micromaSYN 24db/oct filter
/**
* Copyright yonatan ( http://wonderfl.net/user/yonatan )
* MIT License ( http://www.opensource.org/licenses/mit-license.php )
* Downloaded from: http://wonderfl.net/c/91Cg
*/
// forked from hiloya's micromaSYN
package{
import flash.display.Sprite;
public class MicromaSYN extends Sprite{
public function MicromaSYN():void{
graphics.beginFill(0x707070);
graphics.drawRect(0, 0, 465, 465);
graphics.endFill();
new Synthesizer(this);
}
}
}
import flash.display.*;
import flash.events.*;
import flash.text.*;
import flash.media.Sound;
import flash.media.SoundChannel;
import com.bit101.components.*;
const PI:Number = Math.PI;
const SAMPLE_BUFFER_NUM:int = 2048;
const SAMPLE_FREQ:Number = 44100.0;
const WAVEFORM_RECT:int = 0;
const WAVEFORM_SAW:int = 1;
const WAVEFORM_TRI:int = 2;
const WAVEFORM_SINE:int = 3;
const WAVEFORM_NOISE:int = 4;
//modify minimalcomps color style
Style.BACKGROUND = 0xFFFFFF;
Style.BUTTON_FACE = 0x6050F0;
Style.LABEL_TEXT = 0xFFFFFF; //text color
const STYLE_UI_THEME:uint = 0xFFFFFF; //knob color
const STYLE_UI_BACKGROUND:uint = 0xFF1040; //panel color
const STYLE_UI_FRAME:uint = 0xFFFFFF; //line color
//user interface
var ui_osc1_waveform:WaveformSelector;
var ui_osc1_octave:RotarySelectorEx;
var ui_osc1_volume:Knob;
var ui_osc2_waveform:WaveformSelector;
var ui_osc2_octave:RotarySelectorEx;
var ui_osc2_volume:Knob;
var ui_filter_cutoff:Knob;
var ui_filter_resonance:Knob;
var ui_egf_attack:Knob;
var ui_egf_decay:Knob;
var ui_egf_sustain:Knob;
var ui_egf_release:Knob;
var ui_ega_attack:Knob;
var ui_ega_decay:Knob;
var ui_ega_sustain:Knob;
var ui_ega_release:Knob;
var ui_amp_volume:Knob;
var ui_octave_shift:NumericStepper;
function map(val:Number, smin:Number, smax:Number, dmin:Number, dmax:Number):Number{
return (val - smin) / (smax - smin) * (dmax - dmin) + dmin;
}
function constrain(val:Number, min:Number, max:Number):int{
if(val < min) return min;
else if(val > max) return max;
else return val;
}
class Tone{
public var playing:Boolean = false;
public var key_on:Boolean = false;
public var osc_note_id:int = 0; //midi note number
private var osc1_phase:Number = 0; //[rad]
private var osc2_phase:Number = 0; //[rad]
private var note_t:Number = 0; //[sec]
private var egf_level:Number = 0; //0..1, output control signal of filter EG
private var ega_level:Number = 0; //0..1, output control signal of amplifier EG
private var fi:Number = 0.0; //filter state variable
private var fy:Number = 0.0; //
private function midiNoteIdToFreq(note_id:int):Number{
return 440.0 * Math.pow(2.0, (note_id - 69) / 12.0);
}
private function incPhase(osc_phase:Number, osc_octave:Number):Number{
var note_id:int = osc_note_id + (ui_octave_shift.value + osc_octave) * 12;
note_id = constrain(note_id, 0, 127);
var freq:Number = midiNoteIdToFreq(note_id);
var phase_delta:Number = 2.0 * PI * freq / SAMPLE_FREQ;
osc_phase += phase_delta;
osc_phase %= 2.0 * PI;
return osc_phase;
