void Image::recordLayoutTransitionBarrier()

in RenderScriptMigrationSample/app/src/main/cpp/VulkanResources.cpp [318:372]
52 lines of code
13 McCabe index (conditional complexity)

void Image::recordLayoutTransitionBarrier(VkCommandBuffer cmd, VkImageLayout newLayout,
                                          bool preserveData) {
    if (newLayout == mLayout) return;
    if (!preserveData) mLayout = VK_IMAGE_LAYOUT_UNDEFINED;

    const auto getAccessMask = [](VkImageLayout layout) -> VkAccessFlags {
        switch (layout) {
            case VK_IMAGE_LAYOUT_UNDEFINED:
                return 0;
            case VK_IMAGE_LAYOUT_GENERAL:
                // In this sample app, we only use GENERAL layout for output storage images.
                return VK_ACCESS_SHADER_WRITE_BIT;
            case VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL:
                return VK_ACCESS_TRANSFER_READ_BIT;
            case VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL:
                return VK_ACCESS_TRANSFER_WRITE_BIT;
            case VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL:
                return VK_ACCESS_SHADER_READ_BIT;
            default:
                LOGE("Undefined access mask for target image layout");
                return 0;
        }
    };
    const auto getStageFlag = [](VkImageLayout layout) -> VkPipelineStageFlags {
        switch (layout) {
            case VK_IMAGE_LAYOUT_UNDEFINED:
                return VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT;
            case VK_IMAGE_LAYOUT_GENERAL:
            case VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL:
                return VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT;
            case VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL:
            case VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL:
                return VK_PIPELINE_STAGE_TRANSFER_BIT;
            default:
                LOGE("Undefined stage flag for target image layout");
                return 0;
        }
    };

    const VkImageMemoryBarrier barrier = {
            .sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER,
            .pNext = nullptr,
            .srcAccessMask = getAccessMask(mLayout),
            .dstAccessMask = getAccessMask(newLayout),
            .oldLayout = mLayout,
            .newLayout = newLayout,
            .srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
            .dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
            .image = mImage.handle(),
            .subresourceRange = {VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1},
    };
    vkCmdPipelineBarrier(cmd, getStageFlag(mLayout), getStageFlag(newLayout), 0, 0, nullptr, 0,
                         nullptr, 1, &barrier);
    mLayout = newLayout;
}