imfmisc.cpp

对gif

                        writePtr[i] = readPtr[i];

                    readPtr += sizeof (unsigned int);
                    writePtr += xStride;
                }
                break;

              case HALF:

                while (writePtr <= endPtr)
                {
                    half h = *(half *) readPtr;
                    *(unsigned int *) writePtr = halfToUint (h);
                    readPtr += sizeof (half);
                    writePtr += xStride;
                }
                break;

              case FLOAT:

                while (writePtr <= endPtr)
                {
                    float f;

                    for (size_t i = 0; i < sizeof (float); ++i)
                        ((char *)&f)[i] = readPtr[i];

                    *(unsigned int *)writePtr = floatToUint (f);
                    readPtr += sizeof (float);
                    writePtr += xStride;
                }
                break;
            }
            break;

          case HALF:

            switch (typeInFile)
            {
              case UINT:

                while (writePtr <= endPtr)
                {
                    unsigned int ui;

                    for (size_t i = 0; i < sizeof (unsigned int); ++i)
                        ((char *)&ui)[i] = readPtr[i];

                    *(half *) writePtr = uintToHalf (ui);
                    readPtr += sizeof (unsigned int);
                    writePtr += xStride;
                }
                break;

              case HALF:

                while (writePtr <= endPtr)
                {
                    *(half *) writePtr = *(half *)readPtr;
                    readPtr += sizeof (half);
                    writePtr += xStride;
                }
                break;

              case FLOAT:

                while (writePtr <= endPtr)
                {
                    float f;

                    for (size_t i = 0; i < sizeof (float); ++i)
                        ((char *)&f)[i] = readPtr[i];

                    *(half *) writePtr = floatToHalf (f);
                    readPtr += sizeof (float);
                    writePtr += xStride;
                }
                break;
            }
            break;

          case FLOAT:

            switch (typeInFile)
            {
              case UINT:

                while (writePtr <= endPtr)
                {
                    unsigned int ui;

                    for (size_t i = 0; i < sizeof (unsigned int); ++i)
                        ((char *)&ui)[i] = readPtr[i];

                    *(float *) writePtr = float (ui);
                    readPtr += sizeof (unsigned int);
                    writePtr += xStride;
                }
                break;

              case HALF:

                while (writePtr <= endPtr)
                {
                    half h = *(half *) readPtr;
                    *(float *) writePtr = float (h);
                    readPtr += sizeof (half);
                    writePtr += xStride;
                }
                break;

              case FLOAT:

                while (writePtr <= endPtr)
                {
                    for (size_t i = 0; i < sizeof (float); ++i)
                        writePtr[i] = readPtr[i];

                    readPtr += sizeof (float);
                    writePtr += xStride;
                }
                break;
            }
            break;

          default:

            throw Iex::ArgExc ("Unknown pixel data type.");
        }
    }
}


void
skipChannel (const char *& readPtr,
             PixelType typeInFile,
	     size_t xSize)
{
    switch (typeInFile)
    {
      case UINT:
        
        Xdr::skip <CharPtrIO> (readPtr, Xdr::size <unsigned int> () * xSize);
        break;

      case HALF:

        Xdr::skip <CharPtrIO> (readPtr, Xdr::size <half> () * xSize);
        break;

      case FLOAT:

        Xdr::skip <CharPtrIO> (readPtr, Xdr::size <float> () * xSize);
        break;

      default:

        throw Iex::ArgExc ("Unknown pixel data type.");
    }
}


void
convertInPlace (char *& writePtr,
                const char *& readPtr,
		PixelType type,
                size_t numPixels)
{
    switch (type)
    {
      case UINT:
    
        for (int j = 0; j < numPixels; ++j)
        {
            Xdr::write <CharPtrIO> (writePtr, *(const unsigned int *) readPtr);
            readPtr += sizeof(unsigned int);
        }
        break;
    
      case HALF:
    
        for (int j = 0; j < numPixels; ++j)
        {               
            Xdr::write <CharPtrIO> (writePtr, *(const half *) readPtr);
            readPtr += sizeof(half);
        }
        break;
    
