text: #!/usr/bin/env python3
  
  from math import sqrt, sin, cos, acos, pi
  import util
  
  # Graph is plotted across the entire HGR screen, but only coordinates
  #  - in the left half of the screen, AND
  #  - on even rows, AND
  #  - on even columns
  # are included. It is assumed that the graph is symmetrical across
  # the left and half sides of the screen (along an axis at X=140).
  #
  # X coordinates are converted to byte+bitmask (but see notes below).
  # Y coordinates are flipped (so 0,0 ends up on the bottom left) then
  # incremented by 1 so that 0 can terminate the loop,
  #
  # 6502 code will be responsible for plotting each of these coordinates
  # in a 2x2 block. The bitmask usually includes 2 adjacent pixels;
  # the code will also plot the same 2 adjacent pixels in the adjacent row,
  # AND mirror both of those plots in the right half of the screen.
  #
  # Unfortunately, since bytes are 7 bits across, some blocks will cross a
  # byte boundary. To simplify the 6502 code, those are simply listed as
  # separate coordinate pairs, each with a bitmask that includes 1 pixel
  # instead of 2.
  
  max_x = 280
  max_y = 192
  
  def f(theta, k):
      r = k*(10.8+sin(16*theta))
      return r*cos(theta),r*sin(theta)
  
  coords = []
  for k_mul in range(3000):
      for t_mul in range(int(pi*1000+1)):
          a, b = f(float(t_mul/100), float(k_mul)/100.0)
          x = round(max_x//2+a*1.2)
          y = round(max_y//2+b)
          if (x % 2 != 0) or (y % 2 != 0):
              continue
          if x < 0 or x >= max_x//2 or y < 0 or y >= max_y:
              continue
          coords.append((x,y))
  
  unique_coords = util.unique(coords)
  unique_vals = util.vals_2bit(unique_coords)
  with open("../../../src/fx/fx.hgr.wavy.iris.data.a", "w") as f:
      for aval, bval in unique_vals:
          f.write("         !byte %s,%s\n" % (aval, bval))
  
  ripple_vals = util.ripple(unique_vals)
  with open("../../../src/fx/fx.hgr.wavy.ripple.data.a", "w") as f:
      for aval, bval in ripple_vals:
          f.write("         !byte %s,%s\n" % (aval, bval))
  
  unique_vals.reverse()
  with open("../../../src/fx/fx.hgr.wavy.iris.in.data.a", "w") as f:
      for aval, bval in unique_vals:
          f.write("         !byte %s,%s\n" % (aval, bval))
  