Vulkan Extensions

Vulkan Extensions

The Vulkan extension VK_EXT_image_compression_control may be used to verify if default compression (such as AFBC) was applied, and to request fixed-rate compression.

Swapchain images are a special case, and additionally require the VK_EXT_image_compression_control_swapchain extension.

Enable VK_EXT_image_compression_control

In your application, you may use vkEnumerateDeviceExtensionProperties to check if the device supports the extension, and, if so, include it in VkDeviceCreateInfo ’s ppEnabledExtensionNames before calling vkCreateDevice . In the Vulkan Samples framework, this can be handled in the sample’s constructor with this helper function:

    

        
        
            afrc::afrc()
{
	add_device_extension(VK_EXT_IMAGE_COMPRESSION_CONTROL_EXTENSION_NAME);
}
        
    

If a device supports the extension, it does not mean that it also supports fixed-rate compression of images. The extension may still be used to verify if the images use default (lossless) compression.

Before compressing a VkImage, you need to use the extension to query if any given image, with its particular format and usage properties, supports fixed-rate compression, as shown in the next step.