image_conversion.cpp

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#include "utils/image_conversion.h"
#include <OpenImageIO/imagebuf.h>
#include <OpenImageIO/imagebufalgo.h>
#include <spdlog/spdlog.h>
 
namespace CaptureMoment::Core::Utils {
 
std::unique_ptr<Common::ImageRegion> convert_RGBA_F32_to_RGBA_U8(const Common::ImageRegion& input)
{
    if (!input.isValid() || input.m_channels != 4 || input.m_format != Common::PixelFormat::RGBA_F32) {
        spdlog::error("convert_RGBA_F32_to_RGBA_U8: Input is invalid or not RGBA_F32");
        return nullptr;
    }
 
    // 1. Setup OIIO Source Buffer (Zero-Copy)
    OIIO::ImageSpec src_spec(input.m_width, input.m_height, input.m_channels, OIIO::TypeDesc::FLOAT);
    OIIO::ImageBuf src_buf(src_spec, const_cast<float*>(input.m_data.data()));
 
    // 2. Setup OIIO Destination Spec
    OIIO::ImageSpec dst_spec(input.m_width, input.m_height, input.m_channels, OIIO::TypeDesc::UINT8);
    OIIO::ImageBuf dst_buf(dst_spec);
 
    // 3. Perform Conversion (F32 -> U8) using OIIO
    if (!OIIO::ImageBufAlgo::copy(dst_buf, src_buf)) {
        spdlog::error("convert_RGBA_F32_to_RGBA_U8: OIIO conversion failed");
        return nullptr;
    }
 
    // 4. Extract U8 data to ImageRegion
    auto result { std::make_unique<Common::ImageRegion>() };
    result->m_x = input.x();
    result->m_y = input.y();
    result->m_width = input.width();
    result->m_height = input.height();
    result->m_channels = input.channels();
 
    const size_t total_elements { static_cast<size_t>(input.width()) * input.height() * input.channels() };
    result->m_data.resize(total_elements);
 
    if (!dst_buf.get_pixels(OIIO::ROI::All(), OIIO::TypeDesc::UINT8, result->m_data.data())) {
        spdlog::error("convert_RGBA_F32_to_RGBA_U8: Failed to extract U8 pixels from OIIO buffer");
        return nullptr;
    }
 
    return result;
}
 
} // namespace CaptureMoment::Core::Utils