XRWebGLLayer

Secure context
This feature is available only in secure contexts (HTTPS), in some or all supporting browsers .

XRWebGLLayer interface of the WebXR Device API provides a linkage between the WebXR device (or simulated XR device, in the case of an inline session) and a WebGL context used to render the scene for display on the device. In particular, it provides access to the WebGL framebuffer and viewport to ease access to the context.

Although XRWebGLLayer is currently the only type of framebuffer layer supported by WebGL , it's entirely possible that future updates to the WebXR specification may allow for other layer types and corresponding image sources.

构造函数

new XRWebGLLayer()
Creates and returns a new XRWebGLLayer object for use by the specified XRSession , using a particular WebGLRenderingContext or WebGL2RenderingContext as the destination context.

特性

antialias 只读
A Boolean value indicating whether or not the WebGL context's framebuffer supports anti-aliasing. The specific type of anti-aliasing is determined by the user agent .
framebuffer 只读
返回 WebGLFramebuffer suitable for passing into the bindFrameBuffer() 方法。
framebufferWidth 只读
Returns the width of the XRWebGLLayer 's framebuffer.
framebufferHeight 只读
Returns the height of the layer's framebuffer.
ignoreDepthValues 只读
A Boolean which Indicates whether or not the WebXR compositor should make use of the contents of the layer's depth buffer while compositing the scene.

方法

getViewport()
返回新 XRViewport instance representing the position, width, and height to which the WebGL context's viewport must be set to contain drawing to the area of the framebuffer designated for the specified view's contents. In this way, for example, the rendering of the left eye's point of view and of the right eye's point of view are each placed into the correct parts of the framebuffer.

静态方法

getNativeFramebufferScaleFactor()
Returns the scaling factor that can be used to scale the resolution of the recommended WebGL framebuffer resolution to the rendering device's native resolution.

范例

Binding the layer to a WebGL context

This snippet, taken from Drawing a frame in Movement, orientation, and motion: A WebXR example , shows how the XRWebGLLayer is obtained from the XRSession object's rendering state and is then bound as the current rendering WebGL framebuffer by calling the WebGL bindFrameBuffer() 函数。

let glLayer = xrSession.renderState.baseLayer;
gl.bindFrameBuffer(gl.FRAMEBUFFER, glLayer.framebuffer);
					

Rendering every view in a frame

Each time the GPU is ready to render the scene to the XR device, the XR runtime calls the function you specified when you called the XRSession method requestAnimationFrame() to ask to render the frame.

That function receives as input an XRFrame which encapsulates the data needed to render the frame. This information includes the pose (an XRViewerPose object) that describes the position and facing direction of the viewer within the scene as well as a list of XRView objects, each representing one perspective on the scene. In current WebXR implementations, there will never be more than two entries in this list: one describing the position and viewing angle of the left eye and another doing the same for the right.

let pose = xrFrame.getViewerPose(xrReferenceSpace);
if (pose) {
  let glLayer = xrSession.renderState.baseLayer;
  gl.bindFrameBuffer(gl.FRAMEBUFFER, glLayer.Framebffer);
  for (let view of pose.views) {
    let viewport = glLayer.getViewport(view);
    gl.viewport(viewport.x, viewport.y, viewport.width, viewport.height);
    /* Render the view */
  }
}
					

规范

规范 状态 Comment
WebXR 设备 API
The definition of 'XRWebGLLayer' in that specification.
工作草案 初始定义。

浏览器兼容性

更新 GitHub 上的兼容性数据
Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
XRWebGLLayer Chrome 79 Edge 79 Firefox No IE No Opera No Safari No WebView Android No Chrome Android 79 Firefox Android No Opera Android No Safari iOS No Samsung Internet Android 11.2
XRWebGLLayer() 构造函数 Chrome 79 Edge 79 Firefox No IE No Opera No Safari No WebView Android No Chrome Android 79 Firefox Android No Opera Android No Safari iOS No Samsung Internet Android 11.2
antialias Chrome 79 Edge 79 Firefox No IE No Opera No Safari No WebView Android No Chrome Android 79 Firefox Android No Opera Android No Safari iOS No Samsung Internet Android 11.2
framebuffer Chrome 79 Edge 79 Firefox No IE No Opera No Safari No WebView Android No Chrome Android 79 Firefox Android No Opera Android No Safari iOS No Samsung Internet Android 11.2
framebufferHeight Chrome 79 Edge 79 Firefox No IE No Opera No Safari No WebView Android No Chrome Android 79 Firefox Android No Opera Android No Safari iOS No Samsung Internet Android 11.2
framebufferWidth Chrome 79 Edge 79 Firefox No IE No Opera No Safari No WebView Android No Chrome Android 79 Firefox Android No Opera Android No Safari iOS No Samsung Internet Android 11.2
getNativeFramebufferScaleFactor() Chrome 79 Edge 79 Firefox No IE No Opera No Safari No WebView Android No Chrome Android 79 Firefox Android No Opera Android No Safari iOS No Samsung Internet Android 11.2
getViewport() Chrome 79 Edge 79 Firefox No IE No Opera No Safari No WebView Android No Chrome Android 79 Firefox Android No Opera Android No Safari iOS No Samsung Internet Android 11.2
ignoreDepthValues Chrome 79 Edge 79 Firefox No IE No Opera No Safari No WebView Android No Chrome Android 79 Firefox Android No Opera Android No Safari iOS No Samsung Internet Android 11.2

图例

完整支持
完整支持
不支持
不支持

另请参阅