iOS OpenAL 声音不是定位的
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【中文标题】iOS OpenAL 声音不是定位的【英文标题】：iOS OpenAL Sound is not positional 【发布时间】：2015-05-12 14:01:17 【问题描述】：好的，这是我的问题。
我正在开发一些帮助类，它们为我封装了 ios 上的 OpenAL 功能。没错，它工作得很好，这意味着我可以（同时）播放多个声音并在那里配置增益和音高。
对我来说，下一步是添加位置声音。我知道，我必须使用属性来表示听者的位置和源的位置（和速度，但这并不是那么重要，正确的知道）。
问题是，我实现了与互联网上的教程相对应的所有内容，但声音始终没有衰减，所以它不是定位的。
我发现，有时这是由立体声音频文件引起的，所以现在我使用的是单声道文件，但问题仍然存在。事实上，我从苹果下载了这个example project。它适用于 Mac OS 并且可以正常工作。所以我从他们的项目中取出声音文件并在我自己的项目中使用它们。所以声音格式应该没有问题。它仍然不播放位置。
所以我的问题是： 是否可以在 iPhone 上使用 OpenAl 播放声音位置？ 如果是，为实现 3D 播放应设置的最低 OpenAL 属性是什么？也许我只是没有设置一项需要的基本设置。
另外，我认为模拟器是问题所在，但是当我在真正的 iPhone 上测试我的应用时，它也不起作用。
我会知道在这里添加我当前的代码，但我认为直接找到错误太多了。我希望有人知道我烦人的问题的标准解决方案（我认为这将是一些小错误：D）
代码如下：
听众：
class Listener
private:
vec3 position;
vec3 velocity;
vec3 at;
vec3 up;
public:
Listener();
void setOrientation(vec3 at, vec3 up);
vec3 getPosition();
void setPosition(vec3 position);
vec3 getVelocity();
void setVelocity(vec3 velocity);
;
Listener::Listener()
alListenerf(AL_GAIN, 0.5f);
alDistanceModel(AL_INVERSE_DISTANCE_CLAMPED);
void Listener::setOrientation(vec3 at, vec3 up)
printf("Listener Set Orientation\n");
ALfloat *orientation = (ALfloat*)malloc(6*sizeof(ALfloat));
orientation[0] = at.x;
orientation[1] = at.y;
orientation[2] = at.z;
orientation[3] = up.x;
orientation[4] = up.y;
orientation[5] = up.z;
alListenerfv(AL_ORIENTATION, orientation);
this->at = at;
this->up = up;
free(orientation);
vec3 Listener::getPosition()
return position;
void Listener::setPosition(vec3 position)
printf("Listener Set Position\n");
ALfloat *positionArray = (ALfloat*)malloc(3*sizeof(ALfloat));
positionArray[0] = position.x;
positionArray[1] = position.y;
positionArray[2] = position.z;
alListenerfv(AL_POSITION, positionArray);
this->position = position;
free(positionArray);
vec3 Listener::getVelocity()
return velocity;
void Listener::setVelocity(vec3 velocity)
printf("Listener Set Velocity\n");
ALfloat *velArray = (ALfloat*)malloc(3*sizeof(ALfloat));
velArray[0] = velocity.x;
velArray[1] = velocity.y;
velArray[2] = velocity.z;
alListenerfv(AL_VELOCITY, velArray);
this->velocity = velocity;
free(velArray);
样本
class Sample
private:
UInt32 usageCount; // Number of Screens using this sound
const char *filename; // The Filename, should be unique!
