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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,120 +1,78 @@ | ||
| export function createKS(sampleRate: number, minFrequency: number) { | ||
| let active = false; | ||
| let startExciter = false; | ||
| const targetAmplitude = 0.001; // Amplitude decays to 0.1% of initial value | ||
| const maxDelayLineLength = Math.ceil(sampleRate / minFrequency) + 2; // Extra samples for interpolation | ||
|
|
||
| const excite = createExciter(1000); | ||
| const delayLine = new Float32Array(maxDelayLineLength); | ||
|
|
||
| // Delay line | ||
| const maxIndex = Math.floor(sampleRate / minFrequency + 0.5); | ||
| const delay = new InterpolatedDelayLine(maxIndex); | ||
| let delayInSamples = maxDelayLineLength - 2; | ||
| let writeIndex = 0; | ||
|
|
||
| // One pole filter for delay | ||
| let filterAlpha = 0.99; | ||
| let prevFilterOut = 0; | ||
| let isPlaying = false; | ||
| let prevTrigger = 0; | ||
|
|
||
| // Feedback | ||
| let lossFactor = 0.99; | ||
|
|
||
| // Param cache | ||
| let $freq = 0; | ||
| let $damping = 0; | ||
|
|
||
| return function ( | ||
| return ( | ||
| output: Float32Array, | ||
| trigger: number, | ||
| frequency: number, | ||
| damping: number | ||
| ) { | ||
| if ($freq !== frequency) { | ||
| $freq = frequency; | ||
| delay.setDelayLength(sampleRate / frequency); | ||
| } | ||
| if ($damping !== damping) { | ||
| $damping = damping; | ||
| lossFactor = damping * 0.2 + 0.792; | ||
| filterAlpha = Math.max(0, Math.min(1, damping)); | ||
| } | ||
|
|
||
| if (trigger === 1) { | ||
| if (!active) { | ||
| active = true; | ||
| startExciter = true; | ||
| decay: number | ||
| ) => { | ||
| const outputLength = output.length; | ||
|
|
||
| const decayTimeInSamples = decay * sampleRate; | ||
| const filterCoefficient = Math.pow(targetAmplitude, 1 / decayTimeInSamples); | ||
|
|
||
| if (trigger > 0 && prevTrigger <= 0) { | ||
| delayInSamples = sampleRate / frequency; | ||
| delayInSamples = Math.min( | ||
| Math.max(delayInSamples, 1), | ||
| maxDelayLineLength - 2 | ||
| ); | ||
|
|
||
| for (let i = 0; i < maxDelayLineLength; i++) { | ||
| delayLine[i] = Math.random() * 2 - 1; | ||
| } | ||
| } else { | ||
| active = false; | ||
| writeIndex = 0; | ||
| isPlaying = true; | ||
| } | ||
|
|
||
| for (let i = 0; i < output.length; i++) { | ||
| const pluck = excite(startExciter); | ||
| startExciter = false; | ||
|
|
||
| //const prev = delay.read(delayLength - 1); | ||
| const curr = delay.read(); | ||
| const filterOut = | ||
| curr * 1.0 * filterAlpha + prevFilterOut * (1 - filterAlpha); | ||
| prevFilterOut = filterOut; | ||
| output[i] = pluck * filterOut * lossFactor; | ||
| } | ||
| }; | ||
| } | ||
|
|
||
| class InterpolatedDelayLine { | ||
| buffer: Float32Array; | ||
| writeIndex: number; | ||
| delayLength: number; | ||
| position: number; // | ||
|
|
||
| constructor(public readonly size: number) { | ||
| this.buffer = new Float32Array(size); | ||
| this.writeIndex = 0; | ||
| this.delayLength = 10; | ||
| this.position = size - this.delayLength; | ||
| } | ||
|
|
||
| setDelayLength(delayLength: number) { | ||
| this.delayLength = delayLength; | ||
| this.position = this.writeIndex - delayLength; | ||
| while (this.position < 0) this.position += this.size; | ||
| } | ||
|
|
||
| writeAndUpdateIndex(value: number) { | ||
| this.buffer[this.writeIndex] = value; | ||
| this.writeIndex++; | ||
| if (this.writeIndex >= this.size) this.writeIndex = 0; | ||
| this.position++; | ||
| if (this.position >= this.size) this.position -= this.size; | ||
| } | ||
|
|
||
| read() { | ||
| while (this.position < 0) this.position += this.size; | ||
| const curr = Math.floor(this.position); | ||
| let next = curr + 1; | ||
| while (next >= this.size) next -= this.size; | ||
| const frac = this.position - curr; | ||
| const currVal = this.buffer[curr]; | ||
| const nextVal = this.buffer[next]; | ||
| return currVal - frac + (nextVal - currVal); | ||
| } | ||
| } | ||
|
|
||
| function createExciter(durationInSamples: number) { | ||
| const window = new Float32Array(durationInSamples); | ||
|
|
||
| // Create a triangular envelope | ||
| for (let i = 0; i < durationInSamples; i++) { | ||
| window[i] = 1 - Math.abs(i / (durationInSamples / 2) - 1); | ||
| } | ||
|
|
||
| let index = window.length; | ||
|
|
||
| return function (start: boolean) { | ||
