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Update FFT size and oscilloscope calculation

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jberg 2018-07-11 19:24:47 -07:00 • committed by Jordan Eldredge
parent bc75d6efb9
commit 1fffd05856
1 changed files with 4 additions and 5 deletions
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9
js/components/Visualizer.js
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@ -81,7 +81,7 @@ class Visualizer extends React.Component {
this.preRenderBg();
this.preRenderBar();
if (this.props.style === VISUALIZERS.OSCILLOSCOPE) {
this.props.analyser.fftSize = 2048;
this.props.analyser.fftSize = 1024;
this.bufferLength = this.props.analyser.fftSize;
this.dataArray = new Uint8Array(this.bufferLength);
} else if (this.props.style === VISUALIZERS.BAR) {
@ -181,16 +181,15 @@ class Visualizer extends React.Component {
const sliceWidth =
Math.floor(this.bufferLength / this._width()) * PIXEL_DENSITY;
// The max amplitude is half the height
const h = this._height() / 2;
const h = this._height();
this.canvasCtx.beginPath();
// Iterate over the width of the canvas in "real" pixels.
for (let j = 0; j <= this._renderWidth(); j++) {
const amplitude = sliceAverage(this.dataArray, sliceWidth, j);
const percentAmplitude = amplitude / 128; // dataArray gives us bytes
const y = percentAmplitude * h;
const percentAmplitude = (amplitude - 128) / 128; // dataArray gives us bytes
const y = percentAmplitude * h + h / 2; // center wave at half height
const x = j * PIXEL_DENSITY;
// Canvas coordinates are in the middle of the pixel by default.