Vulkan-Docs/doc/specs/vulkan/appendices/glossary.txt

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// Copyright (c) 2015-2017 Khronos Group. This work is licensed under a
// Creative Commons Attribution 4.0 International License; see
// http://creativecommons.org/licenses/by/4.0/
// The asciidoc [glossary] template cannot contain subsections.
// The abbreviations and prefixes probably belong in the upcoming
// API/extension-writing-guidelines appendix, anyway.
[glossary]
= Glossary
The terms defined in this section are used consistently throughout this
Specification and may be used with or without capitalization.
Accessible (Descriptor Binding)::
A descriptor binding is accessible to a shader stage if that stage is
included in the pname:stageFlags of the descriptor binding.
Descriptors using that binding can: only be used by stages in which they
are accessible.
Acquire Operation (Resource)::
An operation that acquires ownership of an image subresource or buffer
range.
Adjacent Vertex::
A vertex in an adjacency primitive topology that is not part of a given
primitive, but is accessible in geometry shaders.
ifdef::VK_EXT_blend_operation_advanced[]
Advanced Blend Operation::
Blending performed using one of the blend operation enums introduced by
the +VK_EXT_blend_operation_advanced+ extension.
See <<framebuffer-blend-advanced, Advanced Blending Operations>>.
endif::VK_EXT_blend_operation_advanced[]
Aliased Range (Memory)::
A range of a device memory allocation that is bound to multiple
resources simultaneously.
Allocation Scope::
An association of a host memory allocation to a parent object or
command, where the allocation's lifetime ends before or at the same time
as the parent object is freed or destroyed, or during the parent
command.
API Order::
A set of ordering rules that govern how primitives in draw commands
affect the framebuffer.
Aspect (Image)::
An image may: contain multiple kinds, or aspects, of data for each
pixel, where each aspect is used in a particular way by the pipeline and
may: be stored differently or separately from other aspects.
For example, the color components of an image format make up the color
aspect of the image, and may: be used as a framebuffer color attachment.
Some operations, like depth testing, operate only on specific aspects of
an image.
Others operations, like image/buffer copies, only operate on one aspect
at a time.
Attachment (Render Pass)::
A zero-based integer index name used in render pass creation to refer to
a framebuffer attachment that is accessed by one or more subpasses.
The index also refers to an attachment description which includes
information about the properties of the image view that will later be
attached.
Availability Operation::
An operation that causes the values generated by specified memory write
accesses to become available for future access.
Available::
A state of values written to memory that allows them to be made visible.
Back-Facing::
See Facingness.
Batch::
A single structure submitted to a queue as part of a
<<devsandqueues-submission, queue submission command>>, describing a set
of queue operations to execute.
Backwards Compatibility::
A given version of the API is backwards compatible with an earlier
version if an application, relying only on valid behavior and
functionality defined by the earlier specification, is able to correctly
run against each version without any modification.
This assumes no active attempt by that application to not run when it
detects a different version.
Full Compatibility::
A given version of the API is fully compatible with another version if
an application, relying only on valid behavior and functionality defined
by either of those specifications, is able to correctly run against each
version without any modification.
This assumes no active attempt by that application to not run when it
detects a different version.
Binding (Memory)::
An association established between a range of a resource object and a
range of a memory object.
These associations determine the memory locations affected by operations
performed on elements of a resource object.
Memory bindings are established using the flink:vkBindBufferMemory
command for non-sparse buffer objects, using the flink:vkBindImageMemory
command for non-sparse image objects, and using the
flink:vkQueueBindSparse command for sparse resources.
Blend Constant::
Four floating point (RGBA) values used as an input to blending.
Blending::
Arithmetic operations between a fragment color value and a value in a
color attachment that produce a final color value to be written to the
attachment.
Buffer::
A resource that represents a linear array of data in device memory.
Represented by a slink:VkBuffer object.
Buffer View::
An object that represents a range of a specific buffer, and state that
controls how the contents are interpreted.
Represented by a slink:VkBufferView object.
Built-In Variable::
A variable decorated in a shader, where the decoration makes the
variable take values provided by the execution environment or values
that are generated by fixed-function pipeline stages.
Built-In Interface Block::
A block defined in a shader that contains only variables decorated with
built-in decorations, and is used to match against other shader stages.
Clip Coordinates::
The homogeneous coordinate space that vertex positions (code:Position
decoration) are written in by vertex processing stages.
Clip Distance::
A built-in output from vertex processing stages that defines a clip
half-space against which the primitive is clipped.
Clip Volume::
The intersection of the view volume with all clip half-spaces.
Color Attachment::
A subpass attachment point, or image view, that is the target of
fragment color outputs and blending.
ifdef::VK_AMD_shader_fragment_mask[]
Color Fragment::
A unique color value within a pixel of a multisampled color image.
The _fragment mask_ will contain indices to the _color fragment_.
endif::VK_AMD_shader_fragment_mask[]
Color Renderable Format::
A elink:VkFormat where ename:VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT is
set in the pname:optimalTilingFeatures or pname:linearTilingFeatures
field of VkFormatProperties::optimalTilingFeatures returned by
flink:vkGetPhysicalDeviceFormatProperties, depending on the tiling used.