| if (start) index = 0; | ||
| if (index < window.length) { | ||
| index++; | ||
| const noise = Math.random() * 2 - 1; | ||
| return noise * window[index]; | ||
| prevTrigger = trigger; | ||
|
|
||
| if (isPlaying) { | ||
| for (let i = 0; i < outputLength; i++) { | ||
| let readIndex = writeIndex - delayInSamples; | ||
| if (readIndex < 0) { | ||
| readIndex += maxDelayLineLength; | ||
| } | ||
|
|
||
| const readIndexInt = Math.floor(readIndex); | ||
| const frac = readIndex - readIndexInt; | ||
|
|
||
| // Wrap around the delay line | ||
| const index0 = readIndexInt % maxDelayLineLength; | ||
| const index1 = (readIndexInt + 1) % maxDelayLineLength; | ||
|
|
||
| // Linear interpolation between two samples | ||
| const sample0 = delayLine[index0]; | ||
| const sample1 = delayLine[index1]; | ||
| const currentSample = sample0 + frac * (sample1 - sample0); | ||
|
|
||
| const nextSample = filterCoefficient * currentSample; | ||
| delayLine[writeIndex] = nextSample; | ||
| output[i] = currentSample; | ||
|
|
||
| writeIndex = (writeIndex + 1) % maxDelayLineLength; | ||
|
|
||
| // Stop playing if the signal has decayed below a threshold | ||
| if (Math.abs(currentSample) < 1e-6) { | ||
| isPlaying = false; | ||
| for (let j = i + 1; j < outputLength; j++) { | ||
| output[j] = 0; | ||
| } | ||
| break; | ||
| } | ||
| } | ||
| } else { | ||
| return 0; | ||
| // Output silence when not playing | ||
| output.fill(0); | ||
| } | ||
| }; | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1 +1 @@ | ||
| export const PROCESSOR = `"use strict";(()=>{function w(s,t){let i=!1,e=!1,r=F(1e3),o=Math.floor(s/t+.5),f=new c(o),a=.99,p=0,b=.99,d=0,x=0;return function(g,y,h,n){d!==h&&(d=h,f.setDelayLength(s/h)),x!==n&&(x=n,b=n*.2+.792,a=Math.max(0,Math.min(1,n))),y===1?i||(i=!0,e=!0):i=!1;for(let l=0;l<g.length;l++){let A=r(e);e=!1;let m=f.read()*1*a+p*(1-a);p=m,g[l]=A*m*b}}}var c=class{constructor(t){this.size=t;this.buffer=new Float32Array(t),this.writeIndex=0,this.delayLength=10,this.position=t-this.delayLength}buffer;writeIndex;delayLength;position;setDelayLength(t){for(this.delayLength=t,this.position=this.writeIndex-t;this.position<0;)this.position+=this.size}writeAndUpdateIndex(t){this.buffer[this.writeIndex]=t,this.writeIndex++,this.writeIndex>=this.size&&(this.writeIndex=0),this.position++,this.position>=this.size&&(this.position-=this.size)}read(){for(;this.position<0;)this.position+=this.size;let t=Math.floor(this.position),i=t+1;for(;i>=this.size;)i-=this.size;let e=this.position-t,r=this.buffer[t],o=this.buffer[i];return r-e+(o-r)}};function F(s){let t=new Float32Array(s);for(let e=0;e<s;e++)t[e]=1-Math.abs(e/(s/2)-1);let i=t.length;return function(e){return e&&(i=0),i<t.length?(i++,(Math.random()*2-1)*t[i]):0}}var u=class extends AudioWorkletProcessor{r;g;constructor(){super(),this.r=!0,this.g=w(sampleRate,20),this.port.onmessage=t=>{switch(t.data.type){case"DISPOSE":this.r=!1;break}}}process(t,i,e){let r=i[0][0];return this.g(r,e.trigger[0],e.frequency[0],e.damping[0]),this.r}static get parameterDescriptors(){return[["trigger",0,0,1],["frequency",440,20,2e4],["damping",.1,0,1]].map(([t,i,e,r])=>({name:t,defaultValue:i,minValue:e,maxValue:r,automationRate:"k-rate"}))}};registerProcessor("KsProcessor",u);})();`; | ||
| export const PROCESSOR = `"use strict";(()=>{function b(o,n){let e=Math.ceil(o/n)+2,t=new Float32Array(e),i=e-2,a=0,f=!1,h=0;return(c,y,S,A)=>{let g=c.length,I=A*o,M=Math.pow(.001,1/I);if(y>0&&h<=0){i=o/S,i=Math.min(Math.max(i,1),e-2);for(let r=0;r<e;r++)t[r]=Math.random()*2-1;a=0,f=!0}if(h=y,f)for(let r=0;r<g;r++){let l=a-i;l<0&&(l+=e);let m=Math.floor(l),k=l-m,w=m%e,F=(m+1)%e,x=t[w],L=t[F],u=x+k*(L-x),P=M*u;if(t[a]=P,c[r]=u,a=(a+1)%e,Math.abs(u)<1e-6){f=!1;for(let p=r+1;p<g;p++)c[p]=0;break}}else c.fill(0)}}var d=class extends AudioWorkletProcessor{r;g;constructor(){super(),this.r=!0,this.g=b(sampleRate,100),this.port.onmessage=n=>{switch(n.data.type){case"DISPOSE":this.r=!1;break}}}process(n,s,e){let t=s[0][0];return this.g(t,e.trigger[0],e.frequency[0],e.decay[0]),this.r}static get parameterDescriptors(){return[["trigger",0,0,1],["frequency",440,20,2e4],["decay",.1,.01,5]].map(([n,s,e,t])=>({name:n,defaultValue:s,minValue:e,maxValue:t,automationRate:"k-rate"}))}};registerProcessor("KsProcessor",d);})();`; |
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