170 lines
5.2 KiB
Plaintext
170 lines
5.2 KiB
Plaintext
// Copyright (c) 2016-2019 Khronos Group. This work is licensed under a
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// Creative Commons Attribution 4.0 International License; see
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// http://creativecommons.org/licenses/by/4.0/
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include::meta/VK_KHR_dedicated_allocation.txt[]
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*Last Modified Date*::
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2017-09-05
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*IP Status*::
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No known IP claims.
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*Interactions and External Dependencies*::
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- Promoted to Vulkan 1.1 Core
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*Contributors*::
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- Jeff Bolz, NVIDIA
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- Jason Ekstrand, Intel
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This extension enables resources to be bound to a dedicated allocation,
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rather than suballocated.
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For any particular resource, applications can: query whether a dedicated
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allocation is recommended, in which case using a dedicated allocation may:
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improve the performance of access to that resource.
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Normal device memory allocations must support multiple resources per
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allocation, memory aliasing and sparse binding, which could interfere with
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some optimizations.
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Applications should query the implementation for when a dedicated allocation
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may: be beneficial by adding sname:VkMemoryDedicatedRequirementsKHR to the
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pname:pNext chain of the sname:VkMemoryRequirements2 structure passed as the
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pname:pMemoryRequirements parameter to a call to
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fname:vkGetBufferMemoryRequirements2 or fname:vkGetImageMemoryRequirements2.
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Certain external handle types and external images or buffers may: also
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depend on dedicated allocations on implementations that associate image or
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buffer metadata with OS-level memory objects.
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This extension adds a two small structures to memory requirements querying
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and memory allocation: a new structure that flags whether an image/buffer
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should have a dedicated allocation, and a structure indicating the image or
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buffer that an allocation will be bound to.
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=== New Object Types
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None.
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=== New Enum Constants
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* Extending elink:VkStructureType:
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** ename:VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS_KHR
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** ename:VK_STRUCTURE_TYPE_MEMORY_DEDICATED_ALLOCATE_INFO_KHR
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=== New Enums
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None.
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=== New Structures
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* slink:VkMemoryDedicatedRequirementsKHR
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* slink:VkMemoryDedicatedAllocateInfoKHR
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=== New Functions
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None.
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=== Promotion to Vulkan 1.1
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All functionality in this extension is included in core Vulkan 1.1, with the
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KHR suffix omitted.
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The original type, enum and command names are still available as aliases of
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the core functionality.
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=== Issues
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None.
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=== Examples
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[source,c++]
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--------------------------------------
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// Create an image with a dedicated allocation based on the
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// implementation's preference
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VkImageCreateInfo imageCreateInfo =
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{
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// Image creation parameters
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};
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VkImage image;
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VkResult result = vkCreateImage(
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device,
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&imageCreateInfo,
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NULL, // pAllocator
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&image);
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VkMemoryDedicatedRequirementsKHR dedicatedRequirements =
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{
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VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS_KHR,
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NULL, // pNext
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};
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VkMemoryRequirements2 memoryRequirements =
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{
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VK_STRUCTURE_TYPE_MEMORY_REQUIREMENTS_2,
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&dedicatedRequirements, // pNext
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};
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const VkImageMemoryRequirementsInfo2 imageRequirementsInfo =
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{
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VK_STRUCTURE_TYPE_IMAGE_MEMORY_REQUIREMENTS_INFO_2,
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NULL, // pNext
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image
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};
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vkGetImageMemoryRequirements2(
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device,
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&imageRequirementsInfo,
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&memoryRequirements);
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if (dedicatedRequirements.prefersDedicatedAllocation) {
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// Allocate memory with VkMemoryDedicatedAllocateInfoKHR::image
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// pointing to the image we are allocating the memory for
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VkMemoryDedicatedAllocateInfoKHR dedicatedInfo =
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{
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VK_STRUCTURE_TYPE_MEMORY_DEDICATED_ALLOCATE_INFO_KHR, // sType
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NULL, // pNext
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image, // image
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VK_NULL_HANDLE, // buffer
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};
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VkMemoryAllocateInfo memoryAllocateInfo =
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{
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VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO, // sType
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&dedicatedInfo, // pNext
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memoryRequirements.size, // allocationSize
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FindMemoryTypeIndex(memoryRequirements.memoryTypeBits), // memoryTypeIndex
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};
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VkDeviceMemory memory;
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vkAllocateMemory(
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device,
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&memoryAllocateInfo,
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NULL, // pAllocator
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&memory);
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// Bind the image to the memory
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vkBindImageMemory(
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device,
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image,
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memory,
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0);
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} else {
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// Take the normal memory sub-allocation path
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}
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--------------------------------------
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=== Version History
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* Revision 1, 2017-02-27 (James Jones)
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- Copy content from VK_NV_dedicated_allocation
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- Add some references to external object interactions to the overview.
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* Revision 2, 2017-03-27 (Jason Ekstrand)
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- Rework the extension to be query-based
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* Revision 3, 2017-07-31 (Jason Ekstrand)
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- Clarify that memory objects created with
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VkMemoryDedicatedAllocateInfoKHR can only have the specified resource
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bound and no others.
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