ALuint audioBuffer; // The sound buffer in which it is stored
public:
Sample(const char* filename);
Sample(std::string);
void load();
bool unload();
std::string getFilename();
ALuint getAudioBuffer();
;
Sample::Sample(const char* filename)
usageCount = 0;
this->filename = filename;
Sample::Sample(std::string filename)
usageCount = 0;
this->filename = filename.c_str();
void Sample::load()
ALenum format;
ALvoid* data;
ALsizei size;
ALsizei freq;
if (usageCount == 0)
data = SampleLoader::GetOpenALAudioData(filename, &size, &format, &freq);
// Generate Buffer
alGenBuffers(1, &audioBuffer);
// Fill Buffer With Data
alBufferData(audioBuffer, format, data, size, freq);
// Free Audio Data
if (data)
free(data);
data = NULL;
usageCount++;
// returns true, if usageCount got zero
bool Sample::unload()
if (usageCount == 1)
// Delete Buffer
alDeleteBuffers(1, &audioBuffer);
return true;
usageCount--;
return false;
std::string Sample::getFilename()
std::string strFilename = std::string(filename);
return strFilename;
ALuint Sample::getAudioBuffer()
return audioBuffer;
来源
class Source
vec3 position;
vec3 velocity;
vec3 direction;
ALfloat gain;
ALfloat pitch;
ALuint sourceID;
Sample *sample;
public:
void load();
void unload();
ALboolean isPlaying();
void play();
void repeat();
void stop();
void updateSample(Sample *sample);
void updatePosition(vec3 position);
void updateVelocity(vec3 velocity);
void updateDirection(vec3 direcation);
void updateOrienation(vec3 position, vec3 velocity, vec3 direction);
void updateGain(ALfloat gain);
void updatePitch(ALfloat pitch);
;
void Source::load()
alGenSources(1, &sourceID);
position = vec3(0.0f, 0.0f, 0.0f);
velocity = vec3(0.0f, 0.0f, 0.0f);
direction = vec3(0.0f, 0.0f, 0.0f);
alSourcefv(sourceID, AL_POSITION, value_ptr(position));
alSourcefv(sourceID, AL_VELOCITY, value_ptr(velocity));
alSourcefv(sourceID, AL_DIRECTION, value_ptr(direction));
gain = 0.5f;
pitch = 1.0f;
alSourcef(sourceID, AL_GAIN, gain);
alSourcef(sourceID, AL_PITCH, pitch);
void Source::unload()
alDeleteSources(1, &sourceID);
ALboolean Source::isPlaying()
ALint sourceState;
alGetSourcei(sourceID, AL_SOURCE_STATE, &sourceState);
return (sourceState == AL_PLAYING);
void Source::play()
alSourcei(sourceID, AL_LOOPING, AL_FALSE);
alSourcePlay(sourceID);
void Source::repeat()
alSourcei(sourceID, AL_LOOPING, AL_TRUE);
alSourcePlay(sourceID);
void Source::stop()
alSourceStop(sourceID);
void Source::updateSample(Sample *sample)
alSourcei(sourceID, AL_BUFFER, sample->getAudioBuffer());
void Source::updatePosition(vec3 position)
alSource3f(sourceID, AL_POSITION, position.x, position.y, position.z);
void Source::updateVelocity(vec3 velocity)
alSourcefv(sourceID, AL_VELOCITY, value_ptr(velocity));
void Source::updateDirection(vec3 direction)
alSourcefv(sourceID, AL_DIRECTION, value_ptr(direction));
void Source::updateOrienation(vec3 position, vec3 velocity, vec3 direction)
alSourcefv(sourceID, AL_POSITION, value_ptr(position));
alSourcefv(sourceID, AL_VELOCITY, value_ptr(velocity));
alSourcefv(sourceID, AL_DIRECTION, value_ptr(direction));
void Source::updateGain(ALfloat gain)
alSourcef(sourceID, AL_GAIN, gain);
void Source::updatePitch(ALfloat pitch)
alSourcef(sourceID, AL_PITCH, pitch);
示例加载器函数，取自苹果项目
