Course reference · 243 explained terms
Clear explanations of the ray-tracing, graphics, mathematical and Vulkan terminology used throughout all 28 lessons.
A reading key for Part II
Vulkan becomes difficult when several different kinds of name are allowed to blur into one another. These statements do not replace the definitions below. They provide a first test for deciding what a new word is asking the program to do.
Vk... names a Vulkan type, including handles and structures. vk... names an API command. vkCmd... records device work into a command buffer; it does not perform that work immediately. VK_... names a constant, flag, result or extension.
An API version states the core vocabulary available. An extension adds a named part of the API. A feature is a reported capability that the logical device enables when it intends to use it. Finding one does not silently establish the other two.
A buffer or image handle describes a resource. Device memory supplies storage. Memory requirements constrain the compatible allocation, and memory binding joins the two. None of those four statements may stand in for the others.
The source stage and access identify where and how the producer wrote. The destination stage and access identify where and how the consumer will read or write. An image layout adds the state required for that image use. A barrier states this route; it is not merely a request to wait for everything.
VK_KHR_synchronization2 introduced the stage-and-access vocabulary used by VkDependencyInfo and vkCmdPipelineBarrier2, and Vulkan 1.3 promoted it to core. The API keeps the official American spelling Synchronization2; the surrounding course prose retains British synchronisation.
GLSL, HLSL and Slang are human-readable shader languages. A shader compiler can turn them into Vulkan-targeted SPIR-V, which the traditional shader-module route consumes. Changing language changes syntax and tooling; it does not remove the descriptor, stage or feature contracts.
A data structure that rejects groups of geometry before individual primitive tests are attempted.
Also encountered as: spatial acceleration structure
Appears in: Lesson 05, Lesson 08, Lesson 10, Lesson 14, Lesson 23, Lesson 26, Lesson 27
Back to glossary top ↑A TLAS record that places and identifies a referenced BLAS for traversal. Several instances may reuse the same geometry while supplying different transforms, masks and application indices.
Also encountered as: TLAS instance, acceleration structure instance
Appears in: Lesson 27
Back to glossary top ↑The part of a Vulkan dependency that identifies the kinds of memory access involved, such as shader storage writes or transfer reads. It answers what memory action must be made safe, not where that action occurs.
Also encountered as: access masks, VkAccessFlags2
Appears in: Lesson 18
Back to glossary top ↑A floating-point image that retains a running sum or related history of sample contributions before a displayed average is produced.
Also encountered as: accumulation buffer
Appears in: Lesson 13, Lesson 18, Lesson 26
Back to glossary top ↑The base proportion or colour of incoming light reflected by a diffuse surface in this course's local model.
Appears in: Lesson 05, Lesson 06, Lesson 22
Back to glossary top ↑A requirement that an address, offset, size or stride be a multiple of a reported value. Enough bytes are not sufficient when the place at which those bytes begin is invalid.
Also encountered as: aligned, alignment requirement, alignment requirements
Appears in: Lesson 07, Lesson 13, Lesson 14, Lesson 16, Lesson 19, Lesson 20, Lesson 22, Lesson 24, Lesson 27, Lesson 28
Back to glossary top ↑Sampling and reconstruction work used to reduce errors caused by representing continuous image detail on a finite pixel grid.
Also encountered as: antialiasing, AA
Appears in: Lesson 13, Lesson 26
Back to glossary top ↑A visibility query that may stop after the first accepted intersection because only existence inside the interval is required.
Appears in: Lesson 23
Back to glossary top ↑An optional ray-tracing shader invoked for candidate intersections that require an application opacity decision. It may accept, ignore or terminate according to the permitted ray-tracing operations; opaque geometry normally avoids this stage.
Also encountered as: any hit shader
Appears in: Lesson 27, Lesson 28
Back to glossary top ↑Application programming interface: the published commands, types and behaviour through which one program uses a system. A successful API call proves that a request was accepted; it does not prove that the requested rendering calculation was the right one.
Also encountered as: application programming interface
Appears in: Lesson 04, Lesson 10, Lesson 11, Lesson 14, Lesson 15
Back to glossary top ↑The Vulkan core version requested by the application and supported by the loader or device. It decides which promoted facilities may be used as core, but it does not promise every optional feature.
Appears in: Lesson 15, Lesson 28
Back to glossary top ↑The image width divided by its height. It is used when the camera maps a rectangular raster to its viewport.
Also encountered as: image aspect ratio
Appears in: Lesson 03, Lesson 19
Back to glossary top ↑A read-modify-write operation performed as one indivisible memory action for the addressed value.
Appears in: Lesson 20, Lesson 21, Lesson 23, Lesson 25
Back to glossary top ↑A total divided by the number of contributions. For a pixel, it is the accumulated sample contribution divided by its sample count.
Appears in: Lesson 13, Lesson 14, Lesson 26
Back to glossary top ↑Three weights that locate a point relative to a triangle's vertices and sum to one.
Also encountered as: barycentric weights
Appears in: Lesson 10, Lesson 24, Lesson 27
Back to glossary top ↑Bottom-level acceleration structure: an opaque Vulkan structure that contains geometry for one or more related primitives, commonly a mesh.
Also encountered as: bottom-level acceleration structure
Appears in: Lesson 27
Back to glossary top ↑A deliberate maximum number of secondary-ray generations used to keep recursive tracing finite.
Appears in: Lesson 11, Lesson 25
Back to glossary top ↑A ray query restricted to a minimum and maximum parameter value, such as the interval from a surface to a light.
Appears in: Lesson 08, Lesson 23, Lesson 27
Back to glossary top ↑A simple volume used to decide whether a more detailed object or group could be hit.
Also encountered as: axis-aligned bounding box, AABB
Appears in: Lesson 14
Back to glossary top ↑A test that rejects an index or invocation coordinate outside the valid extent of a resource. Dispatching extra edge invocations is safe only when those invocations cannot perform an out-of-range access.
Also encountered as: bounds guard, edge guard
Appears in: Lesson 18
Back to glossary top ↑A one-dimensional Vulkan resource describing a byte range and its permitted uses. Its handle, bound memory and shader interpretation remain separate responsibilities.
Also encountered as: VkBuffer
Appears in: Lesson 01, Lesson 06, Lesson 14, Lesson 15, Lesson 17, Lesson 18, Lesson 19, Lesson 20, Lesson 21, Lesson 22, Lesson 23, Lesson 24, Lesson 27, Lesson 28
Back to glossary top ↑A device-visible numeric address obtained for suitably created and allocated buffer storage, used by features including acceleration-structure builds.
Also encountered as: BDA
Appears in: Lesson 27
Back to glossary top ↑Bounding volume hierarchy: a tree that groups objects inside bounds so that many primitive tests can be skipped.
Also encountered as: bounding volume hierarchy
Appears in: Lesson 14
Back to glossary top ↑The host programming language used by the Vulkan application listings in Part II. C++ creates objects, records commands and submits work; the compiled shader stages remain separate device programs.
Also encountered as: CPP
Appears in: Lesson 18, Lesson 21
Back to glossary top ↑An optional ray-tracing pipeline shader invoked explicitly from another ray-tracing shader for application-defined work. It does not trace a ray merely because it is callable.
