Rewrite of the AudioStream API

-Fixes long-standing issues regarding to playing a single stream multiple times simultanteously
-Fixes wrong-looping, starting, caching, etc. Issues resulting from bad original design
-Allows more interesting kinds of streams (stream graphs with streams inside streams!) in the future

3 files changed, 494 insertions, 1 deletions

diff --git a/servers/audio/audio_rb_resampler.cpp b/servers/audio/audio_rb_resampler.cpp
new file mode 100644
index 0000000000..d07d55f1b5
--- /dev/null
+++ b/servers/audio/audio_rb_resampler.cpp
@@ -0,0 +1,356 @@
+#include "audio_rb_resampler.h"
+
+
+int AudioRBResampler::get_channel_count() const {
+
+	if (!rb)
+		return 0;
+
+	return channels;
+}
+
+
+template<int C>
+uint32_t AudioRBResampler::_resample(int32_t *p_dest,int p_todo,int32_t p_increment) {
+
+	uint32_t read=offset&MIX_FRAC_MASK;
+
+	for (int i=0;i<p_todo;i++) {
+
+		offset = (offset + p_increment)&(((1<<(rb_bits+MIX_FRAC_BITS))-1));
+		read+=p_increment;
+		uint32_t pos = offset >> MIX_FRAC_BITS;
+		uint32_t frac = offset & MIX_FRAC_MASK;
+#ifndef FAST_AUDIO
+		ERR_FAIL_COND_V(pos>=rb_len,0);
+#endif
+		uint32_t pos_next = (pos+1)&rb_mask;
+		//printf("rb pos %i\n",pos);
+
+		// since this is a template with a known compile time value (C), conditionals go away when compiling.
+		if (C==1) {
+
+			int32_t v0 = rb[pos];
+			int32_t v0n=rb[pos_next];
+#ifndef FAST_AUDIO
+			v0+=(v0n-v0)*(int32_t)frac >> MIX_FRAC_BITS;
+#endif
+			v0<<=16;
+			p_dest[i]=v0;
+
+		}
+		if (C==2) {
+
+			int32_t v0 = rb[(pos<<1)+0];
+			int32_t v1 = rb[(pos<<1)+1];
+			int32_t v0n=rb[(pos_next<<1)+0];
+			int32_t v1n=rb[(pos_next<<1)+1];
+
+#ifndef FAST_AUDIO
+			v0+=(v0n-v0)*(int32_t)frac >> MIX_FRAC_BITS;
+			v1+=(v1n-v1)*(int32_t)frac >> MIX_FRAC_BITS;
+#endif
+			v0<<=16;
+			v1<<=16;
+			p_dest[(i<<1)+0]=v0;
+			p_dest[(i<<1)+1]=v1;
+
+		}
+
+		if (C==4) {
+
+			int32_t v0 = rb[(pos<<2)+0];
+			int32_t v1 = rb[(pos<<2)+1];
+			int32_t v2 = rb[(pos<<2)+2];
+			int32_t v3 = rb[(pos<<2)+3];
+			int32_t v0n = rb[(pos_next<<2)+0];
+			int32_t v1n=rb[(pos_next<<2)+1];
+			int32_t v2n=rb[(pos_next<<2)+2];
+			int32_t v3n=rb[(pos_next<<2)+3];
+
+#ifndef FAST_AUDIO
+			v0+=(v0n-v0)*(int32_t)frac >> MIX_FRAC_BITS;
+			v1+=(v1n-v1)*(int32_t)frac >> MIX_FRAC_BITS;
+			v2+=(v2n-v2)*(int32_t)frac >> MIX_FRAC_BITS;
+			v3+=(v3n-v3)*(int32_t)frac >> MIX_FRAC_BITS;
+#endif
+			v0<<=16;
+			v1<<=16;
+			v2<<=16;
+			v3<<=16;
+			p_dest[(i<<2)+0]=v0;
+			p_dest[(i<<2)+1]=v1;
+			p_dest[(i<<2)+2]=v2;
+			p_dest[(i<<2)+3]=v3;
+
+		}
+
+		if (C==6) {
+
+			int32_t v0 = rb[(pos*6)+0];
+			int32_t v1 = rb[(pos*6)+1];
+			int32_t v2 = rb[(pos*6)+2];
+			int32_t v3 = rb[(pos*6)+3];
+			int32_t v4 = rb[(pos*6)+4];
+			int32_t v5 = rb[(pos*6)+5];
+			int32_t v0n = rb[(pos_next*6)+0];
+			int32_t v1n=rb[(pos_next*6)+1];
+			int32_t v2n=rb[(pos_next*6)+2];
+			int32_t v3n=rb[(pos_next*6)+3];
+			int32_t v4n=rb[(pos_next*6)+4];