void* SampleLoader::GetOpenALAudioData(const char* filename, ALsizei *outDataSize, ALenum *outDataFormat, ALsizei* outSampleRate)
OSStatus err = noErr;
SInt64 theFileLengthInFrames = 0;
AudioStreamBasicDescription theFileFormat;
UInt32 thePropertySize = sizeof(theFileFormat);
ExtAudioFileRef extRef = NULL;
void* theData = NULL;
AudioStreamBasicDescription theOutputFormat;
// Create Path
NSString *filenameString = [NSString stringWithCString:filename encoding:NSUTF8StringEncoding];
NSArray *components = [filenameString componentsSeparatedByString:@"."];
NSString *audioFilePath = [[NSBundle mainBundle] pathForResource:[components objectAtIndex:0] ofType:[components objectAtIndex:1]];
NSURL *audioFileURL = [NSURL fileURLWithPath:audioFilePath];
CFURLRef inFileURL = (__bridge CFURLRef)audioFileURL;
// Open a file with ExtAudioFileOpen()
err = ExtAudioFileOpenURL(inFileURL, &extRef);
if(err)
printf("MyGetOpenALAudioData: ExtAudioFileOpenURL FAILED, Error = %d\n", (int)err);
// Dispose the ExtAudioFileRef, it is no longer needed
if (extRef) ExtAudioFileDispose(extRef);
return theData;
// Get the audio data format
err = ExtAudioFileGetProperty(extRef, kExtAudioFileProperty_FileDataFormat, &thePropertySize, &theFileFormat);
if(err)
printf("MyGetOpenALAudioData: ExtAudioFileGetProperty(kExtAudioFileProperty_FileDataFormat) FAILED, Error = %d\n", (int)err);
// Dispose the ExtAudioFileRef, it is no longer needed
if (extRef) ExtAudioFileDispose(extRef);
return theData;
if (theFileFormat.mChannelsPerFrame > 2)
printf("MyGetOpenALAudioData - Unsupported Format, channel count is greater than stereo\n");
// Dispose the ExtAudioFileRef, it is no longer needed
if (extRef) ExtAudioFileDispose(extRef);
return theData;
// Set the client format to 16 bit signed integer (native-endian) data
// Maintain the channel count and sample rate of the original source format
theOutputFormat.mSampleRate = theFileFormat.mSampleRate;
theOutputFormat.mChannelsPerFrame = theFileFormat.mChannelsPerFrame;
theOutputFormat.mFormatID = kAudioFormatLinearPCM;
theOutputFormat.mBytesPerPacket = 2 * theOutputFormat.mChannelsPerFrame;
theOutputFormat.mFramesPerPacket = 1;
theOutputFormat.mBytesPerFrame = 2 * theOutputFormat.mChannelsPerFrame;
theOutputFormat.mBitsPerChannel = 16;
theOutputFormat.mFormatFlags = kAudioFormatFlagsNativeEndian | kAudioFormatFlagIsPacked | kAudioFormatFlagIsSignedInteger;
// Set the desired client (output) data format
err = ExtAudioFileSetProperty(extRef, kExtAudioFileProperty_ClientDataFormat, sizeof(theOutputFormat), &theOutputFormat);
if(err)
printf("MyGetOpenALAudioData: ExtAudioFileSetProperty(kExtAudioFileProperty_ClientDataFormat) FAILED, Error = %d\n", (int)err);
// Dispose the ExtAudioFileRef, it is no longer needed
if (extRef) ExtAudioFileDispose(extRef);
return theData;
// Get the total frame count
thePropertySize = sizeof(theFileLengthInFrames);
err = ExtAudioFileGetProperty(extRef, kExtAudioFileProperty_FileLengthFrames, &thePropertySize, &theFileLengthInFrames);
if(err)
printf("MyGetOpenALAudioData: ExtAudioFileGetProperty(kExtAudioFileProperty_FileLengthFrames) FAILED, Error = %d\n", (int)err);
// Dispose the ExtAudioFileRef, it is no longer needed
if (extRef) ExtAudioFileDispose(extRef);
return theData;
// Read all the data into memory