Also encountered as: callable stage
Appears in: Lesson 28
Back to glossary top ↑The origin and orientation from which primary rays are constructed.
Appears in: Lesson 01, Lesson 02, Lesson 03, Lesson 04, Lesson 06, Lesson 07, Lesson 13, Lesson 14, Lesson 17, Lesson 18, Lesson 19, Lesson 20, Lesson 22, Lesson 26, Lesson 27, Lesson 28
Back to glossary top ↑Usually three perpendicular vectors describing the camera's right, up and forward directions.
Also encountered as: camera frame
Appears in: Lesson 03, Lesson 14, Lesson 19
Back to glossary top ↑A possible ray-query intersection reported during traversal before the application or traversal rules decide whether it becomes the committed result.
Also encountered as: candidate hit
Appears in: Lesson 08, Lesson 14, Lesson 22, Lesson 23, Lesson 27
Back to glossary top ↑The browser drawing interface used by Part I to display the raster and laboratory diagrams. It receives values calculated by the course code; it does not choose the ray, hit or colour for the renderer.
Also encountered as: canvas, Canvas 2D API
Appears in: Lesson 01, Lesson 04, Lesson 14, Lesson 20
Back to glossary top ↑Integer division rounded upwards, used to choose enough workgroups to cover an extent that is not an exact multiple of the local size.
Also encountered as: divide and round up
Appears in: Lesson 18
Back to glossary top ↑A procedural material pattern selected from integer regions of a surface position.
Also encountered as: checker pattern
Appears in: Lesson 09, Lesson 13
Back to glossary top ↑The valid intersection with the smallest ray parameter inside the permitted interval.
Also encountered as: nearest hit
Appears in: Lesson 05, Lesson 14, Lesson 20, Lesson 21, Lesson 24
Back to glossary top ↑A ray-tracing shader stage invoked for the accepted closest intersection after traversal has completed.
Appears in: Lesson 12, Lesson 27, Lesson 28
Back to glossary top ↑One component of a stored or calculated colour, such as red, green, blue or alpha. The meaning and numeric representation of a channel depend on the selected format and colour encoding.
Also encountered as: color channel, colour component, color component
Appears in: Lesson 01
Back to glossary top ↑A Vulkan object into which commands are recorded before submission to a queue for device execution.
Also encountered as: VkCommandBuffer
Appears in: Lesson 15, Lesson 17, Lesson 18
Back to glossary top ↑A Vulkan object that owns command-buffer allocation and is associated with one queue family.
Appears in: Lesson 15, Lesson 18
Back to glossary top ↑The ray-query candidate finally accepted as the query result after traversal and any application-controlled confirmation. A query may finish without one.
Also encountered as: committed hit
Appears in: Lesson 27
Back to glossary top ↑A Vulkan pipeline consisting of one compute shader stage and the pipeline layout that defines its resource interface.
Also encountered as: VkComputePipeline
Appears in: Lesson 16, Lesson 17, Lesson 18, Lesson 25, Lesson 26, Lesson 27
Back to glossary top ↑A programmable shader stage executed as workgroups independently of the fixed graphics rasterisation stages.
Appears in: Lesson 16, Lesson 17, Lesson 18, Lesson 19, Lesson 20, Lesson 21, Lesson 23, Lesson 25, Lesson 26, Lesson 27
Back to glossary top ↑The condition in which shader invocations following different branches or loop counts cannot execute the same instruction path together throughout that region.
Appears in: Lesson 25
Back to glossary top ↑A coordinate system relative to a stated origin and basis. A position or direction cannot be compared safely with another until both are known to use compatible spaces.
Also encountered as: coordinate spaces, coordinate system
Appears in: Lesson 01, Lesson 06, Lesson 07, Lesson 10
Back to glossary top ↑Central processing unit: the processor on which the course's host application and JavaScript calculations ordinarily run. In the Vulkan half it prepares data, records commands and submits work; it does not execute the shader invocations.
Also encountered as: central processing unit
Appears in: Lesson 15, Lesson 19, Lesson 20, Lesson 21, Lesson 22, Lesson 24, Lesson 25, Lesson 26
Back to glossary top ↑A vector operation that produces a vector perpendicular to two three-dimensional input vectors.
Appears in: Lesson 02, Lesson 03, Lesson 10
Back to glossary top ↑A triangle whose vertices do not define a non-zero-area surface, for example because they are collinear or repeated. Rejecting its intersection safely does not repair the invalid geometry.
Also encountered as: triangle degeneracy
Appears in: Lesson 10, Lesson 24
Back to glossary top ↑The value below a fraction line. In the ray-plane test it measures directional alignment with the plane normal and must not be zero.
Appears in: Lesson 09
Back to glossary top ↑Shader-resource access information that identifies a buffer, image, sampler or other resource through a declared descriptor type.
Appears in: Lesson 16, Lesson 17, Lesson 18, Lesson 19, Lesson 21, Lesson 22, Lesson 24, Lesson 27, Lesson 28
Back to glossary top ↑A numbered position in a descriptor set layout. Host and shader must agree on its set number, binding number, descriptor type, count and permitted shader stages.
Appears in: Lesson 17, Lesson 21, Lesson 26, Lesson 27
Back to glossary top ↑A Vulkan object from which descriptor sets are allocated. Its sizes reserve descriptor capacity; the pool does not decide which resources the allocated sets will later reference.
Appears in: Lesson 17, Lesson 19, Lesson 24
Back to glossary top ↑A bound collection of descriptors whose actual resources conform to a descriptor set layout.
Also encountered as: VkDescriptorSet
Appears in: Lesson 16, Lesson 17, Lesson 18, Lesson 19, Lesson 21, Lesson 28
Back to glossary top ↑The declaration of descriptor bindings, types, counts and shader-stage visibility expected by one descriptor set.
Also encountered as: VkDescriptorSetLayout
Appears in: Lesson 16, Lesson 17, Lesson 19, Lesson 20, Lesson 21, Lesson 22
Back to glossary top ↑The declared category of resource access at a descriptor binding, such as a uniform buffer, storage buffer or storage image. Host updates and shader declarations must agree with it.
Also encountered as: descriptor types
Appears in: Lesson 17
Back to glossary top ↑The host operation that writes a concrete buffer, image view or other resource reference into an allocated descriptor set. A layout declaration alone does not perform this association.
Appears in: Lesson 17
Back to glossary top ↑The scalar quantity used by the course's ray-triangle test to expose orientation, scale and the parallel or degenerate case before barycentric weights are accepted.
Appears in: Lesson 10, Lesson 24
Back to glossary top ↑A repeatable pseudo-random value produced from a known seed, useful when rendering comparisons must be reproducible.
Appears in: Lesson 13, Lesson 26
Back to glossary top ↑A named addition exposed by a physical device and enabled when the logical device is created, unless the required functionality is available through the requested core API version.
Also encountered as: device extensions
Appears in: Lesson 15, Lesson 27
Back to glossary top ↑Memory allocated from a Vulkan device and bound to buffers or images according to their reported requirements.
Also encountered as: VkDeviceMemory
Appears in: Lesson 16, Lesson 28
Back to glossary top ↑A memory property indicating storage intended for efficient device access. It does not imply that the host can map the allocation directly.