}
private function getWave(waveform:int, r:Number):Number{
var y:Number;
switch(waveform){
case WAVEFORM_RECT: y = (r < PI) ? 1.0 : -1.0; break;
case WAVEFORM_SAW: y = 1.0 - 1.0 / PI * r; break;
case WAVEFORM_TRI: y = (r < PI) ? (2.0 / PI * r - 1.0) : (-2.0 / PI * r + 3.0); break;
case WAVEFORM_SINE: y = Math.sin(r); break;
case WAVEFORM_NOISE: y = Math.random() * 2.0 - 1.0; break;
deault: y = 0; break;
}
return y * 0.05;
}
private function oscillator():Number{
osc1_phase = incPhase(osc1_phase, ui_osc1_octave.choice-3);
osc2_phase = incPhase(osc2_phase, ui_osc2_octave.choice-3);
var v1:Number = getWave(ui_osc1_waveform.choice, osc1_phase) * ui_osc1_volume.value;
var v2:Number = getWave(ui_osc2_waveform.choice, osc2_phase) * ui_osc2_volume.value;
return (v1 + v2) / 2;
}
private var iir:Filter = new Filter();
private function filter(x:Number):Number{
var cutoff:Number = map(egf_level, 0.0, 1.0, ui_filter_cutoff.value, 1.0);
var base_note_id:int = constrain(osc_note_id + (ui_octave_shift.value +
Math.min(ui_osc1_octave.choice-3, ui_osc2_octave.choice-3)) * 12, 0, 127);
var base_freq:Number = midiNoteIdToFreq(base_note_id);
var fc:Number = Math.pow(10000 - base_freq*1.2, cutoff) + base_freq*1.2; //base_freq*1.2..10000
iir.setParams(fc, ui_filter_resonance.value);
return iir.process(x);
}
private function amplifier(x:Number):Number{
return x * ega_level * ui_amp_volume.value;
}
public function processSample():Number{
var v:Number;
v = oscillator();
v = filter(v);
v = amplifier(v);
return v;
}
private function adsr(a:Number, d:Number, s:Number, r:Number, t:Number, is_up:Boolean):Number{
var v:Number;
if(is_up){
if(t < a) v = map(t, 0, a, 0.0, 1.0);
else if(t < a+d) v = map(t, a, a+d, 1.0, s);
else v = s;
}else{
if(t < r) v = map(t, 0, r, s, 0);
else v = 0;
}
return v;
}
private function amplifier_eg():void{
var a:Number = ui_ega_attack.value * 1; //0..1[sec]
var d:Number = ui_ega_decay.value * 1; //0..1[sec]
var s:Number = ui_ega_sustain.value; //0..1
var r:Number = ui_ega_release.value * 2; //0..2[sec]
ega_level = adsr(a, d, s, r, note_t, key_on);
if(!key_on && ega_level == 0) playing = false;
}
private function filter_eg():void{
var a:Number = ui_egf_attack.value * 1; //0..1[sec]
var d:Number = ui_egf_decay.value * 1; //0..1[sec]
var s:Number = ui_egf_sustain.value; //0..1
var r:Number = ui_egf_release.value * 2; //0..2[sec]
egf_level = adsr(a, d, s, r, note_t, key_on);
}
public function processEnvelope():void{
note_t += SAMPLE_BUFFER_NUM / SAMPLE_FREQ;
filter_eg();
amplifier_eg();
}
public function noteOn(note_id:int):void{
playing = true;
key_on = true;
osc_note_id = note_id;
osc1_phase = 0;
osc2_phase = 0;
note_t = 0;
}
public function noteOff(note_id:int):void{
key_on = false;
note_t = 0;
}
public function Tone(note_id:int):void{
noteOn(note_id);
}
}
class Synthesizer extends Sprite{
private const FRAME_PADDING:int = 2;
private const SEPARATOR_SPACE:int = 6;
