SCTV scope clock code

The SCTV Scope Clock from Cathode Corner displays time, words and games on a 3 inch oscilloscope tube, using a Teensy 3.6 computer to generate X-Y-Z signals.

This code makes it run.

The original code from Cathode Corner has been hacked up to add some new things:

• Adjustmnets to make it easier to add new clock faces/screen modes
• Multi-font support - four additional fonts - and a font demo screen to show them
• Adjustable brightness / greyscale support
• Two calibration creens to help with focusing and centering of the display
• Three new analog clock faces
  • A basic clock with second tick marks and a smoothly moving second hand.
  • The above base clock with a 3d rotating cube in the background
  • The above base clock with a starfield flying by in the background
• Several new digital clock faces
• a 3d spinning cube screen effect
• a starfield screen effect
• two 'memory display' screen effects that plot the content of memory onto the screen

Compiling and installation are the same as for the original code. However, I suggest adjusting the optimization settings to get slightly better performance (which means less flicker):

Tools -> Optimize -> "Fastest + pure-code with LTO"

The greyscale code requires the brightness knob to be turned up a bit more than before, to allow a somewhat higher dynamic range. Just play around to find the brightest setting with decent focus.