Processing and teensy arduino problem

This untested but, if you add the bottom 3 lines you should see the results of r, g, b on the processing black monitor.

port.write((byte)(r)); //write red value
port.write((byte)(g)); //write green value
port.write((byte)(b)); //write blue value

//add next  lines
println((byte)(r)); //print on bottom of processing screen
println((byte)(g));
println((byte)(b));