Skip to main content

@novorender/web_app / RenderContext

Class: RenderContext

The view specific context for rendering and picking.

Remarks​

A render context describes a view into which a RenderState can be rendered. It is tightly bound to a HTML canvas and WebGL2RenderingContext. Consequently, it will be disposed if the gl context is lost and recreated when the gl context is restored.

The render context must be initialized with an array of render modules. Unused modules may be removed and custom ones inserted here. Ordering the modules correctly is important as they are rendered in order. The TonemapModule should be last, as it will copy the HDR render buffers into the output canvas to make things visible.

Features such as async picking and shader linking requires poll to be called at regular intervals, e.g. at the start of each frame. Otherwise the promises will never be resolved.

Accessors​

height​

get height(): number

Return the current pixel height of the drawing buffer.

Returns​

number

Defined in​

@novorender/core3d/context.ts:331

width​

get width(): number

Return the current pixel width of the drawing buffer.

Returns​

number

Defined in​

@novorender/core3d/context.ts:326

Methods​

clearPickBuffers()​

clearPickBuffers(): void

Returns​

void

Defined in​

@novorender/core3d/context.ts:735

dispose()​

dispose(): void

Dispose of the GPU resources used by this context, effectively destroying it and freeing up memory.

Returns​

void

Remarks​

Calling this method is optional as the garbage collection of the underlying WebGL render context will do the same thing. This may take some time, however, so calling this function is recommended if you plan to create a new context shortly thereafter.

Defined in​

@novorender/core3d/context.ts:306

getDeviations()​

getDeviations(): Promise<DeviationSample[]>

scan the pick buffer for deviation values

Returns​

Promise<DeviationSample[]>

Return pixel coordinates and deviation values for any deviation on screen

Defined in​

@novorender/core3d/context.ts:799

getLinearDepths()​

getLinearDepths(pick): IterableIterator<number>

Parameters​

ParameterType
pickUint32Array

Returns​

IterableIterator<number>

Defined in​

@novorender/core3d/context.ts:788

getOutlines()​

getOutlines(): Promise<OutlineSample[]>

scan the pick buffer for pixels from clipping outline

Returns​

Promise<OutlineSample[]>

Return pixel coordinates and world position for any clipping outline on screen

Defined in​

@novorender/core3d/context.ts:845

hasStateChanged()​

hasStateChanged(state): boolean

Helper function to check for changes in render state.

Parameters​

ParameterTypeDescription
statePartial<DerivedRenderState>The parts of the render state to check for changes.

Returns​

boolean

True if any of the specified parts has changed since last frame.

Remarks​

Since the render state is immutable, any changes will automatically trickle up to the container object as well. Thus, this function does a shallow strict equality of the parts of the renderstate specified in the state parameter.

Example​

Example of how to check for changes in either camera or output render state.

const {camera, output} = renderState;
if(renderContext.hasStateChanged({camera, output})) {
  // update related GPU state here...
}

Defined in​

@novorender/core3d/context.ts:407

init()​

init(modules?): Promise<void>

Initialize render context with specified render modules.

Parameters​

ParameterType
modules?readonly RenderModule[]

Returns​

Promise<void>

Remarks​

The default/built-in render modules can be retrieved using createDefaultModules. These will be used if no modules are specified. Developers may introduce their own render modules here. Note that the order of the modules matters, as this is the order by which they will be rendered.

Defined in​

@novorender/core3d/context.ts:253

isContextLost()​

isContextLost(): boolean

Query whether the underlying WebGL render context is currently lost.

Returns​

boolean

Remarks​

This could occur when too many resources are allocated or when browser window is dragged across screens. Loss and restoration of WebGL contexts is supported by this API automatically.

Defined in​

@novorender/core3d/context.ts:347

isPickBuffersValid()​

isPickBuffersValid(): boolean

Query if pick buffers are valid.

Returns​

boolean

Remarks​

This could be useful for optimistic/non-async picking.

Defined in​

@novorender/core3d/context.ts:338

makeProgramAsync()​

makeProgramAsync(resourceBin, params): Promise<WebGLProgram>

Compile WebGL/GLSL shader program asynchronously.

Parameters​

ParameterType
resourceBinResourceBin
paramsAsyncProgramParams

Returns​

Promise<WebGLProgram>

Defined in​

@novorender/core3d/context.ts:427

pick()​

pick(
   x, 
   y, 
options?): Promise<PickSample[]>

Pick information about underlying object and geometry.

Parameters​

ParameterTypeDescription
xnumberCenter x coordinate in CSS pixels.
ynumberCenter y coordinate in CSS pixels.
options?PickOptionsMore details of pick operation.

Returns​

Promise<PickSample[]>

A set of pick samples of the specified sample disc.

Defined in​

@novorender/core3d/context.ts:1160

poll()​

poll(): void

Poll the status of WebGL pick fences and timers and resolve associated promises when possible.

Returns​

void

Defined in​

@novorender/core3d/context.ts:533

render()​

render(state): Promise<RenderStatistics>

Render a new frame using the specified render state.

Parameters​

ParameterTypeDescription
stateRenderStateAn object describing what the frame should look like.

Returns​

Promise<RenderStatistics>

A promise to the performance related statistics involved in rendering this frame.

Defined in​

@novorender/core3d/context.ts:582

renderPickBuffers()​

renderPickBuffers(): void

Returns​

void

Defined in​

@novorender/core3d/context.ts:740

resourceBin()​

resourceBin(name): ResourceBin

Create a new named resource bin.

