PointInConcavePolygon

function pointInPolygon(pgon, tx, ty)
    if (#pgon < 6) then
        return false
    end

    local x1 = pgon[#pgon - 1]
    local y1 = pgon[#pgon]
    local cur_quad = getQuad(tx,ty,x1,y1)
    local next_quad
    local total = 0
    local i

    for i = 1,#pgon,2 do
        local x2 = pgon[i]
        local y2 = pgon[i+1]
        next_quad = getQuad(tx,ty,x2,y2)
        local diff = next_quad - cur_quad

        if (diff == 2) or (diff == -2) then
            if (x2 - (((y2 - ty) * (x1 - x2)) / (y1 - y2))) < tx then
                diff = -diff
            end
        elseif diff == 3 then
            diff = -1
        elseif diff == -3 then
            diff = 1
        end

        total = total + diff
        cur_quad = next_quad
        x1 = x2
        y1 = y2
    end
   
    return (math.abs(total)==4)
end

function getQuad(axis_x,axis_y,vert_x,vert_y)
    if vert_x < axis_x then
        if vert_y < axis_y then
            return 1
        else
            return 4
        end
    else
        if vert_y < axis_y then
            return 2
        else
            return 3
        end
    end
end

function love.load()
    poly = {69,119,371,39,724,140,751,491,572,222,420,163,283,232,236,338,399,401,540,446,371,508,195,503,96,327}
    color = {255,255,255}
end

function love.update(dt)
    if pointInPolygon(poly, love.mouse.getX(), love.mouse.getY()) then
        color = {0,255,0}
    else
        color = {255,255,255}
    end
end

function love.draw()
    if #poly >= 6 then
        love.graphics.setColor(color)
        love.graphics.polygon("line",poly)
    end
end

-- Add functions pointInPolygon and getQuad here