fix generated alpha channel

diff --git a/misc/tools/normalmap.sh b/misc/tools/normalmap.sh
index 08ca0fae071d882f6b3590e8521e2594f6b9ba19..49b32200c8e4099ac4560178c1f2891e0cc04f5e 100755 (executable)
--- a/misc/tools/normalmap.sh
+++ b/misc/tools/normalmap.sh
@@ -2,6 +2,7 @@
 
 # usage: ./bump2norm.sh foo_bump.tga foo_norm.tga
 # NOTE: unfortunately requires X-server (otherwise file-tga-save won't work... no joke)
+# also, alpha channel value 0 is avoided as gimp doesn't save it properly
 
 in=$1
 out=$2
@@ -29,9 +30,14 @@ gimp -i -b - <<EOF
                (img (car (gimp-file-load RUN-NONINTERACTIVE "$in" "$in")))
                (drawable (car (gimp-image-active-drawable img)))
                (layer (car (gimp-image-get-active-layer img)))
+               (mycurve (cons-array 256 'byte))
+               (i 1)
        )
        (gimp-layer-add-alpha layer)
        (plug-in-normalmap RUN-NONINTERACTIVE img drawable $filter $minz $scale 1 $heightsource 1 $conv 0 0 1 0 1 layer)
+       (aset mycurve 0 1)
+       (while (< i 256) (aset mycurve i i) (set! i (+ i 1)))
+       (gimp-curves-explicit drawable HISTOGRAM-ALPHA 256 mycurve)
        (file-tga-save RUN-NONINTERACTIVE img drawable "$out" "$out" 1 1)
        (gimp-quit 0)
 )