Enumeration HrzProtocol.AngularDirection.Frame

Defined in hrz/protocol/scene/view_settings.proto.

Frames attached to the camera.

FRAME_ENU (0)

The East-North-Up frame at the camera position: azimuth is measured from the direction to the North, altitude from the local horizontal plane. The Sun keeps its place in the sky as the camera moves.

FRAME_CAMERA_HEADING (1)

A rotated ENU frame at the camera position: azimuth is measured from the camera’s forward vector projected onto the local horizontal plane, and altitude from that plane. Where the projection of the forward vector degenerates (camera pointing at the zenith or nadir), the camera’s up vector projected onto the same plane is used instead, negated when the camera points upward.

FRAME_CAMERA (2)

The camera’s own basis: azimuth is measured around the camera’s up axis from its forward direction, and altitude from the plane its forward and right directions span. The Sun therefore keeps its exact place on screen whatever the camera does. At an azimuth and an altitude of 0 the Sun sits directly ahead.