#!/bin/bash # # Developed by Fred Weinhaus 3/7/2010 .......... revised 4/25/2015 # # ------------------------------------------------------------------------------ # # Licensing: # # Copyright © Fred Weinhaus # # My scripts are available free of charge for non-commercial use, ONLY. # # For use of my scripts in commercial (for-profit) environments or # non-free applications, please contact me (Fred Weinhaus) for # licensing arrangements. My email address is fmw at alink dot net. # # If you: 1) redistribute, 2) incorporate any of these scripts into other # free applications or 3) reprogram them in another scripting language, # then you must contact me for permission, especially if the result might # be used in a commercial or for-profit environment. # # My scripts are also subject, in a subordinate manner, to the ImageMagick # license, which can be found at: http://www.imagemagick.org/script/license.php # # ------------------------------------------------------------------------------ # #### # # USAGE: sphere [-d diameter] [-c color] [-b bgcolor] [-t theta] [-p phi] [-l lambertian] [-s specular] [-e exponent] [infile] outfile # USAGE: sphere [-h or -help] # # OPTIONS: # # -d diameter desired diameter of sphere; integer>0; default=128; # determines the width and height of the output image # -c color desired sphere color; # Any valid IM color is allowed; default=red # -b bgcolor background color outside sphere; # Any valid IM color is allowed; default=black # -t theta white light azimuth angle measure counter clockwise # around the sphere from the positive x axis; # 0<=float<=360; default=135 (lighting from the northwest) # -p phi white light altitude angle measured downward from # zenith (i.e. from out of center of sphere toward viewer); # 0<=float<=180; 0 is light source right over the center # of the sphere; default=50 # -l lambertian lambertian (diffuse) illumination amplitude; 0<=float<=1; # default=0.9 # -s specular specular illumination amplitude; 0<=float<=1; # default=0.6 # -e exponent specular illumination exponent; float>0; default=70 # # If infile is provided, then it will be used in place of the color. The # infile must be square and the diameter will obtained from the dimensions # of the image. # ### # # NAME: SPHERE # # PURPOSE: To create a colored sphere with a combination of diffuse and # specular illumination. # # DESCRIPTION: SPHERE creates a colored sphere with a combination of diffuse # and specular illumination. Lighting is from a white light source. The # diffuse term is computed from the Lambertian shading model. The specular # term is computed from the Blinn-Phong approximation. # # OPTIONS: # # -d diameter ... DIAMETER of the sphere. Also controls the width and height # of the output image. Values are integers>0. The default=128 # # -c color ... COLOR is the desired color for the sphere. The default=red. # Any valid IM color is allowed. # See http://imagemagick.org/script/color.php # # -b bgcolor ... BGCOLOR is the background color around the outside of the # sphere. The default=black. Any valid IM color is allowed. # See http://imagemagick.org/script/color.php # # -t theta ... THETA is the white light azimuth angle measured counter # clockwise from the positive x axis. Values are