Color Sample Mask::
A bitfield associated with a fragment, with one bit for each sample in
the color attachment(s).
Samples are considered to be covered based on the result of the Coverage
Reduction stage.
Uncovered samples do not write to color attachments.
Combined Image Sampler::
A descriptor type that includes both a sampled image and a sampler.
Command Buffer::
An object that records commands to be submitted to a queue.
Represented by a slink:VkCommandBuffer object.
Command Pool::
An object that command buffer memory is allocated from, and that owns
that memory.
Command pools aid multithreaded performance by enabling different
threads to use different allocators, without internal synchronization on
each use.
Represented by a slink:VkCommandPool object.
Compatible Allocator::
When allocators are compatible, allocations from each allocator can: be
freed by the other allocator.
Compatible Image Formats::
When formats are compatible, images created with one of the formats can:
have image views created from it using any of the compatible formats.
Compatible Queues::
Queues within a queue family.
Compatible queues have identical properties.
Component (Format)::
A distinct part of a format.
Depth, stencil, and color channels (e.g. R, G, B, A), are all separate
components.
Compressed Texel Block::
An element of an image having a block-compressed format, comprising a
rectangular block of texel values that are encoded as a single value in
memory.
Compressed texel blocks of a particular block-compressed format have a
corresponding width, height, and depth that define the dimensions of
these elements in units of texels, and a size in bytes of the encoding
in memory.
Coverage::
A bitfield associated with a fragment, where each bit is associated to a
rasterization sample.
Samples are initially considered to be covered based on the result of
rasterization, and then coverage can subsequently be turned on or off by
other fragment operations or the fragment shader.
Uncovered samples do not write to framebuffer attachments.
Cull Distance::
A built-in output from vertex processing stages that defines a cull
half-space where the primitive is rejected if all vertices have a
negative value for the same cull distance.
Cull Volume::
The intersection of the view volume with all cull half-spaces.
Decoration (SPIR-V)::
Auxiliary information such as built-in variables, stream numbers,
invariance, interpolation type, relaxed precision, etc., added to
variables or structure-type members through decorations.
Depth/Stencil Attachment::
A subpass attachment point, or image view, that is the target of depth
and/or stencil test operations and writes.
Depth/Stencil Format::
A elink:VkFormat that includes depth and/or stencil components.
Depth/Stencil Image (or ImageView)::
A slink:VkImage (or slink:VkImageView) with a depth/stencil format.
Derivative Group::
A set of fragment shader invocations that cooperate to compute
derivatives, including implicit derivatives for sampled image
operations.
Descriptor::
Information about a resource or resource view written into a descriptor
set that is used to access the resource or view from a shader.
Descriptor Binding::
An entry in a descriptor set layout corresponding to zero or more
descriptors of a single descriptor type in a set.
Defined by a slink:VkDescriptorSetLayoutBinding structure.
Descriptor Pool::
An object that descriptor sets are allocated from, and that owns the
storage of those descriptor sets.
Descriptor pools aid multithreaded performance by enabling different
threads to use different allocators, without internal synchronization on
each use.
Represented by a slink:VkDescriptorPool object.
Descriptor Set::
An object that resource descriptors are written into via the API, and
that can: be bound to a command buffer such that the descriptors
contained within it can: be accessed from shaders.
Represented by a slink:VkDescriptorSet object.
Descriptor Set Layout::
An object that defines the set of resources (types and counts) and their
relative arrangement (in the binding namespace) within a descriptor set.
Used when allocating descriptor sets and when creating pipeline layouts.
Represented by a slink:VkDescriptorSetLayout object.
Device::
The processor(s) and execution environment that perform tasks requested
by the application via the Vulkan API.
ifdef::VK_KHX_device_group_creation[]
Device Group::
A set of physical devices that support accessing each other's memory and
recording a single command buffer that can: be executed on all the
physical devices.
Device Index::
A zero-based integer that identifies one physical device from a logical
device.
A device index is valid if it is less than the number of physical
devices in the logical device.
Device Mask::
A bitmask where each bit represents one device index.
A device mask value is valid if every bit that is set in the mask is at
a bit position that is less than the number of physical devices in the
logical device.
endif::VK_KHX_device_group_creation[]
Device Memory::
Memory accessible to the device.
Represented by a slink:VkDeviceMemory object.
Device-Level Object::
Logical device objects and their child objects For example,
slink:VkDevice, slink:VkQueue, and slink:VkCommandBuffer objects are
device-level objects.
Device-Local Memory::
Memory that is connected to the device, and may: be more performant for
device access than host-local memory.
Direct Drawing Commands::
_Drawing commands_ that take all their parameters as direct arguments to
the command (and not sourced via structures in buffer memory as the
_indirect drawing commands_).
Includes flink:vkCmdDraw, and flink:vkCmdDrawIndexed.
ifdef::VK_KHR_sampler_ycbcr_conversion[]
Disjoint::
_Disjoint planes_ are _image planes_ to which memory is bound
independently. +
A _disjoint image_ consists of multiple _disjoint planes_, and is
created with the ename:VK_IMAGE_CREATE_DISJOINT_BIT_KHR bit set.
endif::VK_KHR_sampler_ycbcr_conversion[]
Dispatchable Handle::
A handle of a pointer handle type which may: be used by layers as part
of intercepting API commands.
