从内存中检索图像数据

Question

我正在使用FreeImage库来处理加载图像并将它们传递给OpenGL.目前,我支持从文件中读取图像.但是,我想将其扩展为能够从变量中读取游戏内容包的目的.基本上,简而言之,我将整个文件,标题和所有内容写入unsigned char*.我想拿这个缓冲区并用它做类似的事情(假设声明了变量fif):

  FIBITMAP * dib = FreeImage_Load(fif, "someImage.png");

但是我没有使用someImage.png来指定unsigned char*(为了问题,我们可以调用它来缓冲).库中有一个方法可以处理这样的事情吗？

编辑:我应该更具体一点,因为"someImage.png"可以被认为是unsigned char*.

为了清除混淆,如果有的话,unsigned char*buffer的值将由类似这样的伪代码确定:

  fileStream = openFile "someImage.png"
  unsigned char * buffer = fileStream.ReadToEnd

Answer 1

听起来你想使用FreeImage_ConvertToRawBits.以下是文档中的示例:

   // this code assumes there is a bitmap loaded and
   // present in a variable called ‘dib’
   // convert a bitmap to a 32-bit raw buffer (top-left pixel first)
   // --------------------------------------------------------------
   FIBITMAP *src = FreeImage_ConvertTo32Bits(dib);
   FreeImage_Unload(dib);
   // Allocate a raw buffer
   int width = FreeImage_GetWidth(src);
   int height = FreeImage_GetHeight(src);
   int scan_width = FreeImage_GetPitch(src);
   BYTE *bits = (BYTE*)malloc(height * scan_width);
   // convert the bitmap to raw bits (top-left pixel first)
   FreeImage_ConvertToRawBits(bits, src, scan_width, 32, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK, TRUE);
   FreeImage_Unload(src);
   // convert a 32-bit raw buffer (top-left pixel first) to a FIBITMAP
   // ----------------------------------------------------------------
   FIBITMAP *dst = FreeImage_ConvertFromRawBits(bits, width, height, scan_width, 32, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK, FALSE);