Initialising the Swapchain Images

The swapchain images are created alongside the swapchain, but the application must create a corresponding set of image views before using them.

An image view is a view into a specified part of an image. An image view stores the following information:

• A handle to the image.

• The view type (for example, 2D, 3D, or cubemap).

• The image format.

• Any remapping of an image’s colour components.

• The purpose of the image (colour, depth, stencil, and so on).

• The number of mipmap levels and layers.

In the example code, initImagesAndViews(), the application only uses 2D colour render targets, no remapping of components, no mipmapping, and only a single layer. View in context.

void VulkanHelloAPI::initImagesAndViews()
{
    // This vector is used as a temporary vector to hold the retrieved images.
    uint32_t swapchainImageCount;
    std::vector<VkImage> images;

    // Get the number of the images which are held by the swapchain. This is set in InitSwapchain function and is the minimum number of images supported.
    debugAssertFunctionResult(vk::GetSwapchainImagesKHR(appManager.device, appManager.swapchain, &swapchainImageCount, nullptr), "SwapChain Images - Get Count");

    // Resize the temporary images vector to hold the number of images.
    images.resize(swapchainImageCount);

    // Resize the application's permanent swapchain images vector to be able to hold the number of images.
    appManager.swapChainImages.resize(swapchainImageCount);

    // Get all of the images from the swapchain and save them in a temporary vector.
    debugAssertFunctionResult(vk::GetSwapchainImagesKHR(appManager.device, appManager.swapchain, &swapchainImageCount, images.data()), "SwapChain Images - Allocate Data");

    // Iterate over each image in order to create an image view for each one.
    for (uint32_t i = 0; i < swapchainImageCount; ++i)
    {
        // Copy over the images to the permenant vector.
        appManager.swapChainImages[i].image = images[i];

        // Create the image view object itself, referencing one of the retrieved swapchain images.
        VkImageViewCreateInfo image_view_info = {};
        image_view_info.sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO;
        image_view_info.pNext = nullptr;
        image_view_info.flags = 0;
        image_view_info.image = appManager.swapChainImages[i].image;
        image_view_info.viewType = VK_IMAGE_VIEW_TYPE_2D;
        image_view_info.format = appManager.surfaceFormat.format;

        image_view_info.components.r = VK_COMPONENT_SWIZZLE_R;
        image_view_info.components.g = VK_COMPONENT_SWIZZLE_G;
        image_view_info.components.b = VK_COMPONENT_SWIZZLE_B;
        image_view_info.components.a = VK_COMPONENT_SWIZZLE_A;

        image_view_info.subresourceRange.layerCount = 1;
        image_view_info.subresourceRange.levelCount = 1;
        image_view_info.subresourceRange.baseArrayLayer = 0;
        image_view_info.subresourceRange.baseMipLevel = 0;
        image_view_info.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;

       debugAssertFunctionResult(vk::CreateImageView(appManager.device, &image_view_info, nullptr, &appManager.swapChainImages[i].view), "SwapChain Images View Creation");
    }
}