[[LaserLineToc]]
= Sequencing Model =
The '''sequencing model''' is the term used to describe the functional grouping of objects, etc. that store and manage the arrangement and composition of a laser show in LaserLine, that is to say, the sequencing model figures out what gets displayed and when. It is from this model that output will be generated for the [wiki:OutputController output controller] and sent to various [wiki:Drivers devices].


== Model Composition ==
The sequencing model is composed of several types of objects:
 - '''Tracks''': Every laser head is assigned to exactly one track.
 - '''Layers''': Each track has 1 or more layers all of which get composited together rendering frames.
 - '''Sequences''': A sequence is a time-linear arrangement of objects which we call "Sequence Elements". Each layer contains a single root sequence.
 - '''Sequence Elements''': Are objects capable of generating a rawframe at a given progression within (0,1]. Sequences are a special kind of sequence element.

=== Types of Sequence Elements ===
==== Compositing Elements ====
 - '''Sequences''': As mentioned above, sequences are a time-linear (non-overlapping) arrangement of sequence elements. Sequences are one of the most important kinds of sequence elements as they contain the logic necessary to layout elements.
 - '''Animations''': Animations are like sequences but they divide time up evenly among each of its child elements. This is used almost exclusively for grouping frames.

==== Source Elements ====
 - '''Frames''': Frames are the most basic element of a sequence. Frame elements produce constant output, that is, their output is the same regardless of progression.
 - '''Transitions''': Transitions generate rendered frames dynamically. They can be used to connect two different sequence elements together.
 - '''Generators''': Generate rendered frames from a function. This function could create a lissajous pattern, a spirograph, any other mathematical pattern.



You may notice that this list closely mirrors that of [wiki:LZRFileFormat LZR XML Schema].