rename Classes part2

git-svn-id: svn://svn.code.sf.net/p/ultrastardx/svn/trunk@1308 b956fd51-792f-4845-bead-9b4dfca2ff2c

1 files changed, 257 insertions, 0 deletions

diff --git a/src/classes/UAudioCore_Portaudio.pas b/src/classes/UAudioCore_Portaudio.pas
new file mode 100644
index 00000000..bcc8a001
--- /dev/null
+++ b/src/classes/UAudioCore_Portaudio.pas
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+unit UAudioCore_Portaudio;
+
+interface
+
+{$IFDEF FPC}
+  {$MODE Delphi}
+{$ENDIF}
+
+{$I ../switches.inc}
+
+
+uses
+  Classes,
+  SysUtils,
+  portaudio;
+
+type
+  TAudioCore_Portaudio = class
+    public
+      constructor Create();
+      class function GetInstance(): TAudioCore_Portaudio;
+      function GetPreferredApiIndex(): TPaHostApiIndex;
+      function TestDevice(inParams, outParams: PPaStreamParameters; var sampleRate: Double): boolean;
+  end;
+
+implementation
+
+uses
+  ULog;
+
+{*
+ * The default API used by Portaudio is the least common denominator
+ * and might lack efficiency. In addition it might not even work.
+ * We use an array named ApiPreferenceOrder with which we define the order of
+ * preferred APIs to use. The first API-type in the list is tried first.
+ * If it is not available the next one is tried and so on ...
+ * If none of the preferred APIs was found the default API (detected by
+ * portaudio) is used.
+ *
+ * Pascal does not permit zero-length static arrays, so you must use paDefaultApi
+ * as an array's only member if you do not have any preferences.
+ * You can also append paDefaultApi to a non-zero length preferences array but
+ * this is optional because the default API is always used as a fallback.
+ *}
+const
+  paDefaultApi = -1;
+const
+  ApiPreferenceOrder:
+{$IF Defined(MSWINDOWS)}
+    // Note1: Portmixer has no mixer support for paASIO and paWASAPI at the moment
+    // Note2: Windows Default-API is MME, but DirectSound is faster
+    array[0..0] of TPaHostApiTypeId = ( paDirectSound );
+{$ELSEIF Defined(LINUX)}
+    // Note: Portmixer has no mixer support for JACK at the moment
+    array[0..2] of TPaHostApiTypeId = ( paALSA, paJACK, paOSS );
+{$ELSEIF Defined(DARWIN)}
+    array[0..0] of TPaHostApiTypeId = ( paDefaultApi ); // paCoreAudio
+{$ELSE}
+    array[0..0] of TPaHostApiTypeId = ( paDefaultApi );
+{$IFEND}
+
+
+{ TAudioInput_Portaudio }
+
+var
+  Instance: TAudioCore_Portaudio;
+
+constructor TAudioCore_Portaudio.Create();
+begin
+  inherited;
+end;
+
+class function TAudioCore_Portaudio.GetInstance(): TAudioCore_Portaudio;
+begin
+  if not assigned(Instance) then
+    Instance := TAudioCore_Portaudio.Create();
+  Result := Instance;
+end;
+
+function TAudioCore_Portaudio.GetPreferredApiIndex(): TPaHostApiIndex;
+var
+  i: integer;
+  apiIndex: TPaHostApiIndex;
+  apiInfo:  PPaHostApiInfo;
+begin
+  result := -1;
+
+  // select preferred sound-API
+  for i:= 0 to High(ApiPreferenceOrder) do
+  begin
+    if(ApiPreferenceOrder[i] <> paDefaultApi) then
+    begin
+      // check if API is available
+      apiIndex := Pa_HostApiTypeIdToHostApiIndex(ApiPreferenceOrder[i]);
+      if(apiIndex >= 0) then
+      begin
+        // we found an API but we must check if it works
+        // (on linux portaudio might detect OSS but does not provide
+        // any devices if ALSA is enabled)
+        apiInfo := Pa_GetHostApiInfo(apiIndex);
+        if (apiInfo^.deviceCount > 0) then
+        begin
+          Result := apiIndex;
+          break;
+        end;
+      end;
+    end;
+  end;
+
+  // None of the preferred APIs is available -> use default
+  if(result < 0) then
+  begin
+    result := Pa_GetDefaultHostApi();
+  end;
+end;
+
+{*
+ * Portaudio test callback used by TestDevice().
+ *}
+function TestCallback(input: Pointer; output: Pointer; frameCount: Longword;
+      timeInfo: PPaStreamCallbackTimeInfo; statusFlags: TPaStreamCallbackFlags;
+      inputDevice: Pointer): Integer; cdecl;
+begin
+  // this callback is called only once
+  result := paAbort;
+end;
+
+(*
+ * Tests if the callback works. Some devices can be opened without
+ * an error but the callback is never called. Calling Pa_StopStream() on such
+ * a stream freezes USDX then. Probably because the callback-thread is deadlocked
+ * due to some bug in portaudio. The blocking Pa_ReadStream() and Pa_WriteStream()
+ * block forever too and though can't be used for testing.
+ *
