Function exportDDS

Source/Falcor/Utils/Image/ImageIO.cpp:334–409

Saves image data to a DDS file using the specified compression mode. Optionally generates mips.

// Saves image data to a DDS file using the specified compression mode. Optionally generates mips.
void exportDDS(const std::filesystem::path& path, ExportData& image, ImageIO::CompressionMode mode, bool generateMips)
{
    nvtt::CompressionOptions compressionOptions;
    nvtt::Format format = convertModeToNvttFormat(mode);
    compressionOptions.setFormat(format);
    if (format == nvtt::Format::Format_RGBA && !isCompressedFormat(image.format))
    {
        if (getFormatType(image.format) == FormatType::Float)
        {
            compressionOptions.setPixelType(nvtt::PixelType::PixelType_Float);
            if (image.format == ResourceFormat::R32Float)
            {
                compressionOptions.setPixelFormat(32, 0, 0, 0);
            }
            else
            {
                uint32_t bits = getNumChannelBits(image.format, 0);
                compressionOptions.setPixelFormat(bits, bits, bits, bits);
            }
        }
    }
    else if (format == nvtt::Format::Format_BC6S)
    {
        compressionOptions.setPixelType(nvtt::PixelType::PixelType_Float);
    }

    nvtt::OutputOptions outputOptions;
    std::string pathStr = path.string();
    outputOptions.setFileName(pathStr.c_str());
    if (format == nvtt::Format::Format_BC6S || format == nvtt::Format::Format_BC7)
    {
        outputOptions.setContainer(nvtt::Container::Container_DDS10);
    }
    outputOptions.setSrgbFlag(isSrgbFormat(image.format));

    nvtt::Context context;
    if (!context.outputHeader(
            image.type,
            image.width,
            image.height,
            image.depth,
            image.mipLevels,
            image.images[0].isNormalMap(),
            compressionOptions,
            outputOptions
        ))
    {
        FALCOR_THROW("Failed to output file header.");
    }

    for (uint32_t f = 0; f < image.faceCount; ++f)
    {
        size_t faceIndex = f * image.mipLevels;
        nvtt::Surface tmp = image.images[faceIndex];
        if (!context.compress(tmp, f, 0, compressionOptions, outputOptions))
        {
            FALCOR_THROW("Failed to compress file.");
        }