download_image()

std::optional< Kakshya::ImageData > MayaFlux::Portal::Graphics::TextureLoom::download_image	(	const std::shared_ptr< Core::VKImage > &	image,
		const std::shared_ptr< Buffers::VKBuffer > &	staging = nullptr,
		vk::ImageLayout	restore_layout = vk::ImageLayout::eShaderReadOnlyOptimal,
		vk::PipelineStageFlags	restore_stage = vk::PipelineStageFlagBits::eFragmentShader
	)

Download the base level of an image as typed pixels.

Blocking. The element type of the returned storage follows the format: one byte per channel gives uint8, two gives uint16, four gives float.

Parameters

image	Source image. Must satisfy readable_format().
staging	Persistent host-visible staging buffer of at least the base level's byte size, or nullptr for a per-call one.
restore_layout	Layout the image is left in.
restore_stage	Pipeline stage that consumes the image after restore.

Returns

The pixels with width, height, channels and format set, or nullopt, with an error logged, if the image is not readable or the loom is not initialised.

Definition at line 637 of file TextureLoom.cpp.

{
    if (!is_initialized()) {
        MF_ERROR(Journal::Component::Portal, Journal::Context::ImageProcessing,
            "download_image: TextureLoom is not initialised");
        return std::nullopt;
    }
 
    const auto format = readable_format(image);
    if (!format) {
        MF_ERROR(Journal::Component::Portal, Journal::Context::ImageProcessing,
            "download_image: image is not readable as a single-layer 2D base level");
        return std::nullopt;
    }
 
    const size_t byte_count = calculate_image_size(image->get_width(), image->get_height(), 1, *format);
 
    auto result = Kakshya::ImageData::allocate(
        image->get_width(), image->get_height(), get_channel_count(*format), *format);
    if (!result || result->byte_size() != byte_count) {
        MF_ERROR(Journal::Component::Portal, Journal::Context::ImageProcessing,
            "download_image: format {} has no typed pixel storage matching its size", static_cast<int>(*format));
        return std::nullopt;
    }
 
    download_data(image, result->data(), byte_count, staging, false, restore_layout, restore_stage);
 
    if (!result->is_consistent()) {
        MF_ERROR(Journal::Component::Portal, Journal::Context::ImageProcessing,
            "download_image: downloaded pixels do not match format {}", static_cast<int>(*format));
        return std::nullopt;
    }
 
    return result;
}

References MayaFlux::Kakshya::ImageData::allocate(), calculate_image_size(), download_data(), format, get_channel_count(), image, MayaFlux::Journal::ImageProcessing, is_initialized(), MF_ERROR, MayaFlux::Journal::Portal, and readable_format().

Referenced by MayaFlux::IO::download_image().

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