Also encountered as: device local memory
Appears in: Lesson 16, Lesson 21, Lesson 26
Back to glossary top ↑A broad surface-light response based here on the clamped dot product between the normal and light direction.
Appears in: Lesson 07, Lesson 08, Lesson 11, Lesson 14, Lesson 22, Lesson 23, Lesson 25
Back to glossary top ↑A vector describing orientation. Ray directions in this course are normally stored at unit length.
Appears in: Lesson 01, Lesson 02, Lesson 03, Lesson 04, Lesson 06, Lesson 07, Lesson 08, Lesson 09, Lesson 11, Lesson 12, Lesson 14, Lesson 18, Lesson 19, Lesson 20, Lesson 22, Lesson 24, Lesson 25, Lesson 28
Back to glossary top ↑The part of a quadratic equation that reveals whether it has two, one or no real roots.
Appears in: Lesson 04, Lesson 20
Back to glossary top ↑A command that launches a three-dimensional number of compute workgroups.
Appears in: Lesson 17, Lesson 18, Lesson 19, Lesson 20, Lesson 23, Lesson 24, Lesson 25, Lesson 26, Lesson 28
Back to glossary top ↑The deliberate conversion from calculated linear colour to the non-linear representation expected by a display or display-oriented image format. Applying it twice is as wrong as omitting it.
Also encountered as: display transfer, gamma encoding, gamma-encoded
Appears in: Lesson 13, Lesson 14, Lesson 20, Lesson 22, Lesson 26
Back to glossary top ↑A scalar operation that measures directional alignment and is zero for perpendicular unit directions.
Appears in: Lesson 02, Lesson 06, Lesson 07, Lesson 22
Back to glossary top ↑A boundary between image or surface regions. For a triangle, an edge is the displacement from one vertex to another.
Appears in: Lesson 01, Lesson 03, Lesson 10, Lesson 13, Lesson 17, Lesson 18, Lesson 21, Lesson 24, Lesson 27, Lesson 28
Back to glossary top ↑A small, scale-dependent tolerance used when an exact real-number boundary cannot be represented reliably in finite precision.
Appears in: Lesson 04, Lesson 08, Lesson 23
Back to glossary top ↑A synchronisation relationship that constrains when specified device operations may execute relative to one another.
Appears in: Lesson 18
Back to glossary top ↑A shader-source instruction, such as GLSL's #extension line, that asks the shader compiler to enable language support. It is not a Vulkan instance extension, device extension or enabled device feature.
Also encountered as: shader extension directive, #extension
Appears in: Lesson 27
Back to glossary top ↑A synchronisation object that can be waited upon by the host to learn that submitted device work has completed.
Appears in: Lesson 16, Lesson 18, Lesson 19, Lesson 23
Back to glossary top ↑The angular extent covered by the camera. A wider value spreads pixel directions across a wider cone.
Also encountered as: FOV
Appears in: Lesson 03, Lesson 19, Lesson 26
Back to glossary top ↑The fact that a computer number has a limited representation and therefore rounds many real values. A tolerance is a scale-dependent policy for handling that limit, not evidence that two mathematical quantities were exactly equal.
Also encountered as: finite-precision
Appears in: Lesson 03, Lesson 04, Lesson 06, Lesson 08, Lesson 11
Back to glossary top ↑A finite numeric representation with a sign, significand and exponent, used for the course's positions, directions and colour calculations. Its large range does not provide exact real-number arithmetic.
Also encountered as: floating point
Appears in: Lesson 04, Lesson 08, Lesson 19, Lesson 22, Lesson 23, Lesson 26, Lesson 27
Back to glossary top ↑The operation required for relevant host writes to non-coherent mapped device memory before those writes can follow the host-to-device visibility route. Unmapping the allocation is not an implicit flush.
Also encountered as: vkFlushMappedMemoryRanges, mapped-memory flush
Appears in: Lesson 19, Lesson 21
Back to glossary top ↑Capabilities reported for a particular Vulkan format and tiling combination, such as whether that format may be used for storage-image operations. A format name alone does not establish support for every use.
Appears in: Lesson 26
Back to glossary top ↑Submitted frames whose work may overlap because each uses the resources and synchronisation required to avoid premature reuse.
Appears in: Lesson 26
Back to glossary top ↑The angle-dependent division of light between reflection and transmission at a boundary.
Also encountered as: Fresnel reflection, Fresnel effect
Appears in: Lesson 11, Lesson 12
Back to glossary top ↑A hit for which the incoming ray meets the outward-facing side of a surface.
Appears in: Lesson 06
Back to glossary top ↑The three-dimensional identifier available to a shader invocation after dispatch. In the compute renderer, its x and y components select the candidate output texel.
Appears in: Lesson 18
Back to glossary top ↑The high-level shader language used by this course's Vulkan shader listings. The source is compiled to Vulkan-targeted SPIR-V before the traditional shader-module path can consume it.
Also encountered as: OpenGL Shading Language
Appears in: Lesson 17, Lesson 21, Lesson 22, Lesson 25, Lesson 27
Back to glossary top ↑Graphics processing unit: the device processor that executes large amounts of graphics and compute work, including shader invocations. Parallel capacity does not make dependencies, bounds or algorithms correct automatically.
Also encountered as: graphics processing unit
Appears in: Lesson 01, Lesson 06, Lesson 08, Lesson 11, Lesson 13, Lesson 15, Lesson 19, Lesson 20, Lesson 21, Lesson 22, Lesson 25, Lesson 26, Lesson 28
Back to glossary top ↑The normalised direction halfway between the light direction and view direction, used for a compact specular model.
Appears in: Lesson 07
Back to glossary top ↑A valid intersection between a ray and a scene primitive inside the requested parameter interval.
Appears in: Lesson 02, Lesson 04, Lesson 05, Lesson 06, Lesson 07, Lesson 08, Lesson 09, Lesson 10, Lesson 11, Lesson 12, Lesson 13, Lesson 14, Lesson 19, Lesson 20, Lesson 21, Lesson 22, Lesson 23, Lesson 24, Lesson 25, Lesson 26, Lesson 27, Lesson 28
Back to glossary top ↑A ray-tracing pipeline group that associates the compatible closest-hit, any-hit and, for procedural geometry, intersection shaders selected for a class of hits.
Also encountered as: hit shader group
Appears in: Lesson 28
Back to glossary top ↑The shared result of an intersection query, normally including distance, position, normal, face orientation and material.
Appears in: Lesson 05, Lesson 06, Lesson 08, Lesson 09, Lesson 10, Lesson 14, Lesson 20, Lesson 21, Lesson 22, Lesson 24, Lesson 28
Back to glossary top ↑Microsoft's high-level shader language. An appropriate compiler can translate HLSL into Vulkan-targeted SPIR-V, so choosing HLSL changes source syntax and tooling rather than the Vulkan module format consumed by the application.
Also encountered as: High Level Shading Language
Appears in: Lesson 17
Back to glossary top ↑The application-side execution environment that calls Vulkan, normally through CPU threads. Host access, device access and host-visible device memory are related terms, but they are not interchangeable.
Appears in: Lesson 15, Lesson 16, Lesson 17, Lesson 18, Lesson 19, Lesson 20, Lesson 21, Lesson 22, Lesson 23, Lesson 24, Lesson 27, Lesson 28
Back to glossary top ↑Host-visible memory for which explicit mapped-memory flush and invalidation calls are not required to manage host-domain availability and visibility. It does not remove the execution and completion relationships required between host and device accesses.