+			int32_t v5n=rb[(pos_next*6)+5];
+
+#ifndef FAST_AUDIO
+			v0+=(v0n-v0)*(int32_t)frac >> MIX_FRAC_BITS;
+			v1+=(v1n-v1)*(int32_t)frac >> MIX_FRAC_BITS;
+			v2+=(v2n-v2)*(int32_t)frac >> MIX_FRAC_BITS;
+			v3+=(v3n-v3)*(int32_t)frac >> MIX_FRAC_BITS;
+			v4+=(v4n-v4)*(int32_t)frac >> MIX_FRAC_BITS;
+			v5+=(v5n-v5)*(int32_t)frac >> MIX_FRAC_BITS;
+#endif
+			v0<<=16;
+			v1<<=16;
+			v2<<=16;
+			v3<<=16;
+			v4<<=16;
+			v5<<=16;
+			p_dest[(i*6)+0]=v0;
+			p_dest[(i*6)+1]=v1;
+			p_dest[(i*6)+2]=v2;
+			p_dest[(i*6)+3]=v3;
+			p_dest[(i*6)+4]=v4;
+			p_dest[(i*6)+5]=v5;
+
+		}
+
+
+	}
+
+
+	return read>>MIX_FRAC_BITS;//rb_read_pos=offset>>MIX_FRAC_BITS;
+
+}
+
+
+bool AudioRBResampler::mix(int32_t *p_dest, int p_frames) {
+
+
+	if (!rb)
+		return false;
+
+	int write_pos_cache=rb_write_pos;
+
+	int32_t increment=(src_mix_rate*MIX_FRAC_LEN)/target_mix_rate;
+
+	int rb_todo;
+
+	if (write_pos_cache==rb_read_pos) {
+		return false; //out of buffer
+
+	} else if (rb_read_pos<write_pos_cache) {
+
+		rb_todo=write_pos_cache-rb_read_pos; //-1?
+	} else {
+
+		rb_todo=(rb_len-rb_read_pos)+write_pos_cache; //-1?
+	}
+
+	int todo = MIN( ((int64_t(rb_todo)<<MIX_FRAC_BITS)/increment)+1, p_frames );
+#if 0
+	if (int(src_mix_rate)==target_mix_rate) {
+
+
+		if (channels==6) {
+
+			for(int i=0;i<p_frames;i++) {
+
+				int from = ((rb_read_pos+i)&rb_mask)*6;
+				int to = i*6;
+
+				p_dest[from+0]=int32_t(rb[to+0])<<16;
+				p_dest[from+1]=int32_t(rb[to+1])<<16;
+				p_dest[from+2]=int32_t(rb[to+2])<<16;
+				p_dest[from+3]=int32_t(rb[to+3])<<16;
+				p_dest[from+4]=int32_t(rb[to+4])<<16;
+				p_dest[from+5]=int32_t(rb[to+5])<<16;
+			}
+
+		} else {
+			int len=p_frames*channels;
+			int from=rb_read_pos*channels;
+			int mask=0;
+			switch(channels) {
+				case 1: mask=rb_len-1; break;
+				case 2: mask=(rb_len*2)-1; break;
+				case 4: mask=(rb_len*4)-1; break;
+			}
+
+			for(int i=0;i<len;i++) {
+
+				p_dest[i]=int32_t(rb[(from+i)&mask])<<16;
+			}
+		}
+
+		rb_read_pos = (rb_read_pos+p_frames)&rb_mask;
+	} else
+#endif
+	{
+
+		uint32_t read=0;
+		switch(channels) {
+			case 1: read=_resample<1>(p_dest,todo,increment); break;
+			case 2: read=_resample<2>(p_dest,todo,increment); break;
+			case 4: read=_resample<4>(p_dest,todo,increment); break;
+			case 6: read=_resample<6>(p_dest,todo,increment); break;
+		}
+#if 1
+		//end of stream, fadeout
+		int remaining = p_frames-todo;
+		if (remaining && todo>0) {
+
+			//print_line("fadeout");
+			for(int c=0;c<channels;c++) {
+
+				for(int i=0;i<todo;i++) {
+
+					int32_t samp = p_dest[i*channels+c]>>8;
+					uint32_t mul = (todo-i) * 256 /todo;
+					//print_line("mul: "+itos(i)+" "+itos(mul));
+					p_dest[i*channels+c]=samp*mul;
+				}
+
+			}
+
+		}
+
+#else
+		int remaining = p_frames-todo;
+		if (remaining && todo>0) {
+
+
+			for(int c=0;c<channels;c++) {
+
+				int32_t from = p_dest[(todo-1)*channels+c]>>8;
+
+				for(int i=0;i<remaining;i++) {
+
