Crate alpha2_render 

GPU compositing public API.

wgpu interop

The API names no wgpu type by default: sources come in as SourceViews and results go out as RenderedTextures and readbacks. The items that take or return wgpu handles are the interop surface, documented with the wgpu-interop feature and following wgpu’s major version. Without the feature those items are hidden: alpha2’s own crates share handles through them, and they are not part of this crate’s API.

Re-exports

pub use composite::LayerTransform;

pub use readback::PlaneTarget;

pub use readback::Rgba8Readback;

pub use readback::StagingPlane;

pub use readback::Yuv420pPlanes;

pub use readback::Yuv420pReadback;

pub use readback::Yuv420pTargets;

pub use readback::yuv420p_staging_bytes;

pub use yuv::ExternalTextureLease;

pub use yuv::PendingSourceWork;

pub use yuv::PreparedSourceTexture;

pub use yuv::SourceAlpha;

pub use yuv::SourcePlane;

pub use yuv::SourcePresentation;

pub use yuv::Yuv420Frame;

pub use yuv::YuvFrame;

Modules

hdr

HDR sources brought into the SDR working space.

Structs

AdapterDiagnostics

Adapter metadata recorded beside reproducible benchmark samples.

BenchmarkMetadata

Reproducible metadata envelope written beside benchmark measurements.

Color

A premultiplied, sRGB-encoded RGBA storage value with components in the 0..=1 range and no color component above alpha: the values an intermediate texture holds, not linear light.

CompiledEffect

A runtime effect the device compiled, ready for Renderer::register_compiled on the renderer that compiled it.

DegradationDecision

Effective controls and every observable fallback decision.

EffectDef

Data-only runtime effect, transition, or generator definition.

EffectId

Stable identity of one registered effect version.

EffectInputs

Named images one effect node samples besides its source, by the names its definition declares. Kept sorted by name, one node per name; a name is borrowed for 'a or owned, as EffectParams names are.

EffectParams

Named values supplied to one runtime effect invocation.

EffectResources

Named resource identities supplied to one effect invocation.

EffectRuntime

Per-invocation values supplied by the timeline runner.

FrameSubmitTimings

Where one frame’s graph construction and submission spent its time.

GpuErrorReports

GPU errors the embedding saw that no scope of the renderer’s caught: on the browser, every uncaptured error its device reports.

GraphLayer

One owned layer reference in a graph composition node.

InputSpec

One image an effect samples besides its source, by the name its shader reads it under: sample_<name>(uv) and size_<name>().

LayerTransform

Placement and opacity of one composited layer.

Lut3dData

Canonical RGB samples for one cubic 3D lookup table.

LutParseError

Diagnostic returned while parsing .cube text.

MaskCombineNames

The names of one mask of a mask-combine pass: its coverage input and its parameters, as mask_combine_definition declares them.

PaintParams

The parameter names of one of the generator’s paints, as generator_definition declares them.

ParamSpec

One runtime effect parameter.

PassTiming

Most recent timing for one named render pass.

PendingEffect

A runtime effect whose shader module and pipeline exist on the device, with the device’s verdict on them still to come: Renderer::compile_effect made it, PendingEffect::compiled waits for the verdict, and Renderer::register_compiled adds what passed.

PendingSourceWork

One source-presentation pass waiting to be encoded by its first consumer.

PipelineCacheStats

Current pipeline-cache occupancy.

PlaneTarget

A caller-owned destination for one packed plane.

PreparedSourceTexture

A rendered source texture paired with presentation work that can be folded into the command encoder of its first consumer.

ReadbackBufferPoolStats

Allocation and retention counters for mapped readback buffers.

RenderCacheKey

Deterministic 128-bit key for a source or rendered graph result.

RenderDiagnostics

Snapshot of render performance, cache, memory, and scheduling behavior.

RenderGraph

An insertion-ordered, acyclic render program.

RenderNodeId

Stable handle to a node within one render graph.

RenderPlan

Compiled execution and lifetime schedule for a render graph.

RenderQualityControls

Quality controls consumed by graph compilation and pass execution.

RenderSize

A non-zero render-target extent.

RenderedTexture

A GPU texture produced by the renderer. Image passes store premultiplied sRGB RGBA; raw solid clears retain the supplied component values.