+ * To avoid freezing Pa_AbortStream (or Pa_CloseStream which calls Pa_AbortStream)
+ * can be used to force the stream to stop. But for some reason this stops debugging
+ * in gdb with a "no process found" message.
+ *
+ * Because freezing devices are non-working devices we test the devices here to
+ * be able to exclude them from the device-selection list.
+ *
+ * Portaudio does not provide any test to check this error case (probably because
+ * it should not even occur). So we have to open the device, start the stream and
+ * check if the callback is called (the stream is stopped if the callback is called
+ * for the first time, so we can poll until the stream is stopped).
+ *
+ * Another error that occurs is that some devices (even the default device) might
+ * work at the beginning but stop after a few calls (maybe 50) of the callback.
+ * For me this problem occurs with the default output-device. The "dmix" or "front"
+ * device must be selected instead. Another problem is that (due to a bug in
+ * portaudio or ALSA) the "front" device is not detected every time portaudio
+ * is started. Sometimes it needs two or more restarts.
+ *
+ * There is no reasonable way to test for these errors. For the first error-case
+ * we could test if the callback is called 50 times but this can take a second
+ * for each device and it can fail in the 51st or even 100th callback call then.
+ *
+ * The second error-case cannot be tested at all. How should we now that one
+ * device is missing if portaudio is not even able to detect it.
+ * We could start and terminate Portaudio for several times and see if the device
+ * count changes but this is ugly.
+ *
+ * Conclusion: We are not able to autodetect a working device with
+ *   portaudio (at least not with the newest v19_20071207) at the moment.
+ *   So we have to provide the possibility to manually select an output device
+ *   in the UltraStar options if we want to use portaudio instead of SDL.
+ *)
+function TAudioCore_Portaudio.TestDevice(inParams, outParams: PPaStreamParameters; var sampleRate: Double): boolean;
+var
+  stream: PPaStream;
+  err: TPaError;
+  cbWorks: boolean;
+  cbPolls: integer;
+  i: integer;
+const
+  altSampleRates: array[0..1] of Double = (44100, 48000); // alternative sample-rates
+begin
+  Result := false;
+
+  if (sampleRate <= 0) then
+    sampleRate := 44100;
+
+  // check if device supports our input-format
+  err := Pa_IsFormatSupported(inParams, outParams, sampleRate);
+  if(err <> paNoError) then
+  begin
+    // we cannot fix the error -> exit
+    if (err <> paInvalidSampleRate) then
+      Exit;
+
+    // try alternative sample-rates to the detected one
+    sampleRate := 0;
+    for i := 0 to High(altSampleRates) do
+    begin
+      // do not check the detected sample-rate twice
+      if (altSampleRates[i] = sampleRate) then
+        continue;
+      // check alternative
+      err := Pa_IsFormatSupported(inParams, outParams, altSampleRates[i]);
+      if (err = paNoError) then
+      begin
+        // sample-rate works
+        sampleRate := altSampleRates[i];
+        break;
+      end;
+    end;
+    // no working sample-rate found
+    if (sampleRate = 0) then
+      Exit;
+  end;
+
+  // FIXME: for some reason gdb stops after a call of Pa_AbortStream()
+  // which is implicitely called by Pa_CloseStream().
+  // gdb's stops with the message: "ptrace: no process found".
+  // Probably because the callback-thread is killed what confuses gdb.
+  {$IF Defined(Debug) and Defined(Linux)}
+  cbWorks := true;
+  {$ELSE}
+  // open device for testing
+  err := Pa_OpenStream(stream, inParams, outParams, sampleRate,
+          paFramesPerBufferUnspecified,
+          paNoFlag, @TestCallback, nil);
+  if(err <> paNoError) then
+  begin
+    exit;
+  end;
+
+  // start the callback
+  err := Pa_StartStream(stream);
+  if(err <> paNoError) then
+  begin
+    Pa_CloseStream(stream);
+    exit;
+  end;
+
+  cbWorks := false;
+  // check if the callback was called (poll for max. 200ms)
+  for cbPolls := 1 to 20 do
+  begin
+    // if the test-callback was called it should be aborted now
+    if (Pa_IsStreamActive(stream) = 0) then
+    begin
+      cbWorks := true;
+      break;
+    end;
+    // not yet aborted, wait and try (poll) again
+    Pa_Sleep(10);
+  end;
+
+  // finally abort the stream
+  Pa_CloseStream(stream);
+  {$IFEND}
+  
+  Result := cbWorks;
+end;
+
+end.