      case FLOAT:
    
        for (int j = 0; j < numPixels; ++j)
        {
            Xdr::write <CharPtrIO> (writePtr, *(const float *) readPtr);
            readPtr += sizeof(float);
        }
        break;
    
      default:
    
        throw Iex::ArgExc ("Unknown pixel data type.");
    }
}


void
copyFromFrameBuffer (char *& writePtr,
		     const char *& readPtr,
                     const char * endPtr,
		     size_t xStride,
                     Compressor::Format format,
		     PixelType type)
{
    //
    // Copy a horizontal row of pixels from a frame
    // buffer to an output file's line or tile buffer.
    //

    if (format == Compressor::XDR)
    {
        //
        // The the line or tile buffer is in XDR format.
        //

        switch (type)
        {
          case UINT:

            while (readPtr <= endPtr)
            {
                Xdr::write <CharPtrIO> (writePtr,
                                        *(const unsigned int *) readPtr);
                readPtr += xStride;
            }
            break;

          case HALF:

            while (readPtr <= endPtr)
            {
                Xdr::write <CharPtrIO> (writePtr, *(const half *) readPtr);
                readPtr += xStride;
            }
            break;

          case FLOAT:

            while (readPtr <= endPtr)
            {
                Xdr::write <CharPtrIO> (writePtr, *(const float *) readPtr);
                readPtr += xStride;
            }
            break;

          default:

            throw Iex::ArgExc ("Unknown pixel data type.");
        }
    }
    else
    {
        //
        // The the line or tile buffer is in NATIVE format.
        //

        switch (type)
        {
          case UINT:

            while (readPtr <= endPtr)
            {
                for (size_t i = 0; i < sizeof (unsigned int); ++i)
                    *writePtr++ = readPtr[i];

                readPtr += xStride;
            }
            break;

          case HALF:

            while (readPtr <= endPtr)
            {
                *(half *) writePtr = *(const half *) readPtr;
                writePtr += sizeof (half);
                readPtr += xStride;
            }
            break;

          case FLOAT:

            while (readPtr <= endPtr)
            {
                for (size_t i = 0; i < sizeof (float); ++i)
                    *writePtr++ = readPtr[i];

                readPtr += xStride;
            }
            break;
            
          default:

            throw Iex::ArgExc ("Unknown pixel data type.");
        }
    }
}


void
fillChannelWithZeroes (char *& writePtr,
		       Compressor::Format format,
		       PixelType type,
		       size_t xSize)
{
    if (format == Compressor::XDR)
    {
        //
        // Fill with data in XDR format.
        //

        switch (type)
        {
          case UINT:

            for (int j = 0; j < xSize; ++j)
                Xdr::write <CharPtrIO> (writePtr, (unsigned int) 0);

            break;

          case HALF:

            for (int j = 0; j < xSize; ++j)
                Xdr::write <CharPtrIO> (writePtr, (half) 0);

            break;

          case FLOAT:

            for (int j = 0; j < xSize; ++j)
                Xdr::write <CharPtrIO> (writePtr, (float) 0);

            break;
            
          default:

            throw Iex::ArgExc ("Unknown pixel data type.");
        }
    }
    else
    {
        //
        // Fill with data in NATIVE format.
        //

        switch (type)
        {
          case UINT:

            for (int j = 0; j < xSize; ++j)
            {
                static const unsigned int ui = 0;

                for (size_t i = 0; i < sizeof (ui); ++i)
                    *writePtr++ = ((char *) &ui)[i];
            }
            break;

          case HALF:

            for (int j = 0; j < xSize; ++j)
            {
                *(half *) writePtr = half (0);
                writePtr += sizeof (half);
            }
            break;

          case FLOAT:

            for (int j = 0; j < xSize; ++j)
            {
                static const float f = 0;

                for (size_t i = 0; i < sizeof (f); ++i)
                    *writePtr++ = ((char *) &f)[i];
            }
            break;
            
          default:

            throw Iex::ArgExc ("Unknown pixel data type.");
        }
    }
}

} // namespace Imf