Renderer

Renders graphs of sources, effects, transitions and composites on one GPU device, and owns the pipelines, pools and caches they use.

ResourceBudget

Caller-owned resource envelope; zero means the corresponding resource is unavailable.

ResourceSpec

One named external resource required by an effect definition.

ResultCacheStats

Result-cache counters since the renderer was created.

Rgba8Readback

A submitted texture readback whose buffer has not been mapped yet.

ShaderDiagnostic

One schema or WGSL diagnostic.

ShaderDiagnostics

Diagnostics returned when runtime registration fails.

SourcePlane

One borrowed source plane: rows stride bytes apart.

SourcePresentation

GPU presentation transform applied while converting a decoded source.

SourceView

A texture the renderer draws from as a source, borrowed from whoever owns it: a RenderedTexture, an crate::UploadTexture (what crate::Renderer::upload_rgba8 returns), or, through the wgpu interop, any texture view of the renderer’s device.

StagingPlane

Where one plane sits in a mapped readback staging buffer.

TexturePoolStats

Observable allocation counters for the intermediate texture pool.

UniformBufferPoolStats

Allocation and retention counters for submission-scoped uniform arenas.

UniformField

Automatically computed uniform member placement.

UniformLayout

Host layout generated from a parameter schema.

UploadTexture

One source-upload texture retained by the renderer’s descriptor-keyed pool.

UploadTexturePoolStats

Allocation and retention counters for source-upload textures.

WarmupReport

Work completed by a graph warmup request.

Yuv420Frame

Borrowed 8-bit planar 4:2:0 source.

Yuv420pPlanes

Tightly packed planar YUV420 data produced by a GPU readback.

Yuv420pReadback

A submitted GPU RGB-to-YUV420 conversion whose buffer is not mapped yet.

Yuv420pTargets

Destinations for the three planes of one packed frame.

YuvFrame

Borrowed planar or semi-planar YCbCr source of any subsampling and depth YuvFormat::is_supported accepts.

YuvSample

A normalized YUV sample and straight alpha value.

Enums

BlendMode

Artistic RGB operation applied before Porter-Duff source-over coverage.

BlendSpace

Color space in which compositing arithmetic is evaluated.

CacheEligibility

Whether a node’s result can be cached, and if not, why.

CacheIntent

Whether a node’s result may be kept and reused.

CacheInvalidation

Why cached results were dropped all at once.

CapabilityDiagnostic

One deterministic fallback selected from adapter facts and caller budgets.

ColorDiagnostic

Observable color-pipeline diagnostic.

ColorError

Color conversion failure.

ColorPolicy

What happens to an HDR (PQ or HLG) source.

DiagnosticSeverity

Shader compiler message severity.

EffectKind

Runtime shader category.

EffectResourceKind

Representation an effect resource binding expects from its registered data.

GraphError

Structural or execution failure in a render graph.

ParamType

Host-side parameter representation.

ParamUnit

Semantic unit exposed to authoring hosts.

ParamValue

Typed default parameter value.

ReadbackFailure

Where a texture readback failed.

RenderError

Render input or output failure.

RenderNodeKind

Public category of a render graph node.

SdrOutputTransfer

SDR transfer used when encoding a render result.

SourceAlpha

How an RGBA source texture stores color relative to its alpha.

TimingSource

Source of one pass duration.

Constants

CHROMA_KEY_ID

Stable identifier of the built-in chroma-key effect.

DEFAULT_GPU_WAIT_TIMEOUT

How long a native caller waits for GPU work before giving up, unless the renderer is told otherwise.

FILL_PAINT_PARAMS

The fill paint’s parameter names: static, so a caller sets a generator’s paints without formatting a name.

GAUSSIAN_BLUR_ID

Stable identifier of the atomic Gaussian-blur effect.

GENERATOR_EFFECT_ID

Internal identifier of the generator pass.

GLOW_ID

Stable identifier of the built-in glow effect.

GPU_DEVICE_LOST_MESSAGE

The message of RenderError::GpuDeviceLost.

