Capability

구문

type Capability =
  | 'storageBuffer'
  | 'compute'
  | 'msaaTextureLoad'
  | 'storageTexture'
  | 'texture1d'
  | 'textureCubeArray'
  | 'textureGather'
  | 'f16'
  | 'subgroups'
  | 'clipDistances'
  | 'primitiveIndex'
  | 'dualSourceBlending'
  | 'floatRenderTarget'
  | 'float32Blend'
  | 'float32Filterable'
  | 'multiview'
  | 'bgra8unormStorage'
  | 'packed4x8Dot';

설명

Emitting a module that needs an unsupported feature throws UnsupportedFeatureError: a capability absent from the target’s capProfile fails closed, naming the capability.

Ids are neutral; a module never names a raw EXT_* or OVR_* string. Each backend’s capProfile row translates the id into that target’s hostFeature (what the host activates: gl.getExtension(...) on WebGL2, a requiredFeatures entry on WebGPU) and its directive (what the emitted source says), so the same module ports across targets whose extension names differ.

There are three classes:

• Derived resource capabilities, storageBuffer, compute, msaaTextureLoad and storageTexture, are inferred from a module’s shape (a storage binding, a @compute entry, a multisampled texture load, a storage-texture binding) and never declared.
• Opt-in language capabilities, f16, subgroups, clipDistances and primitiveIndex, are declared in ModuleDecl.enables, or — for the two that a @builtin(...) id names outright — derived from that use by requiredCaps, the way enable clip_distances; is what WGSL asks for before @builtin(clip_distances) is spelled. Each is a WGSL enable directive with no GLSL ES 3.00 counterpart, so a module using one fails closed on the GLSL backend.
• Opt-in device capabilities are also declared in ModuleDecl.enables. They change what the device can do and leave what the source may spell unchanged. floatRenderTarget (WebGL2 EXT_color_buffer_float, WebGPU core), float32Blend (EXT_float_blend, WebGPU 'float32-blendable') and float32Filterable (OES_texture_float_linear, WebGPU 'float32-filterable') are host-side: on WebGL2 the host activates them with gl.getExtension before creating the pipeline, and they have no shader-source token, so declaring one leaves the emitted source unchanged on both targets. multiview is the one source-directive capability: GLSL ES 3.00 needs #extension GL_OVR_multiview2 : require in the shader itself. It is absent from the WGSL profile, since WebGPU has no equivalent, so a multiview module fails closed there. Note that multiview buys the directive only: a module declaring it emits the #extension line and still renders single-view, because the DSL cannot spell layout(num_views = N) in; or read gl_ViewID_OVR.

A bit width appears in an id only where the feature is bit-width specific: float32Blend and float32Filterable carry the 32 because both underlying features are 32-bit-float only. floatRenderTarget carries none, because EXT_color_buffer_float makes both 16-bit and 32-bit float attachments renderable.

A host reads what to activate from reflect().requiredFeatures.

함께 보기

• UnsupportedFeatureError

소스

src/core/ir/nodes.ts, 724행, 커밋 c66579bf 기준