#!/usr/bin/env bash
#               GMT ANIMATION 01
#
# Purpose:      Make web page with simple animated GIF of sine function
# GMT modules:  math, basemap, text, plot, movie
# Unix progs:   echo, convert, cat
# Note:         Run with any argument to build movie; otherwise 1st frame is plotted only.

if [ $# -eq 0 ]; then	# Just make master PostScript frame 0
	opt="-Mps -Fnone"
else	# Make animated GIF
	opt="-A+l"
fi
# 1. Create files needed in the loop
cat << EOF > pre.sh
gmt math -T0/360/20 T SIND = sin_point.txt
gmt math -T0/360/2 T SIND = sin_curve.txt
gmt begin
	gmt basemap -R0/360/-1.2/1.6 -JX3.5i/1.65i -X0.35i -Y0.25i \
	-BWSne+glightgreen -Bxa90g90f30+u@. -Bya0.5f0.1g1 --FONT_ANNOT_PRIMARY=9p
gmt end
EOF
# 2. Set up the main frame script
cat << EOF > main.sh
gmt begin
#	Plot smooth blue curve and dark red dots at all angle steps so far
	last=\$(gmt math -Q \${MOVIE_FRAME} 10 MUL =)
	gmt convert sin_curve.txt -Z0:\${last} | gmt plot -W1p,blue -R0/360/-1.2/1.6 -JX3.5i/1.65i -X0.35i -Y0.25i
	gmt convert sin_point.txt -Z0:\${MOVIE_FRAME} | gmt plot -Sc0.1i -Gdarkred
#	Plot bright red dot at current angle and annotate
	gmt plot -Sc0.1i -Gred <<< "\${MOVIE_COL0} \${MOVIE_COL1}"
	printf "0 1.6 a = %3.3d" \${MOVIE_COL0} | gmt text -F+f14p,Helvetica-Bold+jTL -N -Dj0.1i/0.05i
gmt end
EOF
# 3. Run the movie
gmt movie main.sh -Sbpre.sh -C4ix2ix125 -Tsin_point.txt -Zs -Nanim01 -D5 $opt