floats between 0 and 360 # degrees. The default=135, which means the light is coming from the northwest. # # -p phi ... PHI is the white light altitude angle measure downward from zenith # (vertical) towards horizontal. Values are floats between 0 and 180 degrees. # A value of zero means the light is from above the sphere. The default=50. # # -l lambertian ... LAMBERTIAN is the amplitude of the diffuse lighting. Values # are in the range 0<=float<=1. The default=0.9 # # -s specular ... SPECULAR is the amplitude of the reflective lighting. Values # are in the range 0<=float<=1. The default=0.6. A value of zero means not # to compute the specular component. # # -e exponent ... EXPONENT is the specular exponent, which controls the area # of the reflective effect. Larger values means smaller areas. Values are # floats>0. The default=70. # # NOTE: If infile is provided, then it will be used in place of the color. # The infile must be square and the diameter will obtained from the dimensions # of the image. # # REQUIRMENTS: IM 6.5.4-3 or higher due to the use of -compose mathematics. # # THEORY: See the following: # http://en.wikipedia.org/wiki/Lambertian_reflectance # http://en.wikipedia.org/wiki/Blinn–Phong_shading_model # # NOTE: This script may be a little slow due to the use in part of -fx. # # CAVEAT: No guarantee that this script will work on all platforms, # nor that trapping of inconsistent parameters is complete and # foolproof. Use At Your Own Risk. # ###### # # set default values diameter=128 # sphere diameter color="red" # base color of sphere bgcolor="black" # background color outside sphere theta=135 # lighting azimuth angle (cc from +x) phi=50 # lighting altitude angle (down from zenith) ampd=0.9 # diffuse (lambertian) amplitude amps=0.6 # specular amplitude exp=70 # specular exponent sscale=250 # scaling to make amps 250xsmaller so close to ampd infile="" # set directory for temporary files dir="." # suggestions are dir="." or dir="/tmp" # set up functions to report Usage and Usage with Description PROGNAME=`type $0 | awk '{print $3}'` # search for executable on path PROGDIR=`dirname $PROGNAME` # extract directory of program PROGNAME=`basename $PROGNAME` # base name of program usage1() { echo >&2 "" echo >&2 "$PROGNAME:" "$@" sed >&2 -e '1,/^####/d; /^###/g; /^#/!q; s/^#//; s/^ //; 4,$p' "$PROGDIR/$PROGNAME" } usage2() { echo >&2 "" echo >&2 "$PROGNAME:" "$@" sed >&2 -e '1,/^####/d; /^######/g; /^#/!q; s/^#*//; s/^ //; 4,$p' "$PROGDIR/$PROGNAME" } # function to report error messages errMsg() { echo "" echo $1 echo "" usage1 exit 1 } # function to test for minus at start of value of second part of option 1 or 2 checkMinus() { test=`echo "$1" | grep -c '^-.*$'` # returns 1 if match; 0 otherwise [ $test -eq 1 ] && errMsg "$errorMsg" } # test for correct number of arguments and get values if [ $# -eq 0 ] then # help information echo "" usage2 exit 0 elif [ $# -gt 17 ] then errMsg "--- TOO MANY ARGUMENTS WERE PROVIDED ---" else while [ $# -gt 0 ] do # get parameter values case "$1" in -h|-help) # help information echo "" usage2 exit 0 ;; -d) # get diameter shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID DIAMETER SPECIFICATION ---" checkMinus "$1" diameter=`expr "$1" : '\([0-9]*\)'` [ "$diameter" = "" ] && errMsg "--- DIAMETER=$diameter MUST BE A NON-NEGATIVE INTEGER ---" diametertest=`echo "$diameter < 1" | bc` [ $diametertest -eq 1 ] && errMsg "--- DIAMETER=$diameter MUST BE A POSITIVE INTEGER ---" ;; -c) # get color shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID COLOR SPECIFICATION ---" checkMinus "$1" color="$1" ;; -b) # get bgcolor shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID BGCOLOR SPECIFICATION ---" checkMinus "$1" bgcolor="$1" ;; -t) # get theta shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID THETA SPECIFICATION ---" checkMinus "$1" theta=`expr "$1" : '\([.0-9]*\)'` [ "$theta" = "" ] && errMsg "--- THETA=$theta MUST BE A NON-NEGATIVE FLOAT ---" thetatestA=`echo "$theta < 0" | bc` thetatestB=`echo "$theta > 360" | bc` [ $thetatestA -eq 1 -o $thetatestB -eq 1 ] && errMsg "--- THETA=$theta MUST BE A FLOAT BETWEEN 0 AND 360 ---" ;; -p) # get phi shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID PHI SPECIFICATION ---" checkMinus "$1" phi=`expr "$1" : '\([.0-9]*\)'` [ "$phi" = "" ] && errMsg "--- PHI=$phi MUST BE A NON-NEGATIVE FLOAT ---" phitestA=`echo "$phi < 0" | bc` phitestB=`echo "$phi > 180" | bc` [ $phitestA -eq 1 -o $phitestB -eq 1 ] && errMsg "--- PHI=$phi MUST BE A FLOAT BETWEEN 0 AND 180 ---" ;; -l) # get ampd shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID LAMBERTIAN SPECIFICATION ---" checkMinus "$1" ampd=`expr "$1" : '\([.0-9]*\)'` [ "$ampd" = "" ] && errMsg "--- LAMBERTIAN=$ampd MUST BE A NON-NEGATIVE FLOAT ---" ampdtestA=`echo "$ampd < 0" | bc` ampdtestB=`echo "$ampd > 1" | bc` [ $ampdtestA -eq 1 -o $ampdtestB -eq 1 ] && errMsg "--- LAMBERTIAN=$ampd MUST BE A FLOAT BETWEEN 0 AND 1 ---" ;; -s) # get amps shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID SPECULAR SPECIFICATION ---" checkMinus "$1" amps=`expr "$1" : '\([.0-9]*\)'` [ "$amps" = "" ] && errMsg "--- SPECULAR=$amps MUST BE A NON-NEGATIVE FLOAT ---" ampstestA=`echo "$amps < 0" | bc` ampstestB=`echo "$amps > 1" | bc` [ $ampstestA -eq 1 -o $ampstestB -eq 1 ] && errMsg "--- SPECULAR=$amps MUST BE A FLOAT BETWEEN 0 AND 1 ---" ;; -e) # get exponent shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID EXPONENT SPECIFICATION ---" checkMinus "$1" exp=`expr "$1" : '\([.0-9]*\)'` [ "$exp" = "" ] && errMsg "--- EXPONENT=$exp MUST BE A NON-NEGATIVE FLOAT ---" ;; -) # STDIN and end of arguments break ;; -*) # any other - argument errMsg "--- UNKNOWN OPTION ---" ;; *) # end of arguments break ;; esac shift # next option done # # get infile and outfile if [ $# -eq 2 ]; then infile="$1" outfile="$2" elif [ $# -eq 1 ]; then outfile="$1" else errMsg "--- INCONSISTENT NUMBER OF INPUT AND OUTPUT IMAGES SPECIFIED ---" fi fi # test that outfile provided [ "$outfile" = "" ] && errMsg "--- NO OUTPUT FILE SPECIFIED ---" # set directory for temporary files tmpdir="/tmp" dir="$tmpdir/$PROGNAME.