Windows, running processing 3.1.2, getting some errors when compiling the latest code downloaded from https://github.com/euphy/polargraphcontroller/releases/tag/2016-03-29-10-23

For instance:
size(windowWidth, windowHeight);
(cannot be defined as variables, must be sett in numbers).

Which version of processing should be used to make it compile without error?

Downloaded 2.2.1:

Getting these errors

Running polargraph controller
Successfully loaded properties file C:\Users\Morten\Downloads\Polargraph.2016-03-29\Polargraph 2016-03-29\processing-source\polargraphcontroller\default.properties.txt
machine size: 1179.0, 983
loading from filename: C:\Users\sandy_000\Documents\grace-kelly-375x470.jpg
The file "C:\Users\sandy_000\Documents\grace-kelly-375x470.jpg" is missing or inaccessible, make sure the URL is valid or that the file has been added to your sketch and is readable.
Image failed to load: null
loading from filename: C:\Users\sandy_000\Documents\grace-kelly-375x470.jpg
The file "C:\Users\sandy_000\Documents\grace-kelly-375x470.jpg" is missing or inaccessible, make sure the URL is valid or that the file has been added to your sketch and is readable.
Image failed to load: null
windowHeight:725
Polygonizer: 0
PolygonizerLength: 1.0
C:\Users\sandy_000\Documents\Processing\polargraphcontroller\data\midsquare.svg does not exist or could not be read
java.lang.NullPointerException
at processing.data.XML$1.read(XML.java:190)
at com.sun.org.apache.xerces.internal.impl.XMLEntityScanner.load(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLEntityScanner.arrangeCapacity(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLEntityScanner.skipString(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLVersionDetector.determineDocVersion(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(Unknown Source)
at processing.data.XML.<init>(XML.java:187)
at processing.core.PApplet.loadXML(PApplet.java:6322)
at processing.core.PApplet.loadXML(PApplet.java:6312)
at geomerative.RSVG.toShape(RSVG.java:137)
at geomerative.RG.loadShape(RG.java:244)
at polargraphcontroller.loadFromPropertiesFile(polargraphcontroller.java:3101)
at polargraphcontroller.setup(polargraphcontroller.java:598)
at processing.core.PApplet.handleDraw(PApplet.java:2361)
at processing.core.PGraphicsJava2D.requestDraw(PGraphicsJava2D.java:240)
at processing.core.PApplet.run(PApplet.java:2256)
at java.lang.Thread.run(Unknown Source)
Finished loading configuration from properties file.
ControlP5 2.2.5 infos, comments, questions at http://www.sojamo.de/libraries/controlP5
Serial ports available on your machine:

About to connect to serial port in slot 2
No serial ports found.
Polygonizer: 1
PolygonizerLength: 1.0
previewPixelDensityRange: true
Polygonizer: 1
PolygonizerLength: 1.0
regenerating preview queue.
Rectangle pos: [ 10.0, 37.0, 0.0 ], size: [ 208.0, 48.0, 0.0 ].
Rectangle pos: [ 10.0, 85.0, 0.0 ], size: [ 208.0, -105.0, 0.0 ].
Target height is -61.0 pixels
845.02496
-0.072187215
New window size: 1370 x 764
New window size: 1370 x 764

I got the precompiled versions to run, so I haven't tested this any further.

Ok, so the controller.image.filename is the image that's loaded into the controller when it starts up.

I fixed the nullpointer by adding a basic image in the folder and editing the path in default.properties.txt.

controller.vector.filename=C:\\Users\\Ruiji-Sama\\Documents\\Processing\\polargraphcontroller\\data\\midsquares.svgg

controller.image.filename=C:\\Users\\Ruiji-Sama\\Documents\\Processing\\polargraphcontroller\\data\\images.jpg

This fixed it for me, got no more NullPointerExceptions