Babylon.js/src/PostProcess/vrDistortionCorrectionPostProcess.ts

import { Vector2 } from "Math";
import { Camera, VRCameraMetrics } from "Cameras";
import { Effect, Texture } from "Materials";
import { PostProcess } from "PostProcess";
    /**
     * VRDistortionCorrectionPostProcess used for mobile VR
     */
    export class VRDistortionCorrectionPostProcess extends PostProcess {
        private _isRightEye: boolean;
        private _distortionFactors: number[];
        private _postProcessScaleFactor: number;
        private _lensCenterOffset: number;
        private _scaleIn: Vector2;
        private _scaleFactor: Vector2;
        private _lensCenter: Vector2;

        /**
         * Initializes the VRDistortionCorrectionPostProcess
         * @param name The name of the effect.
         * @param camera The camera to apply the render pass to.
         * @param isRightEye If this is for the right eye distortion
         * @param vrMetrics All the required metrics for the VR camera
         */
        constructor(name: string, camera: Camera, isRightEye: boolean, vrMetrics: VRCameraMetrics) {
            super(name, "vrDistortionCorrection", [
                'LensCenter',
                'Scale',
                'ScaleIn',
                'HmdWarpParam'
            ], null, vrMetrics.postProcessScaleFactor, camera, Texture.BILINEAR_SAMPLINGMODE);

            this._isRightEye = isRightEye;
            this._distortionFactors = vrMetrics.distortionK;
            this._postProcessScaleFactor = vrMetrics.postProcessScaleFactor;
            this._lensCenterOffset = vrMetrics.lensCenterOffset;
            this.adaptScaleToCurrentViewport = true;

            this.onSizeChangedObservable.add(() => {
                this._scaleIn = new Vector2(2, 2 / this.aspectRatio);
                this._scaleFactor = new Vector2(.5 * (1 / this._postProcessScaleFactor), .5 * (1 / this._postProcessScaleFactor) * this.aspectRatio);
                this._lensCenter = new Vector2(this._isRightEye ? 0.5 - this._lensCenterOffset * 0.5 : 0.5 + this._lensCenterOffset * 0.5, 0.5);
            });
            this.onApplyObservable.add((effect: Effect) => {
                effect.setFloat2("LensCenter", this._lensCenter.x, this._lensCenter.y);
                effect.setFloat2("Scale", this._scaleFactor.x, this._scaleFactor.y);
                effect.setFloat2("ScaleIn", this._scaleIn.x, this._scaleIn.y);
                effect.setFloat4("HmdWarpParam", this._distortionFactors[0], this._distortionFactors[1], this._distortionFactors[2], this._distortionFactors[3]);
            });
        }
    }