Babylon.js/Viewer/src/managers/sceneManager.ts

import { Scene, ArcRotateCamera, Engine, Light, ShadowLight, Vector3, ShadowGenerator, Tags, CubeTexture, Quaternion, SceneOptimizer, EnvironmentHelper, SceneOptimizerOptions, Color3, IEnvironmentHelperOptions, AbstractMesh, FramingBehavior, Behavior, Observable, Color4, IGlowLayerOptions, PostProcessRenderPipeline, DefaultRenderingPipeline, StandardRenderingPipeline, SSAORenderingPipeline, SSAO2RenderingPipeline, LensRenderingPipeline, RenderTargetTexture, AnimationPropertiesOverride, Animation, Scalar, StandardMaterial, PBRMaterial, Nullable, Mesh, VRExperienceHelperOptions, VRExperienceHelper, Axis, Matrix } from 'babylonjs';
import { ILightConfiguration, ISceneConfiguration, ISceneOptimizerConfiguration, ICameraConfiguration, ISkyboxConfiguration, ViewerConfiguration, IGroundConfiguration, IModelConfiguration, getConfigurationKey, IDefaultRenderingPipelineConfiguration, IVRConfiguration } from '../configuration';
import { ViewerModel, ModelState } from '../model/viewerModel';
import { extendClassWithConfig } from '../helper';
import { CameraBehavior } from '../interfaces';
import { ViewerLabs } from '../labs/viewerLabs';
import { getCustomOptimizerByName } from '../optimizer/custom/';
import { ObservablesManager } from '../managers/observablesManager';
import { ConfigurationContainer } from '../configuration/configurationContainer';
import { deepmerge } from '../helper';
import { IEnvironmentMapConfiguration } from '../configuration/interfaces/environmentMapConfiguration';

/**
 * This interface describes the structure of the variable sent with the configuration observables of the scene manager.
 * O - the type of object we are dealing with (Light, ArcRotateCamera, Scene, etc')
 * T - the configuration type
 */
export interface IPostConfigurationCallback<OBJ, CONF> {
    newConfiguration: CONF;
    sceneManager: SceneManager;
    object: OBJ;
    model?: ViewerModel;
}

export class SceneManager {

    //Observers
    /**
     * Will notify when the scene was initialized
     */
    onSceneInitObservable: Observable<Scene>;
    /**
     * Will notify after the scene was configured. Can be used to further configure the scene
     */
    onSceneConfiguredObservable: Observable<IPostConfigurationCallback<Scene, ISceneConfiguration>>;
    /**
     * Will notify after the scene optimized was configured. Can be used to further configure the scene optimizer
     */
    onSceneOptimizerConfiguredObservable: Observable<IPostConfigurationCallback<SceneOptimizer, ISceneOptimizerConfiguration | boolean>>;
    /**
     * Will notify after the camera was configured. Can be used to further configure the camera
     */
    onCameraConfiguredObservable: Observable<IPostConfigurationCallback<ArcRotateCamera, ICameraConfiguration>>;
    /**
     * Will notify after the lights were configured. Can be used to further configure lights
     */
    onLightsConfiguredObservable: Observable<IPostConfigurationCallback<Array<Light>, { [name: string]: ILightConfiguration | boolean | number }>>;
    /**
     * Will notify after the model(s) were configured. Can be used to further configure models
     */
    onModelsConfiguredObservable: Observable<IPostConfigurationCallback<Array<ViewerModel>, IModelConfiguration>>;
    /**
     * Will notify after the envirnoment was configured. Can be used to further configure the environment
     */
    onEnvironmentConfiguredObservable: Observable<IPostConfigurationCallback<EnvironmentHelper, { skybox?: ISkyboxConfiguration | boolean, ground?: IGroundConfiguration | boolean }>>;

    /**
     * Will notify after the model(s) were configured. Can be used to further configure models
     */
    onVRConfiguredObservable: Observable<IPostConfigurationCallback<VRExperienceHelper, IVRConfiguration>>;

    /**
     * The Babylon Scene of this viewer
     */
    public scene: Scene;
    /**
     * The camera used in this viewer
     */
    public camera: ArcRotateCamera;
    /**
     * Babylon's scene optimizer
     */
    public sceneOptimizer: SceneOptimizer;
    /**
     * Models displayed in this viewer.
     */
    public models: Array<ViewerModel>;
    /**
     * Babylon's environment helper of this viewer
     */
    public environmentHelper?: EnvironmentHelper;

    private _animationBlendingEnabled: boolean = true;

