2023-11-10 07:04:16 -05:00

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# Device
:::caution
The luma.gl v9 API is currently in [public review](/docs/public-review) and may be subject to change.
:::
The `Device` class manages the application's connection with the GPU,
providing methods to:
- create GPU resources
- query the capabilities of the GPU
- detect error conditions.
A `Device` is created through static `Device.create(...)` method.
Note that the actual `Device` returned by `Device.create()` will be either
a `WebGLDevice` wrapping a WebGL context or a `WebGPUDevice` wrapping a WebGPU device
based on what the run-time environment (ie. browser or Node.js) supports.
## Usage
Creates a WebGL2 or WebGL context, auto creating a canvas
```typescript
import {Device} from '@luma.gl/core';
const device = new Device(); // Prefers WebGL 2 but falls back to WebGL 1
```
Creates a WebGL 2 context (throws if WebGL2 not supported)
```typescript
import {Device} from '@luma.gl/core';
const device = createGLContext({
webgl1: false
});
```
Attaching a Device to an externally created WebGLRendering context instruments it
so that it works with other luma.gl classes.
```typescript
import {Device} from '@luma.gl/core';
import {Model} from '@luma.gl/engine';
const device = Device.attach(gl); // "instruments" the external context
// Instrumentation ensures the context works with higher-level classes.
const model = new Model(gl, options);
```
Attaching a device to a WebGL1 context adds WebGL2 "polyfills" to the WebGLRendering context
extends that context with a subset of WebGL2 APIs that are available via WebGL extensions.
```typescript
const gl = canvas.createContext('webgl'); // A WebGL 1 context
const device = Device.attach(gl);
// Can now use a subset of WebGL2 APIs on
const vao = device.gl.createVertexArray();
```
Handle GPU disconnections:
```typescript
if (!device.isLost) {
...
}
const {message} = await device.lost;
console.error(message);
```
## Types
### `DeviceProps`
| Parameter | Default | Description |
| ------------------------------- | ------------------ | --------------------------------------------------------------------------------------------------------------------------- |
| `type` | `'best-available'` | `'webgpu`', `'webgl'`, `'webgl1'`, `'webgl2'` |
| `canvas` | N/A | A _string_ `id` of an existing HTML element or a _DOMElement_. If not provided, a new canvas will be created. |
| priority. |
| `debug?: boolean` | `false` | WebGL API calls will be logged to the console and WebGL errors will generate JavaScript exceptions. |
| `break?: string[]` | `[]` | Insert a break point (`debugger`) if one of the listed gl functions is called. |
| `alpha?: boolean` | `true` | Default render target has an alpha buffer. |
| `depth?: boolean` | `true` | Default render target has a depth buffer of at least `16` bits. |
| `stencil?` | `false` | Default render target has a stencil buffer of at least `8` bits. |
| `antialias?` | `true` | Boolean that indicates whether or not to perform anti-aliasing. |
| `premultipliedAlpha?` | `true` | Boolean that indicates that the page compositor will assume the drawing buffer contains colors with pre-multiplied alpha. |
| `preserveDrawingBuffer?` | `false` | Default render target buffers will preserve their values until cleared or overwritten. Useful for screen capture. |
| `failIfMajorPerformanceCaveat?` | `false` | Do not create if the system performance is low. |
## Static Methods
### create
```typescript
Device.create(props: DeviceProps): Promise<Device>
```
Creating device is done with the static `Device.create()` method.
Creates and returns a WebGL context, both in browsers and in Node.js.
```typescript
const device = await Device.create(props);
```
- `props` (_Object_) - key/value pairs containing context creation options
## Fields
### id
```typescript
readonly id: string
```
A string identifier, for debug purposes.
### statsManager
```typescript
statsManager: StatsManager
```
Provides access to bags of stats containing information about resource usage and performance of the device.
### props
```typescript
props: Required<DeviceProps>
```
A readonly copy of the props that were used to create this device.
### userData
```typescript
userData: Record<string, any>
```
Reserved for the application.
### info
```typescript
info: DeviceInfo
```
Information about the device (vendor, versions etc).
Get debug information about the device
| Field | Type | Description |
| ------------------------ | -------- | --------------------------------- |
| `vendor` | `string` | GPU vendor (unmasked if possible) |
| `renderer` | `string` | Renderer (unmasked if possible) |
| `version` | `string` | WebGL version |
| `shadingLanguageVersion` | `string` | shading language version |
Remarks:
- WebGPU Devices currently do not provide much information due to limitations in the WebGPU API.
- WebGL Devices can usually provide the full set of information (through the `WEBGL_debug_renderer_info` extension).
### features
```typescript
features: Set<DeviceFeature>
```
Applications can determine whether the device implements an optional features by checking `device.features.has(...)`.
### limits
```typescript
limits: DeviceLimits
```
An object with various device limits. WebGPU style.
### isTextureFormatSupported
```typescript
isTextureFormatSupported(format: TextureFormat): boolean
```
Check if device supports a specific texture format (creation and `nearest` sampling).
### isTextureFormatFilterable
```typescript
isTextureFormatFilterable(format: TextureFormat): boolean
```
Check if linear filtering (sampler interpolation) is supported for a specific texture format.
### isTextureFormatRenderable
```typescript
isTextureFormatRenderable(format: TextureFormat): boolean
```
Check if device supports rendering to a specific texture format.
