message: Added comment on oldSwapChain
diff: *
  * A swap chain is a collection of framebuffers used for rendering and presentation to the windowing system
  *
  -* Copyright (C) 2016-2017 by Sascha Willems - www.saschawillems.de
  +* Copyright (C) 2016-2021 by Sascha Willems - www.saschawillems.de
  *
  * This code is licensed under the MIT license (MIT) (http://opensource.org/licenses/MIT)
  */
  @@ -223,6 +223,7 @@ void VulkanSwapChain::connect(VkInstance instance, VkPhysicalDevice physicalDevi
  */
  void VulkanSwapChain::create(uint32_t *width, uint32_t *height, bool vsync)
  {
  + // Store the current swap chain handle so we can use it later on to ease up recreation
  VkSwapchainKHR oldSwapchain = swapChain;
  // Get physical device surface properties and formats
  @@ -316,7 +317,6 @@ void VulkanSwapChain::create(uint32_t *width, uint32_t *height, bool vsync)
  VkSwapchainCreateInfoKHR swapchainCI = {};
  swapchainCI.sType = VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR;
  - swapchainCI.pNext = NULL;
  swapchainCI.surface = surface;
  swapchainCI.minImageCount = desiredNumberOfSwapchainImages;
  swapchainCI.imageFormat = colorFormat;
  @@ -327,8 +327,8 @@ void VulkanSwapChain::create(uint32_t *width, uint32_t *height, bool vsync)
  swapchainCI.imageArrayLayers = 1;
  swapchainCI.imageSharingMode = VK_SHARING_MODE_EXCLUSIVE;
  swapchainCI.queueFamilyIndexCount = 0;
  - swapchainCI.pQueueFamilyIndices = NULL;
  swapchainCI.presentMode = swapchainPresentMode;
  + // Setting oldSwapChain to the saved handle of the previous swapchain aids in resource reuse and makes sure that we can still present already acquired images
  swapchainCI.oldSwapchain = oldSwapchain;
  // Setting clipped to VK_TRUE allows the implementation to discard rendering outside of the surface area
  swapchainCI.clipped = VK_TRUE;
  