The first argument to each Vulkan command is a dispatchable handle type.
Dispatching Commands::
Commands that provoke work using a compute pipeline.
Includes flink:vkCmdDispatch and flink:vkCmdDispatchIndirect.
Drawing Commands::
Commands that provoke work using a graphics pipeline.
Includes flink:vkCmdDraw, flink:vkCmdDrawIndexed,
flink:vkCmdDrawIndirect,
ifdef::VK_AMD_draw_indirect_count[]
flink:vkCmdDrawIndirectCountAMD, flink:vkCmdDrawIndexedIndirectCountAMD,
endif::VK_AMD_draw_indirect_count[]
and flink:vkCmdDrawIndexedIndirect.
Duration (Command)::
The _duration_ of a Vulkan command refers to the interval between
calling the command and its return to the caller.
Dynamic Storage Buffer::
A storage buffer whose offset is specified each time the storage buffer
is bound to a command buffer via a descriptor set.
Dynamic Uniform Buffer::
A uniform buffer whose offset is specified each time the uniform buffer
is bound to a command buffer via a descriptor set.
Dynamically Uniform::
See _Dynamically Uniform_ in section 2.2 "`Terms`" of the
<<spirv-spec,Khronos SPIR-V Specification>>.
Element Size::
The size (in bytes) used to store one element of an uncompressed format
or the size (in bytes) used to store one block of a block-compressed
format.
Explicitly-Enabled Layer::
A layer enabled by the application by adding it to the enabled layer
list in flink:vkCreateInstance or flink:vkCreateDevice.
Event::
A synchronization primitive that is signaled when execution of previous
commands complete through a specified set of pipeline stages.
Events can be waited on by the device and polled by the host.
Represented by a slink:VkEvent object.
Executable State (Command Buffer)::
A command buffer that has ended recording commands and can: be executed.
See also Initial State and Recording State.
Execution Dependency::
A dependency that guarantees that certain pipeline stages' work for a
first set of commands has completed execution before certain pipeline
stages' work for a second set of commands begins execution.
This is accomplished via pipeline barriers, subpass dependencies,
events, or implicit ordering operations.
Execution Dependency Chain::
A sequence of execution dependencies that transitively act as a single
execution dependency.
ifdef::VK_KHR_sampler_ycbcr_conversion[]
Explicit chroma reconstruction::
An implementation of sampler Y'C~B~C~R~ conversion which reconstructs
reduced-resolution chroma samples to luma resolution and then separately
performs texture sample interpolation.
This is distinct from an implicit implementation, which incorporates
chroma sample reconstruction into texture sample interpolation.
endif::VK_KHR_sampler_ycbcr_conversion[]
Extension Scope::
The set of objects and commands that can: be affected by an extension.
Extensions are either device scope or instance scope.
ifdef::VK_KHR_external_memory_capabilities,VK_KHR_external_semaphore_capabilities,VK_KHR_external_fence_capabilities[]
External Handle::
A resource handle which has meaning outside of a specific Vulkan device
or its parent instance.
External handles may: be used to share resources between multiple Vulkan
devices in different instances, or between Vulkan and other APIs.
Some external handle types correspond to platform-defined handles, in
which case the resource may: outlive any particular Vulkan device or
instance and may: be transferred between processes, or otherwise
manipulated via functionality defined by the platform for that handle
type.
endif::VK_KHR_external_memory_capabilities,VK_KHR_external_semaphore_capabilities,VK_KHR_external_fence_capabilities[]
External synchronization::
A type of synchronization required: of the application, where parameters
defined to be externally synchronized must: not be used simultaneously
in multiple threads.
Facingness (Polygon)::
A classification of a polygon as either front-facing or back-facing,
depending on the orientation (winding order) of its vertices.
Facingness (Fragment)::
A fragment is either front-facing or back-facing, depending on the
primitive it was generated from.
If the primitive was a polygon (regardless of polygon mode), the
fragment inherits the facingness of the polygon.
All other fragments are front-facing.
Fence::
A synchronization primitive that is signaled when a set of batches or
sparse binding operations complete execution on a queue.
Fences can: be waited on by the host.
Represented by a slink:VkFence object.
Flat Shading::
A property of a vertex attribute that causes the value from a single
vertex (the provoking vertex) to be used for all vertices in a
primitive, and for interpolation of that attribute to return that single
value unaltered.
Fragment Input Attachment Interface::
A fragment shader entry point's variables with code:UniformConstant
storage class and a decoration of code:InputAttachmentIndex, which
receive values from input attachments.
ifdef::VK_AMD_shader_fragment_mask[]
Fragment Mask::
A lookup table that associates color samples with color fragment values.
endif::VK_AMD_shader_fragment_mask[]
Fragment Output Interface::
A fragment shader entry point's variables with code:Output storage
class, which output to color and/or depth/stencil attachments.
Framebuffer::
A collection of image views and a set of dimensions that, in conjunction
with a render pass, define the inputs and outputs used by drawing
commands.
Represented by a slink:VkFramebuffer object.
