Ilysa by Example: FX - Ripple

A common effect is to delay successive light on events for each light ID to achieve a “ripple” effect that looks like the light is in motion.

 
package main
 
import (
    "github.com/shasderias/ilysa"
    "github.com/shasderias/ilysa/beatsaber"
    "github.com/shasderias/ilysa/colorful"
    "github.com/shasderias/ilysa/colorful/gradient"
    "github.com/shasderias/ilysa/context"
    "github.com/shasderias/ilysa/ease"
    "github.com/shasderias/ilysa/evt"
    "github.com/shasderias/ilysa/fx"
    "github.com/shasderias/ilysa/light"
    "github.com/shasderias/ilysa/timer"
    "github.com/shasderias/ilysa/transform"
)
 
var (
    Red     = colorful.MustParseHex("#FF0000")
    Green   = colorful.MustParseHex("#00FF00")
    Blue    = colorful.MustParseHex("#0000FF")
    RGBGrad = gradient.New(Red, Blue, Green)
)
 
func main() {
    m, _ := beatsaber.NewMockMap(beatsaber.EnvironmentOrigins, 120, "[]")
    p := ilysa.New(m)
 
    l := transform.Light(light.NewBasic(p, evt.BackLasers),
        transform.DivideSingle(),
    )

This effect can be achieved manually.

 
    p.Range(timer.Rng(2, 3, 10, ease.Linear), func(ctx context.Context) {
        ctx.Light(l, func(ctx context.LightContext) {
 
            e := ctx.NewRGBLighting(
                evt.WithLight(evt.BackLasers),
                evt.WithLightValue(evt.LightRedOn),
            )

The Apply() method applies an option to an event that has already been created. The option evt.WithBOffset() shifts the event back by the specified number of beats. In this example, we shift the light on event for the 1st light ID by 0 beats, the light on event for the 2nd light ID by 0.2 beats, the light on event for the 3rd light ID by 0.4 beats, etc.

 
            e.Apply(evt.WithBOffset(float64(ctx.LightIDOrdinal()) * 0.2))

The above line can be replaced with this.

 
            fx.Ripple(ctx, e, 0.2)

Alternatively, you can use fx.RippleT() which delays each successive event by an amount such that the last event is triggered 1 beat later than the first event.

 
            fx.RippleT(ctx, e, 1)
 
        })
    })
}

Next example: Chroma Event Reference.

by shasderias | source | license