Parameters​

ParameterType
namestring

Returns​

ResourceBin

Defined in​

@novorender/core3d/context.ts:422

setPolygonFillMode()​

setPolygonFillMode(mode): void

Parameters​

ParameterType
mode"FILL" | "LINE"

Returns​

void

Defined in​

@novorender/core3d/context.ts:1196

updateIBLTextures()​

updateIBLTextures(params): void

Explicitly update WebGL IBL textures from specified parameters.

Parameters​

ParameterType
paramsnull | object

Returns​

void

Defined in​

@novorender/core3d/context.ts:370

updateUniformBuffer()​

updateUniformBuffer(uniformBuffer, proxy): void

Helper function to update WebGL uniform buffer from proxies.

Parameters​

ParameterType
uniformBufferWebGLBuffer
proxyUniformsProxy

Returns​

void

Defined in​

@novorender/core3d/context.ts:361

nextFrame()​

static nextFrame(context): Promise<number>

Wait for the next frame to be ready for rendering.

Parameters​

ParameterTypeDescription
contextundefined | RenderContextrender context to wait for, if any.

Returns​

Promise<number>

Remarks​

Use this function instead of requestAnimationFrame()!

Defined in​

@novorender/core3d/context.ts:561

Properties​

buffers​

buffers: RenderBuffers;

WebGL render and pick buffers

Remarks​

Note that these buffers will be recreated whenever the RenderState.output size changes.

Defined in​

@novorender/core3d/context.ts:128

cameraUniforms​

readonly cameraUniforms: WebGLBuffer;

WebGL uniform buffer for camera related uniforms.

Defined in​

@novorender/core3d/context.ts:87

canvas​

readonly canvas: HTMLCanvasElement;

The HTML canvas used for this context.

Defined in​

@novorender/core3d/context.ts:152

changed​

changed: boolean = true;

Set to true to force a re-render when state not contained in RenderState has changed, e.g. download complete etc.

Defined in​

@novorender/core3d/context.ts:121

clippingUniforms​

readonly clippingUniforms: WebGLBuffer;

WebGL uniform buffer for clipping related uniforms.

Defined in​

@novorender/core3d/context.ts:89

commonChunk​

readonly commonChunk: string;

WebGL common GLSL code header used across shaders.

Defined in​

@novorender/core3d/context.ts:40

currentState​

currentState: undefined | DerivedRenderState;

RenderState used to make the newest state available during render.

Defined in​

@novorender/core3d/context.ts:118

defaultIBLTextureParams​

readonly defaultIBLTextureParams: TextureParamsCubeUncompressed;

WebGL basic fallback IBL textures to use while loading proper IBL textures.

Defined in​

@novorender/core3d/context.ts:42

deviceProfile​

readonly deviceProfile: DeviceProfile;

The device profile use for this context.

Defined in​

@novorender/core3d/context.ts:150

gl​

readonly gl: WebGL2RenderingContext;

WebGL2 render context associated with this object.

Defined in​

@novorender/core3d/context.ts:38

iblTextures​

iblTextures: object;

WebGL textures used for image based lighting (IBL).

default​

readonly default: boolean;

True if these are the default IBL textures.

diffuse​

readonly diffuse: WebGLTexture;

WebGL cubemap texture containing the irradiance/diffuse values of current IBL environment.

numMipMaps​

readonly numMipMaps: number;

mip maps in current specular texture.

specular​

readonly specular: WebGLTexture;

WebGL cubemap texture containing the radiance/specular values of current IBL environment.

Remarks​

Note that these buffers will be changed by the background module when download of the specified RenderState.background.url IBL textures completes.

The process to create the textures are similar to that of https://github.com/KhronosGroup/glTF-IBL-Sampler/

Defined in​

@novorender/core3d/context.ts:136

imports​

readonly imports: Core3DImports;

Imported resources.

Defined in​

@novorender/core3d/context.ts:154

lut_ggx​

readonly lut_ggx: WebGLTexture;

WebGL GGX/PBR shading lookup table texture.

Defined in​

@novorender/core3d/context.ts:93

outlineRenderers​

outlineRenderers: WeakMap<ReadonlyVec4, OutlineRenderer>;

Defined in​

@novorender/core3d/context.ts:108

outlineUniforms​

readonly outlineUniforms: WebGLBuffer;

WebGL uniform buffer for outline related uniforms.

Defined in​

@novorender/core3d/context.ts:91

prevState​

prevState: undefined | DerivedRenderState;

RenderState used to render the previous frame, if any.

Defined in​

@novorender/core3d/context.ts:114

samplerEnvMip​

readonly samplerEnvMip: WebGLSampler;

WebGL Sampler used to sample mip mapped IBL texture trilinear.

Defined in​

@novorender/core3d/context.ts:95

samplerMip​

readonly samplerMip: WebGLSampler;

WebGL Sampler used to sample mipmapped texture trilinear.

Defined in​

@novorender/core3d/context.ts:97

samplerMipRepeat​

readonly samplerMipRepeat: WebGLSampler;

WebGL Sampler used to sample mipmapped texture trilinear repeating UV.

Defined in​

@novorender/core3d/context.ts:99

samplerSingle​

readonly samplerSingle: WebGLSampler;

WebGL Sampler used to sample other, non-mipmapped IBL textures bilinear.

Defined in​

@novorender/core3d/context.ts:101

usePrepass​

readonly usePrepass: false = false;

Defined in​

@novorender/core3d/context.ts:74

wasm​

readonly wasm: WasmInstance;

Web assembly instance.

Defined in​

@novorender/core3d/context.ts:44