Framebuffer Attachment::
One of the image views used in a framebuffer.
Framebuffer Coordinates::
A coordinate system in which adjacent pixels' coordinates differ by 1 in
x and/or y, with [eq]#(0,0)# in the upper left corner and pixel centers
at half-integers.
Framebuffer-Space::
Operating with respect to framebuffer coordinates.
Framebuffer-Local::
A framebuffer-local dependency guarantees that only for a single
framebuffer region, the first set of operations happens-before the
second set of operations.
Framebuffer-Global::
A framebuffer-global dependency guarantees that for all framebuffer
regions, the first set of operations happens-before the second set of
operations.
Framebuffer Region::
A framebuffer region is a set of sample (x, y, layer, sample)
coordinates that is a subset of the entire framebuffer.
Front-Facing::
See Facingness.
Global Workgroup::
A collection of local workgroups dispatched by a single dispatch
command.
Handle::
An opaque integer or pointer value used to refer to a Vulkan object.
Each object type has a unique handle type.
Happen-after::
A transitive, irreflexive and antisymmetric ordering relation between
operations.
An execution dependency with a source of *A* and a destination of *B*
enforces that *B* happens-after *A*.
The inverse relation of happens-before.
Happen-before::
A transitive, irreflexive and antisymmetric ordering relation between
operations.
An execution dependency with a source of *A* and a destination of *B*
enforces that *A* happens-before *B*.
The inverse relation of happens-after.
Helper Invocation::
A fragment shader invocation that is created solely for the purposes of
evaluating derivatives for use in non-helper fragment shader
invocations, and which does not have side effects.
Host::
The processor(s) and execution environment that the application runs on,
and that the Vulkan API is exposed on.
ifdef::VK_EXT_external_memory_host[]
Host Mapped Foreign Memory::
Memory owned by a foreign device that is mapped for host access.
endif::VK_EXT_external_memory_host[]
Host Memory::
Memory not accessible to the device, used to store implementation data
structures.
Host-Accessible Subresource::
A buffer, or a linear image subresource in either the
ename:VK_IMAGE_LAYOUT_PREINITIALIZED or ename:VK_IMAGE_LAYOUT_GENERAL
layout.
Host-accessible subresources have a well-defined addressing scheme which
can be used by the host.
Host-Local Memory::
Memory that is not local to the device, and may: be less performant for
device access than device-local memory.
Host-Visible Memory::
Device memory that can: be mapped on the host and can: be read and
written by the host.
Identically Defined Objects::
Objects of the same type where all arguments to their creation or
allocation functions, with the exception of pname:pAllocator, are +
. Vulkan handles which refer to the same object or
. identical scalar or enumeration values or
. CPU pointers which point to an array of values or structures which
also satisfy these three constraints.
Image::
A resource that represents a multi-dimensional formatted interpretation
of device memory.
Represented by a slink:VkImage object.
Image Subresource::
A specific mipmap level and layer of an image.
Image Subresource Range::
A set of image subresources that are contiguous mipmap levels and
layers.
Image View::
An object that represents an image subresource range of a specific
image, and state that controls how the contents are interpreted.
Represented by a slink:VkImageView object.
Immutable Sampler::
A sampler descriptor provided at descriptor set layout creation time,
and that is used for that binding in all descriptor sets allocated from
the layout, and cannot be changed.
ifdef::VK_KHR_sampler_ycbcr_conversion[]
Implicit chroma reconstruction::
An implementation of sampler Y'C~B~C~R~ conversion which reconstructs
the reduced-resolution chroma samples directly at the sample point, as
part of the normal texture sampling operation.
This is distinct from an _explicit chroma reconstruction_
implementation, which reconstructs the reduced-resolution chroma samples
to the resolution of the luma samples, then filters the result as part
of texture sample interpolation.
endif::VK_KHR_sampler_ycbcr_conversion[]
Implicitly-Enabled Layer::
A layer enabled by a loader-defined mechanism outside the Vulkan API,
rather than explicitly by the application during instance or device
creation.
Index Buffer::
A buffer bound via flink:vkCmdBindIndexBuffer which is the source of
index values used to fetch vertex attributes for a
flink:vkCmdDrawIndexed or flink:vkCmdDrawIndexedIndirect command.
Indexed Drawing Commands::
_Drawing commands_ which use an _index buffer_ as the source of index
values used to fetch vertex attributes for a drawing command.
Includes flink:vkCmdDrawIndexed,
ifdef::VK_AMD_draw_indirect_count[]
flink:vkCmdDrawIndexedIndirectCountAMD,
endif::VK_AMD_draw_indirect_count[]
and flink:vkCmdDrawIndexedIndirect.
Indirect Commands::
Drawing or dispatching commands that source some of their parameters
from structures in buffer memory.
Includes flink:vkCmdDrawIndirect, flink:vkCmdDrawIndexedIndirect,
ifdef::VK_AMD_draw_indirect_count[]
flink:vkCmdDrawIndirectCountAMD, flink:vkCmdDrawIndexedIndirectCountAMD,
endif::VK_AMD_draw_indirect_count[]
and flink:vkCmdDispatchIndirect.
ifdef::VK_NVX_device_generated_commands[]
Indirect Commands Layout::
A definition of a sequence of commands, that are generated on the device
via flink:vkCmdProcessCommandsNVX.
