path: root/client/draw.js

import {
  browser, requestAudioContext,
  randint, randrange, clamp, mod,
} from './lib/util'

import './lib/vendor/hidpi-canvas'

import mouse from './lib/mouse'
import color from './lib/color'

let w, h
let rx, ry

const pixels_per_second = 512 // 1024

const canvas = document.createElement('canvas')
// document.body.appendChild(canvas)
// document.body.addEventListener('resize', resize)
resize()
recenter()
requestAnimationFrame(animate)

// must request context after resizing
const ctx = canvas.getContext('2d')

const scratch = document.createElement('canvas')
const scratchCtx = scratch.getContext('2d-lodpi')

function resize(ww, hh){
  w = canvas.width = ww || window.innerWidth
  h = canvas.height = hh || window.innerHeight
  canvas.style.width = w + 'px'
  canvas.style.height = h + 'px'
}
function recenter(){
  rx = randint(w), ry = randint(h)
}
let frame = null
function onFrame(fn){
  frame = fn
}
function animate(t){
  requestAnimationFrame(animate)
  if (frame) {
    frame(t)
    frame = null
  }
  // ctx.save()
  // ctx.globalAlpha = 0.0001
  // ctx.translate(w/2, h/2)
  // ctx.rotate(0.1)
  // ctx.translate(-rx, -ry)
  // ctx.drawImage(canvas, 0, 0)
  // ctx.restore()
}
function clear(n, x, y, ww, hh){
  ctx.fillStyle = 'rgba(255,255,255,' + (n || 0.9) + ')'
  ctx.fillRect(x || 0, y || 0, ww || w, hh || h)
  recenter()
}
function triangle(px,py,r){
  setTimeout( () => tri(px,py,r), Math.random()*10)
  // setTimeout( () => tri(px,py,r), Math.random()*200)
  // setTimeout( () => tri(px,py,r), Math.random()*300)
}
function tri(px, py, r) {
  ctx.save()
  ctx.globalCompositeOperation = 'multiply'
  ctx.fillStyle = color.color((px+py)/(w+h), 0, 1, 0.2)
  function p(){
    let theta = randrange(0, Math.PI*2)
    let x = px + Math.cos(theta) * r
    let y = py + Math.sin(theta) * r
    return { x, y }
  }
  ctx.beginPath()
  const p0 = p(), p1 = p(), p2 = p()
  ctx.moveTo(p0.x, p0.y)
  ctx.lineTo(p1.x, p1.y)
  ctx.lineTo(p2.x, p2.y)
  ctx.lineTo(p0.x, p0.y)
  ctx.fill()
  ctx.restore()
}
function line(y){
  ctx.beginPath()
  ctx.moveTo(0, y)
  ctx.lineTo(w, y)
  ctx.strokeStyle = "#888"
  ctx.strokeWidth = 1
  ctx.stroke()
}
function dot(x, y, r){
  ctx.fillStyle = "#f00"
  ctx.beginPath()
  ctx.moveTo(x, y)
  ctx.arc(x, y, r, 0, 2*Math.PI)
  ctx.fill()
}
function waveform(pcm, sr, pos, zoom){
  sr = sr || 44100
  pos = pos || 0

  var width = w
  var height = Math.floor(h/4)
  var half_height = Math.floor(height/2)
  var x0 = 0
  var y0 = 20
  var ymid = y0 + half_height
  var max_width_in_seconds = width / pixels_per_second
  var max_width_in_samples = max_width_in_seconds * sr
  var pcm_length = pcm.length
  var len = Math.min(pcm_length, max_width_in_samples)
  var pcm_step = sr / pixels_per_second
  var i
  ctx.save()

  clear(1, x0, y0, width, height)

  line(ymid)
  ctx.beginPath()
  for (i = 0; i < width; i += 0.5) {
    var si = Math.floor(pcm_step * i + pos)
    if (si > pcm_length) break
    var val = pcm[si] // -1, 1
    // ctx.moveTo(x0 + i, ymid)
    ctx.lineTo(x0 + i, ymid + val * half_height)
  }
  ctx.strokeStyle = "rgba(250,20,0,0.9)"
  ctx.strokeWidth = 1
  ctx.stroke()
  ctx.restore()
}

function spectrum(spec, x0, y0, ww, hh){
  const data = spec.data
  const fft_size = spec.fft_size
  const half_fft_size = spec.fft_size / 2
  const spec_len = data.length

  scratch.width = data.length
  scratch.height = half_fft_size

  var imageData = ctx.createImageData(scratch.width, scratch.height)
  var pixels = imageData.data

