From adaecd14d484d309e4d9ba2353ae843ab5213aec Mon Sep 17 00:00:00 2001
From: neonloop
Date: Wed, 10 Mar 2021 16:53:39 +0000
Subject: Initial trimui model s support

---
 shell/audio/alsa/sound_output.c      |  4 ++++
 shell/audio/oss/sound_output.c       |  4 ++++
 shell/audio/portaudio/sound_output.c |  4 ++++
 shell/audio/sdl/sound_output.c       | 19 +++++++++++++++++--
 shell/audio/sound_output.h           |  2 ++
 5 files changed, 31 insertions(+), 2 deletions(-)

(limited to 'shell/audio')

diff --git a/shell/audio/alsa/sound_output.c b/shell/audio/alsa/sound_output.c
index 5173bb6..4da70a7 100644
--- a/shell/audio/alsa/sound_output.c
+++ b/shell/audio/alsa/sound_output.c
@@ -132,6 +132,10 @@ void Audio_Write(int16_t* restrict buffer, uint32_t buffer_size)
 	}
 }
 
+bool Audio_Underrun_Likely() {
+	return false;
+}
+
 void Audio_Close()
 {
 	if (handle)
diff --git a/shell/audio/oss/sound_output.c b/shell/audio/oss/sound_output.c
index 2d32b1f..39a7ba3 100644
--- a/shell/audio/oss/sound_output.c
+++ b/shell/audio/oss/sound_output.c
@@ -49,6 +49,10 @@ void Audio_Write(int16_t* restrict buffer, uint32_t buffer_size)
 	write(oss_audio_fd, buffer, buffer_size * 4 );
 }
 
+bool Audio_Underrun_Likely() {
+	return false;
+}
+
 void Audio_Close()
 {
 	if (oss_audio_fd >= 0)
diff --git a/shell/audio/portaudio/sound_output.c b/shell/audio/portaudio/sound_output.c
index 226db5c..0c03c93 100644
--- a/shell/audio/portaudio/sound_output.c
+++ b/shell/audio/portaudio/sound_output.c
@@ -35,6 +35,10 @@ void Audio_Write(int16_t* restrict buffer, uint32_t buffer_size)
 	Pa_WriteStream( apu_stream, buffer, buffer_size);
 }
 
+bool Audio_Underrun_Likely() {
+	return false;
+}
+
 void Audio_Close()
 {
 	//Pa_Close();
diff --git a/shell/audio/sdl/sound_output.c b/shell/audio/sdl/sound_output.c
index f14bb1d..ae1ab83 100644
--- a/shell/audio/sdl/sound_output.c
+++ b/shell/audio/sdl/sound_output.c
@@ -1,11 +1,14 @@
 #include <sys/ioctl.h>
 #include <stdint.h>
+#include <stdbool.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <SDL/SDL.h>
 
 #include "sound_output.h"
 
+#define UNDERRUN_THRESHOLD 0.5
+
 static int32_t BUFFSIZE;
 static uint8_t *buffer;
 static uint32_t buf_read_pos = 0;
@@ -36,14 +39,20 @@ static int32_t sdl_read_buffer(uint8_t* data, int32_t len)
 
 static void sdl_write_buffer(uint8_t* data, int32_t len)
 {
+	SDL_LockAudio();
 	for(uint32_t i = 0; i < len; i += 4) 
 	{
-		if(buffered_bytes == BUFFSIZE) return; // just drop samples
+		while (buffered_bytes == BUFFSIZE) {
+			SDL_UnlockAudio();
+			usleep(1000);
+			SDL_LockAudio();
+    }
 		*(int32_t*)((char*)(buffer + buf_write_pos)) = *(int32_t*)((char*)(data + i));
 		//memcpy(buffer + buf_write_pos, data + i, 4);
 		buf_write_pos = (buf_write_pos + 4) % BUFFSIZE;
 		buffered_bytes += 4;
 	}
+	SDL_UnlockAudio();
 }
 
 void sdl_callback(void *unused, uint8_t *stream, int32_t len)
@@ -90,9 +99,15 @@ uint32_t Audio_Init()
 
 void Audio_Write(int16_t* restrict buffer, uint32_t buffer_size)
 {
-	SDL_LockAudio();
 	sdl_write_buffer(buffer, buffer_size * 4);
+}
+
+bool Audio_Underrun_Likely() {
+	bool underrun_likely = false;
+	SDL_LockAudio();
+	underrun_likely = buffered_bytes < BUFFSIZE * UNDERRUN_THRESHOLD;
 	SDL_UnlockAudio();
+	return underrun_likely;
 }
 
 void Audio_Close()
diff --git a/shell/audio/sound_output.h b/shell/audio/sound_output.h
index ba8a318..b770fbe 100644
--- a/shell/audio/sound_output.h
+++ b/shell/audio/sound_output.h
@@ -1,10 +1,12 @@
 #ifndef SOUND_OUTPUT_H
 #define SOUND_OUTPUT_H
 
+#include <stdbool.h>
 #include "shared.h"
 
 extern uint32_t Audio_Init();
 extern void Audio_Write(int16_t* restrict buffer, uint32_t buffer_size);
+extern bool Audio_Underrun_Likely();
 extern void Audio_Close();
 
 #endif
-- 
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