Each sequence is comprised of multiple
elink:VkIndirectCommandsTokenTypeNVX, which represent a subset of
traditional command buffer commands.
Represented as slink:VkIndirectCommandsLayoutNVX.
endif::VK_NVX_device_generated_commands[]
Indirect Drawing Commands::
_Drawing commands_ that source some of their parameters from structures
in buffer memory.
Includes flink:vkCmdDrawIndirect,
ifdef::VK_AMD_draw_indirect_count[]
flink:vkCmdDrawIndirectCountAMD, flink:vkCmdDrawIndexedIndirectCountAMD,
endif::VK_AMD_draw_indirect_count[]
and flink:vkCmdDrawIndexedIndirect.
Initial State (Command Buffer)::
A command buffer that has not begun recording commands.
See also Recorded State and Executable State.
Input Attachment::
A descriptor type that represents an image view, and supports unfiltered
read-only access in a shader, only at the fragment's location in the
view.
Instance::
The top-level Vulkan object, which represents the application's
connection to the implementation.
Represented by a slink:VkInstance object.
Instance-Level Object::
High-level Vulkan objects, which are not logical devices, nor children
of logical devices.
For example, slink:VkInstance and slink:VkPhysicalDevice objects are
instance-level objects.
ifdef::VK_KHX_device_group[]
Instance (Memory)::
In a logical device representing more than one physical device, some
device memory allocations have the requested amount of memory allocated
multiple times, once for each physical device in a device mask.
Each such replicated allocation is an instance of the device memory.
Instance (Resource)::
In a logical device representing more than one physical device, buffer
and image resources exist on all physical devices but can: be bound to
memory differently on each.
Each such replicated resource is an instance of the resource.
endif::VK_KHX_device_group[]
Internal Synchronization::
A type of synchronization required: of the implementation, where
parameters not defined to be externally synchronized may: require
internal mutexing to avoid multithreaded race conditions.
Invocation (Shader)::
A single execution of an entry point in a SPIR-V module.
For example, a single vertex's execution of a vertex shader or a single
fragment's execution of a fragment shader.
Invocation Group::
A set of shader invocations that are executed in parallel and that must:
execute the same control flow path in order for control flow to be
considered dynamically uniform.
[[glossary-linear-resource]]
Linear Resource::
A resource is _linear_ if it is a slink:VkBuffer, or a slink:VkImage
created with ename:VK_IMAGE_TILING_LINEAR.
A resource is _non-linear_ if it is a slink:VkImage created with
ename:VK_IMAGE_TILING_OPTIMAL.
Local Workgroup::
A collection of compute shader invocations invoked by a single dispatch
command, which share shared memory and can synchronize with each other.
Logical Device::
An object that represents the application's interface to the physical
device.
The logical device is the parent of most Vulkan objects.
Represented by a slink:VkDevice object.
Logical Operation::
Bitwise operations between a fragment color value and a value in a color
attachment, that produce a final color value to be written to the
attachment.
Lost Device::
A state that a logical device may: be in as a result of hardware errors
or other exceptional conditions.
Mappable::
See Host-Visible Memory.
Memory Dependency::
A memory dependency is an execution dependency which includes
availability and visibility operations such that:
* The first set of operations happens-before the availability operation
* The availability operation happens-before the visibility operation
* The visibility operation happens-before the second set of operations
Memory Heap::
A region of memory from which device memory allocations can: be made.
Memory Type::
An index used to select a set of memory properties (e.g. mappable,
cached) for a device memory allocation.
Mip Tail Region::
The set of mipmap levels of a sparse residency texture that are too
small to fill a sparse block, and that must: all be bound to memory
collectively and opaquely.
ifdef::VK_KHR_sampler_ycbcr_conversion[]
Multi-planar::
A _multi-planar format_ (or "`planar format`") is an image format
consisting of more than one _plane_, identifiable with a etext:_2PLANE
or etext:_3PLANE component to the format name and listed in
<<features-formats-requiring-sampler-ycbcr-conversion>>.
A _multi-planar image_ (or "`planar image`") is an image of a
multi-planar format.
endif::VK_KHR_sampler_ycbcr_conversion[]
Non-Dispatchable Handle::
A handle of an integer handle type.
Handle values may: not be unique, even for two objects of the same type.
Non-Indexed Drawing Commands::
_Drawing commands_ for which the vertex attributes are sourced in linear
order from the vertex input attributes for a drawing command (i.e. they
do not use an _index buffer_).
Includes flink:vkCmdDraw,
ifdef::VK_AMD_draw_indirect_count[]
flink:vkCmdDrawIndirectCountAMD,
endif::VK_AMD_draw_indirect_count[]
and flink:vkCmdDrawIndirect.
Normalized::
A value that is interpreted as being in the range [eq]#[0,1]# as a
result of being implicitly divided by some other value.
Normalized Device Coordinates::
A coordinate space after perspective division is applied to clip
coordinates, and before the viewport transformation converts to
framebuffer coordinates.
ifdef::VK_NVX_device_generated_commands[]
Object Table::
A binding table for various resources (slink:VkPipeline, slink:VkBuffer,
slink:VkDescriptorSet), so that they can be referenced in
device-generated command processing.
