Enum vma::MemoryUsage

pub enum MemoryUsage {
    Unknown,
    GpuOnly,
    CpuOnly,
    CpuToGpu,
    GpuToCpu,
    CpuCopy,
    GpuLazy,
    Auto,
    AutoPreferDevice,
    AutoPreferHost,
}

Intended usage of memory.

Variants

Unknown

No intended memory usage specified. Use other members of AllocationCreateInfo to specify your requirements.

GpuOnly

👎Deprecated since 0.3

Memory will be used on device only, so fast access from the device is preferred. It usually means device-local GPU (video) memory. No need to be mappable on host. It is roughly equivalent of D3D12_HEAP_TYPE_DEFAULT.

Usage:

• Resources written and read by device, e.g. images used as attachments.
• Resources transferred from host once (immutable) or infrequently and read by device multiple times, e.g. textures to be sampled, vertex buffers, uniform (constant) buffers, and majority of other types of resources used on GPU.

Allocation may still end up in ash::vk::MemoryPropertyFlags::HOST_VISIBLE memory on some implementations. In such case, you are free to map it. You can use AllocationCreateFlags::MAPPED with this usage type.

CpuOnly

👎Deprecated since 0.3

Memory will be mappable on host. It usually means CPU (system) memory. Guarantees to be ash::vk::MemoryPropertyFlags::HOST_VISIBLE and ash::vk::MemoryPropertyFlags::HOST_COHERENT. CPU access is typically uncached. Writes may be write-combined. Resources created in this pool may still be accessible to the device, but access to them can be slow. It is roughly equivalent of D3D12_HEAP_TYPE_UPLOAD.

Usage: Staging copy of resources used as transfer source.

CpuToGpu

👎Deprecated since 0.3

Memory that is both mappable on host (guarantees to be ash::vk::MemoryPropertyFlags::HOST_VISIBLE) and preferably fast to access by GPU. CPU access is typically uncached. Writes may be write-combined.

Usage: Resources written frequently by host (dynamic), read by device. E.g. textures, vertex buffers, uniform buffers updated every frame or every draw call.

GpuToCpu

👎Deprecated since 0.3

Memory mappable on host (guarantees to be ash::vk::MemoryPropertFlags::HOST_VISIBLE) and cached. It is roughly equivalent of D3D12_HEAP_TYPE_READBACK.

Usage:

• Resources written by device, read by host - results of some computations, e.g. screen capture, average scene luminance for HDR tone mapping.
• Any resources read or accessed randomly on host, e.g. CPU-side copy of vertex buffer used as source of transfer, but also used for collision detection.

CpuCopy

👎Deprecated since 0.3

Prefers not VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT.

GpuLazy

Lazily allocated GPU memory having (guarantees to be ash::vk::MemoryPropertFlags::LAZILY_ALLOCATED). Exists mostly on mobile platforms. Using it on desktop PC or other GPUs with no such memory type present will fail the allocation.

Usage:

• Memory for transient attachment images (color attachments, depth attachments etc.), created with VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT. Allocations with this usage are always created as dedicated - it implies #VMA_ALLOCATION_CREATE_DEDICATED_MEMORY_BIT.

Auto

Selects best memory type automatically. This flag is recommended for most common use cases.

When using this flag, if you want to map the allocation (using vmaMapMemory() or #VMA_ALLOCATION_CREATE_MAPPED_BIT), you must pass one of the flags: #VMA_ALLOCATION_CREATE_HOST_ACCESS_SEQUENTIAL_WRITE_BIT or #VMA_ALLOCATION_CREATE_HOST_ACCESS_RANDOM_BIT in VmaAllocationCreateInfo::flags.

It can be used only with functions that let the library know VkBufferCreateInfo or VkImageCreateInfo, e.g. vmaCreateBuffer(), vmaCreateImage(), vmaFindMemoryTypeIndexForBufferInfo(), vmaFindMemoryTypeIndexForImageInfo() and not with generic memory allocation functions.

AutoPreferDevice

Selects best memory type automatically with preference for GPU (device) memory.

When using this flag, if you want to map the allocation (using vmaMapMemory() or #VMA_ALLOCATION_CREATE_MAPPED_BIT), you must pass one of the flags: #VMA_ALLOCATION_CREATE_HOST_ACCESS_SEQUENTIAL_WRITE_BIT or #VMA_ALLOCATION_CREATE_HOST_ACCESS_RANDOM_BIT in VmaAllocationCreateInfo::flags.

It can be used only with functions that let the library know VkBufferCreateInfo or VkImageCreateInfo, e.g. vmaCreateBuffer(), vmaCreateImage(), vmaFindMemoryTypeIndexForBufferInfo(), vmaFindMemoryTypeIndexForImageInfo() and not with generic memory allocation functions.

AutoPreferHost

Selects best memory type automatically with preference for CPU (host) memory.

When using this flag, if you want to map the allocation (using vmaMapMemory() or #VMA_ALLOCATION_CREATE_MAPPED_BIT), you must pass one of the flags: #VMA_ALLOCATION_CREATE_HOST_ACCESS_SEQUENTIAL_WRITE_BIT or #VMA_ALLOCATION_CREATE_HOST_ACCESS_RANDOM_BIT in VmaAllocationCreateInfo::flags.

It can be used only with functions that let the library know VkBufferCreateInfo or VkImageCreateInfo, e.g. vmaCreateBuffer(), vmaCreateImage(), vmaFindMemoryTypeIndexForBufferInfo(), vmaFindMemoryTypeIndexForImageInfo() and not with generic memory allocation functions.

Trait Implementations

impl Clone for MemoryUsage

fn clone(&self) -> MemoryUsage

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for MemoryUsage

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for MemoryUsage

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for MemoryUsage

fn cmp(&self, other: &MemoryUsage) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Selfwhere Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval.

impl PartialEq<MemoryUsage> for MemoryUsage

fn eq(&self, other: &MemoryUsage) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd<MemoryUsage> for MemoryUsage

fn partial_cmp(&self, other: &MemoryUsage) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for MemoryUsage

impl Eq for MemoryUsage

impl StructuralEq for MemoryUsage

impl StructuralPartialEq for MemoryUsage