The Track Struct

The track struct can be used either for top-level asset tracks or for sub-track parameter tracks, and the behaviour of the track is defined by two things, its name and it's type. Track structs are created using the function sequence_track_new() and the properties available to it are:

• type: The following constants can all be used to define the type of track that is being created in the sequence (these constants are also used when generating keyframes and keyframe data, explained in sections below):

• name: When creating an asset track, the name you give here can be any string that you require to identify the track, however for parameter tracks, you need to specify specific strings to tell GameMaker Studio 2 what kind of parameter track you are creating (these strings are only applicable to the seqtracktype_real and seqtracktype_colour parameter track types):
  • "position" - when set on a track which is of type seqtracktype_real this indicates that the contents of this track should be used as positional data.
  • "scale" - when set on a track which is of type seqtracktype_real this indicates that the contents of this track should be used as scaling data.
  • "rotation" - when set on a track which is of type seqtracktype_real this indicates that the contents of this track should be used as rotation data.
  • "blend_multiply" - when set on a track which is of type seqtracktype_colour this indicates that the contents of this track should be used as colour multiplication data. The keyframe data for such a track should be an array of four values with the format [A, R, G, B]. Note that the values for each component are expressed as between 0 and 1, where 0 corresponds to the HEX value #00 and 1 corresponds to the HEX value #FF (0 - 255 as shown in the colour picker for image blend tracks in the Sequences Editor).
  • "image_speed" - when set on a track which is of type seqtracktype_real this indicates that the contents of this track should be used as the image speed value.
  • "image_index" - when set on a track which is of type seqtracktype_real this indicates that the contents of this track should be used as the image index value.
  • "image_angle" - when set on a track which is of type seqtracktype_real this indicates that the contents of this track should be used as the image angle value.
  • "image_blend" - when set on a track which is of type seqtracktype_colour this indicates that the contents of this track should be used as the image blend value. The keyframe data for such a track should be an array of four values with the format [A, R, G, B]. Note that the values for each component are expressed as between 0 and 1, where 0 corresponds to the HEX value #00 and 1 corresponds to the HEX value #FF (0 - 255 as shown in the colour picker for colour multiply tracks in the Sequences Editor).
• tracks: This property allows access to the list of tracks which are children of this track. When getting this property an array of track structs is returned, and when setting this property an array of track structs should be specified.
• visible: This indicates whether this track is visible (the value is true) or not (the value is false). You can get or set this value and if a track not visible then none of its child tracks will be drawn either.
• keyframes: This property allows access to the list of keyframe structs for the track. When getting this property an array of keyframe structs is returned, and when setting this property an array of keyframe structs should be specified.