+					uint32_t mul = (remaining-i) * 256 /remaining;
+					p_dest[(todo+i)*channels+c]=from*mul;
+				}
+
+			}
+
+		}
+#endif
+
+		//zero out what remains there to avoid glitches
+		for(int i=todo*channels;i<int(p_frames)*channels;i++) {
+
+			p_dest[i]=0;
+		}
+
+		if (read>rb_todo)
+			read=rb_todo;
+
+		rb_read_pos = (rb_read_pos+read)&rb_mask;
+
+
+
+
+	}
+
+	return true;
+}
+
+
+Error AudioRBResampler::setup(int p_channels,int p_src_mix_rate,int p_target_mix_rate,int p_buffer_msec,int p_minbuff_needed) {
+
+	ERR_FAIL_COND_V(p_channels!=1 && p_channels!=2 && p_channels!=4 && p_channels!=6,ERR_INVALID_PARAMETER);
+
+
+	//float buffering_sec = int(GLOBAL_DEF("audio/stream_buffering_ms",500))/1000.0;
+	int desired_rb_bits =nearest_shift(MAX((p_buffer_msec/1000.0)*p_src_mix_rate,p_minbuff_needed));
+
+	bool recreate=!rb;
+
+	if (rb && (uint32_t(desired_rb_bits)!=rb_bits || channels!=uint32_t(p_channels))) {
+		//recreate
+
+		memdelete_arr(rb);
+		memdelete_arr(read_buf);
+		recreate=true;
+
+	}
+
+	if (recreate) {
+
+		channels=p_channels;
+		rb_bits=desired_rb_bits;
+		rb_len=(1<<rb_bits);
+		rb_mask=rb_len-1;
+		rb = memnew_arr( int16_t, rb_len * p_channels );
+		read_buf = memnew_arr( int16_t, rb_len * p_channels );
+
+	}
+
+	src_mix_rate=p_src_mix_rate;
+	target_mix_rate=p_target_mix_rate;
+	offset=0;
+	rb_read_pos=0;
+	rb_write_pos=0;
+
+	//avoid maybe strange noises upon load
+	for (int i=0;i<(rb_len*channels);i++) {
+
+		rb[i]=0;
+		read_buf[i]=0;
+	}
+
+	return OK;
+
+}
+
+void AudioRBResampler::clear() {
+
+	if (!rb)
+		return;
+
+	//should be stopped at this point but just in case
+	if (rb) {
+		memdelete_arr(rb);
+		memdelete_arr(read_buf);
+	}
+	rb=NULL;
+	offset=0;
+	rb_read_pos=0;
+	rb_write_pos=0;
+	read_buf=NULL;
+}
+
+AudioRBResampler::AudioRBResampler() {
+
+	rb=NULL;
+	offset=0;
+	read_buf=NULL;
+	rb_read_pos=0;
+	rb_write_pos=0;
+
+	rb_bits=0;
+	rb_len=0;
+	rb_mask=0;
+	read_buff_len=0;
+	channels=0;
+	src_mix_rate=0;
+	target_mix_rate=0;
+
+}
+
+AudioRBResampler::~AudioRBResampler() {
+
+	if (rb) {
+		memdelete_arr(rb);
+		memdelete_arr(read_buf);
+	}
+
+}
+
diff --git a/servers/audio/audio_rb_resampler.h b/servers/audio/audio_rb_resampler.h
new file mode 100644
index 0000000000..3c686374f4
--- /dev/null
+++ b/servers/audio/audio_rb_resampler.h
@@ -0,0 +1,133 @@
+#ifndef AUDIO_RB_RESAMPLER_H
+#define AUDIO_RB_RESAMPLER_H
+
+#include "typedefs.h"
+#include "os/memory.h"
+
+struct AudioRBResampler {
+
+	uint32_t rb_bits;
+	uint32_t rb_len;
+	uint32_t rb_mask;
+	uint32_t read_buff_len;
+	uint32_t channels;
+	uint32_t src_mix_rate;
+	uint32_t target_mix_rate;
+
+	volatile int rb_read_pos;
+	volatile int rb_write_pos;
+
+	int32_t offset; //contains the fractional remainder of the resampler
+	enum {
+		MIX_FRAC_BITS=13,
+		MIX_FRAC_LEN=(1<<MIX_FRAC_BITS),
+		MIX_FRAC_MASK=MIX_FRAC_LEN-1,
+	};
+
+	int16_t *read_buf;
+	int16_t *rb;
+
+
+	template<int C>
+	uint32_t _resample(int32_t *p_dest,int p_todo,int32_t p_increment);
