Extended Features

Besides the official Phigros chart format, pec, and rpe, prpr also supports additional chart features. These are available only in prpr and clients built on top of it:

• Effects
• Video background

All such configuration must be placed in extra.json at the root of the chart package. To use these features, you currently need to edit the JSON by hand. If you are not familiar with JSON, see for example the JSON tutorial.

BPM configuration

Before using these features, you must set the chart BPM in extra.json. Example:

{
   "bpm": [
      { "time": [0, 0, 1], "bpm" : 200.0 },
      { "time": [10, 1, 2], "bpm" : 250.0 }
   ],
   ...
}

This means the chart starts at BPM 200, then at 10.5 beats it changes to 250.

Animation variables

These configs often use animation variables. For example, in RPE, an X-position event is simply the X coordinate expressed as an animation variable.

prpr supports two forms. The first is a single value, which stays constant over time. The second is the same as in RPE: a list of Event objects. A single event looks like this:

{
	"startTime": [0, 0, 1],
	"endTime": [0, 0, 1],
	"easingType": 2,
	"easingLeft": 0.0,
	"easingRight": 1.0,
	"start": ...,
	"end": ...
}

startTime and endTime are the event start and end; easingType is the easing type; easingLeft and easingRight optionally clip the easing.

start and end are the variable values at start and end. The value type depends on the variable; it can be:

• float: single number
• vec2: 2D vector as a two-element array
• color: color as four integers 0–255, format [R, G, B, A]

Example: an animation variable that goes from 0 to 0.1 linearly between two times:

[
	{
		"startTime": [2, 0, 1],
		"endTime": [4, 0, 1],
		"easingType": 2,
		"start": 0.0,
		"end": 0.1
	}
]