cut-up-cubemap

#!/bin/sh
#
# This is a script to cut up an all-in-one cubemap into 6 images
# like space-nerds-in-space expects
#

filename="$1"
fileinfo=$(file "$1")

INFO=$(echo "$fileinfo" | awk -F: '{ print $2; }')
FORMAT=$(echo $INFO | awk -F, '{ print $1; }')
DIMENSIONS=$(echo $INFO | awk -F, '{ print $2; }')
COLORINFO=$(echo $INFO | awk -F, '{ print $3; }')
INTERLACED=$(echo $INFO | awk -F, '{ print $4; }')

errors_found=0

echo "$FORMAT" | grep 'PNG image data' > /dev/null
if [ "$?" != "0" ]
then
	echo "$filename"": PNG image data is required, but data is $FORMAT" 1>&2
	errors_found=1
fi

echo "$DIMENSIONS" | grep '[0-9][0-9]* x [0-9][0-9]*' > /dev/null
if [ "$?" != "0" ]
then
	echo "$filename"": Malformed dimensions: $DIMENSIONS" 1>&2
	errors_found=1
fi
XDIM=$(echo $DIMENSIONS | sed -e 's/^ *//' | awk '{ print $1; }')
YDIM=$(echo $DIMENSIONS | sed -e 's/^ *//' | awk '{ print $3; }')

echo "$COLORINFO" | grep '8[-]bit[/]color RGB$' > /dev/null
if [ "$?" != "0" ]
then
	echo "$filename"": 8-bit/color RGB required, but file is $COLORINFO" 1>&2
	errors_found=1
fi

echo "$INTERLACED" | grep 'non[-]interlaced' > /dev/null
if [ "$?" != "0" ]
then
	echo "$filename"": non-interlaced file required, but format is $INTERLACED" 1>&2
	errors_found=1
fi

if [ "$errors_found" != "0" ]
then
	exit 1
fi

# echo "FORMAT=$FORMAT"
# echo "COLORINFO=$COLORINFO"
# echo "INTERLACED=$INTERLACED"
# echo "XDIM=$XDIM"
# echo "YDIM=$YDIM"

X0=0
X1=$(expr $XDIM / 4)
X2=$(expr $X1 \* 2)
X3=$(expr $X1 \* 3)
X4=$(expr $X1 \* 4)

Y0=0
Y1=$(expr $YDIM / 3)
Y2=$(expr $Y1 \* 2)
Y3=$(expr $Y1 \* 3)

# echo X1=$X1
# echo X2=$X2
# echo X3=$X3
# echo X4=$X4

# echo Y1=$Y1
# echo Y2=$Y2
# echo Y3=$Y3

fname=$(basename $filename .png)

convert "$filename" -crop "$X1"x"$Y1"+"$X1"+0 +repage "$fname"-4.png
convert "$filename" -crop "$X1"x"$Y1"+0+"$Y1" +repage "$fname"-0.png
convert "$filename" -crop "$X1"x"$Y1"+"$X1"+"$Y1" +repage "$fname"-1.png
convert "$filename" -crop "$X1"x"$Y1"+"$X2"+"$Y1" +repage "$fname"-2.png
convert "$filename" -crop "$X1"x"$Y1"+"$X3"+"$Y1" +repage "$fname"-3.png
convert "$filename" -crop "$X1"x"$Y1"+"$X1"+"$Y2" +repage "$fname"-5.png