Set the OrbitCamera default to the framing the UI screenshot shows:
yaw -1.065, pitch -0.335, distance 30, fov 1.0 (the latter two were
already the defaults).
The old default (yaw 0, pitch +0.7) was a 3/4 view from above the disk
plane. The new pitch sits the eye just below the disk plane, so the
gravitationally lensed far side of the disk arcs over the top of the
shadow — the iconic Interstellar framing. yaw -1.065 (~-61°) picks a
viewing azimuth that keeps the lensed arc and photon ring balanced in
frame.
basis() derived `right` from `forward × world_up`, which degenerated to
a zero vector when forward aligned with world-Y (pitch = ±π/2) — the
cross product vanished, normalization produced garbage, and crossing
the pole flipped the image 180°.
Right now depends on yaw alone: Vec3::new(cos yaw, 0, -sin yaw). It is
a unit vector in the y=0 plane for any yaw, so it never goes to zero
regardless of pitch. In the original upper hemisphere (cp > 0) this is
exactly the old value after normalization, so existing views are
unchanged; it additionally stays perfectly horizontal for all pitch,
fixing a subtle roll the cross-product form introduced below the equator.
With the singularity gone, pitch is unclamped from [0.05, π-0.05] to
[-π+0.05, π-0.05]: the camera can now cross both poles and reach below
the disk plane without flipping. The ±0.05 margin only avoids the exact
origin-axis points where forward = ∓Y and yaw becomes meaningless.
yaw is also wrapped to (-π, π] on each drag so it cannot drift out of
the UI slider range (which would snap the view when the slider is later
touched); cos/sin periodicity makes the wrap visually lossless.
The UI pitch slider range is widened to match. Stale "gimbal pole"
comments that described the old restriction are corrected.
basis() still returns (eye, forward, right, up), so the uniform bridge
in plugin.rs and both shaders are untouched.
- Set default pitch to 0.7 rad to keep the camera away from the π/2 gimbal pole, preventing horizontal drag from degenerating into an in-plane roll.
- Adjust scroll zoom logic to divide instead of multiply by the zoom factor, so that scrolling up zooms in (reduces distance) rather than out.