Represented as slink:VkObjectTableNVX.
Entries are registered or unregistered via code:uint32_t indices.
endif::VK_NVX_device_generated_commands[]
Overlapped Range (Aliased Range)::
The aliased range of a device memory allocation that intersects a given
image subresource of an image or range of a buffer.
Ownership (Resource)::
If an entity (e.g. a queue family) has ownership of a resource, access
to that resource is well-defined for access by that entity.
Packed Format::
A format whose components are stored as a single data element in memory,
with their relative locations defined within that element.
ifdef::VK_NV_geometry_shader_passthrough[]
Passthrough Geometry Shader::
A geometry shader which uses the code:PassthroughNV decoration on a
variable in its input interface.
Output primitives in a passthrough geometry shader always have the same
topology as the input primitive and are not produced by emitting
vertices.
endif::VK_NV_geometry_shader_passthrough[]
ifdef::VK_KHR_external_semaphore,VK_KHR_external_fence[]
Payload::
Importable or exportable reference to the internal data of an object in
Vulkan.
endif::VK_KHR_external_semaphore,VK_KHR_external_fence[]
ifdef::VK_KHX_device_group[]
Peer Memory::
An instance of memory corresponding to a different physical device than
the physical device performing the memory access, in a logical device
that represents multiple physical devices.
endif::VK_KHX_device_group[]
Physical Device::
An object that represents a single device in the system.
Represented by a slink:VkPhysicalDevice object.
Pipeline::
An object that controls how graphics or compute work is executed on the
device.
A pipeline includes one or more shaders, as well as state controlling
any non-programmable stages of the pipeline.
Represented by a slink:VkPipeline object.
Pipeline Barrier::
An execution and/or memory dependency recorded as an explicit command in
a command buffer, that forms a dependency between the previous and
subsequent commands.
Pipeline Cache::
An object that can: be used to collect and retrieve information from
pipelines as they are created, and can: be populated with previously
retrieved information in order to accelerate pipeline creation.
Represented by a slink:VkPipelineCache object.
Pipeline Layout::
An object that defines the set of resources (via a collection of
descriptor set layouts) and push constants used by pipelines that are
created using the layout.
Used when creating a pipeline and when binding descriptor sets and
setting push constant values.
Represented by a slink:VkPipelineLayout object.
Pipeline Stage::
A logically independent execution unit that performs some of the
operations defined by an action command.
pname:pNext Chain::
A set of structures <<fundamentals-validusage-pNext,chained together>>
through their ptext:pNext members.
ifdef::VK_KHR_sampler_ycbcr_conversion[]
Planar::
See _multi-planar_.
Plane::
An _image plane_ is part of the representation of an image, containing a
subset of the color channels required to represent the texels in the
image and with a contiguous mapping of coordinates to bound memory.
Most images consist only of a single plane, but some formats spread the
channels across multiple image planes.
The host-accessible properties of each image plane are accessed in a
linear layout using flink:vkGetImageSubresourceLayout.
If a multi-planar image is created with the
ename:VK_IMAGE_CREATE_DISJOINT_BIT_KHR bit set, the image is described
as _disjoint_, and its planes are therefore are bound to memory
independently.
endif::VK_KHR_sampler_ycbcr_conversion[]
Point Sampling (Rasterization)::
A rule that determines whether a fragment sample location is covered by
a polygon primitive by testing whether the sample location is in the
interior of the polygon in framebuffer-space, or on the boundary of the
polygon according to the tie-breaking rules.
ifdef::VK_KHR_swapchain[]
Presentable image::
A sname:VkImage object obtained from a sname:VkSwapchainKHR used to
present to a sname:VkSurfaceKHR object.
endif::VK_KHR_swapchain[]
Preserve Attachment::
One of a list of attachments in a subpass description that is not read
or written by the subpass, but that is read or written on earlier and
later subpasses and whose contents must: be preserved through this
subpass.
Primary Command Buffer::
A command buffer that can: execute secondary command buffers, and can:
be submitted directly to a queue.
Primitive Topology::
State that controls how vertices are assembled into primitives, e.g. as
lists of triangles, strips of lines, etc..
Provoking Vertex::
The vertex in a primitive from which flat shaded attribute values are
taken.
This is generally the "`first`" vertex in the primitive, and depends on
the primitive topology.
Push Constants::
A small bank of values writable via the API and accessible in shaders.
Push constants allow the application to set values used in shaders
without creating buffers or modifying and binding descriptor sets for
each update.
Push Constant Interface::
The set of variables with code:PushConstant storage class that are
statically used by a shader entry point, and which receive values from
push constant commands.
ifdef::VK_KHR_push_descriptor[]
Push Descriptors::
Descriptors that are written directly into a command buffer rather than
into a descriptor set.
Push descriptors allow the application to set descriptors used in
shaders without allocating or modifying descriptor sets for each update.
endif::VK_KHR_push_descriptor[]
ifdef::VK_KHR_descriptor_update_template[]
Descriptor Update Template::
An object that specifies a mapping from descriptor update information in
host memory to elements in a descriptor set, which helps enable more
efficient descriptor set updates.
endif::VK_KHR_descriptor_update_template[]
Query Pool::
An object that contains a number of query entries and their associated
state and results.
