POKEY sound

src/emu.js

@@ -127,6 +127,9 @@ var VectorVideo = function(mainElement, width, height) {
   var canvas, ctx;
   var persistenceAlpha = 0.5;
   var jitter = 1.0;
+  var gamma = 0.8;
+  var sx = width/1024.0;
+  var sy = height/1024.0;
 
   this.create = function() {
     canvas = __createCanvas(mainElement, width, height);
@@ -155,13 +158,13 @@ var VectorVideo = function(mainElement, width, height) {
   }
 
   var COLORS = [
-    '#000000',
+    '#111111',
-    '#0000ff',
+    '#1111ff',
-    '#00ff00',
+    '#11ff11',
-    '#00ffff',
+    '#11ffff',
-    '#ff0000',
+    '#ff1111',
-    '#ff00ff',
+    '#ff11ff',
-    '#ffff00',
+    '#ffff11',
     '#ffffff'
   ];
 
@@ -169,7 +172,8 @@ var VectorVideo = function(mainElement, width, height) {
     //console.log(x1, y1, x2, y2, intensity);
     if (intensity > 0) {
       // TODO: landscape vs portrait
-      ctx.globalAlpha = intensity / 255.0;
+      var alpha = Math.pow(intensity / 255.0, gamma);
+      ctx.globalAlpha = alpha;
       ctx.beginPath();
       // TODO: bright dots
       var jx = jitter * (Math.random() - 0.5);
@@ -178,8 +182,11 @@ var VectorVideo = function(mainElement, width, height) {
       x2 += jx;
       y1 += jy;
       y2 += jy;
-      ctx.moveTo(x1, height-y1);
+      ctx.moveTo(x1*sx, height-y1*sy);
-      ctx.lineTo(x2+1, height-y2);
+      if (x1 == x2 && y1 == y2)
+        ctx.lineTo(x2*sx+1, height-y2*sy);
+      else
+        ctx.lineTo(x2*sx, height-y2*sy);
       ctx.strokeStyle = COLORS[color & 7];
       ctx.stroke();
     }
@@ -248,13 +255,12 @@ var SampleAudio = function(clockfreq) {
   }
 
   function createContext() {
-    if ( typeof AudioContext !== 'undefined') {
+    var AudioContext = AudioContext || webkitAudioContext || mozAudioContext;
-      self.context = new AudioContext();
+    if (! AudioContext) {
-    } else if (typeof webkitAudioContext !== 'undefined' ){
+      console.log("no web audio context");
-      self.context = new webkitAudioContext();
-    } else {
       return;
     }
+    self.context = new AudioContext();
     self.sr=self.context.sampleRate;
     self.bufferlen=(self.sr > 44100) ? 4096 : 2048;
 
