OPL4 WIP

Author: ppeccin

src/main/msx/audio/OPL4Audio.js

@@ -89,7 +89,7 @@ wmsx.OPL4Audio = function(pName, cart) {
 
     var audioSocket, audioSignal;
 
-    var VOLUME = 0.85 * (3 / 24 / 4096);      // X channels, samples -4096 .. +4096
+    var VOLUME = 0.65 * (7 / 24 / 4096);      // X channels, samples -4096 .. +4096
     var SAMPLE_RATE = 44100;                  // Main CPU clock / 81.2734693877551 = 44100 Hz
     var CLOCK = 49780;                        // Main CPU clock / 72 = 49780 Hz
 

src/main/msx/audio/OPL4AudioWave.js

@@ -15,6 +15,7 @@ wmsx.OPL4AudioWave = function(opl4) {
         kslValues = tabs.getKSLValues();
         rateAttackDurTable = tabs.getRateAttackDurations();
         rateDecayDurTable = tabs.getRateDecayDurations();
+        envAttackCurve = tabs.getEnvAttackCurve();
     }
 
     this.connect = function(machine) {
@@ -60,24 +61,24 @@ wmsx.OPL4AudioWave = function(opl4) {
         wmsx.Util.arrayFill(dl, 0);
         wmsx.Util.arrayFill(d2r, 0);
         wmsx.Util.arrayFill(rr, 0);
-        wmsx.Util.arrayFill(volume, 0);
+        wmsx.Util.arrayFill(volume, 0x7f);
         wmsx.Util.arrayFill(am, 0);
         wmsx.Util.arrayFill(vib, 0);
         wmsx.Util.arrayFill(rc, 0);
 
         // Dynamic values
 
-        wmsx.Util.arrayFill(volumeAtt, 0);
+        wmsx.Util.arrayFill(volumeAtt, 0x7f << 4);
         wmsx.Util.arrayFill(amAtt, 0);
-        wmsx.Util.arrayFill(envAtt, 0);
-        wmsx.Util.arrayFill(totalAtt, 0);
+        wmsx.Util.arrayFill(envAtt, 0x100 << 4);
+        wmsx.Util.arrayFill(totalAtt, 0x100 << 4);
         wmsx.Util.arrayFill(envStep, IDLE);
         wmsx.Util.arrayFill(envStepLevelDur, 0);
         wmsx.Util.arrayFill(envStepLevelIncClock, 0);
         wmsx.Util.arrayFill(envStepLevelInc, 0);
         wmsx.Util.arrayFill(envStepNext, IDLE);
         wmsx.Util.arrayFill(envStepNextAtLevel, 0);
-        wmsx.Util.arrayFill(envLevel, 0);
+        wmsx.Util.arrayFill(envLevel, 256);
         wmsx.Util.arrayFill(rcOffset, 0);
     };
 
@@ -449,7 +450,7 @@ wmsx.OPL4AudioWave = function(opl4) {
                 envLevel[cha] = 256;
                 envStepLevelIncClock[cha] = envStepLevelDur[cha] = 0;     // Never
                 envStepLevelInc[cha] = 0;
-                envStepNextAtLevel[cha] = 255;   // Never
+                envStepNextAtLevel[cha] = 257;   // Never
                 envStepNext[cha] = IDLE;
                 break;
         }
@@ -476,14 +477,12 @@ wmsx.OPL4AudioWave = function(opl4) {
     }
 
     function updateEnvAttenuation(cha) {
-        envAtt[cha] = envLevel[cha] << 4;
-        // envAtt[cha] = (envLevel[cha] === 128 ? 256 : envLevel[cha]) << 5;         // Higher attenuation in case of minimum level to produce silence
+        envAtt[cha] = (envStep[cha] === ATTACK ? envAttackCurve[envLevel[cha]] : envLevel[cha]) << 4;
         updateTotalAttenuation(cha);
     }
 
     function updateVolumeAttenuation(cha) {
         volumeAtt[cha] = volume[cha] << 4;
-        // volumeAtt[cha] = (volume[cha] === 15 ? 30 : volume[cha]) << 7;            // Higher attenuation in case of minimum volume to produce silence
         updateTotalAttenuation(cha);
     }
 
@@ -555,7 +554,7 @@ wmsx.OPL4AudioWave = function(opl4) {
 
     // Pre calculated tables, factors, values
 
-    var linearTable, expTable, vibValues, kslValues, rateAttackDurTable, rateDecayDurTable;
+    var linearTable, expTable, vibValues, kslValues, rateAttackDurTable, rateDecayDurTable, envAttackCurve;
 
 
     // Savestate  -------------------------------------------

src/main/msx/audio/OPL4WaveTables.js

@@ -3,6 +3,16 @@
 wmsx.OPL4WaveTables = function() {
 "use strict";
 
+    this.getEnvAttackCurve = function() {
+        var tab = new Array(257);
+        tab[0] = 0;
+        tab[256] = 256;
+        for (var i = 1; i < 256; ++i)
+            tab[i] = 256 - Math.floor((Math.log(((256 - i)/256) + 0.0188) / 4 + 0.995) * 256);
+        return tab;
+    };
+
+
     this.getLinearTable12Bits = function() {
         // Complete table for all possible values (4096 entries). -255 .. 255 values, sign in bit 14
         var tab = new Array(4096);
@@ -34,7 +44,7 @@ wmsx.OPL4WaveTables = function() {
         var tab = new Array(76);
         for (var i = 0; i < 64; ++i) {
             var dur = this.RATE_ATTACK_DURATIONS[i];
-            tab[i] = dur >= 0 ? Math.max(1, Math.round(dur / 10 / 1000 * 49780 / 256)) : 0;      // Valid Durations are at least 1 clock. 0 = infinite
+            tab[i] = dur >= 0 ? Math.max(1, Math.round(dur / 1000 * 49780 / 256)) : 0;      // Valid Durations are at least 1 clock. 0 = infinite
         }
         // Repeat last value for exceeding rates (> 63), possible when Rate = 15 and KSR offset > 3, as (Rate x 4 + KSROffset) can be > 63!
         for (i = 64; i < 60 + 16; ++i)