Module controls 

Arcball orbit/pan/zoom (R22) — the ArcballControls feel the user base has muscle memory for, as a pure state machine over ViewCamera:

• left drag = trackball rotate (Shoemake sphere/hyperbola blend, 1:1),
• right/middle drag = pan (scene follows the cursor),
• wheel = zoom about the target, a gentle exponential step per notch (enableAnimations was false in the app, so there is deliberately NO inertia/damping; the smooth ramp comes from egui’s own per-frame scroll smoothing — see [ZOOM_PER_NOTCH]).

Input arrives as forwarded browser pointer/wheel events through the R3 API (CSS pixels); the same struct drives the winit desktop shell.

Structs

ArcballControls

Enums

Gesture

Constants

BUTTON_LEFT

Buttons follow the browser PointerEvent.button values.

BUTTON_MIDDLE

BUTTON_RIGHT

Functions

pan

Pan by a screen-space delta in CSS px: the scene follows the cursor (dragging right moves the model right, i.e. the camera left).

zoom

Zoom by a frustum-scale factor (>1 zooms out).

zoom_toward

Zoom by factor while keeping the world point under the cursor fixed — “zoom toward the mouse”. cx,cy are cursor CSS px (top-left origin).