---

title: Hydra

layout: ../../layouts/MainLayout.astro

---

import { MiniRepl } from '../../docs/MiniRepl';

# Using Hydra inside Strudel

You can write [hydra](https://hydra.ojack.xyz/) code in strudel! All you have to do is to call `await initHydra()` at the top:

<MiniRepl

  client:only="react"

  tune={`await initHydra()

// licensed with CC BY-NC-SA 4.0 https://creativecommons.org/licenses/by-nc-sa/4.0/

// by Zach Krall

// http://zachkrall.online/

osc(10, 0.9, 300)

.color(0.9, 0.7, 0.8)

.diff(

osc(45, 0.3, 100)

.color(0.9, 0.9, 0.9)

.rotate(0.18)

.pixelate(12)

.kaleid()

)

.scrollX(10)

.colorama()

.luma()

.repeatX(4)

.repeatY(4)

.modulate(

osc(1, -0.9, 300)

)

.scale(2)

.out()

note("[a,c,e,<a4 ab4 g4 gb4>,b4]/2")

.s("sawtooth").vib(2)

.lpf(600).lpa(2).lpenv(6)

`}

/>

## H patterns

There is a special function `H` that allows you to use a pattern as an input to hydra:

<MiniRepl

  client:only="react"

  tune={`await initHydra()

let pattern = "3 4 5 [6 7]*2"

shape(H(pattern)).out(o0)

n(pattern).scale("A:minor").piano().room(1)

`}

/>

## detectAudio

To use hydra audio capture, call `initHydra` with `{detectAudio:true}` configuration param:

<MiniRepl

  client:only="react"

  tune={`await initHydra({detectAudio:true})

let pattern = "<3 4 5 [6 7]*2>"

shape(H(pattern)).repeat()

  .scrollY(

    ()=> a.fft[0]*.25

  )

  .add(src(o0).color(.71 ).scrollX(.005),.95)

.out(o0)

n(pattern).scale("A:minor").piano().room(1)

`}

/>

You might now be able to see this properly here: [open in REPL](/#YXdhaXQgaW5pdEh5ZHJhKCkKbGV0IHBhdHRlcm4gPSAiMyA0IDUgWzYgN10qMiIKc2hhcGUoSChwYXR0ZXJuKSkub3V0KG8wKQpuKHBhdHRlcm4pLnNjYWxlKCJBOm1pbm9yIikucGlhbm8oKS5yb29tKDEpIA%3D%3D)

Similar to `detectAudio`, all the [available hydra options](https://github.com/hydra-synth/hydra-synth#api) can be passed to `initHydra`.

## feedStrudel

Using the `feedStrudel` option, you can transform strudel visualizations with hydra:

<MiniRepl

  client:only="react"

  tune={`await initHydra({feedStrudel:1})

//

src(s0).kaleid(H("<4 5 6>"))

  .diff(osc(1,0.5,5))

  .modulateScale(osc(2,-0.25,1))

  .out()

//

$: s("bd*4,[hh:0:<.5 1>]*8,~ rim").bank("RolandTR909").speed(.9)

$: note("[<g1!3 <bb1 <f1 d1>>>]\*3").s("sawtooth")

.room(.75).sometimes(add(note(12))).clip(.3)

.lpa(.05).lpenv(-4).lpf(2000).lpq(8).ftype('24db')

all(x=>x.fft(4).scope({pos:0,smear:.95}))`}

/>