mirror of https://github.com/stella-emu/stella.git
Added ALSA v0.9 API sound backend to the X11 and SDL versions.
This is BETA code and should be thoroughly tested. git-svn-id: svn://svn.code.sf.net/p/stella/code/trunk@148 8b62c5a3-ac7e-4cc8-8f21-d9a121418aba
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//============================================================================
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//
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// SSSS tt lll lll
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// SS SS tt ll ll
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// SS tttttt eeee ll ll aaaa
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// SSSS tt ee ee ll ll aa
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// SS tt eeeeee ll ll aaaaa -- "An Atari 2600 VCS Emulator"
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// SS SS tt ee ll ll aa aa
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// SSSS ttt eeeee llll llll aaaaa
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//
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// Copyright (c) 1995-2002 by Bradford W. Mott
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//
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// See the file "license" for information on usage and redistribution of
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// this file, and for a DISCLAIMER OF ALL WARRANTIES.
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//
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// $Id: SoundALSA.cxx,v 1.1 2002-12-01 02:12:26 stephena Exp $
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//============================================================================
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#include <alsa/asoundlib.h>
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#include <stdio.h>
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#include "SoundALSA.hxx"
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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SoundALSA::SoundALSA()
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: myIsInitializedFlag(false),
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myPcmHandle(0),
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myMixerHandle(0),
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myMixerElem(0),
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myOriginalVolumeLeft(-1),
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myOriginalVolumeRight(-1),
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myBufferSize(0),
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mySampleRate(0)
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{
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Int32 err;
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char pcmName[] = "plughw:0,0";
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char mixerName[] = "PCM";
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char mixerCard[] = "default";
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snd_pcm_hw_params_t* hwparams;
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// Allocate the snd_pcm_hw_params_t structure on the stack
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snd_pcm_hw_params_alloca(&hwparams);
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// Open the PCM device for writing
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if((err = snd_pcm_open(&myPcmHandle, pcmName, SND_PCM_STREAM_PLAYBACK, 0)) < 0)
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{
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cerr << "SoundALSA: " << snd_strerror(err) << endl;
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return;
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}
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// Init hwparams with full configuration space
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if((err = snd_pcm_hw_params_any(myPcmHandle, hwparams)) < 0)
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{
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cerr << "SoundALSA: " << snd_strerror(err) << endl;
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snd_pcm_close(myPcmHandle);
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return;
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}
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// Set interleaved access
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if((err = snd_pcm_hw_params_set_access(myPcmHandle, hwparams,
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SND_PCM_ACCESS_RW_INTERLEAVED)) < 0)
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{
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cerr << "SoundALSA: " << snd_strerror(err) << endl;
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snd_pcm_close(myPcmHandle);
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return;
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}
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// Set the audio data format
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if((err = snd_pcm_hw_params_set_format(myPcmHandle, hwparams, SND_PCM_FORMAT_U8)) < 0)
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{
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cerr << "SoundALSA: " << snd_strerror(err) << endl;
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snd_pcm_close(myPcmHandle);
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return;
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}
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// Set the number of audio channels to 1 (mono mode)
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if((err = snd_pcm_hw_params_set_channels(myPcmHandle, hwparams, 1)) < 0)
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{
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cerr << "SoundALSA: " << snd_strerror(err) << endl;
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snd_pcm_close(myPcmHandle);
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return;
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}
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// Set the audio sample rate. If the exact rate is not supported by
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// the hardware, use nearest possible rate
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mySampleRate = 31400;
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if((err = snd_pcm_hw_params_set_rate_near(myPcmHandle, hwparams, mySampleRate, 0)) < 0)
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{
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cerr << "SoundALSA: " << snd_strerror(err) << endl;
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snd_pcm_close(myPcmHandle);
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mySampleRate = 0;
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return;
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}
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// Set number of fragments to 2
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if((err = snd_pcm_hw_params_set_periods(myPcmHandle, hwparams, 2, 0)) < 0)
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{
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cerr << "SoundALSA: " << snd_strerror(err) << endl;
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snd_pcm_close(myPcmHandle);
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mySampleRate = 0;
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return;
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}
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// Set size of fragments to 512 bytes
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myBufferSize = 512;
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if((err = snd_pcm_hw_params_set_period_size(myPcmHandle, hwparams,
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myBufferSize, 0)) < 0)
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{
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cerr << "SoundALSA: " << snd_strerror(err) << endl;
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snd_pcm_close(myPcmHandle);
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mySampleRate = 0;
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return;
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}
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// Apply HW parameter settings to PCM device
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if((err = snd_pcm_hw_params(myPcmHandle, hwparams)) < 0)
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{
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cerr << "SoundALSA: " << snd_strerror(err) << endl;
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snd_pcm_close(myPcmHandle);
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mySampleRate = 0;
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return;
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}
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////////////////////////////////////////////////////////////
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// Now, open the mixer so we'll be able to change the volume