+
+
+public:
+
+	_FORCE_INLINE_ void flush() {
+		rb_read_pos=0;
+		rb_write_pos=0;
+	}
+
+	_FORCE_INLINE_ bool is_ready() const{
+		return rb!=NULL;
+	}
+
+
+	_FORCE_INLINE_ int get_total() const {
+
+		return rb_len-1;
+	}
+
+	_FORCE_INLINE_ int get_todo() const { //return amount of frames to mix
+
+		int todo;
+		int read_pos_cache=rb_read_pos;
+
+		if (read_pos_cache==rb_write_pos) {
+			todo=rb_len-1;
+		} else if (read_pos_cache>rb_write_pos) {
+
+			todo=read_pos_cache-rb_write_pos-1;
+		} else {
+
+			todo=(rb_len-rb_write_pos)+read_pos_cache-1;
+		}
+
+		return todo;
+	}
+
+	_FORCE_INLINE_ int16_t *get_write_buffer() { return read_buf; }
+	_FORCE_INLINE_ void write(uint32_t p_frames) {
+
+		ERR_FAIL_COND(p_frames >= rb_len);
+
+		switch(channels) {
+			case 1: {
+
+				for(uint32_t i=0;i<p_frames;i++) {
+
+					rb[ rb_write_pos ] = read_buf[i];
+					rb_write_pos=(rb_write_pos+1)&rb_mask;
+				}
+			} break;
+			case 2: {
+
+				for(uint32_t i=0;i<p_frames;i++) {
+
+					rb[ (rb_write_pos<<1)+0 ] = read_buf[(i<<1)+0];
+					rb[ (rb_write_pos<<1)+1 ] = read_buf[(i<<1)+1];
+					rb_write_pos=(rb_write_pos+1)&rb_mask;
+				}
+			} break;
+			case 4: {
+
+				for(uint32_t i=0;i<p_frames;i++) {
+
+					rb[ (rb_write_pos<<2)+0 ] = read_buf[(i<<2)+0];
+					rb[ (rb_write_pos<<2)+1 ] = read_buf[(i<<2)+1];
+					rb[ (rb_write_pos<<2)+2 ] = read_buf[(i<<2)+2];
+					rb[ (rb_write_pos<<2)+3 ] = read_buf[(i<<2)+3];
+					rb_write_pos=(rb_write_pos+1)&rb_mask;
+				}
+			} break;
+			case 6: {
+
+				for(uint32_t i=0;i<p_frames;i++) {
+
+					rb[ (rb_write_pos*6)+0 ] = read_buf[(i*6)+0];
+					rb[ (rb_write_pos*6)+1 ] = read_buf[(i*6)+1];
+					rb[ (rb_write_pos*6)+2 ] = read_buf[(i*6)+2];
+					rb[ (rb_write_pos*6)+3 ] = read_buf[(i*6)+3];
+					rb[ (rb_write_pos*6)+4 ] = read_buf[(i*6)+4];
+					rb[ (rb_write_pos*6)+5 ] = read_buf[(i*6)+5];
+					rb_write_pos=(rb_write_pos+1)&rb_mask;
+				}
+			} break;
+
+
+		}
+
+	}
+
+	int get_channel_count() const;
+
+	Error setup(int p_channels, int p_src_mix_rate, int p_target_mix_rate, int p_buffer_msec, int p_minbuff_needed=-1);
+	void clear();
+	bool mix(int32_t *p_dest, int p_frames);
+
+	AudioRBResampler();
+	~AudioRBResampler();
+};
+
+#endif // AUDIO_RB_RESAMPLER_H
diff --git a/servers/audio/audio_server_sw.cpp b/servers/audio/audio_server_sw.cpp
index 8a3ab7ce70..09cb4eca5f 100644
--- a/servers/audio/audio_server_sw.cpp
+++ b/servers/audio/audio_server_sw.cpp
@@ -830,10 +830,14 @@ void AudioServerSW::finish() {
 void AudioServerSW::_update_streams(bool p_thread) {
 
 	_THREAD_SAFE_METHOD_
-	for(List<Stream*>::Element *E=active_audio_streams.front();E;E=E->next()) {
+	for(List<Stream*>::Element *E=active_audio_streams.front();E;) { //stream might be removed durnig this callback
+
+		List<Stream*>::Element *N=E->next();
 
 		if (E->get()->audio_stream && p_thread == E->get()->audio_stream->can_update_mt())
 			E->get()->audio_stream->update();
+
+		E=N;
 	}
 
 }