UInt32 theFramesToRead = (UInt32)theFileLengthInFrames;
UInt32 dataSize = theFramesToRead * theOutputFormat.mBytesPerFrame;;
theData = malloc(dataSize);
if (theData)
AudioBufferList theDataBuffer;
theDataBuffer.mNumberBuffers = 1;
theDataBuffer.mBuffers[0].mDataByteSize = dataSize;
theDataBuffer.mBuffers[0].mNumberChannels = theOutputFormat.mChannelsPerFrame;
theDataBuffer.mBuffers[0].mData = theData;
// Read the data into an AudioBufferList
err = ExtAudioFileRead(extRef, &theFramesToRead, &theDataBuffer);
if(err == noErr)
// success
*outDataSize = (ALsizei)dataSize;
*outDataFormat = (theOutputFormat.mChannelsPerFrame > 1) ? AL_FORMAT_STEREO16 : AL_FORMAT_MONO16;
*outSampleRate = (ALsizei)theOutputFormat.mSampleRate;
else
// failure
free (theData);
theData = NULL; // make sure to return NULL
printf("MyGetOpenALAudioData: ExtAudioFileRead FAILED, Error = %d\n", (int)err);
// Dispose the ExtAudioFileRef, it is no longer needed
if (extRef) ExtAudioFileDispose(extRef);
return theData;
// Dispose the ExtAudioFileRef, it is no longer needed
if (extRef) ExtAudioFileDispose(extRef);
return theData;
声音管理器
namespace SoundManager
extern ALCdevice *openALDevice;
extern ALCcontext *openALContext;
extern std::vector<Sample*> samples;
void initialize();
void release();
Sample* manage(const char* filename);
Sample* manage(std::string filename);
void remove(Sample *sample);
namespace SoundManager
ALCdevice *openALDevice;
ALCcontext *openALContext;
std::vector<Sample*> samples;
void AudioInterruptionListenerCallback(void* user_data, UInt32 interruption_state)
if (kAudioSessionBeginInterruption == interruption_state)
alcMakeContextCurrent(NULL);
else if (kAudioSessionEndInterruption == interruption_state)
AudioSessionSetActive(true);
alcMakeContextCurrent(SoundManager::openALContext);
void SoundManager::initialize()
AudioSessionInitialize(NULL, NULL, AudioInterruptionListenerCallback, NULL);
UInt32 session_category = kAudioSessionCategory_MediaPlayback;
AudioSessionSetProperty(kAudioSessionProperty_AudioCategory, sizeof(session_category), &session_category);
AudioSessionSetActive(true);
// Open Device
openALDevice = alcOpenDevice(NULL);
// Create and activate context
openALContext = alcCreateContext(openALDevice, NULL);
alcMakeContextCurrent(openALContext);
void SoundManager::release()
// Give up Context and destroy it
alcMakeContextCurrent(NULL);
alcDestroyContext(openALContext);
// Close device
alcCloseDevice(openALDevice);
Sample* SoundManager::manage(const char* filename)
return manage(std::string(filename));
Sample* SoundManager::manage(std::string filename)
if (samples.size() >= kMaxNumberOfSamples)
Engine::warning("Max number of samples reached! Release one first");
return NULL;
// If Sound is already managed, load the managed again
for (int i=0; i<samples.size(); i++)
if (samples[i]->getFilename().compare(filename) == 0)
printf("Already loaded\n");
samples[i]->load();
return samples[i];
// Otherwise load the new sound and manage it
printf("Load new sound\n");
Sample *sample = new Sample(filename);
sample->load();
samples.push_back(sample);
return sample;
void SoundManager::remove(Sample *sample)
for (int i=0; i<samples.size(); i++)
if (samples[i]->getFilename().compare(sample->getFilename()) == 0)
