webxr-polyfill/polyfill/XRViewPose.js

import MatrixMath from './fill/MatrixMath.js'
import Quaternion from './fill/Quaternion.js'

/*
XRDevicePose describes the position and orientation of an XRDisplay relative to the query XRCoordinateSystem.
It also describes the view and projection matrices that should be used by the application to render a frame of the XR scene.
*/
export default class XRViewPose {
	constructor(position=[0, 0, 0], orientation=[0, 0, 0, 1]){
		this._poseModelMatrix = new Float32Array(16)
		MatrixMath.mat4_fromRotationTranslation(this._poseModelMatrix, orientation, position)
	}

	get poseModelMatrix(){ return this._poseModelMatrix }

	_setPoseModelMatrix(array16){
		for(let i=0; i < 16; i++){
			this._poseModelMatrix[i] = array16[i]
		}
	}

	get _position(){
		return [this._poseModelMatrix[12], this._poseModelMatrix[13], this._poseModelMatrix[14]]
	}

	set _position(array3){
		this._poseModelMatrix[12] = array3[0]
		this._poseModelMatrix[13] = array3[1]
		this._poseModelMatrix[14] = array3[2]
	}

	get _orientation(){
		let quat = new Quaternion()
		quat.setFromRotationMatrix(this._poseModelMatrix)
		return quat.toArray()
	}

	set _orientation(array4){
		MatrixMath.mat4_fromRotationTranslation(this._poseModelMatrix, array4, this._position)
	}

	_translate(array3){
		this._poseModelMatrix[12] += array3[0]
		this._poseModelMatrix[13] += array3[1]
		this._poseModelMatrix[14] += array3[2]
	}

	getViewMatrix(view, out=null){
		if(out === null){
			out = new Float32Array(16)
		}
		MatrixMath.mat4_eyeView(out, this._poseModelMatrix) // TODO offsets
		return out
	}
}

// We are not going to use this any more.  The way it was handled was broken, we'll just
// use the raw values for the coordinate systems.
XRViewPose.SITTING_EYE_HEIGHT = 0 // meters