private var tones:Array = new Array();
public function Synthesizer(parent:Sprite):void{
makeControlPanel(parent);
initSoundOutput();
}
public function drawFrame(x:int, y:int, w:int, h:int):void{
var p:int = FRAME_PADDING;
var g:Graphics = this.graphics;
graphics.lineStyle(1, STYLE_UI_FRAME);
graphics.drawRect(x+p, y+p, w-p*2, h-p*2);
graphics.endFill();
}
private function drawSeparatorH(x:int, y:int, w:int):void{
x += (FRAME_PADDING + SEPARATOR_SPACE);
w -= (FRAME_PADDING + SEPARATOR_SPACE) * 2;
graphics.lineStyle(1, STYLE_UI_FRAME);
graphics.moveTo(x, y);
graphics.lineTo(x+w, y);
}
private function makeControlPanel(parent:Sprite):void{
var pane:Sprite = this;
graphics.beginFill(STYLE_UI_BACKGROUND);
graphics.drawRect(2, 2, 448, 380);
graphics.endFill();
parent.addChild(this);
this.x = 6;
this.y = 42;
drawFrame(0 , 0, 452, 384);
new Label(this, 379, 5, "micromaSYN");
var x0:int = 36;
var y0:int = 50;
var ax:int = 70;
var ay:int = 65;
var kw:int = 20;
var kh:int = 32;
var kh2:int = 20;
ui_osc1_waveform = new WaveformSelector(this, x0, y0, "waveform");
ui_osc1_octave = new RotarySelectorEx(this, x0, y0+ay, "octave");
ui_osc1_octave.choiceTexts = ["-3", "-2", "-1", "0", "+1", "+2", "+3"];
ui_osc1_octave.choice = 3;
ui_osc1_volume = new SynthKnob(this, x0, y0+ay*2, "volume", 1.0);
drawFrame(x0-kw, y0-kh, ax, ay*3+kh2);
new Label(this, x0-kw+4, y0-kh, "OSC1");
x0 += ax;
ui_osc2_waveform = new WaveformSelector(this, x0, y0, "waveform");
ui_osc2_waveform.choice = 1;
ui_osc2_octave = new RotarySelectorEx(this, x0, y0+ay, "octave");
ui_osc2_octave.choiceTexts = ["-3", "-2", "-1", "0", "+1", "+2", "+3"];
ui_osc2_octave.choice = 4;
ui_osc2_volume = new SynthKnob(this, x0, y0+ay*2, "volume", 1.0);
drawFrame(x0-kw, y0-kh, ax, ay*3+kh2);
new Label(this, x0-kw+4, y0-kh, "OSC2");
x0 += ax;
ui_filter_cutoff = new SynthKnob(this, x0, y0, "cutoff", 0.7);
ui_filter_resonance = new SynthKnob(this, x0+ax, y0, "resonance", 0.0);
ui_egf_attack = new SynthKnob(this, x0, y0+ay, "attack", 0.0);
ui_egf_decay = new SynthKnob(this, x0+ax, y0+ay, "decay", 0.0);
ui_egf_sustain = new SynthKnob(this, x0, y0+ay*2, "sustain", 0.0);
ui_egf_release = new SynthKnob(this, x0+ax, y0+ay*2, "release", 0.0);
drawFrame(x0-kw, y0-kh, ax*2, ay*3+kh2);
drawSeparatorH(x0-kw, y0-kh2+ay+7, ax*2);
new Label(this, x0-kw+4, y0-kh, "FILTER");
x0 += ax * 2;
ui_amp_volume = new SynthKnob(this, x0+ax, y0, "volume", 0.5);
ui_ega_attack = new SynthKnob(this, x0, y0+ay, "attack", 0.0);
ui_ega_decay = new SynthKnob(this, x0+ax, y0+ay, "decay", 0.0);
ui_ega_sustain = new SynthKnob(this, x0, y0+ay*2, "sustain", 1.0);
ui_ega_release = new SynthKnob(this, x0+ax, y0+ay*2, "release", 0.5);
drawFrame(x0-kw, y0-kh, ax*2, ay*3+kh2);
drawSeparatorH(x0-kw, y0-kh2+ay+7, ax*2);
new Label(this, x0-kw+4, y0-kh, "AMPILFIER");
x0 -= ax * 4;
y0 += ax * 3;
x0 -= 20;
y0 -= 28;
new Label(this, x0+4, y0+4, "octave shift");
ui_octave_shift = new NumericStepper(this, x0+60, y0+4);
