Function createDFDPackedShifted

external/dfdutils/createdfd.c:254–369

* @~English * @brief Create a Data Format Descriptor for a packed format. * * @param bigEndian Big-endian flag: Set to 1 for big-endian byte ordering and * 0 for little-endian byte ordering. * @param numChannels The number of color channels. * @param bits[] An array of length numChannels. * Each entry is the number of bits composing the channel, in *

 *         for freeing the descriptor.
 **/
uint32_t *createDFDPackedShifted(int bigEndian, int numChannels,
                                 int bits[], int shiftBits[], int channels[],
                                 enum VkSuffix suffix)
{
    uint32_t *DFD = 0;
    if (numChannels == 6) {
        /* Special case E5B9G9R9 */
        DFD = writeHeader(numChannels, 4, s_UFLOAT, i_COLOR);
        writeSample(DFD, 0, 0,
                    9, 0,
                    1, 1, s_UNORM);
        KHR_DFDSETSVAL((DFD+1), 0, SAMPLEUPPER, 8448);
        writeSample(DFD, 1, 0 | KHR_DF_SAMPLE_DATATYPE_EXPONENT,
                    5, 27,
                    1, 1, s_UNORM);
        KHR_DFDSETSVAL((DFD+1), 1, SAMPLELOWER, 15);
        KHR_DFDSETSVAL((DFD+1), 1, SAMPLEUPPER, 31);
        writeSample(DFD, 2, 1,
                    9, 9,
                    1, 1, s_UNORM);
        KHR_DFDSETSVAL((DFD+1), 2, SAMPLEUPPER, 8448);
        writeSample(DFD, 3, 1 | KHR_DF_SAMPLE_DATATYPE_EXPONENT,
                    5, 27,
                    1, 1, s_UNORM);
        KHR_DFDSETSVAL((DFD+1), 3, SAMPLELOWER, 15);
        KHR_DFDSETSVAL((DFD+1), 3, SAMPLEUPPER, 31);
        writeSample(DFD, 4, 2,
                    9, 18,
                    1, 1, s_UNORM);
        KHR_DFDSETSVAL((DFD+1), 4, SAMPLEUPPER, 8448);
        writeSample(DFD, 5, 2 | KHR_DF_SAMPLE_DATATYPE_EXPONENT,
                    5, 27,
                    1, 1, s_UNORM);
        KHR_DFDSETSVAL((DFD+1), 5, SAMPLELOWER, 15);
        KHR_DFDSETSVAL((DFD+1), 5, SAMPLEUPPER, 31);
    } else if (bigEndian) {
        /* No packed format is larger than 32 bits. */
        /* No packed channel crosses more than two bytes. */
        int totalBits = 0;
        int bitChannel[32];
        int beChannelStart[4];
        int channelCounter;
        int bitOffset = 0;
        int BEMask;
        int numSamples = numChannels;
        int sampleCounter;
        for (channelCounter = 0; channelCounter < numChannels; ++channelCounter) {
            beChannelStart[channelCounter] = totalBits;
            totalBits += shiftBits[channelCounter] + bits[channelCounter];
        }
        BEMask = (totalBits - 1) & 0x18;
        for (channelCounter = 0; channelCounter < numChannels; ++channelCounter) {
            bitOffset += shiftBits[channelCounter];
            bitChannel[bitOffset ^ BEMask] = channelCounter;
            if (((bitOffset + bits[channelCounter] - 1) & ~7) != (bitOffset & ~7)) {
                /* Continuation sample */
                bitChannel[((bitOffset + bits[channelCounter] - 1) & ~7) ^ BEMask] = channelCounter;
                numSamples++;