Revert "Simplify logic around tones ending" and fix triangle tone pop…

…ping

This reverts commit 4e50857. That change
was causing tones to stop before the end of their release if an ending
tick came in first. I've decided to let tones that aren't replaced with
another tone to overrun the ending tick instead, to prevent sudden stops
and popping.

runtimes/native/src/apu.c

@@ -158,7 +158,7 @@ void w4_apuTone (int frequency, int duration, int volume, int flags) {
     // Restart the phase if the channel isn't already playing, but be
     // careful to keep the phase if the channel is already playing to allow
     // for continuous tones and smooth transitions to or from a glide etc.
-    if (ticks > channel->endTick) {
+    if (time > channel->releaseTime && ticks > channel->endTick) {
         channel->phase = (channelIdx == 2) ? 0.25 : 0;
     }
     if (noteMode) {
@@ -220,7 +220,7 @@ void w4_apuWriteSamples (int16_t* output, unsigned long frames) {
         for (int channelIdx = 0; channelIdx < 4; ++channelIdx) {
             Channel* channel = &channels[channelIdx];
 
-            if (ticks <= channel->endTick) {
+            if (time < channel->releaseTime || ticks <= channel->endTick) {
                 float freq = getCurrentFrequency(channel);
                 int16_t volume = getCurrentVolume(channel);
                 int16_t sample;

runtimes/web/src/apu-worklet.ts

@@ -5,7 +5,8 @@ const SAMPLE_RATE = 44100;
 const MAX_VOLUME = 0.15;
 // The triangle channel sounds a bit quieter than the others, so give it higher amplitude
 const MAX_VOLUME_TRIANGLE = 0.25;
-// Also the triangle channel prevent popping on hard stops by adding a 1 ms release
+// Also the triangle channel has a short release by default to reduce popping. Popping isn't
+// as noticable on the other channels.
 const RELEASE_TIME_TRIANGLE = Math.floor(SAMPLE_RATE / 1000);
 
 class Channel {
@@ -113,7 +114,7 @@ class APUProcessor extends AudioWorkletProcessor {
 
     getCurrentVolume (channel: Channel) {
         const time = this.time;
-        if (time >= channel.sustainTime && (channel.releaseTime - channel.sustainTime) > RELEASE_TIME_TRIANGLE) {
+        if (time >= channel.sustainTime) {
             // Release
             return this.ramp(channel.sustainVolume, 0, channel.sustainTime, channel.releaseTime);
         } else if (time >= channel.decayTime) {
@@ -158,7 +159,7 @@ class APUProcessor extends AudioWorkletProcessor {
         // Restart the phase if the channel isn't already playing, but be
         // careful to keep the phase if the channel is already playing to allow
         // for continuous tones and smooth transitions to or from a glide etc.
-        if (this.ticks > channel.endTick) {
+        if (this.time > channel.releaseTime && this.ticks > channel.endTick) {
             channel.phase = (channelIdx == 2) ? 0.25 : 0;
         }
         if (noteMode) {
@@ -209,7 +210,7 @@ class APUProcessor extends AudioWorkletProcessor {
             for (let channelIdx = 0; channelIdx < 4; ++channelIdx) {
                 const channel = this.channels[channelIdx];
 
-                if (this.ticks <= channel.endTick) {
+                if (this.time < channel.releaseTime || this.ticks <= channel.endTick) {
                     const freq = this.getCurrentFrequency(channel);
                     const volume = this.getCurrentVolume(channel);
                     let sample;