v2.1.1

Patch Changes

• #23 186ed09 Thanks @ParthJadhav! - perf: cache the void mask as an inverse-alpha band and erase with destination-out on slow-canvas browsers

  The frame's "void mask" — which clips surface-bound effects (bugs, water,
  flames) to the page's surviving pixels — used to be one full-band
  destination-in draw of the content surface. On CPU-rasterized Canvas2D
  (Firefox/Gecko, and WebKit's non-GL path) that op is doubly poisonous: it
  touches every pixel of the fx canvas, and it knocks the canvas off the
  accelerated path so every later canvas-source draw in the same frame (smoke,
  steam, flame sprites) pays a fixed toll. Heavy water and bug scenarios ran
  3–5× slower than Chrome at desktop viewports.

  Browsers whose canvas→GL upload probe reads slow now mask with one
  destination-out draw of a cached inverse of the visible band's page alpha
  (opaque where the page is gone, including past the document's edges) —
  fx · (1 − holes) is exactly fx · pageAlpha, and destination-out leaves
  pixels outside its source untouched, so nothing deopts. The cache rebuilds on
  scroll or resize and otherwise refreshes only the accumulated surface-damage
  rect. Independently, the opacity map now tracks which 128px cells might be
  missing alpha, so frames with no holes in view skip the mask outright in
  every browser; fast-canvas browsers (Chrome) keep the original single
  destination-in draw. Interleaved A/B on Firefox at 1904×1034: flood and
  swarm gain ~17ms/frame, mayhem ~2ms, inferno and singularity unchanged;
  Chrome is unchanged.