Represented by a slink:VkQueryPool object.
Queue::
An object that executes command buffers and sparse binding operations on
a device.
Represented by a slink:VkQueue object.
Queue Family::
A set of queues that have common properties and support the same
functionality, as advertised in slink:VkQueueFamilyProperties.
Queue Operation::
A unit of work to be executed by a specific queue on a device, submitted
via a <<devsandqueues-submission, queue submission command>>.
Each queue submission command details the specific queue operations that
occur as a result of calling that command.
Queue operations typically include work that is specific to each
command, and synchronization tasks.
Queue Submission::
Zero or more batches and an optional fence to be signaled, passed to a
command for execution on a queue.
See the <<devsandqueues-submission, Devices and Queues chapter>> for
more information.
Recording State (Command Buffer)::
A command buffer that is ready to record commands.
See also Initial State and Executable State.
Release Operation (Resource)::
An operation that releases ownership of an image subresource or buffer
range.
Render Pass::
An object that represents a set of framebuffer attachments and phases of
rendering using those attachments.
Represented by a slink:VkRenderPass object.
Render Pass Instance::
A use of a render pass in a command buffer.
Required Extensions::
Extensions which must: be enabled to use a specific enabled extension
(see <<extended-functionality-extensions-dependencies, Extension
Dependencies>>).
Reset (Command Buffer)::
Resetting a command buffer discards any previously recorded commands and
puts a command buffer in the initial state.
Residency Code::
An integer value returned by sparse image instructions, indicating
whether any sparse unbound texels were accessed.
Resolve Attachment::
A subpass attachment point, or image view, that is the target of a
multisample resolve operation from the corresponding color attachment at
the end of the subpass.
Retired Swapchain::
A swapchain that has been used as the pname:oldSwapchain parameter to
flink:vkCreateSwapchainKHR.
Images cannot be acquired from a retired swapchain, however images that
were acquired (but not presented) before the swapchain was retired can:
be presented.
Sampled Image::
A descriptor type that represents an image view, and supports filtered
(sampled) and unfiltered read-only acccess in a shader.
Sampler::
An object that contains state that controls how sampled image data is
sampled (or filtered) when accessed in a shader.
Also a descriptor type describing the object.
Represented by a slink:VkSampler object.
Secondary Command Buffer::
A command buffer that can: be executed by a primary command buffer, and
must: not be submitted directly to a queue.
Self-Dependency::
A subpass dependency from a subpass to itself, i.e. with
pname:srcSubpass equal to pname:dstSubpass.
A self-dependency is not automatically performed during a render pass
instance, rather a subset of it can: be performed via
flink:vkCmdPipelineBarrier during the subpass.
Semaphore::
A synchronization primitive that supports signal and wait operations,
and can: be used to synchronize operations within a queue or across
queues.
Represented by a slink:VkSemaphore object.
Shader::
Instructions selected (via an entry point) from a shader module, which
are executed in a shader stage.
Shader Code::
A stream of instructions used to describe the operation of a shader.
Shader Module::
A collection of shader code, potentially including several functions and
entry points, that is used to create shaders in pipelines.
Represented by a slink:VkShaderModule object.
Shader Stage::
A stage of the graphics or compute pipeline that executes shader code.
ifdef::VK_KHR_shared_presentable_image[]
Shared presentable image::
A presentable image created from a swapchain with elink:VkPresentModeKHR
set to either ename:VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR or
ename:VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR.
endif::VK_KHR_shared_presentable_image[]
Side Effect::
A store to memory or atomic operation on memory from a shader
invocation.
ifdef::VK_KHR_sampler_ycbcr_conversion[]
Single-plane format::
A format that is not _multi-planar_.
endif::VK_KHR_sampler_ycbcr_conversion[]
Sparse Block::
An element of a sparse resource that can be independently bound to
memory.
Sparse blocks of a particular sparse resource have a corresponding size
in bytes that they use in the bound memory.
Sparse Image Block::
A sparse block in a sparse partially-resident image.
In addition to the sparse block size in bytes, sparse image blocks have
a corresponding width, height, and depth that define the dimensions of
these elements in units of texels or compressed texel blocks, the latter
being used in case of sparse images having a block-compressed format.
Sparse Unbound Texel::
A texel read from a region of a sparse texture that does not have memory
bound to it.
Static Use::
An object in a shader is statically used by a shader entry point if any
function in the entry point's call tree contains an instruction using
the object.
Static use is used to constrain the set of descriptors used by a shader
entry point.
Storage Buffer::
A descriptor type that represents a buffer, and supports reads, writes,
and atomics in a shader.
Storage Image::
A descriptor type that represents an image view, and supports unfiltered
loads, stores, and atomics in a shader.
Storage Texel Buffer::
A descriptor type that represents a buffer view, and supports
unfiltered, formatted reads, writes, and atomics in a shader.
ifdef::VK_EXT_shader_subgroup_vote[]
Subgroup::
The set of shader invocations exposed as running concurrently with the
current shader invocation.