@@ -381,6 +387,180 @@ var AY38910_Audio = function(master) {
   }
 }
 
+// https://en.wikipedia.org/wiki/POKEY
+// https://user.xmission.com/~trevin/atari/pokey_regs.html
+// http://krap.pl/mirrorz/atari/homepage.ntlworld.com/kryten_droid/Atari/800XL/atari_hw/pokey.htm
+
+var POKEYDeviceChannel = function() {
+
+  /* definitions for AUDCx (D201, D203, D205, D207) */
+  var NOTPOLY5    = 0x80     /* selects POLY5 or direct CLOCK */
+  var POLY4       = 0x40     /* selects POLY4 or POLY17 */
+  var PURE        = 0x20     /* selects POLY4/17 or PURE tone */
+  var VOL_ONLY    = 0x10     /* selects VOLUME OUTPUT ONLY */
+  var VOLUME_MASK = 0x0f     /* volume mask */
+
+  /* definitions for AUDCTL (D208) */
+  var POLY9       = 0x80     /* selects POLY9 or POLY17 */
+  var CH1_179     = 0x40     /* selects 1.78979 MHz for Ch 1 */
+  var CH3_179     = 0x20     /* selects 1.78979 MHz for Ch 3 */
+  var CH1_CH2     = 0x10     /* clocks channel 1 w/channel 2 */
+  var CH3_CH4     = 0x08     /* clocks channel 3 w/channel 4 */
+  var CH1_FILTER  = 0x04     /* selects channel 1 high pass filter */
+  var CH2_FILTER  = 0x02     /* selects channel 2 high pass filter */
+  var CLOCK_15    = 0x01     /* selects 15.6999kHz or 63.9210kHz */
+
+  /* for accuracy, the 64kHz and 15kHz clocks are exact divisions of
+     the 1.79MHz clock */
+  var DIV_64      = 28       /* divisor for 1.79MHz clock to 64 kHz */
+  var DIV_15      = 114      /* divisor for 1.79MHz clock to 15 kHz */
+
+  /* the size (in entries) of the 4 polynomial tables */
+  var POLY4_SIZE  = 0x000f
+  var POLY5_SIZE  = 0x001f
+  var POLY9_SIZE  = 0x01ff
+
+  var POLY17_SIZE = 0x0001ffff    /* else use the full 17 bits */
+
+  /* channel/chip definitions */
+  var CHAN1       = 0
+  var CHAN2       = 1
+  var CHAN3       = 2
+  var CHAN4       = 3
+  var CHIP1       = 0
+  var CHIP2       = 4
+  var CHIP3       = 8
+  var CHIP4       = 12
+  var SAMPLE      = 127
+
+  var FREQ_17_EXACT     = 1789790.0  /* exact 1.79 MHz clock freq */
+  var FREQ_17_APPROX    = 1787520.0  /* approximate 1.79 MHz clock freq */
+
+  // LFSR sequences
+  var bit1 = [ 0,1 ];
+  var bit4 = [ 1,1,0,1,1,1,0,0,0,0,1,0,1,0,0 ];
+  var bit5 = [ 0,0,1,1,0,0,0,1,1,1,1,0,0,1,0,1,0,1,1,0,1,1,1,0,1,0,0,0,0,0,1 ];
+  var bit17 = new Uint8Array(1<<17);
+  var bit17_5 = new Uint8Array(1<<17);
+  var bit5_4 = new Uint8Array(1<<17);
+  for (var i=0; i<bit17.length; i++) {
+    bit17[i] = Math.random() > 0.5;
+    bit17_5[i] = bit17[i] & bit5[i % bit5.length];
+    bit5_4[i] = bit5[i % bit5.length] & bit4[i % bit4.length];
+  }
+  var wavetones = [
+    bit17_5, bit5, bit5_4, bit5,
+    bit17, bit1, bit4, bit1
+  ];
+
+  // registers
+  var regs = new Uint8Array(16);
+  var counters = new Float32Array(4);
+  var deltas = new Float32Array(4);
+  var volume = new Float32Array(4);
+  var audc = new Uint8Array(4);
+  var waveforms = [bit1, bit1, bit1, bit1];
+  var buffer;
+  var sampleRate = 44100;
+  var clock, baseDelta;
+  var dirty = true;
+
+  //
+
+  this.setBufferLength = function (length) {
+    buffer = new Int32Array(length);
+  };
+
+  this.getBuffer = function () {
+    return buffer;
+  };
+
+  this.setSampleRate = function (rate) {
+    sampleRate = rate;
+    baseDelta = FREQ_17_EXACT / rate / 1.2; // TODO?
+  };
+
+  function updateValues(addr) {
+    var ctrl = regs[8];
+    var base = (ctrl & CLOCK_15) ? DIV_15 : DIV_64;
+    var div;
+    var i = addr & 4;
+    var j = i>>1;
+    var k = i>>2;
+    if (ctrl & (CH1_CH2>>k)) {
+      if (ctrl & (CH1_179>>k))
+         div = regs[i+2] * 256 + regs[i+0] + 7;
+      else
+         div = (regs[i+2] * 256 + regs[i+0] + 1) * base;
+      deltas[j+1] = baseDelta / div;
+      deltas[j+0] = 0;
+    } else {
+      if (ctrl & (CH1_179>>k)) {
+        div = regs[i+0] + 4;
+      } else {
+        div = (regs[i+0] + 1) * base;
+      }
+      deltas[j+0] = baseDelta / div;
+      div = (regs[i+2] + 1) * base;
+      deltas[j+1] = baseDelta / div;
+    }
+    //console.log(addr, ctrl.toString(16), div, deltas[j+0], deltas[j+1]);
+  }
+
+  this.setRegister = function(addr, value) {
+    addr &= 0xf;
+    value &= 0xff;
+    if (regs[addr] != value) {
+      regs[addr] = value;
+      switch (addr) {
+        case 0:
+        case 2:
+        case 4:
+        case 6: // AUDF
+        case 8: // ctrl
+          dirty = true;
+          break;
+        case 1:
+        case 3:
+        case 5:
+        case 7: // AUDC
+          volume[addr>>1] = value & 0xf;
+          waveforms[addr>>1] = wavetones[value>>5];
+          break;
+      }
+    }
+  }
+
+  this.generate = function (length) {
+    if (dirty) {
+      updateValues(0);
+      updateValues(4);
+      dirty = false;
+    }
+    for (var s=0; s<length; s+=2) {
+      var sample = 0;
+      for (var i=0; i<4; i++) {
+        var d = deltas[i];
+        var v = volume[i];
+        if (d > 0 && d < 1 && v > 0) {
+          var wav = waveforms[i];
+          var cnt = counters[i] += d;
+          if (cnt > POLY17_SIZE+1) {
+            counters[i] -= POLY17_SIZE+1;
+          }
+          var on = wav[Math.floor(cnt % wav.length)];
+          if (on) {
+            sample += v;
+          }
+        }
+      }
+      sample *= 273;
+      buffer[s] = sample;
+      buffer[s+1] = sample;
+    }
+  }
+}
+
 ////// 6502
 
 var Base6502Platform = function() {

src/platform/vector.js

@@ -31,6 +31,17 @@ var GRAVITAR_KEYCODE_MAP = makeKeycodeMap([
   [Keys.VK_LEFT, 1, -0x8],
 ]);
 