ui_octave_shift.minimum = -4;
ui_octave_shift.maximum = 4;
drawFrame(x0, y0, ax*6, 24);
y0 += 26;
var kbd:KeyboardPanel = new KeyboardPanel(parent, this);
this.addChild(kbd);
kbd.x = x0;
kbd.y = y0;
}
public function noteOn(note_id:int):void{
for(var i:int = 0; i< tones.length; i++){
if(tones[i] && tones[i].key_on && tones[i].osc_note_id == note_id) return;
}
tones.push(new Tone(note_id));
}
public function noteOff(note_id:int):void{
for(var i:int = 0; i< tones.length; i++){
if(tones[i] && tones[i].key_on && tones[i].osc_note_id == note_id){
tones[i].noteOff(note_id);
}
}
for(i = 0; i< tones.length; i++){
if(tones[i] && !tones[i].playing){
tones[i] = null;
tones.slice(i);
continue;
}
}
}
private function initSoundOutput():void{
var sound:Sound = new Sound();
sound.addEventListener(SampleDataEvent.SAMPLE_DATA,
this.processSoundBuffer);
sound.play();
}
//sample data event handler
private function processSoundBuffer(event:SampleDataEvent):void{
for(var i:int = 0; i<SAMPLE_BUFFER_NUM; i++){
var v:Number = 0;
for(var k:int =0; k< tones.length; k++){
if(tones[k] && tones[k].playing){
v += tones[k].processSample();
}
}
event.data.writeFloat(v);
event.data.writeFloat(v);
}
for(k = 0; k< tones.length; k++){
if(tones[k]){
tones[k].processEnvelope();
}
}
}
}
class KeyboardPanel extends Sprite{
private const KBD_W:int = 420;
private const KBD_H:int = 100;
private const KEY_WHT_W:int = 28;
private const KEY_BLK_W:int = 20;
private const KEY_WHT_H:int = 90;
private const KEY_BLK_H:int = 55;
private const KEY_ON_COLOR:uint = 0xFF0000;
private const KEY_ON_ALPHA:Number = 0.7;
private const KEY_LINE_COLOR:uint = 0x303030;
private const KEY_NUM:int = 25;
private const keyNames:String = "ZSXDCVGBHNJMQ2W3ER5T6Y7UI";
private const keycolors:Array = [0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0];
private const BASE_NOTE:int = 48;
private var synth:Synthesizer;
private var keys:Array = new Array();
private var keys_is_on:Array = new Array();
public function makeRectSprite(x:int, y:int, w:int, h:int, fill_color:int, line_color:int):Sprite{
var sp:Sprite = new Sprite();
sp.x = x;
sp.y = y;
sp.graphics.beginFill(fill_color);
sp.graphics.lineStyle(1, line_color);
sp.graphics.drawRect(0, 0, w, h);
sp.graphics.endFill();
return sp;
}
private function makeKey(x:int, y:int, idx:int, keycolor:int, keyName:String):void{
var w:int, h:int;
var c:uint, text_c:uint;
if(keycolor== 0){
w = KEY_WHT_W;
h = KEY_WHT_H;
c = 0xFFFFFF;
text_c = 0x606060;
}else{
w = KEY_BLK_W;
h = KEY_BLK_H;
x += 4;
c = 0x404040;
text_c = 0xC0C0C0;
}
//under sprite, non transparent, solid color
var sp0:Sprite = makeRectSprite(x, y, w, h, KEY_ON_COLOR, KEY_LINE_COLOR);
//top sprite, semi transparent when key is on
var sp:Sprite = makeRectSprite(x, y, w, h, c, KEY_LINE_COLOR);
var tf:TextField = new TextField();
tf.text = keyName;
tf.autoSize = TextFieldAutoSize.CENTER;
tf.selectable = false;
tf.x = (keycolor == 0) ? 7 : 4;