In compute shaders, the _local workgroup_ is a superset of the subgroup.
endif::VK_EXT_shader_subgroup_vote[]
ifdef::VK_EXT_shader_subgroup_ballot[]
Subgroup Mask::
A bitmask for all invocations in the current subgroup with one bit per
invocation, starting with the least significant bit in the first vector
component, continuing to the last bit (less than code:SubgroupSize) in
the last required vector component.
endif::VK_EXT_shader_subgroup_ballot[]
Subpass::
A phase of rendering within a render pass, that reads and writes a
subset of the attachments.
Subpass Dependency::
An execution and/or memory dependency between two subpasses described as
part of render pass creation, and automatically performed between
subpasses in a render pass instance.
A subpass dependency limits the overlap of execution of the pair of
subpasses, and can: provide guarantees of memory coherence between
accesses in the subpasses.
Subpass Description::
Lists of attachment indices for input attachments, color attachments,
depth/stencil attachment, resolve attachments, and preserve attachments
used by the subpass in a render pass.
Subset (Self-Dependency)::
A subset of a self-dependency is a pipeline barrier performed during the
subpass of the self-dependency, and whose stage masks and access masks
each contain a subset of the bits set in the identically named mask in
the self-dependency.
Texel Coordinate System::
One of three coordinate systems (normalized, unnormalized, integer) that
define how texel coordinates are interpreted in an image or a specific
mipmap level of an image.
Uniform Texel Buffer::
A descriptor type that represents a buffer view, and supports
unfiltered, formatted, read-only access in a shader.
Uniform Buffer::
A descriptor type that represents a buffer, and supports read-only
access in a shader.
Unnormalized::
A value that is interpreted according to its conventional
interpretation, and is not normalized.
User-Defined Variable Interface::
A shader entry point's variables with code:Input or code:Output storage
class that are not built-in variables.
Vertex Input Attribute::
A graphics pipeline resource that produces input values for the vertex
shader by reading data from a vertex input binding and converting it to
the attribute's format.
ifdef::VK_EXT_validation_cache[]
Validation Cache::
An object that can: be used to collect and retrieve validation results
from the validation layers, and can: be populated with previously
retrieved results in order to accelerate the validation process.
Represented by a slink:VkValidationCacheEXT object.
endif::VK_EXT_validation_cache[]
Vertex Input Binding::
A graphics pipeline resource that is bound to a buffer and includes
state that affects addressing calculations within that buffer.
Vertex Input Interface::
A vertex shader entry point's variables with code:Input storage class,
which receive values from vertex input attributes.
Vertex Processing Stages::
A set of shader stages that comprises the vertex shader, tessellation
control shader, tessellation evaluation shader, and geometry shader
stages.
ifdef::VK_KHX_multiview[]
View Mask::
When multiview is enabled, a view mask is a property of a subpass
controlling which views the rendering commands are broadcast to.
endif::VK_KHX_multiview[]
View Volume::
A subspace in homogeneous coordinates, corresponding to post-projection
x and y values between -1 and +1, and z values between 0 and +1.
Viewport Transformation::
A transformation from normalized device coordinates to framebuffer
coordinates, based on a viewport rectangle and depth range.
Visibility Operation::
An operation that causes available values to become visible to specified
memory accesses.
Visible::
A state of values written to memory that allows them to be accessed by a
set of operations.
// To be added per issue 18:
// Current State <<fundamentals-queueoperation>>
// Barycentric Coordinates <<primsrast-polygons-basic>>
// Internal Allocations <<memory-host-allocation-scope>>
// Unavailable, Available <<queries-operation>> - NB: this clashes with available/visible in terms of memory
// Signaled, Unsignaled <<synchronization-semaphores>> <<synchronization-fences>>
// Interior Vertices <<tessellation-tessellator-spacing>>
// Inner Vertices <<tessellation-triangle-tessellation>> <<tessellation-quad-tessellation>>
// Isolines <<tessellation-isoline-tessellation>>
// Binding Range <<sparsemem-memory-binding>>
[glossary]
= Common Abbreviations
Abbreviations and acronyms are sometimes used in the Specification and the
API where they are considered clear and commonplace, and are defined here:
Src::
Source
Dst::
Destination
Min::
Minimum
Max::
Maximum
Rect::
Rectangle
Info::
Information
LOD::
Level of Detail
ID::
Identifier
UUID::
Universally Unique Identifier
Op::
Operation
R::
Red color component
G::
Green color component
B::
Blue color component
A::
Alpha color component
[glossary]
= Prefixes
Prefixes are used in the API to denote specific semantic meaning of Vulkan
names, or as a label to avoid name clashes, and are explained here:
VK/Vk/vk::
Vulkan namespace +
All types, commands, enumerants and defines in this specification are
prefixed with these two characters.
PFN/pfn::
Function Pointer +
Denotes that a type is a function pointer, or that a variable is of a
pointer type.
p::
Pointer +
Variable is a pointer.
vkCmd::
Commands that record commands in command buffers +
These API commands do not result in immediate processing on the device.
Instead, they record the requested action in a command buffer for
execution when the command buffer is submitted to a queue.
s::
Structure +
Used to denote the etext:VK_STRUCTURE_TYPE* member of each structure in
pname:sType