From 9f3bffd4ddfd4422391d83c83a67268deea555b2 Mon Sep 17 00:00:00 2001
From: Lior Halphon <LIJI32@gmail.com>
Date: Fri, 27 Mar 2020 19:10:42 +0300
Subject: [PATCH] Add volume control to SDL

---
 SDL/gui.c  | 27 ++++++++++++++++++++++++++-
 SDL/gui.h  |  1 +
 SDL/main.c |  5 +++++
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/SDL/gui.c b/SDL/gui.c
index e34028d..8bc6551 100644
--- a/SDL/gui.c
+++ b/SDL/gui.c
@@ -106,7 +106,8 @@ configuration_t configuration =
     .scaling_mode = GB_SDL_SCALING_INTEGER_FACTOR,
     .blending_mode = GB_FRAME_BLENDING_MODE_ACCURATE,
     .rewind_length = 60 * 2,
-    .model = MODEL_CGB
+    .model = MODEL_CGB,
+    .volume = 100,
 };
 
 
@@ -681,8 +682,32 @@ void cycle_highpass_filter_backwards(unsigned index)
     }
 }
 
+const char *volume_string(unsigned index)
+{
+    static char ret[5];
+    sprintf(ret, "%d%%", configuration.volume);
+    return ret;
+}
+
+void increase_volume(unsigned index)
+{
+    configuration.volume += 5;
+    if (configuration.volume > 100) {
+        configuration.volume = 100;
+    }
+}
+
+void decrease_volume(unsigned index)
+{
+    configuration.volume -= 5;
+    if (configuration.volume > 100) {
+        configuration.volume = 0;
+    }
+}
+
 static const struct menu_item audio_menu[] = {
     {"Highpass Filter:", cycle_highpass_filter, highpass_filter_string, cycle_highpass_filter_backwards},
+    {"Volume:", increase_volume, volume_string, decrease_volume},
     {"Back", return_to_root_menu},
     {NULL,}
 };
diff --git a/SDL/gui.h b/SDL/gui.h
index 8ef2a68..4a3b55f 100644
--- a/SDL/gui.h
+++ b/SDL/gui.h
@@ -104,6 +104,7 @@ typedef struct {
     /* v0.13 */
     uint8_t dmg_palette;
     GB_border_mode_t border_mode;
+    uint8_t volume;
 } configuration_t;
 
 extern configuration_t configuration;
diff --git a/SDL/main.c b/SDL/main.c
index c2b5549..35c9a75 100644
--- a/SDL/main.c
+++ b/SDL/main.c
@@ -420,6 +420,11 @@ static void gb_audio_callback(GB_gameboy_t *gb, GB_sample_t *sample)
         return;
     }
     
+    if (configuration.volume != 100) {
+        sample->left = sample->left * configuration.volume / 100;
+        sample->right = sample->right * configuration.volume / 100;
+    }
+    
     SDL_QueueAudio(device_id, sample, sizeof(*sample));
     
 }