tf.y = h - 20;
var fm:TextFormat = new TextFormat();
fm.color = text_c;
fm.font = "_sans";
fm.size = 12;
tf.setTextFormat(fm);
sp.addChild(tf);
sp.addEventListener(MouseEvent.MOUSE_DOWN, function(e:MouseEvent):void{ noteOn(idx); });
sp.addEventListener(MouseEvent.MOUSE_UP, function(e:MouseEvent):void{ noteOff(idx); });
sp.addEventListener(MouseEvent.MOUSE_OUT, function(e:MouseEvent):void{ noteOff(idx); });
if(keycolor == 0){
addChildAt(sp, 0);
addChildAt(sp0, 0);
}else{
addChild(sp0);
addChild(sp);
}
keys.push(sp);
keys_is_on.push(false);
}
public function KeyboardPanel(parent:Sprite, synth:Synthesizer):void{
this.synth = synth;
parent.stage.addEventListener(KeyboardEvent.KEY_DOWN, onKeyDown);
parent.stage.addEventListener(KeyboardEvent.KEY_UP, onKeyUp);
var x0:int = 0;
var y0:int = 3;
for(var i:int = 0; i< KEY_NUM; i++){
makeKey(x0, y0, i, keycolors[i%12], keyNames.charAt(i));
x0 += KEY_WHT_W/2;
if(i % 12 == 4 || i % 12 == 11) x0 += KEY_WHT_W/2;
}
}
private function noteOn(i:int):void{
if(!keys_is_on[i]){
synth.noteOn(BASE_NOTE + i);
keys[i].alpha = KEY_ON_ALPHA;
keys_is_on[i] = true;
}
}
private function noteOff(i:int):void{
if(keys_is_on[i]){
synth.noteOff(BASE_NOTE + i);
keys[i].alpha = 1.0;
keys_is_on[i] = false;
}
}
private function onKeyDown(e:KeyboardEvent):void{
var c:String = String.fromCharCode(e.charCode).toUpperCase();
var i:int = keyNames.indexOf(c);
if(i != -1) noteOn(i);
}
private function onKeyUp(e:KeyboardEvent):void{
var c:String = String.fromCharCode(e.charCode).toUpperCase();
var i:int = keyNames.indexOf(c);
if(i != -1) noteOff(i);
}
}
//Knob, design modified
class SynthKnob extends Knob{
public function SynthKnob(parent:DisplayObjectContainer = null,
xpos:Number = 0, ypos:Number = 0, label:String = "",
defaultValue:Number = 0.0, defaultHandler:Function = null):void{
super(parent, xpos, ypos, label, defaultHandler);
minimum = 0.0;
maximum = 1.0;
showValue = false;
radius = 16;
y -= 20; //adjust to same y position as RotarySelector
value = defaultValue;
dispatchEvent(new Event(Event.CHANGE));
}
override protected function drawKnob():void{
_knob.graphics.clear();
_knob.graphics.beginFill(STYLE_UI_THEME);
_knob.graphics.drawCircle(0, 0, _radius);
_knob.graphics.endFill();
_knob.graphics.beginFill(STYLE_UI_BACKGROUND);
_knob.graphics.drawCircle(0, 0, _radius - 3);
_knob.graphics.endFill();
//inner marker
_knob.graphics.lineStyle(4, STYLE_UI_THEME, 1.0, false,
LineScaleMode.NORMAL, CapsStyle.NONE);
_knob.graphics.moveTo(_radius*0.3, 0);
_knob.graphics.lineTo(_radius-2, 0);
_knob.x = _radius;
_knob.y = _radius + 20;
updateKnob();
}
override public function draw():void{
super.draw();
_label.y = _radius * 2 + 20 - 1; //show label under knob
}
}
//RotarySelecter, modified for drawing custom choice symbol
class RotarySelectorEx extends RotarySelector{
public function RotarySelectorEx(parent:DisplayObjectContainer = null,
xpos:Number = 0, ypos:Number = 0, label:String = "",
