XRWebGLBinding.createEquirectLayer()

The createEquirectLayer() method of the XRWebGLBinding interface returns an XREquirectLayer object, which is a layer that maps equirectangular coded data onto the inside of a sphere.

Syntax

createEquirectLayer(init)

Parameters

init

An object to configure the XREquirectLayer. It must have the space, viewPixelHeight, and viewPixelWidth properties. init has the following properties:

• centralHorizontalAngle: Optional. A number indicating the central horizontal angle in radians of the sphere. Default value: 6.28318 (2π).
• colorFormat: Optional. A GLenum defining the data type of the color texture data. Possible values:
  • gl.RGB
  • gl.RGBA
  Additionally, for contexts with the EXT_sRGB extension enabled:
  • ext.SRGB_EXT
  • ext.SRGB_ALPHA_EXT
  Additionally, for WebGL2RenderingContext contexts:
  • gl.RGBA8
  • gl.RGB8
  • gl.SRGB8
  • gl.RGB8_ALPHA8
  Additionally, for contexts with the WEBGL_compressed_texture_etc extension enabled:
  • ext.COMPRESSED_RGB8_ETC2
  • ext.COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2
  • ext.COMPRESSED_RGBA8_ETC2_EAC
  • ext.COMPRESSED_SRGB8_ETC2
  • ext.COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2
  • ext.COMPRESSED_SRGB8_ALPHA8_ETC2_EAC
  Additionally, for contexts with the WEBGL_compressed_texture_astc extension enabled:
  • All of the formats the extension supports.
  The default value is gl.RGBA.
• depthFormat: Optional. A GLenum defining the data type of the depth texture data, or else 0 to indicate that the layer should not provide a depth texture (in that case XRProjectionLayer.ignoreDepthValues will be true). Possible values within WebGLRenderingContext contexts with the WEBGL_depth_texture extension enabled, or within WebGL2RenderingContext contexts (no extension required):
  • gl.DEPTH_COMPONENT
  • gl.DEPTH_STENCIL
  Additionally, for WebGL2RenderingContext contexts:
  • gl.DEPTH_COMPONENT24
  • gl.DEPTH24_STENCIL24
  The default value is gl.DEPTH_COMPONENT.
• isStatic: Optional. A boolean that, if true, indicates you can only draw to this layer when needsRedraw is true. The default value is false.
• layout: Optional. A string indicating the layout of the layer. Possible values:
  • default: The layer accommodates all views of the session.
  • mono: A single XRSubImage is allocated and presented to both eyes.
  • stereo: The user agent decides how it allocates the XRSubImage (one or two) and the layout (top/bottom or left/right).
  • stereo-left-right: A single XRSubImage is allocated. Left eye gets the left area of the texture, right eye the right.
  • stereo-top-bottom: A single XRSubImage is allocated. Left eye gets the top area of the texture, right eye the bottom.
  The default value is mono.
• lowerVerticalAngle: Optional. A number indicating the lower vertical angle in radians of the sphere. Default value: -1.570795 (-π/2).
• mipLevels: Optional. A number specifying desired number of mip levels. The default value is 1.
• radius: Optional. A number indicating the radius of the sphere. Default value: 0 (infinite sphere).
• space: Required. An XRSpace object defining the layer's spatial relationship with the user’s physical environment.
• textureType: Optional. A string defining the type of texture the layer will have. Possible values:
  • texture: The textures of XRWebGLSubImage will be of type gl.TEXTURE_2D.
  • texture-array: the textures of XRWebGLSubImage will be of type gl.TEXTURE_2D_ARRAY (WebGL 2 contexts only).
  The default value is texture.
• transform: Optional. An XRRigidTransform object defining the offset and orientation relative to space.
• upperVerticalAngle: Optional. A number indicating the upper vertical angle in radians of the sphere. Default value: 1.570795 (π/2).
• viewPixelHeight: Required. A number specifying the pixel height of the layer view.
• viewPixelWidth: Required. A number specifying the pixel width of the layer view.

Return value

An XREquirectLayer object.

Examples

Creating an XREquirectLayer

Configure the equirect layer using the properties listed above in a call to createEquirect(). To present layers to the XR device, add them to the layers render state using XRSession.updateRenderState().

function onXRSessionStarted(xrSession) {
  const glCanvas = document.createElement("canvas");
  const gl = glCanvas.getContext("webgl2", { xrCompatible: true });
  const xrGlBinding = new XRWebGLBinding(xrSession, gl);
  const equirectLayer = xrGlBinding.createEquirectLayer({
    space: xrReferenceSpace,
    viewPixelWidth: 1200,
    viewPixelHeight: 600,
    centralHorizontalAngle: 2 * Math.PI,
    upperVerticalAngle: Math.PI / 2.0,
    lowerVerticalAngle: -Math.PI / 2.0,
    radius: 0
  });

  xrSession.updateRenderState({
    layers: [equirectLayer]
  });
}

Specifications

Browser compatibility

See also

• XREquirectLayer
• WebGL constants