Class Context

constructor

• new Context(gl): Context

• Creates a rendering context.

  Parameters

  • gl: WebGL2RenderingContext

    The rendering context.

  Returns Context
• new Context(canvas, alpha?, depth?, stencil?, desynchronized?, antialias?, failIfMajorPerformanceCaveat?, powerPreference?, premultipliedAlpha?, preserveDrawingBuffer?): Context

• Creates a rendering context.

  Parameters

  • canvas: Canvas

    The canvas of the rendering context.

  • Optional alpha: boolean

    Whether the canvas contains an alpha buffer.

  • Optional depth: boolean

    Whether the drawing buffer should have a depth buffer of at least 16 bits.

  • Optional stencil: boolean

    Whether the drawing buffer should have a stencil buffer of at least 8 bits.

  • Optional desynchronized: boolean

    Whether the user agent should reduce latency by desynchronizing the canvas paint cycle from the event loop.

  • Optional antialias: boolean

    Whether or not to perform anti-aliasing if possible.

  • Optional failIfMajorPerformanceCaveat: boolean

    Whether the context will fail to be created if the system performance is low or if no hardware GPU is available.

  • Optional powerPreference: PowerPreference

    Which configuration of GPU is suitable for the context.

  • Optional premultipliedAlpha: boolean

    Whether the page compositor will assume that the drawing buffer contains colors with pre-multiplied alpha.

  • Optional preserveDrawingBuffer: boolean

    Whether the buffers will preserve their values until cleared or overwritten by the author.

  Returns Context

Readonly canvas

Readonly internal

blendFunctions

• get blendFunctions(): undefined | BlendFunctionSet

• The blending functions. Disables blending if not defined.

  Returns undefined | BlendFunctionSet

  See

  blendFunc

• set blendFunctions(value): void

• The blending functions. Disables blending if not defined.

  Parameters

  • value: undefined | BlendFunctionSet

  Returns void

  See

  blendFunc

cullFace

• get cullFace(): undefined | FaceDirection

• The direction that polygons face to be culled. Disables polygon culling if not defined.

  Returns undefined | FaceDirection

  See

  cullFace

• set cullFace(value): void

• The direction that polygons face to be culled. Disables polygon culling if not defined.

  Parameters

  • value: undefined | FaceDirection

  Returns void

  See

  cullFace

depthFunction

• get depthFunction(): undefined | TestFunction

• The depth comparison function in use. Disables the depth test if not defined.

  Returns undefined | TestFunction

  See

  depthFunc

• set depthFunction(value): void

• The depth comparison function in use. Disables the depth test if not defined.

  Parameters

  • value: undefined | TestFunction

  Returns void

  See

  depthFunc

doDither

• get doDither(): boolean

• Whether color components are dithered before they get written to the color buffer.

  Returns boolean
• set doDither(value): void

• Whether color components are dithered before they get written to the color buffer.

  Parameters

  • value: boolean

  Returns void

doRasterizerDiscard

• get doRasterizerDiscard(): boolean

• Whether primitives are discarded immediately before the rasterization stage.

  Returns boolean

  See

  GPGPU

• set doRasterizerDiscard(value): void

• Whether primitives are discarded immediately before the rasterization stage.

  Parameters

  • value: boolean

  Returns void

  See

  GPGPU

doSampleAlphaToCoverage

• get doSampleAlphaToCoverage(): boolean

• Whether a temporary coverage value is computed based on the alpha value.

  Returns boolean
• set doSampleAlphaToCoverage(value): void

• Whether a temporary coverage value is computed based on the alpha value.

  Parameters

  • value: boolean

  Returns void

frontFace

• get frontFace(): WindingOrientation

• The winding orientation of front-facing polygons.

  Returns WindingOrientation

  See

  frontFace

• set frontFace(value): void

• The winding orientation of front-facing polygons.

  Parameters

  • value: WindingOrientation

  Returns void

  See

  frontFace

polygonOffset

• get polygonOffset(): undefined | PolygonOffset

• The scale factor and units used to calculate depth values. Disables polygon offset fill if not defined.