defaultHandler:Function = null){
super(parent, xpos, ypos, label, defaultHandler);
setSize(32, 32); //same radius as Knob
}
//choice label texts
protected var _choiceTexts:Array;
public function set choiceTexts(texts:Array):void{
_choiceTexts = texts;
numChoices = texts.length;
draw();
}
public function get choiceTexts():Array{
return _choiceTexts;
}
override protected function drawKnob(radius:Number):void{
_knob.graphics.clear();
_knob.graphics.beginFill(STYLE_UI_THEME);
_knob.graphics.drawCircle(0, 0, radius);
_knob.graphics.endFill();
_knob.graphics.beginFill(STYLE_UI_BACKGROUND);
_knob.graphics.drawCircle(0, 0, radius - 3);
_knob.x = _width / 2;
_knob.y = _height / 2;
}
override public function draw():void{
super.draw();
var radius:Number = Math.min(_width, _height) / 2;
drawKnob(radius);
resetLabels();
var arc:Number = Math.PI * 1.5 / _numChoices;
var start:Number = - Math.PI / 2 - arc * (_numChoices - 1) / 2;
graphics.clear();
for(var i:int = 0; i < _numChoices; i++){
var angle:Number = start + arc * i;
var sin:Number = Math.sin(angle);
var cos:Number = Math.cos(angle);
graphics.lineStyle(4, STYLE_UI_THEME, 0.3, false,
LineScaleMode.NORMAL, CapsStyle.SQUARE);
graphics.moveTo(_knob.x, _knob.y);
graphics.lineTo(_knob.x + cos * (radius + 2), _knob.y + sin * (radius + 2));
var lab:Label = new Label(_labels, cos * (radius + 7), sin * (radius + 7));
lab.mouseEnabled = true;
lab.buttonMode = true;
lab.useHandCursor = true;
lab.addEventListener(MouseEvent.CLICK, onLabelClick);
//choice labels
lab.text = (choiceTexts && i < choiceTexts.length) ? choiceTexts[i] : " ";
//custom choice symbol draw
customChoiceDraw(i, _knob.x + cos * (radius + 7), _knob.y + sin * (radius + 7));
}
angle = start + arc * _choice;
//knob, inner marker
_knob.graphics.lineStyle(4, STYLE_UI_THEME, 1.0, false,
LineScaleMode.NORMAL, CapsStyle.NONE);
_knob.graphics.moveTo(Math.cos(angle) * radius * 0.4, Math.sin(angle) * radius*0.4);
_knob.graphics.lineTo(Math.cos(angle) * radius * 0.9, Math.sin(angle) * radius*0.9);
_label.text = _labelText;
_label.draw();
_label.x = _width / 2 - _label.width / 2;
_label.y = _height-1;
}
protected function customChoiceDraw(i:int, x:int, y:int):void{
//if required, override this and draw custom choice symbol here
}
}
//osc waveform selector
class WaveformSelector extends RotarySelectorEx{
private const RECTWAVE_LINES:Array =[[-4, 3], [0, -6], [4, 0], [0, 6], [4, 0], [0, -6]];
private const SAWWAVE_LINES:Array = [[-4, 3], [0, -6], [8, 6], [0, -6]];
private const TRIWAVE_LINES:Array = [[-1, 0], [3, -4], [4, 5], [3, -4]];
private const NOISEWAVE_LINES:Array = [
[4, 4], [0, -6], [2, 0], [0, 4], [2, 0], [0, -2], [2, 0], [0, 4], [2, 0], [0, -6]];
public function WaveformSelector(parent:DisplayObjectContainer = null,
xpos:Number = 0, ypos:Number = 0, label:String = "",
defaultHandler:Function = null){
super(parent, xpos, ypos, label, defaultHandler);
numChoices = 5;
}