Appears in: Lesson 19
Back to glossary top ↑Device memory that the host is permitted to map into its address space. Visibility to the host does not by itself make the memory device local or coherent.
Appears in: Lesson 19, Lesson 20
Back to glossary top ↑A Vulkan resource describing multidimensional texel storage, its format, extent, usage and other creation properties; memory is bound separately.
Appears in: Lesson 01, Lesson 02, Lesson 03, Lesson 04, Lesson 05, Lesson 06, Lesson 09, Lesson 11, Lesson 12, Lesson 13, Lesson 14, Lesson 15, Lesson 16, Lesson 17, Lesson 18, Lesson 19, Lesson 20, Lesson 21, Lesson 22, Lesson 24, Lesson 26, Lesson 27, Lesson 28
Back to glossary top ↑The swapchain operation that supplies an image index for the next frame and signals the requested synchronisation object when that image may be used according to the acquire operation.
Appears in: Lesson 18
Back to glossary top ↑The declared organisation and interpretation of an image's texel components, including component widths and numeric representation. Support must still be checked for the intended tiling and usage.
Appears in: Lesson 16, Lesson 26
Back to glossary top ↑A Vulkan image subresource state describing the organisation expected for a class of accesses; transitions require appropriate synchronisation.
Appears in: Lesson 17, Lesson 18, Lesson 28
Back to glossary top ↑The conceptual plane sampled by the camera to obtain one primary-ray direction per sample.
Also encountered as: view plane
Appears in: Lesson 01, Lesson 03, Lesson 12, Lesson 19
Back to glossary top ↑A selected part of an image identified by aspects, mip levels and array layers. Image barriers and views state which subresources they affect.
Appears in: Lesson 16
Back to glossary top ↑The implementation-facing arrangement selected when an image is created, commonly optimal or linear. Tiling affects supported uses and memory access; it is not the image's pixel dimensions.
Appears in: Lesson 16
Back to glossary top ↑A typed interpretation of image subresources used when an image is attached or referenced through a descriptor.
Also encountered as: VkImageView
Appears in: Lesson 16, Lesson 17, Lesson 26
Back to glossary top ↑The browser object used here to hold a raster as row-major RGBA channel values before it is placed on a canvas. Changing an array address and changing the colour stored at that address are different operations.
Also encountered as: canvas image data
Appears in: Lesson 01
Back to glossary top ↑A buffer containing integer indices that select vertices or other records when primitives are assembled or traversed.
Appears in: Lesson 10, Lesson 24, Lesson 27
Back to glossary top ↑A material value that relates the speed of light in a medium to its speed in vacuum and controls bending at a boundary.
Also encountered as: refractive index, IOR
Appears in: Lesson 06, Lesson 12
Back to glossary top ↑A named addition enabled when the Vulkan instance is created, normally for facilities that connect the application to the loader, platform surface or diagnostic environment.
Also encountered as: instance extensions
Appears in: Lesson 15
Back to glossary top ↑An eight-bit value used during acceleration-structure traversal to include or exclude TLAS instances by bitwise comparison with the ray's cull mask.
Appears in: Lesson 27
Back to glossary top ↑The matrix stored with a TLAS instance that maps its referenced BLAS geometry into the instance's placed coordinate space. Moving an instance need not duplicate or rebuild its unchanged triangle records.
Also encountered as: instance transforms
Appears in: Lesson 27
Back to glossary top ↑Constructing an attribute between known values using weights. Barycentric interpolation changes the selected attribute while retaining the same three location weights for the triangle hit.
Also encountered as: interpolate, interpolated, interpolating
Appears in: Lesson 10, Lesson 24
Back to glossary top ↑A point or parameter value at which a ray satisfies a geometric primitive's equation.
Appears in: Lesson 01, Lesson 04, Lesson 05, Lesson 06, Lesson 08, Lesson 09, Lesson 10, Lesson 14, Lesson 19, Lesson 20, Lesson 22, Lesson 23, Lesson 24, Lesson 27
Back to glossary top ↑A ray-tracing pipeline shader that reports candidate intersections for procedural geometry whose hit calculation is not supplied by built-in triangle traversal.
Also encountered as: procedural intersection shader
Appears in: Lesson 18, Lesson 28
Back to glossary top ↑An operation supplied directly by a programming or shader language implementation, such as dot, cross or normalize. The compact name removes handwritten arithmetic; it does not remove the operation's input requirements.
Also encountered as: intrinsic functions, shader intrinsic
Appears in: Lesson 02
Back to glossary top ↑The host cache operation required before reading relevant device writes through non-coherent mapped memory, after the device work has been made available to the host and host execution has waited appropriately.
Also encountered as: vkInvalidateMappedMemoryRanges, mapped-memory invalidation
Appears in: Lesson 19
Back to glossary top ↑One execution of a shader entry point for a particular work item, pixel, vertex, ray or other stage-specific input.
Appears in: Lesson 01, Lesson 03, Lesson 04, Lesson 07, Lesson 09, Lesson 13, Lesson 17, Lesson 18, Lesson 19, Lesson 20, Lesson 21, Lesson 22, Lesson 23, Lesson 24, Lesson 25, Lesson 26, Lesson 27
Back to glossary top ↑The host programming language used by Part I to calculate the manual ray tracer and drive its browser laboratories. Canvas displays the result, while the JavaScript code decides the values.
Appears in: Lesson 01, Lesson 02, Lesson 03, Lesson 11, Lesson 14, Lesson 15, Lesson 18, Lesson 19
Back to glossary top ↑A controlled offset that moves a sample away from a fixed repeated position within a pixel.
Appears in: Lesson 13
Back to glossary top ↑An ideal diffuse model whose outgoing appearance is independent of viewing direction and proportional to the clamped normal-light dot product.
Also encountered as: Lambertian reflection, Lambertian diffuse
Appears in: Lesson 07
Back to glossary top ↑The stage-provided three-dimensional coordinate of one ray-generation shader invocation within a trace-rays launch. It commonly selects the output pixel or sample whose primary ray is being constructed.
Also encountered as: launch identifier, launch index
Appears in: Lesson 28
Back to glossary top ↑GLSL syntax inside layout parentheses that declares facts such as descriptor set, binding, image format or compute local size. The declaration must agree with the host-created Vulkan objects; it does not create them.
Also encountered as: layout qualifiers, format qualifier
Appears in: Lesson 17
Back to glossary top ↑Colour values before a display transfer function has been applied. Lighting, sample accumulation and averaging are performed in this representation in the course.
Also encountered as: linear color, linear RGB
Appears in: Lesson 13, Lesson 22, Lesson 26
Back to glossary top ↑The number of compute invocations in one workgroup along x, y and z, normally declared by the shader. It is distinct from the number of workgroups launched by a dispatch.
Appears in: Lesson 18
Back to glossary top ↑The application-created Vulkan device object that exposes enabled features, extensions, queues and child resources for one physical device.
Also encountered as: VkDevice
Appears in: Lesson 15
Back to glossary top ↑A stated portion of mapped device memory used by a flush or invalidation operation. Non-coherent ranges must obey the implementation's range and atom-size requirements.
