- Last Modified Date
-
2016-05-31
- IP Status
-
No known IP claims.
- Contributors
-
-
Jeff Bolz, NVIDIA
-
This extension allows device memory to be allocated for a particular buffer or image resource, which on some devices can significantly improve the performance of that resource. Normal device memory allocations must support memory aliasing and sparse binding, which could interfere with optimizations like framebuffer compression or efficient page table usage. This is important for render targets and very large resources, but need not (and probably should not) be used for smaller resources that can benefit from suballocation.
This extension adds a few small structures to resource creation and memory allocation: a new structure that flags whether am image/buffer will have a dedicated allocation, and a structure indicating the image or buffer that an allocation will be bound to.
// Create an image with
// VkDedicatedAllocationImageCreateInfoNV::dedicatedAllocation
// set to VK_TRUE
VkDedicatedAllocationImageCreateInfoNV dedicatedImageInfo =
{
.sType = VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_IMAGE_CREATE_INFO_NV,
.pNext = NULL,
.dedicatedAllocation = VK_TRUE,
};
VkImageCreateInfo imageCreateInfo =
{
.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO,
.pNext = &dedicatedImageInfo
// Other members set as usual
};
VkImage image;
VkResult result = vkCreateImage(
device,
&imageCreateInfo,
NULL, // pAllocator
&image);
VkMemoryRequirements memoryRequirements;
vkGetImageMemoryRequirements(
device,
image,
&memoryRequirements);
// Allocate memory with VkDedicatedAllocationMemoryAllocateInfoNV::image
// pointing to the image we are allocating the memory for
VkDedicatedAllocationMemoryAllocateInfoNV dedicatedInfo =
{
.sType = VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_MEMORY_ALLOCATE_INFO_NV,
.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);