SDL正在播放wav文件，但我似乎无法播放简单的波形

Question

我正在尝试通过主音频回调函数在SDL中播放简单的方波。但是，尽管数据似乎已写入音频缓冲区，但我似乎无法播放任何音频。

但是，如果我加载.wav文件，则音频可以正常播放（将数据写入同一位置

在编写了自己的代码以尝试解决问题之后，我尝试了网上发现的许多正弦/方波。看来问题可能与波形无关，但是由于wav文件有效，因此我不确定还有什么可能导致问题：

#include "x:\SDL2-2.0.10\include\SDL.h"

#define INITIAL_SCREEN_WIDTH (8*80)
#define INITIAL_SCREEN_HEIGHT (8*60)

typedef struct audio_user_data audio_user_data;
struct audio_user_data
{
    int SamplesPerSecond;
    int BytesPerSample;
    int SampleIndex;
    int ToneHz;
    int ToneVolume;
    int WavePeriod;
    Uint32 FileLength;
    Uint16* BufferLocation;
};

void
AudioCallback(void* UserData, Uint8* Stream, int Length)
{
    audio_user_data* AudioUserData = (audio_user_data*)UserData;
    static Uint32 Count = 0;

    Sint16* SampleBuffer = (Sint16*)Stream;
    int SamplesToWrite = Length / AudioUserData->BytesPerSample;
    for(int SampleIndex = 0; SampleIndex < SamplesToWrite; SampleIndex++)
    {
        Sint16 SampleValue = ((Count++ / (AudioUserData->WavePeriod/2)) % 2) ? AudioUserData->ToneVolume : -AudioUserData->ToneVolume;
        *SampleBuffer++ = SampleValue;
        *SampleBuffer++ = SampleValue;
    }
}

int
main(int argc, char* argv[])
{
    SDL_Init(SDL_INIT_VIDEO|SDL_INIT_AUDIO);

    SDL_Window* Window = SDL_CreateWindow("Spell Checker", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, INITIAL_SCREEN_WIDTH*2, INITIAL_SCREEN_HEIGHT*2, 0);
    SDL_Renderer* Renderer = SDL_CreateRenderer(Window, 0, SDL_RENDERER_SOFTWARE);
    SDL_PixelFormat* Format = SDL_AllocFormat(SDL_PIXELFORMAT_RGB888);
    SDL_Texture* Screen = SDL_CreateTexture(Renderer, Format->format, SDL_TEXTUREACCESS_STREAMING, INITIAL_SCREEN_WIDTH, INITIAL_SCREEN_HEIGHT);

    audio_user_data AudioUserData = {0};
    AudioUserData.SamplesPerSecond = 48000;//44100;
    AudioUserData.BytesPerSample = 2 * sizeof(Sint16);
    AudioUserData.SampleIndex = 0;
    AudioUserData.ToneVolume = 5000;
    AudioUserData.ToneHz = 256;
    AudioUserData.WavePeriod = AudioUserData.SamplesPerSecond / AudioUserData.ToneHz;

    SDL_AudioSpec Want, Have;
    SDL_AudioDeviceID AudioDeviceID;
    Want.freq = 48000; // 44100;
    Want.format = AUDIO_S16;
    Want.channels = 2;
    Want.samples = 4096;
    Want.callback = &AudioCallback;
    Want.userdata = &AudioUserData;
    AudioDeviceID = SDL_OpenAudioDevice(0, 0, &Want, &Have, SDL_AUDIO_ALLOW_ANY_CHANGE);
    SDL_PauseAudioDevice(AudioDeviceID, 0); // Start playing

    Uint32* PixelMap = calloc(INITIAL_SCREEN_WIDTH * INITIAL_SCREEN_HEIGHT, sizeof(PixelMap));

    int PixelMapLocation = 0;
    int Running = 1;
    while(Running)
    {

        SDL_Event Event;
        while(SDL_PollEvent(&Event))
        {
            if(Event.type == SDL_QUIT)
            {
                Running = 0;
                break;
            }
        }

        // Test colors
        PixelMapLocation = 0;
        for(int Row = 0; Row < INITIAL_SCREEN_WIDTH; ++Row)
        {
            for(int Col = 0; Col < INITIAL_SCREEN_HEIGHT; ++Col)
            {
                PixelMap[PixelMapLocation++] = 0xFF00FF;
            }
        }
        for(int Row = 0; Row < INITIAL_SCREEN_WIDTH; ++Row)
        {
            for(int Col = 0; Col < INITIAL_SCREEN_HEIGHT; ++Col)
            {
                PixelMap[PixelMapLocation++] = 0x00FFFF;
            }
        }

        SDL_UpdateTexture(Screen, 0, PixelMap, INITIAL_SCREEN_WIDTH * sizeof(PixelMap));
        SDL_RenderClear(Renderer);
        SDL_RenderCopy(Renderer, Screen, 0, 0);
        SDL_RenderPresent(Renderer);
    }

    return(0);
}