Rotating Balls [Ben Beaumont]

[Richmond Mathewson]

Ben Beaumont gave a most stimulating talk last night about the jazzy new
visual effectsin RR 4. At one point he showed us a simulation of a solar
system featuring a sun and
4 or 5 planets in orbit about it. The particularly fancy bit was that the
side of a planet
facing towards the sun was always 'lit'. Ben Beaumont claimed that this
effect was
a bit difficult.

. . . I went back to my lodgings and jumped into a good, hot bath . . .

Bingo: all one has to do is set up a sequence of numbers round a circle like
this:

repeat with XYZ = 0 to 6.28 step 0.05
  put (cos(XYZ) * 150) into KOZ
  put (cos(XYZ - 1.54) * 150) into KOZ2
  put (sine(XYZ) * 150) into SIGN
  put (sine(XYZ - 1.54) * 150) into SIGN2


then one sets up a circular graphic of, say, 300,300 with a linear
fillGradient of black
to green/blue/red and sets the following:

  set the fillGradient["to"] to (KOZ + 400),(SIGN + 400)
  set the fillGradient["from"] to (KOZ2 + 400),(SIGN2 + 400)
end repeat

[ mind you, this might be complete rubbish as I haven't tried it yet . . .]