Timeline
- For the user interface, see: TimelineUI.
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Notation
Timeline notation contains keyframes which describe a value that changes over time. Timelines usually describe one of: float values, color values, or vector values.
Keyframe
A timeline keyframe is composed of three elements, separated by colons, and surrounded by square brackets.
[A:B:C]
- Element A is the time index. This parameter ranges from 0 to 1.
- Element B is the value at this keyframe.
- Element C is the interpolation type. This parameter decides how the interpolation from this key to the next key takes place.
- L - Linear
- H - Hold
- I - Ease In
- O - Ease Out
- S - Smooth
- T - Twist
See also the documentation on Interpolation Curves.
An example keyframe would be:
[0.5:#0,0,0,1:L]
This keyframe has time index == 0.5, a color value of "#0,0,0,1", and an interpolation type of "Linear".
Timeline
A timeline is composed of several keyframes strung together, followed by a loop type, then a lifetime length.
[Key][Key] ... [Key]A;B
- Element A is the loop type. This parameter decides whether it traverses the timeline once, loops, or ping-pongs. The value is one of:
- O - Once. The timeline runs through once, and thereafter always returns the value of the last keyframe.
- L - Loop. The timeline runs through, and when it reaches the end, snaps to the beginning and continues again.
- P - Ping pong. The timeline runs through, and when it reaches the end, it reverses itself. When it then reaches the beginning, it reverses itself again. Things ping-pongs back and forth between the beginning and the end, smoothly, without snapping.
- Element B is the lifetime duration. This parameter specifies how long the timeline lasts for. If this parameter is 3.0, then it will take 3 seconds to run through the entire timeline once.
An example color timeline might look like:
[0.0:#0.0,0.0,0.0,1.0:H][0.5:#1.0,1.0,1.0,1.0:L][1.0:#0.0,0.0,0.0,1.0:L]P;1.0
This timeline, from time value [0.0,0.5), will return the color #0,0,0,1, due to the hold parameter. At time value 0.5, it will return the color #1,1,1,1. From time value [0.5,1.0] it will linearly interpolate between #1,1,1,1 to #0,0,0,1. It will take 1 second to traverse the entire timeline. When the traversal reaches the end, it is set to ping-pong, so it reverses and repeats the process backwards. When it then reaches the beginning, it reverses again, and repeats the process forwards.
