Handle a scroll wheel zoom. Ctrl/Meta+scroll is ceded to the window-level
FOV handler for perspective cameras only (ortho has no FOV, so a pinch must
still zoom there). Normalizes deltaY to pixel-mode equivalent first
(normalizeWheelDelta, so a Firefox line-mode notch is not ~32x smaller
than a Chromium pixel-mode one), converts that into a zoom-scale (at
zoomSpeed × wheelZoomSensitivity, which therefore multiplies a
browser-independent delta) and accumulates a signed zoom delta (scroll up =
zoom in), then dispatches change so the damped zoom is picked up in the
next update. No-op while disabled or zoom is off.
Handle a scroll wheel zoom. Ctrl/Meta+scroll is ceded to the window-level FOV handler for perspective cameras only (ortho has no FOV, so a pinch must still zoom there). Normalizes
deltaYto pixel-mode equivalent first (normalizeWheelDelta, so a Firefox line-mode notch is not ~32x smaller than a Chromium pixel-mode one), converts that into a zoom-scale (atzoomSpeed × wheelZoomSensitivity, which therefore multiplies a browser-independent delta) and accumulates a signed zoom delta (scroll up = zoom in), then dispatcheschangeso the damped zoom is picked up in the next update. No-op while disabled or zoom is off.