Accumulate a vertical pan (scaled by distance). In screen-space mode this
follows the camera's Y axis; otherwise it uses cameraUp × cameraX, the
ground-plane direction orthogonal to the world up, so world-up-locked panning
slides across the horizontal plane rather than tilting out of it.
Accumulate a vertical pan (scaled by
distance). In screen-space mode this follows the camera's Y axis; otherwise it usescameraUp × cameraX, the ground-plane direction orthogonal to the world up, so world-up-locked panning slides across the horizontal plane rather than tilting out of it.