// If Sound isn't in use from anywhere else, unmanage it
if (samples[i]->unload())
samples.erase(std::remove(samples.begin(), samples.end(), sample), samples.end());
return;
Engine::warning("The sound to be removed wasn't managed!");
所以在这里，这些都是 Source、Buffer 和 Listener 的包装类，以及一个管理器，它只是确保一个 Sample 只加载一次。所有这些都应用在一个屏幕类中，该类在我的简单引擎中呈现。它是独立的，应该只播放从左到右再返回的声音。但它没有：
class SoundTestScreen : public Screen
private:
void initialize();
void load();
void unload();
void update(Time &time);
void draw(Time &time);
private:
Listener listener;
Sample *bubbles;
Source *bubbleSource;
double totalTime;
double lastPlayTime;
;
void SoundTestScreen::initialize()
listener.setPosition(vec3(0, 0, 0));
listener.setVelocity(vec3(0, 0, 0));
listener.setOrientation(vec3(0, 0, -1),vec3(0, 1, 0));
totalTime = 0;
lastPlayTime = 0;
// Create Sources to play the samples
bubbleSource = new Source();
void SoundTestScreen::load()
// Only load sample once
bubbles = SoundManager::manage("sound_electric.wav");
bubbleSource->load();
bubbleSource->updateSample(bubbles);
bubbleSource->updatePosition(vec3(0,0,0));
bubbleSource->repeat();
void SoundTestScreen::unload()
// Only unload sample once
SoundManager::remove(bubbles);
bubbleSource->unload();
void SoundTestScreen::update(Time &time)
bubbleSource->updatePosition(vec3(100*sinf(time.ElapsedTime),0,0));
void SoundTestScreen::draw(Time &time)
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
这一切只是一些基本的实现，但我真的不知道为什么声音没有位置。
我真的希望有人能发现我的错误，这很烦人。
问候
编辑：
现在可以了，只是我现在纠正了一些小错误，但很长时间没有发现。 我将把这段代码留给正在为 OpenAL 搜索一些示例 iOS 声音系统的人，就我而言，这在互联网上很少见。
【问题讨论】：
【参考方案1】：哇，你在提供示例代码时把雷声给毁了！ :D
所以我从中学到的位置代码是这样的：
#include <conio.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>
#include <AL\al.h>
#include <AL\alc.h>
#include <AL\alut.h>
// Maximum data buffers we will need.
#define NUM_BUFFERS 3
// Maximum emissions we will need.
#define NUM_SOURCES 3
// These index the buffers and sources.
#define BATTLE 0
#define GUN1 1
#define GUN2 2
// Buffers hold sound data.
ALuint Buffers[NUM_BUFFERS];
// Sources are points of emitting sound.
ALuint Sources[NUM_SOURCES];
// Position of the source sounds.
ALfloat SourcesPos[NUM_SOURCES][3];
// Velocity of the source sounds.
ALfloat SourcesVel[NUM_SOURCES][3];
// Position of the listener.
ALfloat ListenerPos[] = 0.0, 0.0, 0.0 ;
// Velocity of the listener.
ALfloat ListenerVel[] = 0.0, 0.0, 0.0 ;
// Orientation of the listener. (first 3 elements are "at", second 3 are "up")
ALfloat ListenerOri[] = 0.0, 0.0, -1.0, 0.0, 1.0, 0.0 ;
/*
* ALboolean LoadALData()
*
* This function will load our sample data from the disk using the Alut
* utility and send the data into OpenAL as a buffer. A source is then
* also created to play that buffer.
*/
ALboolean LoadALData()
alutInit (NULL, NULL);
//ALUT allows us to point to a buffer object using an ALuint.
// furthermore, there are calls that allow you to load from memory.
Buffers[BATTLE] = alutCreateBufferFromFile("C:\\Users\\Lee\\Desktop\\OpenAL\\OpenALStaticSound\\wavdata\\Battle.wav");
Buffers[GUN1] = alutCreateBufferFromFile("C:\\Users\\Lee\\Desktop\\OpenAL\\OpenALStaticSound\\wavdata\\Gun1.wav");
Buffers[GUN2] = alutCreateBufferFromFile("C:\\Users\\Lee\\Desktop\\OpenAL\\OpenALStaticSound\\wavdata\\Gun2.wav");
// Bind the buffer with the source.
