Feature: Allow base sounds set to be changed mid-game. (#12399)

src/mixer.cpp

@@ -35,6 +35,7 @@ struct MixerChannel {
 };
 
 static std::atomic<uint8_t> _active_channels;
+static std::atomic<uint8_t> _stop_channels;
 static MixerChannel _channels[8];
 static uint32_t _play_rate = 11025;
 static uint32_t _max_size = UINT_MAX;
@@ -108,6 +109,16 @@ static void MxCloseChannel(uint8_t channel_index)
 	_active_channels.fetch_and(~(1 << channel_index), std::memory_order_release);
 }
 
+/**
+ * Close all mixer channels.
+ * This signals to the mixer that each channel should be closed even if it has not played all remaining samples.
+ * This is safe (and designed) to be called from the main thread.
+ */
+void MxCloseAllChannels()
+{
+	_stop_channels.fetch_or(~0, std::memory_order_release);
+}
+
 void MxMixSamples(void *buffer, uint samples)
 {
 	PerformanceMeasurer framerate(PFE_SOUND);
@@ -126,6 +137,12 @@ void MxMixSamples(void *buffer, uint samples)
 		if (_music_stream) _music_stream((int16_t*)buffer, samples);
 	}
 
+	/* Check if any channels should be stopped. */
+	uint8_t stop = _stop_channels.load(std::memory_order_acquire);
+	for (uint8_t idx : SetBitIterator(stop)) {
+		MxCloseChannel(idx);
+	}
+
 	/* Apply simple x^3 scaling to master effect volume. This increases the
 	 * perceived difference in loudness to better match expectations. effect_vol
 	 * is expected to be in the range 0-127 hence the division by 127 * 127 to
@@ -200,6 +217,7 @@ void MxSetChannelVolume(MixerChannel *mc, uint volume, float pan)
 void MxActivateChannel(MixerChannel *mc)
 {
 	uint8_t channel_index = mc - _channels;
+	_stop_channels.fetch_and(~(1 << channel_index), std::memory_order_release);
 	_active_channels.fetch_or((1 << channel_index), std::memory_order_release);
 }
 

src/mixer.h

@@ -27,6 +27,7 @@ MixerChannel *MxAllocateChannel();
 void MxSetChannelRawSrc(MixerChannel *mc, int8_t *mem, size_t size, uint rate, bool is16bit);
 void MxSetChannelVolume(MixerChannel *mc, uint volume, float pan);
 void MxActivateChannel(MixerChannel*);
+void MxCloseAllChannels();
 
 uint32_t MxSetMusicSource(MxStreamCallback music_callback);
 

src/settings_gui.cpp

@@ -47,6 +47,7 @@
 #include "network/network_survey.h"
 #include "video/video_driver.hpp"
 #include "social_integration.h"
+#include "sound_func.h"
 
 #include "safeguards.h"
 
@@ -940,13 +941,7 @@ struct GameOptionsWindow : Window {
 				break;
 
 			case WID_GO_BASE_SFX_DROPDOWN:
-				if (_game_mode == GM_MENU) {
-					auto set = BaseSounds::GetSet(index);
-					BaseSounds::ini_set = set->name;
-					BaseSounds::SetSet(set);
-					this->reload = true;
-					this->InvalidateData();
-				}
+				ChangeSoundSet(index);
 				break;
 
 			case WID_GO_BASE_MUSIC_DROPDOWN:
@@ -982,7 +977,6 @@ struct GameOptionsWindow : Window {
 #endif /* HAS_TRUETYPE_FONT */
 
 		this->SetWidgetDisabledState(WID_GO_BASE_GRF_DROPDOWN, _game_mode != GM_MENU);
-		this->SetWidgetDisabledState(WID_GO_BASE_SFX_DROPDOWN, _game_mode != GM_MENU);
 
 		this->SetWidgetDisabledState(WID_GO_BASE_GRF_PARAMETERS, BaseGraphics::GetUsedSet() == nullptr || !BaseGraphics::GetUsedSet()->IsConfigurable());
 

src/sound.cpp

@@ -233,6 +233,34 @@ void SndCopyToPool()
 	}
 }
 
+/**
+ * Change the configured sound set and reset sounds.
+ * @param index Index of sound set to switch to.
+ */
+void ChangeSoundSet(int index)
+{
+	if (BaseSounds::GetIndexOfUsedSet() == index) return;
+
+	auto set = BaseSounds::GetSet(index);
+	BaseSounds::ini_set = set->name;
+	BaseSounds::SetSet(set);
+
+	MxCloseAllChannels();
+	InitializeSound();
+
+	/* Replace baseset sounds in the pool with the updated original sounds. This is safe to do as
+	 * any sound still playing owns its sample data. */
+	for (uint i = 0; i < ORIGINAL_SAMPLE_COUNT; i++) {
+		SoundEntry *sound = GetSound(i);
+		/* GRF Container 0 means the sound comes from the baseset, and isn't overridden by NewGRF. */
+		if (sound == nullptr || sound->grf_container_ver != 0) continue;
+
+		*sound = _original_sounds[_sound_idx[i]];
+		sound->volume = _sound_base_vol[i];
+		sound->priority = 0;
+	}
+}
+
 /**
  * Decide 'where' (between left and right speaker) to play the sound effect.
  * Note: Callers must determine if sound effects are enabled. This plays a sound regardless of the setting.

src/sound_func.h

@@ -14,6 +14,8 @@
 #include "vehicle_type.h"
 #include "tile_type.h"
 
+void ChangeSoundSet(int index);
+
 void SndPlayTileFx(SoundID sound, TileIndex tile);
 void SndPlayVehicleFx(SoundID sound, const Vehicle *v);
 void SndPlayFx(SoundID sound);