selected object material bitmap gamma override adjust

i refered some script and maked

i made this
but that is not work

fn GetBitmapTextures theObjects =
(
-- Because some submaps can also contain submaps we have to collect materials first, and then still append subMapContainers in the loop bitmapTextureMaps loop
subMapContainers = #()
for obj in theObjects do
(
if obj.material != undefined then
(
submatcount = getNumSubMtls obj.material
for i in 1 to submatcount do
(
append subMapContainers (getSubMtl obj.material i)
)
append subMapContainers (obj.material)
)
)
bitmapTextureMaps = #()
for subMapContainer in subMapContainers do
(
subtexcount = getNumSubTexmaps subMapContainer
for i in 1 to subtexcount do
(
theSubTexMap = (getSubTexMap subMapContainer i)
if theSubTexMap != undefined then
(
if (getNumSubTexmaps theSubTexMap) > 0 then
(
append subMapContainers theSubTexMap
)
else if classof theSubTexMap == bitmapTexture then
(

if theSubTexMap.gamma==1 then
(
newgamma=1/2.2
)
else
(
newgamma=1/theSubTexMap.gamma
)

theSubTexMap=bitmap theSubTexMap.width theSubTexMap.height filename:theSubTexMap.filename gamma:newgamma
append bitmapTextureMaps theSubTexMap
)
)
)
)
makeUniqueArray bitmapTextureMaps
)