Guide

Motions and expressions

Motions are the file's scenes and compositions, plus any you add with ay2d_add_motion3. One motion plays in front at a time:

• ay2d_motion_play starts a motion. It fades in while whatever played before fades out, so a switch is a crossfade.
• A one-shot motion holds its last frame when it ends; ay2d_motion_finished tells you so. A looping one wraps.
• ay2d_motion_stop fades everything out.

Each update a motion writes its curves over the pose by its weight. Parameters it has no curve for keep what you set. That is what lets tracking and a motion work together: drive the face from the camera and let an idle motion sway the body.

Events are text a motion fires at a set time (motion3 UserData). Read them with ay2d_motion_events after each update; the next update replaces the list. Nothing calls you back.

Expressions are sets of parameter changes, shown one at a time with fades, applied after motions:

Fades are in seconds. Pass a negative fade to use the one the file authored (or one second when it has none), and 0 to switch at once.