Method clearScreen

src/library/screencapture/ScreenCapture_Vulkan.cpp:614–685

}

void ScreenCapture_Vulkan::clearScreen()
{
    GlobalNative gn;

    if (vk::context.swapchainRebuild) return;
    
    /* A bit hackish code: we must only acquire a new image if redrawing. For 
     * the first draw of the current frame, we are clearing the current image,
     * because it hasn't yet been presented. I'm checking which case based on 
     * the current semaphore that we should wait on */
    if (vk::context.currentSemaphore != vk::context.frameSemaphores[vk::context.semaphoreIndex].screenCompleteSemaphore)
        acquireImage();

    if (vk::context.swapchainRebuild) return;

    VkCommandBuffer cmdBuffer = vk::context.frames[vk::context.frameIndex].clearCommandBuffer;
    VkImage backbuffer = vk::context.frames[vk::context.frameIndex].backbuffer;

    beginCommand(cmdBuffer);

    /* Transition destination image to transfer destination layout */
    VkImageMemoryBarrier dstBarrier{};
    dstBarrier.sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
    dstBarrier.oldLayout = VK_IMAGE_LAYOUT_PRESENT_SRC_KHR;
    dstBarrier.newLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL;
    dstBarrier.srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
    dstBarrier.dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
    dstBarrier.image = backbuffer;
    dstBarrier.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
    dstBarrier.subresourceRange.baseMipLevel = 0;
    dstBarrier.subresourceRange.levelCount = 1;
    dstBarrier.subresourceRange.baseArrayLayer = 0;
    dstBarrier.subresourceRange.layerCount = 1;
    dstBarrier.srcAccessMask = 0;
    dstBarrier.dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
    
    orig::vkCmdPipelineBarrier(cmdBuffer,
        VK_PIPELINE_STAGE_TRANSFER_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT,
        0,
        0, nullptr,
        0, nullptr,
        1, &dstBarrier
    );

    VkClearColorValue clearColor = { 0.0f, 0.0f, 0.0f, 0.0f };
    VkClearValue clearValue = {};
    clearValue.color = clearColor;

    VkImageSubresourceRange imageRange = {};
    imageRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
    imageRange.levelCount = 1;
    imageRange.layerCount = 1;

    orig::vkCmdClearColorImage(cmdBuffer, backbuffer, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, &clearColor, 1, &imageRange);

    /* Transition destination image to general layout, which is the required layout for mapping the image memory later on */
    dstBarrier.sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
    dstBarrier.oldLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL;