Spread the 6 scanlines evenly across the full height

Skipping the last two of the 8 candidate positions (at y=24, 28) left an
8px gap with nothing in it at the bottom of every 32-row cycle. Skipping
two interspersed positions instead (y=12, 28) spreads the resulting
slightly-larger gaps across the full height instead of clustering them
in one spot.

subwave_nowplaying.star

@@ -551,14 +551,18 @@ def _glitch_scanlines():
     # the starting position, so the snap is invisible -- a standard
     # infinite-scrolling-texture trick -- while the translate distance
     # never has to leave the small range already confirmed safe.
+    # SCANLINE_PERIOD=4 over ART_SLOT=32 gives 8 evenly-spaced candidate
+    # positions (0, 4, 8, ..., 28); skipping 2 of those 8 (rather than
+    # changing the period itself, which the sweep's periodicity depends
+    # on) to land on 6 visible lines. Skipping two *interspersed*
+    # positions instead of the last two in the run -- which left an 8px
+    # gap with nothing in it at the bottom of every cycle -- spreads the
+    # resulting two, slightly-larger gaps across the full height instead.
+    SCANLINE_SKIP = (12, 28)
     tall = ART_SLOT + SCANLINE_PERIOD
     lines = []
     for y in range(tall):
-        # SCANLINE_PERIOD=4 over ART_SLOT=32 gives 8 evenly-spaced lines
+        if y % SCANLINE_PERIOD == 0 and (y % ART_SLOT) not in SCANLINE_SKIP:
-        # per window; skipping 2 of those 8 positions (dropping the last
-        # two in each 32-row repeat, rather than changing the period
-        # itself) keeps the period dividing evenly into things cleanly.
-        if y % SCANLINE_PERIOD == 0 and (y % ART_SLOT) < ART_SLOT - 2 * SCANLINE_PERIOD:
             lines.append(render.Box(width = ART_SLOT, height = 1, color = "#00000080"))
         else:
             lines.append(render.Box(width = ART_SLOT, height = 1, color = "#00000000"))