创建指向unsigned char []的指针并将其传递给sf :: SoundBuffer :: loadFromMemory

时间:2016-12-17 09:44:26

标签: c++ arrays pointers sfml memcpy

在我的游戏中,我有一张地图std::map<Sound, sf::SoundBuffer> mySounds,我将其用作声音的资源持有者。

Sound是一个看起来像这样的枚举:

enum class Sound {
  SOUND_ONE,
  SOUND_TWO,
  SOUND_THREE,
  NUMBER_OF_SOUNDS
};

现在,为了加载我当前使用sf::SoundBuffer::loadFromFile的声音,代码如下所示:

std::vector<std::string> paths;
paths.resize(static_cast<unsigned int>(Sound::NUMBER_OF_SOUNDS));
paths[static_cast<std::size_t>(Sound::SOUND_ONE)] = "sound1.ogg";
paths[static_cast<std::size_t>(Sound::SOUND_TWO)] = "sound2.ogg";
paths[static_cast<std::size_t>(Sound::SOUND_THREE)] = "sound3.ogg";

for (std::size_t i = 0; i < static_cast<std::size_t>(Sound::NUMBER_OF_SOUNDS); ++i) {
  mySounds[static_cast<Sound>(i)].loadFromFile("./data/" + paths[i]);
}

这很好用。

现在问题:

对于我的发布版本,我想将所有声音转换为字节数组(使用名为bin2h的工具),然后使用sf::SoundBuffer::loadFromMemory()

数组看起来像这样:

unsigned char RES_SOUND_ONE[] = {0x4f,0x67,0x67,0x53,...};
unsigned char RES_SOUND_TWO[] = {0x52,0x88,0x29,0x47,...};
unsigned char RES_SOUND_THREE[] = {0x96,0x65,0x59,0x02,...};

如果我只有一个声音,我可以写一下:

mySound.loadFromMemory(RES_SOUND_ONE, sizeof(RES_SOUND_ONE));

它会很完美。

虽然我有多个声音,所以我想在for-loop中有一个指针(最初只是一个空指针)。

然后我根据我当前所处的循环索引将指针设置为适当的字节数组(参见下面代码中的switch)。

然后我将指针传递给loadFromMemory函数的数据。

for (std::size_t i = 0; i < static_cast<std::size_t>(Sound::NUMBER_OF_SOUNDS); ++i) {
  void *buffer = nullptr;
  switch (static_cast<Sound>(i)) {
    case Sound::SOUND_ONE:   { buffer = (unsigned char*)RES_SOUND_ONE; } break;
    case Sound::SOUND_TWO:   { buffer = (unsigned char*)RES_SOUND_TWO; } break;
    case Sound::SOUND_THREE: { buffer = (unsigned char*)RES_SOUND_THREE; } break;
  }
  mySounds[static_cast<Sound>(i)].loadFromMemory(buffer, sizeof(buffer));
}

SFML错误消息是:

Failed to open sound file from memory (format not supported)

我做错了什么

我还尝试了其他各种事情,例如memcpy,这一切都导致失败lol

基本上我要问的是:如何创建指向unsigned char数组的指针并将其传递给SFML函数sf::SoundBuffer::loadFromMemory(const void *data, size_t sizeInBytes)

1 个答案:

答案 0 :(得分:1)

问题可能是您拨打loadFromMemory()

特别是,sizeof(buffer)的值可能是一个常量,取决于指针占用多少内存。 (例如,64位平台上的8个字节。)

我怀疑它会大到足以包含声音信息...... :)

您想传递数组的大小。要遵循你的模式:

for (size_t i = 0; i < static_cast<size_t>(Sound::NUMBER_OF_SOUNDS); ++i)
{
    unsigned char *buf = nullptr;
    size_t siz = 0;
    switch (static_cast<Sound>(i))
    {
        case Sound::SOUND_ONE:
            buf = RES_SOUND_ONE;
            siz = sizeof (RES_SOUND_ONE);
            break;
        case Sound::SOUND_TWO:
            buf = RES_SOUND_TWO;
            siz = sizeof (RES_SOUND_TWO);
            break;
        case Sound::SOUND_THREE:
            buf = RES_SOUND_THREE;
            siz = sizeof (RES_SOUND_THREE);
            break;
    }
    mySounds[static_cast<Sound>(i)].loadFromMemory(buf, siz);
}
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