    //The following are configuration objects, default values.
    protected _defaultHighpTextureType: number;
    protected _shadowGeneratorBias: number;
    protected _defaultPipelineTextureType: number;

    /**
     * The maximum number of shadows supported by the curent viewer
     */
    protected _maxShadows: number;
    /**
     * is HDR supported?
     */
    private _hdrSupport: boolean;

    private readonly _white = Color3.White();

    private _forceShadowUpdate: boolean = false;

    /**
     * The labs variable consists of objects that will have their API change.
     * Please be careful when using labs in production.
     */
    public labs: ViewerLabs;

    private _defaultRenderingPipeline: Nullable<DefaultRenderingPipeline>;

    private _assetsRootURL: string;

    public get defaultRenderingPipeline() {
        return this._defaultRenderingPipeline;
    }

    protected _vrHelper?: VRExperienceHelper;

    public get vrHelper() {
        return this._vrHelper;
    }

    constructor(private _engine: Engine, private _configurationContainer: ConfigurationContainer, private _observablesManager?: ObservablesManager) {
        this.models = [];

        this.onCameraConfiguredObservable = new Observable();
        this.onLightsConfiguredObservable = new Observable();
        this.onModelsConfiguredObservable = new Observable();
        this.onSceneConfiguredObservable = new Observable();
        this.onSceneInitObservable = new Observable();
        this.onSceneOptimizerConfiguredObservable = new Observable();
        this.onEnvironmentConfiguredObservable = new Observable();
        this.onVRConfiguredObservable = new Observable();

        //this._viewer.onEngineInitObservable.add(() => {
        this._handleHardwareLimitations();
        //});

        this.onSceneInitObservable.add((scene) => {
            this.scene.animationPropertiesOverride = this.scene.animationPropertiesOverride || new AnimationPropertiesOverride();

            this.labs = new ViewerLabs(scene);

            let updateShadows = () => {
                for (let light of this.scene.lights) {
                    let generator = light.getShadowGenerator();
                    if (generator) {
                        // Processing shadows if animates
                        let shadowMap = generator.getShadowMap();
                        if (shadowMap) {
                            shadowMap.refreshRate = RenderTargetTexture.REFRESHRATE_RENDER_ONCE;
                        }
                    }
                }
            };
            scene.registerBeforeRender(() => {
                if (this._forceShadowUpdate || (scene.animatables && scene.animatables.length > 0)) {
                    // make sure all models are loaded
                    updateShadows();
                    this._forceShadowUpdate = false;
                } else if (!(this.models.every((model) => {
                    if (!model.shadowsRenderedAfterLoad) {
                        model.shadowsRenderedAfterLoad = true;
                        return false;
                    }
                    return model.state === ModelState.COMPLETE && !model.currentAnimation;
                }))) {
                    updateShadows();
                }
            });
            return this._observablesManager && this._observablesManager.onSceneInitObservable.notifyObserversWithPromise(this.scene);
        });
        if (this._observablesManager) {
            this._observablesManager.onModelLoadedObservable.add((model) => {
                for (let light of this.scene.lights) {
                    let generator = light.getShadowGenerator();
                    if (generator) {
                        // Processing shadows if animates
                        let shadowMap = generator.getShadowMap();
                        if (shadowMap) {
                            shadowMap.refreshRate = RenderTargetTexture.REFRESHRATE_RENDER_ONCE;
                        }
                    }
                }
                this._focusOnModel(model);
            });

            this._observablesManager.onModelAddedObservable.add((model) => {
                this.models.push(model);
            });
            this._observablesManager.onModelRemovedObservable.add((model) => {
                this.models.splice(this.models.indexOf(model), 1);
            });

        }

    }

    /**
     * Returns a boolean representing HDR support
     */
    public get isHdrSupported() {
        return this._hdrSupport;
    }

    /**
     * Return the main color defined in the configuration.
     */
    public get mainColor(): Color3 {
        return this._configurationContainer.mainColor;
    }

    public get reflectionColor(): Color3 {
        return this._configurationContainer.reflectionColor;
    }

    public get animationBlendingEnabled() {
        return this.scene && this.scene.animationPropertiesOverride!.enableBlending;
    }

    public set animationBlendingEnabled(value: boolean) {
        this.scene.animationPropertiesOverride!.enableBlending = value;
    }

    public get observablesManager() {
        return this._observablesManager;
    }

    private _processShadows: boolean = true;

    /**
     * The flag defining whether shadows are rendered constantly or once.
     */
    public get processShadows() {
        return this._processShadows;
    }