Also encountered as: VkMappedMemoryRange, mapped range
Appears in: Lesson 19
Back to glossary top ↑The surface information and rules used to decide how a hit contributes light and whether it creates more rays.
Appears in: Lesson 01, Lesson 05, Lesson 06, Lesson 07, Lesson 09, Lesson 10, Lesson 11, Lesson 12, Lesson 14, Lesson 20, Lesson 21, Lesson 22, Lesson 23, Lesson 24, Lesson 25, Lesson 26, Lesson 27, Lesson 28
Back to glossary top ↑The upper end of the ray parameter interval accepted by an intersection query.
Appears in: Lesson 05, Lesson 08, Lesson 20, Lesson 21, Lesson 23
Back to glossary top ↑The first memory part of a Vulkan dependency: specified writes from the source operations are completed and made available for later visibility work.
Appears in: Lesson 18
Back to glossary top ↑The association between a created buffer or image and a compatible region of allocated device memory. Creating either object separately does not perform this association.
Appears in: Lesson 16, Lesson 24
Back to glossary top ↑A synchronisation relationship that makes specified writes available and visible to later specified accesses.
Appears in: Lesson 16, Lesson 18, Lesson 26
Back to glossary top ↑The operation that gives the host a pointer to a range of host-visible device memory. Mapping permits host access; it does not by itself order that access with device work or make non-coherent writes visible.
Also encountered as: mapped memory, map memory
Appears in: Lesson 19, Lesson 21
Back to glossary top ↑The size, alignment and compatible memory-type information reported for a Vulkan buffer or image before memory is bound.
Appears in: Lesson 15, Lesson 16, Lesson 21
Back to glossary top ↑A physical-device memory category combining a heap index with properties such as host visibility or device locality.
Appears in: Lesson 16
Back to glossary top ↑The second memory part of a Vulkan dependency: writes made available by the source are made visible to the specified destination accesses.
Appears in: Lesson 18
Back to glossary top ↑A collection of connected primitives, commonly triangles, used to approximate a surface.
Appears in: Lesson 09, Lesson 10, Lesson 24, Lesson 27
Back to glossary top ↑The lower end of the accepted ray interval, used to reject hits behind or too close to the ray origin.
Appears in: Lesson 05, Lesson 20, Lesson 23
Back to glossary top ↑A ray-tracing shader stage invoked when traversal finds no accepted intersection for the traced ray.
Appears in: Lesson 11, Lesson 28
Back to glossary top ↑In this course, a diagnostic view that converts a surface normal's components into display colours; it is not a texture-based normal map.
Appears in: Lesson 06
Back to glossary top ↑Divide a non-zero vector by its length so that it retains direction but has unit length.
Also encountered as: normalize, normalisation, normalization, unit vector
Appears in: Lesson 02, Lesson 03, Lesson 04, Lesson 06, Lesson 07, Lesson 08, Lesson 09, Lesson 11, Lesson 14, Lesson 19, Lesson 20, Lesson 22, Lesson 24, Lesson 25
Back to glossary top ↑The condition in which another surface blocks the relevant interval between an origin and a target.
Appears in: Lesson 05, Lesson 08, Lesson 23
Back to glossary top ↑Acceleration-structure geometry declared not to require an opacity decision during traversal. It is appropriate only when the application does not intend an any-hit or alpha-test rejection for that geometry.
Appears in: Lesson 27
Back to glossary top ↑A small displacement or minimum ray distance used to stop a secondary ray immediately re-hitting its generating surface.
Also encountered as: ray bias, shadow bias
Appears in: Lesson 08, Lesson 09, Lesson 10, Lesson 23
Back to glossary top ↑Bytes inserted so that later members, records or regions begin at required offsets. Padding occupies storage but does not become an additional shader value or shader group handle.
Appears in: Lesson 16, Lesson 19, Lesson 21, Lesson 24, Lesson 28
Back to glossary top ↑A ray whose direction has zero dot product with a plane normal, so it does not approach or leave that plane.
Appears in: Lesson 09
Back to glossary top ↑Independent work that can be executed concurrently, such as evaluating many pixel samples, subject to data and scheduling constraints.
Appears in: Lesson 14
Back to glossary top ↑The explicit ray, accumulated radiance, throughput, depth and related values carried while an iterative or queued path is traced.
Appears in: Lesson 14, Lesson 25
Back to glossary top ↑A Vulkan handle describing an available implementation and its reported properties, queue families, extensions, features and memory types.
Also encountered as: VkPhysicalDevice, GPU adapter
Appears in: Lesson 15, Lesson 16, Lesson 26, Lesson 28
Back to glossary top ↑A recorded command that declares execution and memory dependencies, and may include image-layout transitions, between device operations.
Also encountered as: memory barrier
Appears in: Lesson 18, Lesson 21, Lesson 26
Back to glossary top ↑The Vulkan object that defines descriptor set layouts and push-constant ranges accessible to a pipeline's shaders.
Also encountered as: VkPipelineLayout
Appears in: Lesson 17, Lesson 20, Lesson 27, Lesson 28
Back to glossary top ↑A named scope in Vulkan's execution model used to describe where operations occur for scheduling and dependencies. It is not necessarily one physical hardware step, and not every pipeline stage is a programmable shader stage.
Also encountered as: pipeline stages
Appears in: Lesson 17, Lesson 18, Lesson 28
Back to glossary top ↑One stored element of the raster. Its final value represents reconstructed sample information over a small image region.
Appears in: Lesson 01, Lesson 03, Lesson 04, Lesson 05, Lesson 06, Lesson 07, Lesson 09, Lesson 11, Lesson 12, Lesson 13, Lesson 14, Lesson 15, Lesson 17, Lesson 18, Lesson 19, Lesson 20, Lesson 21, Lesson 22, Lesson 23, Lesson 25, Lesson 26, Lesson 28
Back to glossary top ↑An infinite flat surface described by a point and a normal.
Appears in: Lesson 02, Lesson 03, Lesson 05, Lesson 08, Lesson 09, Lesson 10, Lesson 11, Lesson 14, Lesson 19
Back to glossary top ↑Vulkan's linked structure mechanism for attaching additional feature, property or creation structures to a base structure. Every chained structure identifies its own type and points to the next one or to null.
Also encountered as: feature chain, structure chain
Appears in: Lesson 15, Lesson 27, Lesson 28
Back to glossary top ↑A location in space. Subtracting two points produces a displacement vector.
Appears in: Lesson 01, Lesson 02, Lesson 03, Lesson 04, Lesson 05, Lesson 06, Lesson 07, Lesson 08, Lesson 09, Lesson 10, Lesson 11, Lesson 17, Lesson 19, Lesson 22, Lesson 23, Lesson 24, Lesson 25
Back to glossary top ↑A compact teaching model that emits from one position and supplies a direction and distance at each surface point.
Appears in: Lesson 07, Lesson 08, Lesson 22, Lesson 23
Back to glossary top ↑A Vulkan object representing the platform window or display target against which presentation support, formats and modes are queried.
Appears in: Lesson 15
Back to glossary top ↑A ray generated by the camera for an image sample.