//alGenSources (1, &Source);
alGenSources(NUM_SOURCES, Sources);
//Attach any special modifications to the source
//alSourcei (Source, AL_BUFFER, Buffer );
//alSourcef (Source, AL_PITCH, 1.0 );
//alSourcef (Source, AL_GAIN, 1.0 );
//alSourcefv(Source, AL_POSITION, SourcePos);
//alSourcefv(Source, AL_VELOCITY, SourceVel);
//alSourcei (Source, AL_LOOPING, AL_TRUE );
alSourcei (Sources[BATTLE], AL_BUFFER, Buffers[BATTLE] );
alSourcef (Sources[BATTLE], AL_PITCH, 1.0 );
alSourcef (Sources[BATTLE], AL_GAIN, 1.0 );
alSourcefv(Sources[BATTLE], AL_POSITION, SourcesPos[BATTLE]);
alSourcefv(Sources[BATTLE], AL_VELOCITY, SourcesVel[BATTLE]);
alSourcei (Sources[BATTLE], AL_LOOPING, AL_TRUE );
alSourcei (Sources[GUN1], AL_BUFFER, Buffers[GUN1] );
alSourcef (Sources[GUN1], AL_PITCH, 1.0 );
alSourcef (Sources[GUN1], AL_GAIN, 1.0 );
alSourcefv(Sources[GUN1], AL_POSITION, SourcesPos[GUN1]);
alSourcefv(Sources[GUN1], AL_VELOCITY, SourcesVel[GUN1]);
alSourcei (Sources[GUN1], AL_LOOPING, AL_FALSE );
alSourcei (Sources[GUN2], AL_BUFFER, Buffers[GUN2] );
alSourcef (Sources[GUN2], AL_PITCH, 1.0 );
alSourcef (Sources[GUN2], AL_GAIN, 1.0 );
alSourcefv(Sources[GUN2], AL_POSITION, SourcesPos[GUN2]);
alSourcefv(Sources[GUN2], AL_VELOCITY, SourcesVel[GUN2]);
alSourcei (Sources[GUN2], AL_LOOPING, AL_FALSE );
return AL_TRUE;
/*
* void SetListenerValues()
*
* We already defined certain values for the Listener, but we need
* to tell OpenAL to use that data. This function does just that.
*/
void SetListenerValues()
alListenerfv(AL_POSITION, ListenerPos);
alListenerfv(AL_VELOCITY, ListenerVel);
alListenerfv(AL_ORIENTATION, ListenerOri);
/*
* void KillALData()
*
* We have allocated memory for our buffers and sources which needs
* to be returned to the system. This function frees that memory.
*/
void KillALData()
alDeleteBuffers(NUM_BUFFERS, &Buffers[0]);
alDeleteSources(NUM_SOURCES, &Sources[0]);
alutExit();
int main()
printf("Original Tutorial : MindCode's OpenAL Lesson 1: Single Static Source\n\n");
printf("Updated Tutorial : Lesley A. Gushurst\n");
alutInit(NULL, 0);
//alGetError();
// Load the wav data.
if(LoadALData() == AL_FALSE)
printf("Error loading data.");
return 0;
else
// Begin the battle sample to play.
alSourcePlay(Sources[BATTLE]);
// Go through all the sources and check that they are playing.
// Skip the first source because it is looping anyway (will always be playing).
ALint play;
while (!_kbhit())
for (int i = 1; i < NUM_SOURCES; i++)
alGetSourcei(Sources[i], AL_SOURCE_STATE, &play);
if (play != AL_PLAYING)
// Pick a random position around the listener to play the source.
double theta = (double) (rand() % 360) * 3.14 / 180.0;
SourcesPos[i][0] = -float(cos(theta));
SourcesPos[i][1] = -float(rand()%2);
SourcesPos[i][2] = -float(sin(theta));
alSourcefv(Sources[i], AL_POSITION, SourcesPos[i] );
alSourcePlay(Sources[i]);
getchar();
return 0;
我会尝试这段代码，如果它有效，那么您的问题可能是“是否可以在 iPhone 上使用 OpenAl 回放声音位置？”将得到答复。我不确定，因为我没有做过移动开发，但我认为这将是一个很好的起点。非常尊重 MindCode。您必须用其他东西替换 wav 文件才能对其进行测试（而不是像我那样对其进行硬编码）。
【讨论】：
谢谢你！即使在根据您的示例修改我的代码后，iOS 上不支持 alut，我也喜欢我的错误。这真的很愚蠢，必须交换一个变量：D 在 Sample::load() AL_FORMAT_STEREO16 中必须替换为从前一个函数计算的“格式”。这就是为什么它不是定位的！ 糟糕！使用 ALUT 和 iOS 时完全忘记了这一点。以上是关于iOS OpenAL 声音不是定位的的主要内容，如果未能解决你的问题，请参考以下文章
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