOfSightClear

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This function checks if there are obstacles between two points of the game world, optionally ignoring certain kinds of elements. Use processLineOfSight if you want more information about what the ray hits.

Note

This function does currently NOT support collisions with the "shootthrough" flag enabled. That means: isLineOfSightClear will never collide with such collisions and this can lead to unreliabilities. The "shootthrough" flag is used by many beach/sand/underwater objects.

Syntax

 isLineOfSightClear ( )

Code Examples

client

isLineOfSightClear is the economical way to cast a ray in the world. This example demonstrates how you can easily implement basic NPC behaviour such as jumping obstacles. A 3D line is drawn connecting the two points in the ray.

local t_Data = {}


local function updateNPC ()
    if (not isElement(t_Data.ped) or (getElementHealth(t_Data.ped) == 0)) then
        return toggleNPCFollower ()
    end


    local t_PlayerPos = {getElementPosition(localPlayer)}
    local t_PedPos = {getElementPosition(t_Data.ped)}


    local intDistance = getDistanceBetweenPoints3D (t_PedPos[1], t_PedPos[2], t_PedPos[3], unpack(t_PlayerPos))
    if (intDistance < 4) then
        setPedControlState (t_Data.ped, 'forwards', false)
        return true
    end


    -- Calculate the rotation between ped and player position
    local intPedRot = -math.deg (math.atan2(t_PlayerPos[1] - t_PedPos[1], t_PlayerPos[2] - t_PedPos[2]))
    if intPedRot < 0 then intPedRot = intPedRot + 360 end;


    setElementRotation (t_Data.ped, 0, 0, intPedRot, 'default', true)
    -- At this point we know that the ped needs to move it
    setPedControlState (t_Data.ped, 'forwards', true)


    local bPathClear = true
    local t_Matrix = getElementMatrix (t_Data.ped)


    -- Calculate a position 1m ahead of ped
    local int_RayX = t_Matrix[2][1] + t_Matrix[4][1]
    local int_RayY = t_Matrix[2][2] + t_Matrix[4][2]
    local int_RayZ = t_Matrix[2][3] + t_Matrix[4][3]


    -- We cast 10 rays 1m ahead of the ped
    for i = 1, 10 do
        local intSourceX, intSourceY, intSourceZ = t_PedPos[1], t_PedPos[2], t_PedPos[3]


        -- The target position height is identical to the center of the ped (1m above ground)
        -- We lower this value by 0.5m to detect short obstacles
        local intTargetX, intTargetY, intTargetZ = int_RayX, int_RayY, int_RayZ - 0.5 + i*0.2


        bPathClear = isLineOfSightClear (intSourceX, intSourceY, intSourceZ, intTargetX, intTargetY, intTargetZ, true, true, false, true)
        dxDrawLine3D (intSourceX, intSourceY, intSourceZ, intTargetX, intTargetY, intTargetZ, bPathClear and tocolor(255,255,255,255) or tocolor(255,0,0,255))


        if (not bPathClear) then
            break
        end
    end


    if (not bPathClear) then
        setPedControlState (t_Data.ped, 'jump', true)
    else
        setPedControlState (t_Data.ped, 'jump', false)
    end


    if (intDistance > 15) then
        setPedControlState (t_Data.ped, 'sprint', true)
    else
        setPedControlState (t_Data.ped, 'sprint', false)
    end
end


function toggleNPCFollower ()
    if (t_Data.ped) then
        if (t_Data.updateNPCTimer) then
            if (isTimer(t_Data.updateNPCTimer)) then
                killTimer (t_Data.updateNPCTimer)
            end
        end
        if (isElement(t_Data.ped)) then
            destroyElement (t_Data.ped)
        end
        t_Data.ped = nil
        return true
    end


    local intX, intY, intZ = getElementPosition (localPlayer)
    local _, _, intRZ = getElementRotation (localPlayer)
    local t_Matrix = getElementMatrix (localPlayer)


    -- Calculate a position 4m behind local player
    local intPedX = -4 * t_Matrix[2][1] + t_Matrix[4][1]
    local intPedY = -4 * t_Matrix[2][2] + t_Matrix[4][2]
    local intPedZ = -4 * t_Matrix[2][3] + t_Matrix[4][3]


    t_Data.ped = createPed (0, intPedX, intPedY, intPedZ, intRZ)
    t_Data.updateNPCTimer = setTimer (updateNPC, 50, 0)
end
addCommandHandler ('npc', toggleNPCFollower)

See Also

World Functions
Reference