Also encountered as: camera ray, eye ray
Appears in: Lesson 01, Lesson 02, Lesson 03, Lesson 04, Lesson 05, Lesson 07, Lesson 08, Lesson 11, Lesson 12, Lesson 13, Lesson 15, Lesson 19, Lesson 20, Lesson 21, Lesson 22, Lesson 25, Lesson 27, Lesson 28
Back to glossary top ↑The identifier of the primitive within the relevant geometry or traversal result. It names which triangle or other primitive was hit; it is not the hit distance or material by itself.
Also encountered as: primitive identity
Appears in: Lesson 22, Lesson 24, Lesson 27
Back to glossary top ↑One attempt to intersect a ray with a geometric object such as a sphere, plane or triangle.
Also encountered as: intersection test
Appears in: Lesson 05, Lesson 14, Lesson 21, Lesson 23
Back to glossary top ↑A surface appearance computed from values such as position rather than read from a stored image texture.
Appears in: Lesson 09
Back to glossary top ↑A small block of values supplied through a command buffer and made directly accessible to selected shader stages through a pipeline layout range.
Appears in: Lesson 19, Lesson 20
Back to glossary top ↑An equation containing a squared unknown. Substituting a ray into a sphere equation produces one in the ray parameter.
Appears in: Lesson 04, Lesson 09, Lesson 19, Lesson 20
Back to glossary top ↑A logical-device handle to which command buffers and synchronisation operations are submitted for execution.
Also encountered as: VkQueue
Appears in: Lesson 15, Lesson 18, Lesson 21, Lesson 25, Lesson 26, Lesson 27
Back to glossary top ↑A group of queues on a physical device that share a declared set of capabilities and presentation support properties.
Appears in: Lesson 15, Lesson 18, Lesson 28
Back to glossary top ↑A batch of command buffers and semaphore waits or signals sent to a queue. Submission schedules device work; it does not normally wait for that work on the host.
Appears in: Lesson 18
Back to glossary top ↑The paired release and acquire relationship used when an exclusively shared resource moves between different queue families. Command order on one family does not silently transfer ownership to another.
Also encountered as: queue ownership transfer, queue ownership transfers
Appears in: Lesson 18
Back to glossary top ↑A directional measure of light transport. The browser tracer uses RGB values as a compact teaching representation of it.
Appears in: Lesson 07, Lesson 20, Lesson 25, Lesson 26, Lesson 28
Back to glossary top ↑A finite two-dimensional grid of pixels.
Appears in: Lesson 01, Lesson 02, Lesson 03
Back to glossary top ↑An account of how many rays and intersection tests a rendering configuration is permitted or expected to spend.
Appears in: Lesson 13, Lesson 14
Back to glossary top ↑Bit flags supplied with a hardware traversal request to alter traversal behaviour, such as culling faces or treating geometry as opaque. They do not change the ray equation.
Appears in: Lesson 27
Back to glossary top ↑The permitted minimum and maximum values of the ray parameter for one query. The equation describes an unbounded line of possible points; the interval decides which part is useful for the present question.
Also encountered as: intersection interval, accepted interval
Appears in: Lesson 04, Lesson 05, Lesson 08, Lesson 09, Lesson 15, Lesson 20, Lesson 23, Lesson 28
Back to glossary top ↑The scalar t in P(t) = O + tD. It locates a point along a ray and orders hits when D has unit length.
Also encountered as: ray t, parameter t
Appears in: Lesson 02, Lesson 04, Lesson 05, Lesson 20, Lesson 21
Back to glossary top ↑Application-defined data carried between ray-generation, hit and miss shader stages during a ray-tracing pipeline trace.
Appears in: Lesson 12, Lesson 28
Back to glossary top ↑Shader-controlled traversal of an acceleration structure from a compute, graphics or other supported shader stage without creating a ray-tracing pipeline.
Appears in: Lesson 11, Lesson 27, Lesson 28
Back to glossary top ↑A Vulkan pipeline containing ray-generation and optional hit, miss, intersection and callable shader groups used with a trace-rays command.
Also encountered as: RT pipeline
Appears in: Lesson 27, Lesson 28
Back to glossary top ↑The ray-tracing pipeline stage invoked once for each launch identifier to construct initial rays and begin tracing.
Also encountered as: raygen shader
Appears in: Lesson 28
Back to glossary top ↑A deliberate route that makes selected device results available to the host for inspection, normally through a copy, dependency, completion wait and host-visible buffer. A plausible image is not a numerical readback.
Also encountered as: read-back, debug readback
Appears in: Lesson 19, Lesson 20, Lesson 23, Lesson 24
Back to glossary top ↑A control structure in which tracing one ray invokes the same tracing process for a secondary ray with a reduced budget.
Appears in: Lesson 11, Lesson 25, Lesson 28
Back to glossary top ↑The number of nested ray-tracing shader calls permitted by the pipeline. Declaring a larger maximum permits deeper calls; it does not create secondary rays by itself.
Appears in: Lesson 28
Back to glossary top ↑A direction mirrored about the surface normal so that the incident and reflected angles match.
Appears in: Lesson 05, Lesson 06, Lesson 07, Lesson 11, Lesson 12, Lesson 13, Lesson 14, Lesson 22, Lesson 23, Lesson 25, Lesson 28
Back to glossary top ↑A change in direction when a transmitted ray crosses between media with different indices of refraction.
Appears in: Lesson 06, Lesson 11, Lesson 12, Lesson 22
Back to glossary top ↑Three colour components representing red, green and blue. The tuple does not state whether its values are linear, display encoded, floating point or stored as integers; that requires an additional format or encoding contract.
Appears in: Lesson 01, Lesson 06, Lesson 10, Lesson 13, Lesson 14, Lesson 22, Lesson 24
Back to glossary top ↑RGB with a fourth alpha component. Names such as RGBA8 and RGBA16F add storage information, while RGBA alone describes only the four-component arrangement.
Also encountered as: RGBA8, RGBA16F
Appears in: Lesson 01, Lesson 16
Back to glossary top ↑One evaluation made at a chosen position within or around a pixel before reconstruction.
Appears in: Lesson 01, Lesson 02, Lesson 03, Lesson 04, Lesson 08, Lesson 09, Lesson 12, Lesson 13, Lesson 14, Lesson 17, Lesson 19, Lesson 25, Lesson 26, Lesson 28
Back to glossary top ↑The integer identifying which sample in a reproducible sequence is being evaluated for a pixel or path.
Appears in: Lesson 13, Lesson 26
Back to glossary top ↑Visible variance caused by estimating a result from a finite changing sample set. It differs from structured aliasing even though adding well-chosen samples may reduce both.
Also encountered as: sample noise
Appears in: Lesson 13
Back to glossary top ↑One aligned shader-binding-table record containing a shader group handle and, when used, application record data. Its address and stride must obey the reported ray-tracing pipeline properties.
Also encountered as: shader binding table record
Appears in: Lesson 28
Back to glossary top ↑One device-address range passed to the trace-rays command for ray-generation, miss, hit or callable records. Each non-empty region states an address, stride and size under Vulkan's alignment rules.
Also encountered as: shader binding table region
Appears in: Lesson 28
Back to glossary top ↑The collection of geometry, materials, lights and camera state considered by a render.