private function drawPolyLines(x:int, y:int, p:Array):void{
var px:int = x - 4;
var py:int = y;
for(var i:int = 0; i< p.length; i++){
px += p[i][0];
py += p[i][1];
if(i == 0) graphics.moveTo(px, py);
else graphics.lineTo(px, py);
}
}
private function drawSineSymbol(x:int, y:int):void{
graphics.moveTo(x, y);
for(var ix:int = -1; ix<=9; ix++){
var iy:int = -Math.sin(2.0 * PI * ix / 8.0) * 3;
graphics.lineTo(x + ix, y + iy);
}
}
override protected function customChoiceDraw(i:int, x:int, y:int):void{
graphics.lineStyle(1, Style.LABEL_TEXT, 1.0, false,
LineScaleMode.NORMAL, CapsStyle.SQUARE);
switch(i){
case WAVEFORM_RECT: drawPolyLines(x, y, RECTWAVE_LINES); break;
case WAVEFORM_SAW: drawPolyLines(x, y, SAWWAVE_LINES); break;
case WAVEFORM_TRI: drawPolyLines(x, y, TRIWAVE_LINES); break;
case WAVEFORM_SINE: drawSineSymbol(x, y); break;
case WAVEFORM_NOISE: drawPolyLines(x, y, NOISEWAVE_LINES); break;
default: break;
}
}
}
// ported from http://www.musicdsp.org/showArchiveComment.php?ArchiveID=243
// which is based on zxform's USENET posts: http://www.musicdsp.org/files/filters004.txt
// Parameters:
// Cutoff [0.f -> Nyquist.f]
// Resonance [0.f -> 1.f]
class Filter {
public static const BUDDA_Q_SCALE:Number = 6.0;
private var fs:Number = 44100;
private var history1:Number = 0;
private var history2:Number = 0;
private var history3:Number = 0;
private var history4:Number = 0;
private var t0:Number;
private var t1:Number;
private var t2:Number;
private var t3:Number;
private var coef0:Number;
private var coef1:Number;
private var coef2:Number;
private var coef3:Number;
private var gain:Number;
private var max_cutoff:Number;
private var min_cutoff:Number;
public function Filter(sampleRate:Number = 44100) {
fs = sampleRate;
t0 = 4 * fs * fs;
t1 = 8 * fs * fs;
t2 = 2 * fs;
t3 = Math.PI / fs;
min_cutoff = fs * 0.001;
max_cutoff = fs * 0.45;
setParams(22050, 0);
}
public function setParams(cutoff:Number, q:Number):void {
if (cutoff < min_cutoff) cutoff = min_cutoff;
else if(cutoff > max_cutoff) cutoff = max_cutoff;
if(q < 0) q = 0;
else if(q > 1) q = 1;
var wp:Number = t2 * Math.tan(t3 * cutoff);
var bd:Number, bd_tmp:Number, b1:Number, b2:Number;
q *= BUDDA_Q_SCALE;
q += 1;
b1 = (0.765367 / q) / wp;
b2 = 1 / (wp * wp);
bd_tmp = t0 * b2 + 1;
bd = 1 / (bd_tmp + t2 * b1);
gain = bd * 0.5;
coef2 = (2 - t1 * b2);
coef0 = coef2 * bd;
coef1 = (bd_tmp - t2 * b1) * bd;
b1 = (1.847759 / q) / wp;
bd = 1 / (bd_tmp + t2 * b1);
gain *= bd;
coef2 *= bd;
coef3 = (bd_tmp - t2 * b1) * bd;
}
public function process(input:Number):Number {
var output:Number = input * gain;
var new_hist:Number;
output -= history1 * coef0;
new_hist = output - history2 * coef1;
output = new_hist + history1 * 2;
output += history2;
history2 = history1;
history1 = new_hist;
output -= history3 * coef2;
new_hist = output - history4 * coef3;
output = new_hist + history3 * 2;
output += history4;
history4 = history3;
history3 = new_hist;
return output;
}
}