    /**
     * Should shadows be rendered every frame, or only once and stop.
     * This can be used to optimize a scene.
     *
     * Not that the shadows will NOT disapear but will remain in place.
     * @param process if true shadows will be updated once every frame. if false they will stop being updated.
     */
    public set processShadows(process: boolean) {

        let refreshType = process ? RenderTargetTexture.REFRESHRATE_RENDER_ONEVERYFRAME : RenderTargetTexture.REFRESHRATE_RENDER_ONCE;

        for (let light of this.scene.lights) {
            let generator = light.getShadowGenerator();

            if (generator) {
                let shadowMap = generator.getShadowMap();
                if (shadowMap) {
                    shadowMap.refreshRate = refreshType;
                }
            }
        }

        this._processShadows = process;
    }

    private _groundEnabled: boolean = true;

    public get groundEnabled() {
        return this._groundEnabled;
    }

    public set groundEnabled(newValue: boolean) {
        if (newValue === this._groundEnabled) { return; }

        this._groundEnabled = newValue;

        if (this.environmentHelper && this.environmentHelper.ground) {
            this.environmentHelper.ground.setEnabled(this._groundEnabled);
        }
    }

    private _groundMirrorEnabled = true;
    /**
     * gets wether the reflection is disabled.
     */
    public get groundMirrorEnabled(): boolean {
        return this._groundMirrorEnabled;
    }
    /**
     * sets wether the reflection is disabled.
     */
    public set groundMirrorEnabled(value: boolean) {
        if (this._groundMirrorEnabled === value) {
            return;
        }

        this._groundMirrorEnabled = value;
        if (this.environmentHelper && this.environmentHelper.groundMaterial && this.environmentHelper.groundMirror) {
            if (!value) {
                this.environmentHelper.groundMaterial.reflectionTexture = null;
            } else {
                this.environmentHelper.groundMaterial.reflectionTexture = this.environmentHelper.groundMirror;
            }
        }
    }

    private _defaultRenderingPipelineEnabled: boolean = false;

    public get defaultRenderingPipelineEnabled() {
        return this._defaultRenderingPipelineEnabled;
    }

    public set defaultRenderingPipelineEnabled(value: boolean) {
        if (value === this._defaultRenderingPipelineEnabled) {
            return;
        }

        this._defaultRenderingPipelineEnabled = value;
        this._rebuildPostprocesses();
        if (this._defaultRenderingPipeline) {
            this._defaultRenderingPipelineShouldBuild = false;
            this._defaultRenderingPipeline.prepare();
            this.scene.imageProcessingConfiguration.applyByPostProcess = true;
        }
    }

    /**
     * Sets the engine flags to unlock all babylon features.
     * Can also be configured using the scene.flags configuration object
     */
    public unlockBabylonFeatures() {
        this.scene.shadowsEnabled = true;
        this.scene.particlesEnabled = true;
        this.scene.postProcessesEnabled = true;
        this.scene.collisionsEnabled = true;
        this.scene.lightsEnabled = true;
        this.scene.texturesEnabled = true;
        this.scene.lensFlaresEnabled = true;
        this.scene.proceduralTexturesEnabled = true;
        this.scene.renderTargetsEnabled = true;
        this.scene.spritesEnabled = true;
        this.scene.skeletonsEnabled = true;
        this.scene.audioEnabled = true;
    }

    /**
     * initialize the scene. Calling this function again will dispose the old scene, if exists.
     */
    public initScene(sceneConfiguration: ISceneConfiguration = {}, optimizerConfiguration?: boolean | ISceneOptimizerConfiguration): Promise<Scene> {

        // if the scen exists, dispose it.
        if (this.scene) {
            this.scene.dispose();
        }

        // create a new scene
        this.scene = new Scene(this._engine);

        this._configurationContainer.scene = this.scene;

        // set a default PBR material
        if (!sceneConfiguration.defaultMaterial) {
            var defaultMaterial = new BABYLON.PBRMaterial('defaultMaterial', this.scene);
            defaultMaterial.reflectivityColor = new BABYLON.Color3(0.1, 0.1, 0.1);
            defaultMaterial.microSurface = 0.6;

            if (this.scene.defaultMaterial) {
                this.scene.defaultMaterial.dispose();
            }

            this.scene.defaultMaterial = defaultMaterial;
        }

        this.scene.animationPropertiesOverride = new AnimationPropertiesOverride();

        Animation.AllowMatricesInterpolation = true;