GPU_TIMEOUT_MESSAGE

The message every GPU wait timeout carries, so a host that sees only error text can still classify it: one sentence for the renderer, the native interop helpers, and encoder inputs alike. The sentence every wait on GPU work that timed out carries, wherever it was waited on (the renderer, a native interop helper, an encoder input), so a host that sees only error text tells a hung GPU from a generic failure. Hosts classify it as GPU_TIMEOUT.

GPU_WORK_DROPPED_MESSAGE

The message of RenderError::GpuWorkDropped. It names a lost device, which is what the host classifies it as.

LUT_3D_ID

Stable identifier of the resource-backed 3D LUT effect.

MASK_COMBINE_EFFECT_IDS

Internal identifiers of the mask-combine passes, by mask count minus one: the pass for n masks is MASK_COMBINE_EFFECT_IDS[n - 1].

MASK_COMBINE_NAMES

Each mask’s names, by mask index: static, so a caller sets a frame’s masks without formatting a name.

MASK_MODES

Enum values of a mask’s mode{i} parameter.

MAX_EFFECT_INPUTS

The most named inputs an effect declares. Its source pair, resources, and inputs must also fit the sampled textures a device offers a shader stage (16 on WebGL2-class limits), which registration checks per device.

MAX_GENERATOR_STOPS

Stops one paint carries. The project model allows as many.

MAX_SHAPE_MASKS

Masks one mask-combine pass combines at most. The project model allows as many, and each is one of its named inputs.

PAINT_KINDS

Enum values of a paint’s kind parameter.

PAINT_SPREADS

Enum values of a paint’s spread parameter.

TRACK_MATTE_EFFECT_ID

Internal identifier of the track-matte pass.

Traits

ExternalTextureLease

Keeps an imported native texture and its decoder surface alive until the queue has completed the submission that samples it.

Functions

builtin_catalog

Returns the complete engine-owned effect catalog as a host-friendly JSON value.

builtin_catalog_json

Serializes builtin_catalog for process and WebAssembly boundaries.

builtin_effect_definitions

Returns fresh definitions for every public built-in clip effect.

builtin_transition_definitions

Returns fresh, data-only definitions for all built-in transitions.

builtin_wgsl_modules

Returns every WGSL module the renderer can create, labelled: the built-in pipeline modules and the generated module of every built-in effect and transition.

chroma_key_definition

Returns the data-only definition of the built-in chroma-key effect.

convert_yuv_to_linear_rgba

Converts one integer-code-normalized YUV sample to premultiplied linear RGB.

effect_wgsl

Returns the complete module the renderer compiles for definition: the generated preamble for its parameters and resources, followed by its body.

encode_linear_rgb

Encodes linear-light RGB for an SDR output target.

filter_sample_limit

The most filter samples a pass takes on a device of tier: crate::RenderQualityControls::MAX_FILTER_SAMPLES, and 16 on Tier B (WebGL2, GL ES), whose fill rate the larger budgets outrun.

gaussian_blur_definition

Returns the data-only definition of the built-in Gaussian blur.

generator_definition

The generator pass: the fill paint over the whole picture.

glow_definition

Returns the data-only definition of the built-in glow.

is_hdr

Whether color is an HDR signal: PQ or HLG, or declared HDR.

lut_3d_definition

Returns the data-only definition of the resource-backed 3D LUT effect.

mask_combine_definition

The pass combining count masks (1 to MAX_SHAPE_MASKS) into its source’s coverage. Mask i is the named input m{i}, whose alpha is the mask’s coverage (drawn by the vector pass, feathered by a blur), inverted when invert{i} is set, and combined with the masks before it by mode{i}: coverage starts empty when the first mask adds and full otherwise; add is c + m - c m, subtract c (1 - m), intersect c m. The source is kept by the result.

mask_combine_definitions

Every mask-combine pass, for one to MAX_SHAPE_MASKS masks.

resolve_degradation

Resolves deterministic degradation without product- or device-name assumptions.

track_matte_definition

The track-matte pass: the first input kept where the second input’s alpha (or luminance over black: BT.709 weights on linear light, times alpha) says, optionally inverted.

yuv420p_staging_bytes

The bytes one planar YUV420 readback of size stages: each plane’s rows padded to the copy alignment, each plane starting on a placement boundary, and the 16-byte canary that proves the GPU wrote them. This is what an in-flight readback holds, and what a budget must reserve for it.