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////////////////////////////////////////////////////////////
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snd_mixer_selem_id_t* mixerID;
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// Allocate simple mixer ID
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snd_mixer_selem_id_alloca(&mixerID);
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// Sets simple mixer ID and name
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snd_mixer_selem_id_set_index(mixerID, 0);
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snd_mixer_selem_id_set_name(mixerID, mixerName);
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// Open the mixer device
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if((err = snd_mixer_open(&myMixerHandle, 0)) < 0)
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{
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cerr << "SoundALSA: " << snd_strerror(err) << endl;
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snd_pcm_close(myPcmHandle);
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mySampleRate = 0;
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return;
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}
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// Attach the mixer to the default sound card
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if((err = snd_mixer_attach(myMixerHandle, mixerCard)) < 0)
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{
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cerr << "SoundALSA: " << snd_strerror(err) << endl;
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snd_pcm_close(myPcmHandle);
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snd_mixer_close(myMixerHandle);
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mySampleRate = 0;
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return;
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}
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// Register the mixer with the sound system
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if((err = snd_mixer_selem_register(myMixerHandle, NULL, NULL)) < 0)
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{
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cerr << "SoundALSA: " << snd_strerror(err) << endl;
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snd_pcm_close(myPcmHandle);
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snd_mixer_close(myMixerHandle);
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mySampleRate = 0;
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return;
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}
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if((err = snd_mixer_load(myMixerHandle)) < 0)
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{
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cerr << "SoundALSA: " << snd_strerror(err) << endl;
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snd_pcm_close(myPcmHandle);
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snd_mixer_close(myMixerHandle);
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mySampleRate = 0;
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return;
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}
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// Get the mixer element that will be used to control volume
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if((myMixerElem = snd_mixer_find_selem(myMixerHandle, mixerID)) == 0)
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{
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cerr << "SoundALSA: " << snd_strerror(err) << endl;
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snd_pcm_close(myPcmHandle);
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snd_mixer_close(myMixerHandle);
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mySampleRate = 0;
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return;
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}
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// Save the original volume so we can restore it on exit
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snd_mixer_selem_get_playback_volume(myMixerElem, (_snd_mixer_selem_channel_id) 0,
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&myOriginalVolumeLeft);
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snd_mixer_selem_get_playback_volume(myMixerElem, (_snd_mixer_selem_channel_id) 1,
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&myOriginalVolumeRight);
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// Prepare the audio device for playback
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snd_pcm_prepare(myPcmHandle);
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// Indicate that the sound system is fully initialized
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myIsInitializedFlag = true;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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SoundALSA::~SoundALSA()
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{
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closeDevice();
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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void SoundALSA::closeDevice()
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{
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if(myIsInitializedFlag)
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{
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// Restore original volume
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if(myMixerHandle)
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{
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if((myOriginalVolumeLeft != -1) && (myOriginalVolumeRight != -1))
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{
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snd_mixer_selem_set_playback_volume(myMixerElem, (_snd_mixer_selem_channel_id) 0,
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myOriginalVolumeLeft);
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snd_mixer_selem_set_playback_volume(myMixerElem, (_snd_mixer_selem_channel_id) 1,
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myOriginalVolumeRight);
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}
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snd_mixer_close(myMixerHandle);
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}
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if(myPcmHandle)
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snd_pcm_close(myPcmHandle);
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}
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myIsInitializedFlag = false;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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uInt32 SoundALSA::getSampleRate() const
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{
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return myIsInitializedFlag ? mySampleRate : 0;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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bool SoundALSA::isSuccessfullyInitialized() const
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{
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return myIsInitializedFlag;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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void SoundALSA::setSoundVolume(uInt32 volume)
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{
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if(myIsInitializedFlag && myMixerElem)
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{
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if(volume < 0)
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{
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volume = 0;
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}
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if(volume > 100)
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{
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volume = 100;
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}
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long int lowerBound, upperBound, newVolume;
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snd_mixer_selem_get_playback_volume_range(myMixerElem, &lowerBound, &upperBound);
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newVolume = (long int) (((upperBound - lowerBound) * volume / 100.0) + lowerBound);
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snd_mixer_selem_set_playback_volume(myMixerElem, (_snd_mixer_selem_channel_id) 0,
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newVolume);
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snd_mixer_selem_set_playback_volume(myMixerElem, (_snd_mixer_selem_channel_id) 1,
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newVolume);
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}
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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void SoundALSA::updateSound(MediaSource& mediaSource)
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{
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if(myIsInitializedFlag)
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{