        /*if (sceneConfiguration.glow) {
            let options: Partial<IGlowLayerOptions> = {
                mainTextureFixedSize: 512
            };
            if (typeof sceneConfiguration.glow === 'object') {
                options = sceneConfiguration.glow
            }
            var gl = new BABYLON.GlowLayer("glow", this.scene, options);
        }*/

        return this.onSceneInitObservable.notifyObserversWithPromise(this.scene);
    }

    public clearScene(clearModels: boolean = true, clearLights: boolean = false) {
        if (clearModels) {
            this.models.forEach((m) => m.dispose());
            this.models.length = 0;
        }
        if (clearLights) {
            this.scene.lights.forEach((l) => l.dispose());
        }
    }

    private _globalConfiguration: ViewerConfiguration = {};

    /**
     * This will update the scene's configuration, including camera, lights, environment.
     * @param newConfiguration the delta that should be configured. This includes only the changes
     * @param globalConfiguration The global configuration object, after the new configuration was merged into it
     */
    public updateConfiguration(newConfiguration: Partial<ViewerConfiguration>) {

        if (this._configurationContainer) {
            this._globalConfiguration = this._configurationContainer.configuration;
        } else {
            this._globalConfiguration = newConfiguration;
        }

        // update scene configuration
        if (newConfiguration.scene) {
            this._configureScene(newConfiguration.scene);
        }

        // optimizer
        if (newConfiguration.optimizer !== undefined) {
            this._configureOptimizer(newConfiguration.optimizer);
        }

        // configure model
        /*if (newConfiguration.model && typeof newConfiguration.model === 'object') {
            this._configureModel(newConfiguration.model);
        }*/

        // lights
        this._configureLights(newConfiguration.lights);

        // environment
        if (newConfiguration.skybox !== undefined || newConfiguration.ground !== undefined) {
            this._configureEnvironment(newConfiguration.skybox, newConfiguration.ground);
        }

        // camera
        this._configureCamera(newConfiguration.camera);

        if (newConfiguration.environmentMap !== undefined) {
            this._configureEnvironmentMap(newConfiguration.environmentMap);
        }

        if (newConfiguration.vr !== undefined) {
            this._configureVR(newConfiguration.vr);
        }

        if (newConfiguration.lab) {

            // rendering piplines
            if (newConfiguration.lab.defaultRenderingPipelines) {
                let pipelineConfig = newConfiguration.lab.defaultRenderingPipelines;
                if (typeof pipelineConfig === 'boolean') {
                    this.defaultRenderingPipelineEnabled = pipelineConfig;
                } else {
                    this.defaultRenderingPipelineEnabled = true;
                }
            }

            if (this.environmentHelper && newConfiguration.lab.environmentMainColor) {
                let mainColor = new Color3().copyFrom(newConfiguration.lab.environmentMainColor as Color3);
                this.environmentHelper.setMainColor(mainColor);
            }

            if (newConfiguration.lab.globalLightRotation !== undefined) {
                // rotate all lights that are shadow lights
                this.scene.lights.filter((light) => light instanceof ShadowLight).forEach((light) => {
                    // casting and '!' are safe, due to the constraints tested before
                    this.labs.rotateShadowLight(<ShadowLight>light, newConfiguration.lab!.globalLightRotation!);
                });
                this._forceShadowUpdate = true;
            }
        }

        if (this._defaultRenderingPipeline && this._defaultRenderingPipeline.imageProcessing) {
            this._defaultRenderingPipeline.imageProcessing.fromLinearSpace = true;
        }

        if (this._defaultRenderingPipelineShouldBuild && this._defaultRenderingPipeline) {
            this._defaultRenderingPipelineShouldBuild = false;
            this._defaultRenderingPipeline.prepare();
        }
    }

    private _defaultRenderingPipelineShouldBuild: boolean = true;

    private _rebuildPostprocesses(configuration?: IDefaultRenderingPipelineConfiguration): void {
        if (!this._defaultRenderingPipelineEnabled || !getConfigurationKey("scene.imageProcessingConfiguration.isEnabled", this._globalConfiguration)) {
            if (this._defaultRenderingPipeline) {
                this._defaultRenderingPipeline.dispose();
                this._defaultRenderingPipeline = null;
                this.scene.autoClearDepthAndStencil = true;
                this.scene.autoClear = true;
                this.scene.imageProcessingConfiguration.applyByPostProcess = false;
            }

            return;
        }

        let pipelineConfig = configuration || (this._globalConfiguration.lab && this._globalConfiguration.lab.defaultRenderingPipelines);
        if (pipelineConfig) {

            if (!this._defaultRenderingPipeline) {
                // Create pipeline in manual mode to avoid triggering multiple shader compilations
                this._defaultRenderingPipeline = new DefaultRenderingPipeline("default rendering pipeline", this._hdrSupport, this.scene, [this.camera], false);
            }
            this.scene.autoClear = false;
            this.scene.autoClearDepthAndStencil = false;
            this._defaultRenderingPipelineShouldBuild = true;

