Texture Compression and Decompression

Compressonator SDK’s supported codecs includes BC1-BC7/DXTC, ETC1, ETC2, ASTC, ATC, ATI1N, ATI2N.

The main API call for both compression and decompression as well as texture conversion:

/// Converts the source texture to the destination texture
/// This can be compression, decompression or converting between two uncompressed formats.
/// \param[in] pSourceTexture A pointer to the source texture.
/// \param[in] pDestTexture A pointer to the destination texture.
/// \param[in] pOptions A pointer to the compression options - can be NULL.
/// \param[in] pFeedbackProc A pointer to the feedback function - can be NULL.
/// \param[in] pUser1 User data to pass to the feedback function.
/// \param[in] pUser2 User data to pass to the feedback function.
/// \return    CMP_OK if successful, otherwise the error code.
CMP_ERROR CMP_API CMP_ConvertTexture(CMP_Texture* pSourceTexture, CMP_Texture* pDestTexture, const CMP_CompressOptions* pOptions,
                                     CMP_Feedback_Proc pFeedbackProc, CMP_DWORD_PTR pUser1, CMP_DWORD_PTR pUser2);

Example Usage of Compressonator SDK

You will need to include a header file and a lib file: Compressonator.h and Compressonator_MD.lib

and a simple usage is shown as below:

//==========================
// Load Source Texture
//==========================
CMP_Texture srcTexture;
// note that LoadDDSFile function is a utils function to initialize the source CMP_Texture
// you can also initialize the source CMP_Texture the same way as initialize destination CMP_Texture
if (!LoadDDSFile(pszSourceFile, srcTexture))
{
    std::printf("Error loading source file!\n");
    return 0;
}

//===================================
// Initialize Compressed Destination
//===================================
CMP_Texture destTexture;
destTexture.dwSize     = sizeof(destTexture);
destTexture.dwWidth    = srcTexture.dwWidth;
destTexture.dwHeight   = srcTexture.dwHeight;
destTexture.dwPitch    = 0;
destTexture.format     = destFormat;
destTexture.dwDataSize = CMP_CalculateBufferSize(&destTexture);
destTexture.pData = (CMP_BYTE*)malloc(destTexture.dwDataSize);

//==========================
// Set Compression Options
//==========================
CMP_CompressOptions options = {0};
options.dwSize       = sizeof(options);
options.fquality     = fQuality;
options.dwnumThreads = 8;

//==========================
// Compress Texture
//==========================
CMP_ERROR   cmp_status;
cmp_status = CMP_ConvertTexture(&srcTexture, &destTexture, &options, &CompressionCallback, NULL, NULL);
if (cmp_status != CMP_OK)
{
    free(srcTexture.pData);
    free(destTexture.pData);
    std::printf("Compression returned an error %d\n", cmp_status);
    return cmp_status;
}

//==========================
// Save Compressed Testure
//==========================
if (cmp_status == CMP_OK)
    SaveDDSFile(pszDestFile, destTexture);

free(srcTexture.pData);
free(destTexture.pData);

Example projects have been provided here with:

• example1 demonstrates simple SDK API usage as shown above.
• example2 demonstrates how to use the SDK API in multihreaded environment.
• example3 demonstrates how to use the block level SDK API.

These examples are also distributed through Compressonator SDK installer in the release page.