  Returns undefined | PolygonOffset

  See

  polygonOffset

• set polygonOffset(value): void

• The scale factor and units used to calculate depth values. Disables polygon offset fill if not defined.

  Parameters

  • value: undefined | PolygonOffset

  Returns void

  See

  polygonOffset

sampleCoverage

• get sampleCoverage(): undefined | MultiSampleCoverageParameters

• Whether fragments should be combined with the temporary coverage value. Disabled if not defined.

  Returns undefined | MultiSampleCoverageParameters
• set sampleCoverage(value): void

• Whether fragments should be combined with the temporary coverage value. Disabled if not defined.

  Parameters

  • value: undefined | MultiSampleCoverageParameters

  Returns void

scissorBox

• get scissorBox(): undefined | Box

• The scissor box, which limits drawing to a specified rectangle. Disabled if not defined.

  Returns undefined | Box

  See

  scissor

• set scissorBox(value): void

• The scissor box, which limits drawing to a specified rectangle. Disabled if not defined.

  Parameters

  • value: undefined | Box

  Returns void

  See

  scissor

stencilFunctions

• get stencilFunctions(): undefined | StencilTestSet

• The stencil test function and reference value. The stencil test is disabled if not defined.

  Returns undefined | StencilTestSet

  See

  stencilFunc

• set stencilFunctions(value): void

• The stencil test function and reference value. The stencil test is disabled if not defined.

  Parameters

  • value: undefined | StencilTestSet

  Returns void

  See

  stencilFunc

viewport

• get viewport(): Box

• The viewport box, which specifies the affine transformation of coordinates from normalized device coordinates to window coordinates.

  Returns Box

  See

  viewport

• set viewport(value): void

• The viewport box, which specifies the affine transformation of coordinates from normalized device coordinates to window coordinates.

  Parameters

  • value: Box

  Returns void

  See

  viewport

clear

• clear(color?, depth?, stencil?): void

• Clears the specified buffers to the specified values.

  Parameters

  • Optional color: ColorLike

    The color to clear the color buffer to, if any.

  • Optional depth: number

    The value to clear the depth buffer to, if any.

  • Optional stencil: number

    The value to clear the stencil buffer to, if any.

  Returns void

fitDrawingBuffer

• fitDrawingBuffer(): boolean

• Resizes this context's canvas' drawing buffer to match its physical size.

  Returns boolean

  Whether the drawing buffer was resized.

fitViewport

• fitViewport(): void

• Resizes this context's viewport to match the size of its current drawing buffer.

  Returns void

getExtension

• getExtension(extension): undefined | ExtensionObject

• Gets the requested extension.

  Parameters

  • extension: Extension

    The extension's name.

  Returns undefined | ExtensionObject

  The extension.

getSupportedExtensions

• getSupportedExtensions(): Extension[]

• Gets a list of all of the supported extensions.

  Returns Extension[]

  A list of all of the supported extensions.

makeXrCompatible

• makeXrCompatible(): Promise<void>

• Makes this context XR-compatible.

  Returns Promise<void>

  A promise that resolves once the WebGL context is ready to be used for rendering WebXR content.

  See

  WebXR Device API

resize

• resize(): boolean

• Resizes this context's canvas' drawing buffer to match its physical size, a viewport to match the drawing buffer, and disables the scissor test.

  Returns boolean

  Whether the drawing buffer was resized.
• resize(x, y, width, height): boolean

• Resizes this context's canvas' drawing buffer to match its physical size, the context's viewport and scissor box to match the given size, and enables the scissor test.

  Parameters

  • x: number

    The horizontal offset of the viewport and scissor box.

  • y: number

    The vertical offset of the viewport and scissor box.

  • width: number

    The horizontal size of the viewport and scissor box.

  • height: number

    The vertical size of the viewport and scissor box.

  Returns boolean

  Whether the drawing buffer was resized.