Package org.lwjgl.vulkan

Class KHRDedicatedAllocation

java.lang.Object
org.lwjgl.vulkan.KHRDedicatedAllocation
public final class KHRDedicatedAllocation extends Object
This extension enables resources to be bound to a dedicated allocation, rather than suballocated. For any particular resource, applications can query whether a dedicated allocation is recommended, in which case using a dedicated allocation may improve the performance of access to that resource. Normal device memory allocations must support multiple resources per allocation, memory aliasing and sparse binding, which could interfere with some optimizations. Applications should query the implementation for when a dedicated allocation may be beneficial by adding a VkMemoryDedicatedRequirementsKHR structure to the pNext chain of the VkMemoryRequirements2 structure passed as the pMemoryRequirements parameter of a call to vkGetBufferMemoryRequirements2 or vkGetImageMemoryRequirements2. Certain external handle types and external images or buffers may also depend on dedicated allocations on implementations that associate image or buffer metadata with OS-level memory objects.

This extension adds a two small structures to memory requirements querying and memory allocation: a new structure that flags whether an image/buffer should have a dedicated allocation, and a structure indicating the image or buffer that an allocation will be bound to.

Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum, and command names are still available as aliases of the core functionality.

Examples

     // Create an image with a dedicated allocation based on the
     // implementation's preference
 
     VkImageCreateInfo imageCreateInfo =
     {
         // Image creation parameters
     };
 
     VkImage image;
     VkResult result = vkCreateImage(
         device,
         &imageCreateInfo,
         NULL,               // pAllocator
         &image);
 
     VkMemoryDedicatedRequirementsKHR dedicatedRequirements =
     {
         .sType = VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS_KHR,
         .pNext = NULL,
     };
 
     VkMemoryRequirements2 memoryRequirements =
     {
         .sType = VK_STRUCTURE_TYPE_MEMORY_REQUIREMENTS_2,
         .pNext = &dedicatedRequirements,
     };
 
     const VkImageMemoryRequirementsInfo2 imageRequirementsInfo =
     {
         .sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_REQUIREMENTS_INFO_2,
         .pNext = NULL,
         .image = image
     };
 
     vkGetImageMemoryRequirements2(
         device,
         &imageRequirementsInfo,
         &memoryRequirements);
 
     if (dedicatedRequirements.prefersDedicatedAllocation) {
         // Allocate memory with VkMemoryDedicatedAllocateInfoKHR::image
         // pointing to the image we are allocating the memory for
 
         VkMemoryDedicatedAllocateInfoKHR dedicatedInfo =
         {
             .sType = VK_STRUCTURE_TYPE_MEMORY_DEDICATED_ALLOCATE_INFO_KHR,
             .pNext = NULL,
             .image = image,
             .buffer = VK_NULL_HANDLE,
         };
 
         VkMemoryAllocateInfo memoryAllocateInfo =
         {
             .sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO,
             .pNext = &dedicatedInfo,
             .allocationSize = memoryRequirements.size,
             .memoryTypeIndex = FindMemoryTypeIndex(memoryRequirements.memoryTypeBits),
         };
 
         VkDeviceMemory memory;
         vkAllocateMemory(
             device,
             &memoryAllocateInfo,
             NULL,               // pAllocator
             &memory);
 
         // Bind the image to the memory
 
         vkBindImageMemory(
             device,
             image,
             memory,
             0);
     } else {
         // Take the normal memory sub-allocation path
     }
Name String
VK_KHR_dedicated_allocation
Extension Type
Device extension
Registered Extension Number
128
Revision
3
Extension and Version Dependencies
VK_KHR_get_memory_requirements2 or Version 1.1
Deprecation State
Contact
Other Extension Metadata
Last Modified Date
2017-09-05
IP Status
No known IP claims.
Contributors
  • Jeff Bolz, NVIDIA
  • Faith Ekstrand, Intel