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snd_pcm_sframes_t frames;
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uInt8 periodCount = 0;
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// Dequeue samples as long as full fragments are available
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while(mediaSource.numberOfAudioSamples() >= myBufferSize)
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{
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uInt8 buffer[myBufferSize];
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mediaSource.dequeueAudioSamples(buffer, myBufferSize);
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if((frames = snd_pcm_writei(myPcmHandle, buffer, myBufferSize)) == -EPIPE)
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{
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snd_pcm_prepare(myPcmHandle);
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break;
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}
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periodCount++;
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}
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// Fill any unused fragments with silence so that we have a lower
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// risk of having playback underruns
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for(int i = 0; i < 1-periodCount; ++i)
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{
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frames = snd_pcm_avail_update(myPcmHandle);
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if (frames > 0)
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{
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uInt8 buffer[frames];
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memset((void*)buffer, 0, frames);
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snd_pcm_writei(myPcmHandle, buffer, frames);
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}
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else if(frames == -EPIPE) // this should never happen
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{
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cerr << "EPIPE after write\n";
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break;
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}
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}
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}
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}
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//============================================================================
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//
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// SSSS tt lll lll
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// SS SS tt ll ll
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// SS tttttt eeee ll ll aaaa
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// SSSS tt ee ee ll ll aa
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// SS tt eeeeee ll ll aaaaa -- "An Atari 2600 VCS Emulator"
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// SS SS tt ee ll ll aa aa
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// SSSS ttt eeeee llll llll aaaaa
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//
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// Copyright (c) 1995-2002 by Bradford W. Mott
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//
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// See the file "license" for information on usage and redistribution of
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// this file, and for a DISCLAIMER OF ALL WARRANTIES.
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//
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// $Id: SoundALSA.hxx,v 1.1 2002-12-01 02:12:26 stephena Exp $
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//============================================================================
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#ifndef SOUNDALSA_HXX
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#define SOUNDALSA_HXX
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#include <alsa/asoundlib.h>
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#include "Sound.hxx"
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#include "bspf.hxx"
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#include "MediaSrc.hxx"
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/**
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This class implements a sound class using the
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Advanced Linux Sound Architecture (ALSA) version 0.9.x API.
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@author Stephen Anthony
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@version $Id: SoundALSA.hxx,v 1.1 2002-12-01 02:12:26 stephena Exp $
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*/
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class SoundALSA : public Sound
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{
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public:
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/**
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Create a new sound object
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*/
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SoundALSA();
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/**
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Destructor
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*/
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virtual ~SoundALSA();
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public:
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/**
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Closes the sound device
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*/
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void closeDevice();
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/**
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Return the playback sample rate for the sound device.
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@return The playback sample rate
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*/
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uInt32 getSampleRate() const;
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/**
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Return true iff the sound device was successfully initlaized.
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@return true iff the sound device was successfully initlaized.
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*/
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bool isSuccessfullyInitialized() const;
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/**
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Sets the volume of the sound device to the specified level. The
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volume is given as a precentage from 0 to 100.
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@param volume The new volume for the sound device
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*/
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void setSoundVolume(uInt32 volume);
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/**
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Update the sound device using the audio sample from the specified
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media source.
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@param mediaSource The media source to get audio samples from.
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*/
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void updateSound(MediaSource& mediaSource);
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private:
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// Indicates if the sound device was successfully initialized
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bool myIsInitializedFlag;
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// Handle for the PCM device
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snd_pcm_t* myPcmHandle;
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// Handle for the mixer device
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snd_mixer_t* myMixerHandle;
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// Mixer elem, used to set volume
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snd_mixer_elem_t* myMixerElem;
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// Original mixer volume when the sound device was opened
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long int myOriginalVolumeLeft;
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long int myOriginalVolumeRight;
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// PCM buffer size
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uInt32 myBufferSize;
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// PCM sample rate
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uInt32 mySampleRate;
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};
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#endif
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