音频 – C特定声音输出？

您需要生成一个包含代表所需输出的PCM编码数据的数组,然后使用所需的采样频率和格式调用阵列上的a??lBufferData().有关alBufferData()函数所需的格式,请参见OpenAL Programmers Guide的第21页.

例如,以下代码播放100hz音调.

#include <iostream>

#include <cmath>

#include <al.h>
#include <alc.h>
#include <AL/alut.h>

#pragma comment(lib,"OpenAL32.lib")
#pragma comment(lib,"alut.lib")

int main(int argc,char** argv)
{
  alutInit(&argc,argv);
  alGetError();

  ALuint buffer;
  alGenBuffers(1,&buffer);

  {
    // Creating a buffer that hold about 1.5 seconds of audio data.
    char data[32 * 1024];

    for (int i = 0; i < 32 * 1024; ++i)
    {
      // get a value in the interval [0,1) over the length of a second
      float intervalPerSecond = static_cast<float>(i % 22050) / 22050.0f;

      // increase the frequency to 100hz
      float intervalPerHundreth = fmod(intervalPerSecond * 100.0f,1.0f);

      // translate to the interval [0,2PI)
      float x = intervalPerHundreth * 2 * 3.14159f;

      // and then convert back to the interval [0,255] for our amplitude data.
      data[i] = static_cast<char>((sin(x) + 1.0f) / 2.0f * 255.0f);
    }

    alBufferData(buffer,AL_FORMAT_MONO8,data,32 * 1024,22050);
  }

  ALuint source;
  alGenSources(1,&source);

  alSourcei(source,AL_BUFFER,buffer);

  alSourcePlay(source);

  system("pause");

  alSourceStop(source);

  alDeleteSources(1,&source);

  alDeleteBuffers(1,&buffer);

  alutExit();

  return 0;
}