XRWebGLLayerInit.framebufferScaleFactor - Web APIs 编辑

Secure context

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

The XRWebGLLayerInit dictionary's framebufferScaleFactor property, when specified upon instantiating a new XRWebGLLayer using its constructor, XRWebGLLayer(), specifies the scaling factor to use when determining the size of the frame buffer to use when rendering the scene, relative to the default XR device display resolution.

For example, a value of 1.0 indicates that the frame buffer should be the same resolution as the actual display, while a value of 0.5 indicates that the frame buffer should be half the resolution of the display. A value of 2.0, on the other hand, creates a frame buffer whose resolution is double that of the actual display buffer.

There are valid use cases for all of these kinds of scaling. See Managing rendering quality in WebXR performance guide for more information.

You can determine the scaling factor that you would need to apply to match the default frame buffer resolution by using the XRWebGLLayer.getNativeFramebufferScaleFactor() static function.

Syntax

let layerInit = {
  framebufferScaleFactor: scaleFactor
};
let glLayer = new XRWebGLLayer(xrSession, gl, layerInit);

let glLayer = new XRWebGLLayer(xrSession, gl, { framebufferScaleFactor: scaleFactor });

Value

A floating-point value indicating a multiplier to apply to the default frame buffer resolution in order to determine the resolution of the frame buffer for the XRWebGLLayer.

Example

In this example, a new XRWebGLLayer is created for a WebXR session, xrSession, with a frame buffer whose resolution is half that of the default display resolution of the XR device.

xrSession.updateRenderState({
  baseLayer: new XRWebGLLayer(xrSession, gl, {
     framebufferScaleFactor: 0.5
  });
});

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• WebXR Device API
• Getting started with WebGL
• WebXR performance guide
• XRWebGLLayer.getNativeFramebufferScaleFactor()