Added DirectSound audio backend

This commit adds the DirectSound audio backend, which is a modified
version of core/oslib/ds_audiostream.cpp.

Porting this was a bit tricky, since ds_audiostream.cpp defined 3
extern functions that the other backends didn't have:
* bool os_IsAudioBuffered();
* bool os_IsAudioBufferedLots();
* int os_getusedSamples();

I came to the conclusion that these methods are obsolete since they are
only used core/windows/winmain.cpp in the function void os_wait_cycl(u32
cycl) - which is used nowhere. Thus, I removed os_wait_cycl and the
headers of the three functions in core/oslib/oslib.h. I also removed the
functions themselves (except for int os_getusedSamples(), which is still
used inside the directsound backend, but can safely declared static for
that purpose).

The DirectSound backend will be included during compilation if HOST_OS
is OS_WINDOWS.

core/oslib/audiobackend_directsound.cpp

@@ -1,10 +1,8 @@
-#include "types.h"
-
+#include "oslib/audiobackend_directsound.h"
 #if HOST_OS==OS_WINDOWS
+#include "oslib.h"
 #include <initguid.h>
 #include <dsound.h>
-#include "audiostream.h"
-#include "oslib.h"
 
 void* SoundThread(void* param);
 #define V2_BUFFERSZ (16*1024)
@@ -14,7 +12,7 @@ IDirectSoundBuffer8* buffer;
 
 u32 ds_ring_size;
 
-void os_InitAudio()
+static void directsound_init()
 {
 	verifyc(DirectSoundCreate8(NULL,&dsound,NULL));
 
@@ -80,7 +78,7 @@ void os_InitAudio()
 DWORD wc=0;
 
 
-int os_getfreesz()
+static int directsound_getfreesz()
 {
 	DWORD pc,wch;
 
@@ -96,25 +94,12 @@ int os_getfreesz()
 	return fsz;
 }
 
-int os_getusedSamples()
+static int directsound_getusedSamples()
 {
-	return (ds_ring_size-os_getfreesz())/4;
+	return (ds_ring_size-directsound_getfreesz())/4;
 }
 
-
-bool os_IsAudioBuffered()
-{
-	return os_getusedSamples()>=3000;
-}
-
-
-bool os_IsAudioBufferedLots()
-{
-	u32 xxx=os_getusedSamples();
-	return xxx>=4096;
-}
-
-u32 os_Push_nw(void* frame, u32 samplesb)
+static u32 directsound_push_nw(void* frame, u32 samplesb)
 {
 	DWORD pc,wch;
 
@@ -155,8 +140,7 @@ u32 os_Push_nw(void* frame, u32 samplesb)
 	//ds_ring_size
 }
 
-#if 0
-u32 PushAudio(void* frame, u32 samples, bool wait)
+static u32 directsound_push(void* frame, u32 samples, bool wait)
 {
 
 	u16* f=(u16*)frame;
@@ -176,18 +160,17 @@ u32 PushAudio(void* frame, u32 samples, bool wait)
 
 	int ffs=1;
 	
-	while (os_IsAudioBufferedLots() && wait)
+	while (directsound_IsAudioBufferedLots() && wait)
 		if (ffs == 0)
-			ffs = printf("AUD WAIT %d\n",os_getusedSamples());
+			ffs = printf("AUD WAIT %d\n", directsound_getusedSamples());
 
-	while(!os_Push_nw(frame,samples) && wait)
-		printf("FAILED waiting on audio FAILED %d\n",os_getusedSamples());
+	while(!directsound_Push_nw(frame,samples) && wait)
+		printf("FAILED waiting on audio FAILED %d\n", directsound_getusedSamples());
 
 	return 1;
 }
-#endif
 
-void os_TermAudio()
+static void directsound_term()
 {
 	buffer->Stop();
 	
@@ -195,4 +178,11 @@ void os_TermAudio()
 	dsound->Release();
 }
 
+audiobackend_t audiobackend_directsound = {
+    "directsound", // Slug
+    "Microsoft DirectSound", // Name
+    &directsound_init,
+    &directsound_push,
+    &directsound_term
+};
 #endif

core/oslib/audiobackend_directsound.h

@@ -0,0 +1,4 @@
+#pragma once
+#include "oslib/audiostream.h"
+
+extern audiobackend_t audiobackend_directsound;

core/oslib/audiostream.cpp

@@ -2,6 +2,7 @@
 #include "cfg/cfg.h"
 #include "oslib/oslib.h"
 #include "audiostream.h"
+#include "oslib/audiobackend_directsound.h"
 #include "oslib/audiobackend_alsa.h"
 #include "oslib/audiobackend_oss.h"
 
@@ -69,6 +70,9 @@ bool RegisterAudioBackend(audiobackend_t *backend)
 }
 
 void RegisterAllAudioBackends() {
+		#if HOST_OS==OS_WINDOWS
+		RegisterAudioBackend(&audiobackend_directsound);
+		#endif
 		#if USE_OSS
 		RegisterAudioBackend(&audiobackend_oss);
 		#endif

core/oslib/oslib.h

@@ -7,9 +7,6 @@ double os_GetSeconds();
 
 void os_DoEvents();
 void os_CreateWindow();
-bool os_IsAudioBuffered();
-int os_getusedSamples();
-bool os_IsAudioBufferedLots();
 void WriteSample(s16 right, s16 left);
 
 #if BUILD_COMPILER==COMPILER_VC

core/windows/winmain.cpp

@@ -365,48 +365,6 @@ cResetEvent evt_hld(false,true);
 double speed_load_mspdf;
 extern double full_rps;
 
-void os_wait_cycl(u32 cycl)
-{
-	if (cycl>8*1000*1000)
-		cycl=8*1000*1000;
-
-	
-	static double trolol=os_GetSeconds();
-
-	double newt=os_GetSeconds();
-	double ets=(newt-trolol)*200*1000*1000;
-
-	bool fast_enough=ets < cycl;
-	
-	bool wait = full_rps >5 && (fast_enough || os_IsAudioBufferedLots());
-
-	speed_load_mspdf=(speed_load_mspdf*0.96235 + ets/cycl*10)/1.96235;
-
-	if (wait &&  os_IsAudioBuffered())
-	{
-		while (cycl_glob<cycl && os_IsAudioBuffered())
-			evt_hld.Wait(8);
-
-		if (cycl_glob>cycl)
-			InterlockedExchangeSubtract(&cycl_glob,cycl);
-	}
-	else //if (os_IsAudioBufferedLots())
-	{
-		//cycl_glob=0;
-	}
-
-
-	static int last_fe=fast_enough;
-	if (!fast_enough || !last_fe)
-		printf("Speed %.2f (%.2f%%) (%d)\n",ets/cycl*10,cycl/ets*100,os_getusedSamples());
-	
-	last_fe=fast_enough;
-
-
-
-	trolol=os_GetSeconds();
-}
-
 
 void os_consume(double t)
 {