+function newPOKEYAudio() {
+  var pokey1 = new POKEYDeviceChannel();
+  var pokey2 = new POKEYDeviceChannel();
+  var audio = new MasterAudio();
+  audio.pokey1 = pokey1;
+  audio.pokey2 = pokey2;
+  audio.master.addChannel(pokey1);
+  audio.master.addChannel(pokey2);
+  return audio;
+}
+
 var AtariVectorPlatform = function(mainElement) {
   var self = this;
   var cpuFrequency = 1500000.0;
@@ -78,7 +89,7 @@ var AtariVectorPlatform = function(mainElement) {
     // create video/audio
     video = new VectorVideo(mainElement,1024,1024);
     dvg = new DVGBWStateMachine(bus, video, 0x4000);
-    audio = new SampleAudio(cpuFrequency);
+    audio = newPOKEYAudio();
     video.create();
     timer = new AnimationTimer(60, function() {
       video.clear();
@@ -120,9 +131,11 @@ var AtariVectorPlatform = function(mainElement) {
   }
   this.pause = function() {
     timer.stop();
+    audio.stop();
   }
   this.resume = function() {
     timer.start();
+    audio.start();
   }
   this.reset = function() {
     this.clearDebug();
@@ -202,8 +215,8 @@ var AtariColorVectorPlatform = function(mainElement) {
       write: new AddressDecoder([
         [0x0,    0x7ff,  0x7ff,  function(a,v) { cpuram.mem[a] = v; }],
         [0x2000, 0x27ff, 0x7ff,  function(a,v) { dvgram.mem[a] = v; }],
-        [0x6000, 0x67ff, 0x7ff,  function(a,v) { /* pokey1 */ }],
+        [0x6000, 0x67ff, 0xf,    function(a,v) { audio.pokey1.setRegister(a, v); }],
-        [0x6800, 0x6fff, 0x7ff,  function(a,v) { /* pokey2 */ }],
+        [0x6800, 0x6fff, 0xf,    function(a,v) { audio.pokey2.setRegister(a, v); }],
         [0x8800, 0x8800, 0,      function(a,v) { /* LEDs, etc */ }],
         [0x8840, 0x8840, 0,      function(a,v) { dvg.runUntilHalt(0); }],
         [0x8880, 0x8880, 0,      function(a,v) { dvg.reset(); }],
@@ -223,7 +236,7 @@ var AtariColorVectorPlatform = function(mainElement) {
     // create video/audio
     video = new VectorVideo(mainElement,1024,1024);
     dvg = new DVGColorStateMachine(bus, video, 0x2000);
-    audio = new SampleAudio(cpuFrequency);
+    audio = newPOKEYAudio();
     video.create();
     timer = new AnimationTimer(60, function() {
       video.clear();
@@ -260,9 +273,11 @@ var AtariColorVectorPlatform = function(mainElement) {
   }
   this.pause = function() {
     timer.stop();
+    audio.stop();
   }
   this.resume = function() {
     timer.start();
+    audio.start();
   }
   this.reset = function() {
     this.clearDebug();
@@ -322,6 +337,8 @@ var Z80ColorVectorPlatform = function(mainElement, proto) {
       ]),
 
       write: new AddressDecoder([
+        [0x8000, 0x800f, 0xf,    function(a,v) { audio.pokey1.setRegister(a, v); }],
+        [0x8010, 0x801f, 0xf,    function(a,v) { audio.pokey2.setRegister(a, v); }],
         [0x8840, 0x8840, 0,      function(a,v) { dvg.runUntilHalt(0); }],
         [0x8880, 0x8880, 0,      function(a,v) { dvg.reset(); }],
         [0xa000, 0xdfff, 0x3fff, function(a,v) { dvgram.mem[a] = v; }],
@@ -333,7 +350,7 @@ var Z80ColorVectorPlatform = function(mainElement, proto) {
     // create video/audio
     video = new VectorVideo(mainElement,1024,1024);
     dvg = new DVGColorStateMachine(bus, video, 0xa000);
-    audio = new SampleAudio(cpuFrequency);
+    audio = newPOKEYAudio();
     video.create();
     timer = new AnimationTimer(60, function() {
       video.clear();
@@ -358,9 +375,11 @@ var Z80ColorVectorPlatform = function(mainElement, proto) {
   }
   this.pause = function() {
     timer.stop();
+    audio.stop();
   }
   this.resume = function() {
     timer.start();
+    audio.start();
   }
   this.reset = function() {
     cpu.reset();