  let i, j, u, v, _r, _i, col, hsl

  for (i = 0; i < spec_len; i++) {
    col = data[i]

    for (j = 0; j < half_fft_size; j++) {
      u = ((half_fft_size - j) * spec_len + i) * 4
      v = j * 2
      _r = col[v]
      _i = mod(col[v+1], Math.PI*2) / (Math.PI*2)
      hsl = color.hsl2rgb((_i + 1) / 2, 1.0, 1 - Math.abs(_r / 10))
      // red - real part
      // pixels[u] = _r * 127 + 127
      // // green - imag part
      // pixels[u+1] = _i * 127 + 127
      // // blue - magnitude
      // pixels[u+2] = Math.sqrt(Math.pow(_r, 2) + Math.pow(_i, 2)) * 128 + 127
      // pixels[u+3] = 255
      pixels[u] = hsl[0]
      pixels[u+1] = hsl[1]
      pixels[u+2] = hsl[2]
      pixels[u+3] = 255
    }
  }

  scratchCtx.putImageData(imageData, 0, 0)

  var pcm_length = spec.fft_overlap * spec_len

  x0 = x0 * devicePixelRatio || 0
  y0 = y0 * devicePixelRatio || Math.floor(h/4)
  ww = ww * devicePixelRatio || w
  hh = hh * devicePixelRatio || h/4

  const width = Math.round(pcm_length / spec.sr * pixels_per_second)
  const height = Math.floor(hh)

  ctx.save()
  clear(1, x0, y0, w, height)
  ctx.drawImage(scratch, x0, y0, width, height)
  ctx.restore()
}
function raw_spectrum(spec, x0, y0, ww, hh, def_min_r, def_min_i){
  const data = spec.data
  const fft_size = spec.fft_size
  const half_fft_size = spec.fft_size / 2
  const spec_len = data.length

  const _scratch = document.createElement('canvas')
  const _scratchCtx = _scratch.getContext('2d-lodpi')
  _scratch.width = data.length
  _scratch.height = half_fft_size
  // console.log("spectrum w/h:", _scratch.width, _scratch.height)

  var imageData = _scratchCtx.createImageData(_scratch.width, _scratch.height)
  var pixels = imageData.data

  let i, j, u, v, _r, _i, col, hsl
  // let min_r = Infinity, max_r = -Infinity
  // let min_i = Infinity, max_i = -Infinity

  // determined empirically..
  // let min_r = -60.4894057005308
  // let max_r = 107.23800966675353
  // let min_i = -59.4894057005308
  // let max_i = 108.23800966675353
  let min_r = -def_min_r
  let max_r = def_min_r
  let min_i = -def_min_i
  let max_i = def_min_i
  let delta_r = max_r - min_r
  let delta_i = max_i - min_i
  let mean_r = 0
  let mean_i = 0
  let sum_mean_r = 0, sum_mean_i = 0
  let real, imag

  for (i = 0; i < spec_len; i++) {
    col = data[i]
    mean_r = 0
    mean_i = 0

    for (j = 0; j < half_fft_size; j++) {
      u = (j * spec_len + i) * 4
      v = j * 2
      real = col[v]
      imag = col[v+1]
      mean_r += real
      mean_i += imag
      _r = clamp((real - min_r) / delta_r * 255, 0, 255)
      _i = clamp((imag - min_i) / delta_i * 255, 0, 255)

      // hsl = color.hsl2rgb((_i + 1) / 2, 1.0, 1 - Math.abs(_r / 10))
      pixels[u+0] = _r
      pixels[u+1] = _i
      pixels[u+2] = 0 // hsl[2]
      pixels[u+3] = 255

      // min_r = Math.min(min_r, col[v])
      // max_r = Math.max(max_r, col[v])
      // min_i = Math.min(min_i, col[v]+1)
      // max_i = Math.max(max_i, col[v]+1)
    }
    mean_r /= half_fft_size
    mean_i /= half_fft_size
    sum_mean_r += mean_r
    sum_mean_i += mean_i
  }

  sum_mean_r /= spec_len
  sum_mean_i /= spec_len
  // console.log(sum_mean_r, sum_mean_i)
  // console.log("r:", min_r, max_r)
  // console.log("i:", min_i, max_i)
  _scratchCtx.putImageData(imageData, 0, 0)

  return { canvas: _scratch, imageData }
}

export default {
  canvas, ctx, onFrame, resize,
  triangle, clear, line, dot,
  waveform, spectrum, raw_spectrum,
}