The lowerVerticalAngle property of the XREquirectLayer interface represents the lower vertical angle in radians for the sphere.

A number representing the lower vertical angle in radians for the sphere. Setting lowerVerticalAngle to a value less than -π/2 will set it to -π/2 and setting it to a value higher than π/2 will set it to π/2.

The XRWebGLBinding.createEquirectLayer() method creates an equirect layer and allows specifying a lowerVerticalAngle. The XREquirectLayer.lowerVerticalAngle property can be used after layer creation to get the lower vertical angle used or to set it to a new one.

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,
});

equirectLayer.lowerVerticalAngle; // -1.5707963267948966

• XREquirectLayer.radius
• XREquirectLayer.centralHorizontalAngle
• XREquirectLayer.upperVerticalAngle