From 30917d2b566fdc94b30f824e358a42544e443a29 Mon Sep 17 00:00:00 2001
From: tudnai <tamas.rudnai@gmail.com>
Date: Thu, 25 May 2023 20:23:41 -0700
Subject: [PATCH] Speaker Fade Out

---
 A2Mac/ViewController.swift |  3 +++
 src/dev/audio/speaker.c    | 21 ++++++++++++++-------
 src/dev/audio/speaker.h    |  2 +-
 3 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/A2Mac/ViewController.swift b/A2Mac/ViewController.swift
index f406b87..cf0e00e 100644
--- a/A2Mac/ViewController.swift
+++ b/A2Mac/ViewController.swift
@@ -1849,6 +1849,7 @@ class ViewController: NSViewController  {
 
             fps = DEFAULT_FPS
             video_fps_divider = ECO_VIDEO_DIV
+            spkr_fps_divider = DEF_SPKR_DIV
             break
             
         case "Game":
@@ -1857,6 +1858,7 @@ class ViewController: NSViewController  {
 
             fps = GAME_FPS
             video_fps_divider = GAME_VIDEO_DIV
+            spkr_fps_divider = GAME_SPKR_DIV
             break
             
         default:
@@ -1865,6 +1867,7 @@ class ViewController: NSViewController  {
             
             fps = DEFAULT_FPS
             video_fps_divider = DEF_VIDEO_DIV
+            spkr_fps_divider = DEF_SPKR_DIV
             break
         }
 
diff --git a/src/dev/audio/speaker.c b/src/dev/audio/speaker.c
index a6b0674..bafd2f7 100644
--- a/src/dev/audio/speaker.c
+++ b/src/dev/audio/speaker.c
@@ -125,7 +125,7 @@ float spkr_vol = 0.5;
 
 
 unsigned spkr_fps = DEFAULT_FPS;
-//unsigned spkr_fps_divider = 1;
+unsigned spkr_fps_divider = DEF_SPKR_DIV;
 unsigned spkr_frame_cntr = 0;
 unsigned spkr_clk = 0;
 
@@ -498,14 +498,17 @@ char spkr_state = 0;
 
 
 #define _NO_SPKR_EARLY_ZERO_LEVEL 500
+const float SPKR_FADE_TRAILING_SLOPE = 0.2;
 
 INLINE void spkr_finish_square(const int new_idx) {
 
+    float level = spkr_level;
+    const float slope = spkr_level >= 0 ? SPKR_FADE_TRAILING_SLOPE : -SPKR_FADE_TRAILING_SLOPE;
+
     // avoid buffer under/over runs
     if ( (new_idx < 0) || (new_idx >= SPKR_BUF_SLOT_SIZE(BUFFER_COUNT)) ) {
         return;
     }
-
     
     // only fill small enough gaps and larger ones will go back to 0
 #ifdef SPKR_EARLY_ZERO_LEVEL
@@ -513,6 +516,10 @@ INLINE void spkr_finish_square(const int new_idx) {
 #endif
         // finish the aquare wave
         while ( spkr_sample_last_idx < new_idx ) {
+            if ( fabs(level) > SPKR_FADE_TRAILING_SLOPE ) {
+                level -= slope;
+                spkr_level = level;
+            }
             spkr_samples[ spkr_sample_last_idx++ ] = spkr_level;
             spkr_samples[ spkr_sample_last_idx++ ] = spkr_level; // stereo
         }
@@ -1156,7 +1163,7 @@ void spkr_buffer_with_prebuf(void) {
 
 
 void spkr_update() {
-//    if ( ++spkr_frame_cntr >= spkr_fps_divider ) {
+    if ( ++spkr_frame_cntr >= spkr_fps_divider ) {
         spkr_frame_cntr = 0;
         
         // Fix: Unqueue was not working properly some cases, so we need to monitor
@@ -1248,10 +1255,10 @@ void spkr_update() {
         
         spkr_clk = 0;
         
-//    }
-//    else {
-//        spkr_clk += m6502.clkfrm;
-//    }
+    }
+    else {
+        spkr_clk += m6502.clkfrm;
+    }
     
     // free up unused buffers
     spkr_unqueue( spkr_src[SPKR_SRC_GAME_SFX] );
diff --git a/src/dev/audio/speaker.h b/src/dev/audio/speaker.h
index dfe674c..d824031 100644
--- a/src/dev/audio/speaker.h
+++ b/src/dev/audio/speaker.h
@@ -85,7 +85,7 @@ extern const double spkr_sample_rate;
 extern const unsigned spkr_buf_alloc_size;
 extern const unsigned spkr_buf_size;
 extern unsigned spkr_fps;
-//extern unsigned spkr_fps_divider;
+extern unsigned spkr_fps_divider;
 extern spkr_sample_t * spkr_samples;
 extern int spkr_sample_idx;
 extern int spkr_level;