problem with alpha

[Overkillz]

Hey dear guys, Im having a problem building a Lib, well, my idea is to create a rectangle which when the mouse is over it, the alpha increase only to it.

Well, its a system to create animate buttons

local sX,sY = guiGetScreenSize() 
  
function animB(posX,posY,sizeX,sizeY,r,g,b) 
    if isCursorHover(posX,posY,sizeX,sizeY) then 
        aFinal = math.min(aFinal + 20, 255) 
        dxDrawRectangle(posX,posY,sizeX,sizeY,tocolor(r,g,b,aFinal)) 
    else 
        aFinal = math.min(aFinal - 20, 0) 
        dxDrawRectangle(posX,posY,sizeX,sizeY,tocolor(r,g,b,aFinal)) 
    end 
end 
  
function isCursorHover(posX,posY,sizeX,sizeY) 
    local x,y = 0,0 
    if isCursorShowing() then x,y = getCursorPosition() x,y = sX*x,sY*y else return false end 
    if x>=posX and x<=posX+sizeX and y>=posY and y<=posY+sizeY then 
        return true 
    else 
        return false 
    end 
end 
-- ## LETS TEST IT 
function testingIt() 
    animB(500,500,270,40,255,255,255) 
end 
addEventHandler("onClientRender",getRootElement(),testingIt) 

Well, the error that I get on Debugscript 3 is:

attemt to perfom arithmetic on global 'aFinal' (a nil value)

I hope u can tell me how can I define it

Regards.

[ViRuZGamiing]

can't you just add this on line 2:

local aFinal = 0 

[Overkillz]

Ye, I know it, but if I add more than one element, like this

animB(800,500,270,40,255,255,255) 
    animB(800,700,270,40,255,255,255) 
    animB(300,700,270,40,255,255,255) 

The animation doesn't work.

[ViRuZGamiing]

Not 100% but I think you can do:

if (aFinal == nil) then 
 aFinal = 0 
end 

tested in LUA Demo

[Overkillz]

I didnt get u, whats the goal of mark the alpha as nil.

[ViRuZGamiing]

then you can declare the alpha as 0 the first time.

function animB(posX,posY,sizeX,sizeY,r,g,b) 
    if (aFinal == nil) then 
        aFinal = 0 
    end 
    if isCursorHover(posX,posY,sizeX,sizeY) then 
        aFinal = math.min(aFinal + 20, 255) 
        dxDrawRectangle(posX,posY,sizeX,sizeY,tocolor(r,g,b,aFinal)) 
    else 
        aFinal = math.min(aFinal - 20, 0) 
        dxDrawRectangle(posX,posY,sizeX,sizeY,tocolor(r,g,b,aFinal)) 
    end 
end 

[IIYAMA]

There is also math.max (another problem)

  
    else 
        aFinal = math.min(aFinal - 20, 0) 
        dxDrawRectangle(posX,posY,sizeX,sizeY,tocolor(r,g,b,aFinal)) 
    end 

    else 
        aFinal = math.max(aFinal - 20, 0) 
        dxDrawRectangle(posX,posY,sizeX,sizeY,tocolor(r,g,b,aFinal)) 
    end