Convert all input to DDS and replace using nvcompress or Crunch

convertdds.sh

#!/bin/bash

mkdir -p /tmp/dds > /dev/null
tool="nvcompress"

for file in "$@"
do
    echo "$file"
    dirname=$(dirname "$file")
    basename=$(basename "$file")
    extname="${file#${file%.*}}"
    filename=$(basename "$basename" "$extname")

    convert -flip "$file" "/tmp/dds/$basename"
    alpha=$(convert "$file" -resize 1x1 -format "%[fx:int(255*a+.5)]" info:-)
    if [ "$tool" == "crunch" ]
    then
        if [ $alpha -lt 255 ]
        then
            format="-dxt5"
        else
            format="-dxt1"
        fi

        crunch -quiet -file "/tmp/dds/$basename" -fileformat dds $format && rm $file
    else
        if [ $alpha -lt 255 ]
        then
            format="-bc3"
        else
            format="-bc1"
        fi

        nvcompress $format "/tmp/dds/$basename" "$dirname/$filename.dds" && rm $file
    fi
done⏎