### isLost
```typescript
isLost: boolean
```
True if the device is already lost (GPU is disconnected).
### lost
```typescript
lost: Promise<{reason: 'destroyed', message: string}>
```
Promise that resolves with an error message if the device is lost (GPU is disconnected).
:::info
GPU disconnections normally happen when the computer goes to sleep but it can also happen
when too many applications use the GPU, too many `Device` instances are created etc.
:::
:::info
Recovering from a lost GPU device is typically challenging as all GPU resources need to be
recreated. For applications that auto-save state, it may be better to simply reload the page
or ask the user to reload the page.
:::
### canvasContext
```typescript
canvasContext?: CanvasContext
```
Returns the default [`CanvasContext`](./canvas-context).
Note that a WebGPU `Device` may not have a canvas context.
## Methods
### constructor
:::info
`Device` is an abstract class and the constructor should not be called directly.
Use the static `Device.create()` method to create classes.
:::
### destroy()
Releases resources associated with this `Device`.
:::info
Whether destroying a device actually releases resources depends on the underlying `Device` implementation in use.
- WebGL does not have a context destroy function.
- However, if headless gl is running the destroy extension will be called.
:::
:::info
Interaction between `Device.destroy()`, `Device.lost` and `Device.isLost` is implementation-dependent.
Whether destroying a device trigger a device loss, the order of isLost promise resolution versus API errors caused by destroyed device etc, should not be relied upon.
:::
### createCanvasContext()
```typescript
createCanvasContext(props?: CanvasContextProps): CanvasContext
```
:::info
WebGPU only. (WebGL devices can only render into the canvas they were created with).
:::
Creates a new [`CanvasContext`](./canvas-context).
### getCanvasContext()
```typescript
getCanvasContext(): CanvasContext
```
Returns the primary canvas context of a device.
In TypeScript applications this helps applications avoid having to repeatedly check if `device.canvasContext` is null,
otherwise the two are equivalent.
Throws an error if no canvas context is available (a WebGPU compute device).
### submit
```typescript
submit(): void
```
Call after rendering a frame is complete.
### createBuffer
```typescript
createBuffer(props: BufferProps): Buffer
createBuffer(data: ArrayBuffer | ArrayBufferView): Buffer
```
Creates a [`Buffer`](./resources/buffer) used to manage memory on the GPU.
Deduces `indexType` if usage.
### createTexture
```typescript
createTexture(props: TextureProps): Texture
createTexture(data: Promise<TextureData>): Texture
```
Creates a [`Texture`](./resources/texture), used to manage image data memory on the GPU.
### createSampler
```typescript
createSampler(props: SamplerProps): Sampler
```
Creates a [`Sampler`](./resources/sampler).
### createFramebuffer
```typescript
createFramebuffer(props: FramebufferProps): Framebuffer
```
Creates a [`Framebuffer`](./resources/framebuffer).
### createShader
```typescript
createShader(props: ShaderProps): Shader
```
Creates a [`Shader`](./resources/shader).
### createRenderPipeline
```typescript
createRenderPipeline(props: RenderPipelineProps): RenderPipeline
```
Creates a [`RenderPipeline`](./resources/render-pipeline) (aka program)
### createComputePipeline
```typescript
createComputePipeline(props: ComputePipelineProps): ComputePipeline
```
Creates a [`ComputePipeline`](./resources/compute-pipeline) (aka program)
### beginRenderPass
```typescript
beginRenderPass(props: RenderPassProps): RenderPass
```
Creates a [`RenderPass`](./resources/render-pass).
### beginComputePass
```typescript
beginComputePass(props?: ComputePassProps): ComputePass
```
Creates a [`ComputePass`](./resources/compute-pass) which can be used to bind data and run compute operations using compute pipelines.
### getDefaultRenderPass
```typescript
getDefaultRenderPass(): RenderPass
```
A default `RenderPass` is provided for applications that don't need to create
multiple or specially configured render passes.
Note that a new default `RenderPass` is returned every animation frame.
## Remarks
- Note that the actual `Device` returned by `Device.create()` can be either
a `WebGLDevice` wrapping a WebGL context or a `WebGPUDevice` wrapping a WebGPU device
based on what the run-time environment (ie. browser or Node.js) supports.
- The `Device` API is intentionally similar, but not identical, to the [WebGPU `GPUDevice`](https://www.w3.org/TR/webgpu/#gpu-device) class API.
### loseDevice
```typescript
loseDevice(): boolean
```
Triggers device loss (see below). After this call, the `Device.lost` promise will be resolved with an error message and `Device.isLost` will be set to true.
- Returns `true` if an actual or emulated device loss was triggered, `false` otherwise. Note that even if device loss emulation is not supported by the platform this function will still update the `Device` instance to indicate that the device was lost, however the device can still be used.
:::note
The `loseDevice()` method is primarily intended for debugging of device loss handling and should not be relied upon for production code.
`loseDevice()` can currently only emulate context loss on WebGL devices on platform's where WebGL API provides the required `WEBGL_lose_context` WebGL debug extension.
:::
## WebGL specific fields
### isWebGL
```typescript
isWebGL: boolean
```
`true` if the context is a WebGL 1 or 2 Context.
### isWebGL2
```typescript
isWebGL2: boolean
```
Test if an object is a WebGL context.
Returns `true` if the context is a WebGL 2 Context.