Appears in: Lesson 01, Lesson 02, Lesson 03, Lesson 04, Lesson 05, Lesson 07, Lesson 08, Lesson 09, Lesson 10, Lesson 11, Lesson 12, Lesson 13, Lesson 14, Lesson 15, Lesson 17, Lesson 18, Lesson 19, Lesson 20, Lesson 21, Lesson 22, Lesson 23, Lesson 24, Lesson 26, Lesson 27, Lesson 28
Back to glossary top ↑A compact approximation of unpolarised Fresnel reflectance based on view angle and refractive indices.
Also encountered as: Schlick's approximation
Appears in: Lesson 12
Back to glossary top ↑Temporary buffer storage supplied to an acceleration-structure build or update operation and sized from Vulkan's build requirements.
Appears in: Lesson 27
Back to glossary top ↑A ray created at a surface hit, for example a shadow, reflection or transmission ray.
Also encountered as: recursive ray
Appears in: Lesson 05, Lesson 11, Lesson 14, Lesson 22, Lesson 23, Lesson 24, Lesson 25, Lesson 28
Back to glossary top ↑A false immediate hit caused when a secondary ray begins numerically on or just inside the surface that created it.
Also encountered as: shadow acne
Appears in: Lesson 08, Lesson 23
Back to glossary top ↑A Vulkan synchronisation object used to order queue operations, including acquisition and presentation relationships.
Appears in: Lesson 18, Lesson 26
Back to glossary top ↑A device-addressed buffer of aligned shader-group records that selects ray-generation, miss, hit and callable groups for a trace-rays command.
Also encountered as: SBT
Appears in: Lesson 28
Back to glossary top ↑A stage-defined shader input or output supplied by the execution environment, such as a global invocation ID or ray launch ID. It is not fetched through an application descriptor binding.
Also encountered as: shader built-ins, built-in input, built-ins
Appears in: Lesson 17, Lesson 27, Lesson 28
Back to glossary top ↑A nested invocation from one ray-tracing shader to another through a trace or callable operation. Pipeline recursion limits permit such calls; they do not create them automatically.
Also encountered as: shader calls
Appears in: Lesson 28
Back to glossary top ↑A tool that translates human-readable shader source into a target such as Vulkan SPIR-V and reports source or target errors. Successful compilation does not establish runtime feature support or agreement with the host resource layout.
Also encountered as: glslc, glslangValidator, DXC, slangc
Appears in: Lesson 17, Lesson 20
Back to glossary top ↑A named shader function selected for one pipeline stage, such as main in the course examples. A module may contain code, but the pipeline stage states which entry point and stage use are intended.
Also encountered as: entry point, shader entry points
Appears in: Lesson 17
Back to glossary top ↑A ray-tracing pipeline record that associates one general shader or a compatible set of hit shaders for later selection through the shader binding table.
Appears in: Lesson 28
Back to glossary top ↑Implementation-provided bytes that identify a ray-tracing pipeline shader group when copied into a shader-binding-table record. The bytes are obtained from the created pipeline rather than invented by the application.
Appears in: Lesson 28
Back to glossary top ↑The agreement between host-created layouts and shader declarations for descriptors, push constants, buffer members and stage inputs or outputs.
Appears in: Lesson 06, Lesson 17
Back to glossary top ↑A human-readable language used to express graphics or compute shader work. GLSL, HLSL and Slang can target Vulkan, while Vulkan's traditional shader-module route consumes their compiled SPIR-V rather than the source text.
Also encountered as: shader languages, shading language, shading languages
Appears in: Lesson 02, Lesson 17
Back to glossary top ↑A Vulkan object containing shader code, traditionally SPIR-V, used when pipeline shader stages are created.
Appears in: Lesson 17, Lesson 28
Back to glossary top ↑The human-readable program supplied to a shader compiler. Keeping source and the compiler command permits the SPIR-V module input to be reproduced rather than treated as an unexplained binary.
Also encountered as: shader source code
Appears in: Lesson 17
Back to glossary top ↑One programmable responsibility in a pipeline, such as compute, ray generation, miss or closest hit. A shader stage is code selected for that responsibility; a pipeline stage is the wider Vulkan execution-scope term.
Also encountered as: shader stages
Appears in: Lesson 11, Lesson 17, Lesson 27, Lesson 28
Back to glossary top ↑A descriptor-accessed buffer whose shader interface permits storage-class reads and, where declared, writes to structured data.
Also encountered as: SSBO, storage buffer
Appears in: Lesson 19, Lesson 20, Lesson 21, Lesson 23, Lesson 24, Lesson 25
Back to glossary top ↑A bounded visibility ray sent from a surface point towards a light sample.
Appears in: Lesson 05, Lesson 07, Lesson 08, Lesson 10, Lesson 21, Lesson 22, Lesson 23, Lesson 27, Lesson 28
Back to glossary top ↑A high-level shader language and toolchain with an HLSL-related syntax and facilities for reusable shader code. It can emit Vulkan-targeted SPIR-V, so Vulkan still receives a compiled module representation rather than Slang source.
Also encountered as: Slang shader language
Appears in: Lesson 17
Back to glossary top ↑The relationship between incident angle, transmitted angle and the two refractive indices at a boundary.
Also encountered as: Snell law
Appears in: Lesson 12
Back to glossary top ↑Structured image error produced when the sample pattern cannot represent or distinguish spatial variation in the scene signal. Blurring the result can hide an edge but cannot recover visibility that was never sampled.
Also encountered as: aliasing
Appears in: Lesson 09, Lesson 13
Back to glossary top ↑A view-dependent local highlight used here to represent concentrated reflection around a preferred direction.
Appears in: Lesson 06, Lesson 07, Lesson 08, Lesson 11, Lesson 22, Lesson 23
Back to glossary top ↑A surface whose points are all one radius from a centre point.
Appears in: Lesson 01, Lesson 03, Lesson 04, Lesson 05, Lesson 06, Lesson 07, Lesson 08, Lesson 09, Lesson 10, Lesson 11, Lesson 12, Lesson 13, Lesson 14, Lesson 18, Lesson 19, Lesson 20, Lesson 21, Lesson 22, Lesson 23, Lesson 24, Lesson 27
Back to glossary top ↑The binary intermediate language consumed by Vulkan shader modules for the traditional Vulkan shader ingestion path.
Also encountered as: SPIRV
Appears in: Lesson 17, Lesson 28
Back to glossary top ↑A standard non-linear colour encoding used for display-oriented values. When an sRGB image format performs the relevant conversion, the shader must not apply the same display encoding a second time.
Also encountered as: SRGB
Appears in: Lesson 22
Back to glossary top ↑The part of a Vulkan dependency that identifies where in device execution the source or destination operations occur. It answers where the relevant access happens, while the access mask answers what kind of memory access it is.
Also encountered as: stage masks, VkPipelineStageFlags2
Appears in: Lesson 18
Back to glossary top ↑Host-accessible temporary buffer storage used to transfer data into a device-local resource.
Appears in: Lesson 21
Back to glossary top ↑A shader block layout convention that defines member alignment, offsets and array or structure strides for storage-buffer data.
Appears in: Lesson 21, Lesson 24
Back to glossary top ↑An image view exposed through a storage-image descriptor for unfiltered shader loads, stores and supported atomic operations.
