Fix UAESND stream volume handling

- Apply writes to the current sample set volume register immediately.
  The stream volume was only loaded when a sample set was (re)loaded,
  so volume changes during playback (e.g. AHI volume fades on a
  looping sound) were silently ignored, even though current-set
  register writes are documented to take effect on the next sample
  period.
- Scale samples by the set volume and board channel volume
  multiplicatively. The previous averaging formula had a 0.5 gain
  floor, so volume 0 still played at half loudness.
- Initialize the board channel volumes for all stream channels, not
  just the first two.

diff --git a/sndboard.cpp b/sndboard.cpp
index ba7de9505497769bd48426b555fe1c2ce5273801..edf553ea4652368e74b01d1212acb0b4ee0d33ff 100644 (file)
--- a/sndboard.cpp
+++ b/sndboard.cpp
@@ -562,6 +562,11 @@ static bool uaesnd_directload(struct uaesndboard_data *data, struct uaesndboard_
        if (reg < 0 || reg == 20) {
                s->replen = get_long_host(s->io + 20);
        }
+       if (reg < 0 || reg == 24 || reg == 26) {
+               // repeat count + volume share a long word; reload volume so
+               // current-set volume writes take effect while playing
+               s->volume = get_word_host(s->io + 26);
+       }
        return uaesnd_validate(data, s);
 }
 
@@ -686,7 +691,9 @@ static bool audio_state_sndboard_uae(int streamid, void *params)
                                if (sign)
                                        sample -= 0x8000;
                                uae_s16 samples = (uae_s16)sample;
-                               s->sample[i] = samples * ((s->volume + 1) / 2 + (data->volume[i] + 1) / 2) / 32768;
+                               // scale by set volume and board channel volume multiplicatively
+                               // so volume 0 is silent (the old averaged formula had a 0.5 gain floor)
+                               s->sample[i] = samples * s->volume / 32768 * data->volume[i] / 32768;
                        }
                        if (len < 0)
                                addr -= s->framesize;
@@ -1213,8 +1220,9 @@ bool uaesndboard_init (struct autoconfig_info *aci, int z)
        if (!ert)
                return false;
        data->streammask = 0;
-       data->volume[0] = 32768;
-       data->volume[1] = 32768;
+       for (int i = 0; i < MAX_UAE_CHANNELS; i++) {
+               data->volume[i] = 32768;
+       }
        put_long_host(data->info + 0, (UAEMAJOR << 16) | (UAEMINOR << 8) | (UAESUBREV));
        put_long_host(data->info + 4, (1 << 16) | (0));
        put_long_host(data->info + 8, currprefs.sound_freq);