$$" mkdir "$dir" || errMsg "--- FAILED TO CREATE TEMPORARY FILE DIRECTORY ---" trap "rm -rf $dir;" 0 trap "rm -rf $dir; exit 1" 1 2 3 15 trap "rm -rf $dir; exit 1" ERR if [ "$infile" != "" ]; then convert -quiet "$infile" +repage $dir/tmpI.mpc || errMsg "--- FILE $infile NOT READABLE OR HAS ZERO SIZE ---" ww=`convert $dir/tmpI.mpc -ping -format "%w" info:` hh=`convert $dir/tmpI.mpc -ping -format "%h" info:` [ $ww -ne $hh ] && errMsg "--- INFILE MUST BE SQUARE ---" diameter=$ww fi # Theory # lambertian shading # dot product between surface normal and light direction # kn(N•L) # surface normal = gradient direction # sphere equation = f(x,y,z) = x^2 + y^2 + z^2 - r^2 = 0 # gradient vector = df/dx i + df/dy j + df/dz k (i,j,k) unit vectors along axes # gradient vector of point x,y,z on sphere = 2xi + 2yj + 2zk # normalized by magnitude 2*sqrt(x^2 + y^2 + z^2) = 2r # normalize gradient = (xi + yj + zk)/r # where z= sqrt(r^2 - x^2 - y^2) # normalized gradient = (xi + yj + sqrt(r^2 - x^2 - y^2)k)/r, # where i,j,k are unit vectors along x,y,z directions. # move origin to center of sphere # with x to right and y to top and z out of picture # sphere = f(x,y,z) = (x-xc)^2 - (yc-y)^2 + z^2 - r^2 = 0 # or due to square of y term # sphere = f(x,y,z) = (x-xc)^2 - (y-yc)^2 + z^2 - r^2 = 0 # gradient = 2(x-xc)i + 2(y-yc)j + 2zk # normalize by magnitude 2*sqrt((x-xc)^2 + (y-yc)^2 + z^2) = 2r # where z= sqrt(r^2 - (x-xc)^2 + (y-yc)^2) # normalized gradient = ((x-xc)i + (y-yc)j + sqrt(r^2 - (x-xc)^2 - (y-yc)^2)k)/r # or # normalized gradient = ((x-xc)/r)i + ((y-yc)/r)j + sqrt(1 - ((x-xc)/r)^2 - ((y-yc)/r)^2)k # light direction given by azimuth (theta) and altitude (phi) angles and r=1 # light direction is from origin toward light source # theta counter clockwise from +x # phi downward from +z (zero when straight up) # xl = sin(phi)cos(theta) # yl = sin(phi)sin(theta) # zl = cos(phi) #lambertian shading = xl*(x-xc)/r + yl*(y-yc)/r + zl*sqrt(1 - ((x-xc)/r)^2 -((y-yc)/r)^2) # Blinn-Phong Shading = ka + kn(N•L) + ks(N•H)^exp # where ka is ambient color # kn is diffuse amplitude, N is normal, L is lighting direction # ks is specular amplitude, N is normal, H=(V+L)/2, V is viewer direction # and exp is some large exponent # H is a constant vector that is midway between V and L # change sign on theta due to y down in picture thetam=`convert xc: -format "%[fx:-$theta]" info:` rad=`convert xc: -format "%[fx:$diameter/2]" info:` radsq=`convert xc: -format "%[fx:$rad*$rad]" info:` # compute lighting direction # include $ampd as it will be a multiplier of each term xl=`convert xc: -format "%[fx:$ampd*sin(pi*$phi/180)*cos(pi*$thetam/180)]" info:` yl=`convert xc: -format "%[fx:$ampd*sin(pi*$phi/180)*sin(pi*$thetam/180)]" info:` zl=`convert xc: -format "%[fx:$ampd*cos(pi*$phi/180)]" info:` xl2=`convert xc: -format "%[fx:2*$xl]" info:` yl2=`convert xc: -format "%[fx:2*$yl]" info:` xlpyl=`convert xc: -format "%[fx:($xl+$yl)]" info:` #echo "xl=$xl; yl=$yl; zl=$zl; xl2=$xl2; yl2=$yl2; xlpyl=$xlpyl;" # compute specular halfway vector H=(L+V)/2 # V=(0,0,1) viewer is along z axis above middle of sphere xh=`convert xc: -format "%[fx:(1/$ampd)*$xl/2]" info:` yh=`convert xc: -format "%[fx:(1/$ampd)*$yl/2]" info:` zh=`convert xc: -format "%[fx:(($zl/$ampd)+1)/2]" info:` xh2=`convert xc: -format "%[fx:2*$xh]" info:` yh2=`convert xc: -format "%[fx:2*$yh]" info:` xhpyh=`convert xc: -format "%[fx:($xh+$yh)]" info:` ssamps=`convert xc: -format "%[fx:$sscale*$amps]" info:` #echo "xh=$xh; yh=$yh; zh=$zh; xh2=$xh2; yh2=$yh2; xhpyh=$xhpyh; ssamps=$ssamps" if [ "$bgcolor" = "none" ]; then channelize="-channel rgba -alpha on" else channelize="" fi : <