Appears in: Lesson 15, Lesson 16, Lesson 17, Lesson 18, Lesson 19, Lesson 20, Lesson 22, Lesson 26, Lesson 27, Lesson 28
Back to glossary top ↑Dividing a sample domain into regions and taking samples from each to improve coverage.
Appears in: Lesson 13
Back to glossary top ↑The byte distance from the start of one array element or table record to the start of the next. It includes required padding and must satisfy the layout or device alignment contract.
Also encountered as: record stride, array stride
Appears in: Lesson 21, Lesson 24, Lesson 28
Back to glossary top ↑A region assigned from a larger device-memory allocation and bound to one resource at an offset satisfying that resource's size, alignment and memory-type requirements.
Appears in: Lesson 16
Back to glossary top ↑A unit direction perpendicular to a surface at the hit point.
Also encountered as: geometric normal, normal
Appears in: Lesson 05, Lesson 06, Lesson 07, Lesson 08, Lesson 09, Lesson 10, Lesson 11, Lesson 12, Lesson 19, Lesson 20, Lesson 22, Lesson 23, Lesson 24, Lesson 25
Back to glossary top ↑A Vulkan object that provides a rotating set of presentable images for a surface and coordinates image acquisition with presentation.
Appears in: Lesson 15, Lesson 18
Back to glossary top ↑An image provided by a swapchain for presentation. The application obtains its handle and uses it according to the swapchain's format, usage, acquisition and presentation rules rather than creating it independently.
Appears in: Lesson 16, Lesson 18
Back to glossary top ↑The Vulkan synchronisation interface used by this course. Introduced by VK_KHR_synchronization2 and promoted to Vulkan 1.3, it places stage and access masks together in barrier structures used by commands such as vkCmdPipelineBarrier2. It makes a dependency clearer; it does not infer one.
Also encountered as: synchronisation2, synchronization 2, synchronisation 2, sync2, VK_KHR_synchronization2
Appears in: Lesson 15, Lesson 18
Back to glossary top ↑A local surface coordinate space formed around tangent, bitangent and normal directions, commonly used to interpret texture normal maps. It is distinct from displaying the geometric normal directly as colour.
Also encountered as: tangent-space
Appears in: Lesson 06
Back to glossary top ↑Combining sample contributions produced across successive frames while the represented camera and scene state remain compatible.
Appears in: Lesson 26
Back to glossary top ↑The deliberate rule that prevents a ray path from continuing indefinitely, such as a bounce limit or contribution policy.
Appears in: Lesson 11, Lesson 14, Lesson 25
Back to glossary top ↑One stored element of an image resource. A texel is storage; a displayed pixel is an image region reconstructed from samples, even when a simple renderer maps them one to one.
Appears in: Lesson 16, Lesson 17, Lesson 18, Lesson 19
Back to glossary top ↑The accumulated fraction or colour weight carried by a ray path as surface interactions are applied.
Appears in: Lesson 11, Lesson 12, Lesson 25, Lesson 28
Back to glossary top ↑A query that records implementation timestamp values at supported pipeline points so elapsed device work can be measured within the timestamp validity rules.
Appears in: Lesson 28
Back to glossary top ↑Top-level acceleration structure: an opaque Vulkan structure containing instances that reference bottom-level acceleration structures and supply transforms and instance data.
Also encountered as: top-level acceleration structure
Appears in: Lesson 27, Lesson 28
Back to glossary top ↑The case in which no real transmitted direction exists and all of the considered contribution reflects.
Also encountered as: TIR
Appears in: Lesson 12
Back to glossary top ↑A Vulkan device operation that copies, clears, fills or otherwise transfers resource data. It has stated source and destination uses and participates in execution and memory dependencies like other device work.
Also encountered as: transfer operations, device transfer
Appears in: Lesson 18, Lesson 21
Back to glossary top ↑Three non-collinear vertices and the finite planar region between them; a primitive from which general meshes are commonly assembled.
Appears in: Lesson 03, Lesson 05, Lesson 09, Lesson 10, Lesson 13, Lesson 14, Lesson 21, Lesson 23, Lesson 24, Lesson 26, Lesson 27, Lesson 28
Back to glossary top ↑A descriptor-accessed buffer containing read-only shader parameters laid out according to the shader interface contract.
Also encountered as: UBO
Appears in: Lesson 19, Lesson 22
Back to glossary top ↑Unsigned normalised storage: an unsigned integer range interpreted as floating-point values from zero to one. Eight stored bits still provide only 256 representable values for that channel.
Also encountered as: unsigned normalised, unsigned normalized
Appears in: Lesson 22
Back to glossary top ↑Bits supplied when a Vulkan resource is created to declare its intended operations, such as storage-image writes or transfer source use. A later operation is invalid if the required use was not declared and supported.
Appears in: Lesson 16
Back to glossary top ↑A Vulkan layer, commonly VK_LAYER_KHRONOS_validation, that checks API use and reports diagnostic messages without replacing application correctness tests.
Also encountered as: VK_LAYER_KHRONOS_validation
Appears in: Lesson 15
Back to glossary top ↑A displacement with magnitude and direction but no fixed location.
Appears in: Lesson 02, Lesson 03, Lesson 07, Lesson 10, Lesson 11, Lesson 12, Lesson 14, Lesson 19, Lesson 21, Lesson 22
Back to glossary top ↑A buffer containing vertex attribute records such as positions, normals or texture coordinates.
Appears in: Lesson 10, Lesson 24
Back to glossary top ↑The camera's conceptual rectangle in space through which primary rays are aimed.
Appears in: Lesson 03, Lesson 19
Back to glossary top ↑A boolean capability reported by a physical device and explicitly enabled for a logical device when the application intends to use it. An API version or extension name alone does not enable the feature.
Also encountered as: device feature, device features
Appears in: Lesson 15
Back to glossary top ↑The value by which the application refers to a Vulkan object. A handle identifies the object; it is not the object's memory contents and does not by itself prove that required backing memory or state exists.
Appears in: Lesson 16
Back to glossary top ↑The top-level Vulkan object that connects the application to the loader and enabled instance layers and extensions.
Also encountered as: VkInstance
Appears in: Lesson 15
Back to glossary top ↑The component that exposes Vulkan entry points to the application, reports supported instance capability and locates available Vulkan implementations and layers.
Appears in: Lesson 15
Back to glossary top ↑The development package that supplies Vulkan headers, libraries, validation components and tools used to build and inspect applications. Installing the SDK does not add a device feature that the implementation and hardware do not support.
Also encountered as: SDK
Appears in: Lesson 17
Back to glossary top ↑The ordering of triangle vertices, which determines the sign of a derived face normal.
Appears in: Lesson 10, Lesson 24
Back to glossary top ↑A local group of compute shader invocations that may share workgroup memory and synchronise with one another.
Appears in: Lesson 17, Lesson 18
Back to glossary top ↑The x, y and z numbers supplied to a compute dispatch. Multiplying these counts by the shader's local size gives the full grid of launched invocations.
Appears in: Lesson 17, Lesson 18
Back to glossary top ↑A point expressed in the shared scene coordinate system.
Also encountered as: world-space position
Appears in: Lesson 05, Lesson 09, Lesson 22
Back to glossary top ↑No glossary terms match that search.