            let bloomEnabled = this._bloomEnabled;

            if (typeof pipelineConfig !== 'boolean') {
                extendClassWithConfig(this._defaultRenderingPipeline, pipelineConfig);
                this._bloomEnabled = !!pipelineConfig.bloomEnabled;
                this._fxaaEnabled = !!pipelineConfig.fxaaEnabled;
                bloomEnabled = this._bloomEnabled && pipelineConfig.bloomWeight !== undefined && pipelineConfig.bloomWeight > 0;

                this._defaultRenderingPipeline.bloomWeight = (pipelineConfig.bloomWeight !== undefined && pipelineConfig.bloomWeight) || (this._defaultRenderingPipeline.bloomWeight);
            }

            this._defaultRenderingPipeline.bloomEnabled = bloomEnabled;
            this._defaultRenderingPipeline.fxaaEnabled = this.fxaaEnabled;
        }

    }

    // default from rendering pipeline
    private _bloomEnabled: boolean = false;

    public get bloomEnabled() {
        return this._bloomEnabled;
    }

    public set bloomEnabled(value: boolean) {
        if (this._bloomEnabled === value) {
            return;
        }

        this._bloomEnabled = value;
        this._rebuildPostprocesses();
        if (this._defaultRenderingPipeline) {
            this._defaultRenderingPipelineShouldBuild = false;
            this._defaultRenderingPipeline.prepare();
            this.scene.imageProcessingConfiguration.applyByPostProcess = true;
        }
    }

    // default from rendering pipeline
    private _fxaaEnabled: boolean = false;

    public get fxaaEnabled() {
        return this._fxaaEnabled;
    }

    public set fxaaEnabled(value: boolean) {
        if (this._fxaaEnabled === value) {
            return;
        }

        this._fxaaEnabled = value;
        this._rebuildPostprocesses();
        if (this._defaultRenderingPipeline) {
            this._defaultRenderingPipelineShouldBuild = false;
            this._defaultRenderingPipeline.prepare();
            this.scene.imageProcessingConfiguration.applyByPostProcess = true;
        }
    }

    /**
     * internally configure the scene using the provided configuration.
     * The scene will not be recreated, but just updated.
     * @param sceneConfig the (new) scene configuration
     */
    protected _configureScene(sceneConfig: ISceneConfiguration) {
        // sanity check!
        if (!this.scene) {
            return;
        }

        let cc = sceneConfig.clearColor;
        let oldcc = this.scene.clearColor;
        if (cc) {
            if (cc.r !== undefined) {
                oldcc.r = cc.r;
            }
            if (cc.g !== undefined) {
                oldcc.g = cc.g;
            }
            if (cc.b !== undefined) {
                oldcc.b = cc.b;
            }
            if (cc.a !== undefined) {
                oldcc.a = cc.a;
            }
        }

        if (sceneConfig.assetsRootURL) {
            this._assetsRootURL = sceneConfig.assetsRootURL;
        }

        // image processing configuration - optional.
        if (sceneConfig.imageProcessingConfiguration) {
            extendClassWithConfig(this.scene.imageProcessingConfiguration, sceneConfig.imageProcessingConfiguration);
        }
        //animation properties override
        if (sceneConfig.animationPropertiesOverride) {
            extendClassWithConfig(this.scene.animationPropertiesOverride, sceneConfig.animationPropertiesOverride);
        }
        if (sceneConfig.environmentTexture) {
            if (!(this.scene.environmentTexture && (<CubeTexture>this.scene.environmentTexture).url === sceneConfig.environmentTexture)) {
                if (this.scene.environmentTexture && this.scene.environmentTexture.dispose) {
                    this.scene.environmentTexture.dispose();
                }
                const environmentTexture = CubeTexture.CreateFromPrefilteredData(sceneConfig.environmentTexture, this.scene);
                this.scene.environmentTexture = environmentTexture;
            }
        }

        if (sceneConfig.debug === true) {
            this.scene.debugLayer.show();
        } else if (sceneConfig.debug === false) {
            if (this.scene.debugLayer.isVisible()) {
                this.scene.debugLayer.hide();
            }
        }

        if (sceneConfig.disableHdr) {
            this._handleHardwareLimitations(false);
        } else {
            this._handleHardwareLimitations(true);
        }

        if (sceneConfig.renderInBackground !== undefined) {
            this._engine.renderEvenInBackground = !!sceneConfig.renderInBackground;
        }

        let canvas = this._engine.getRenderingCanvas();

        if (canvas) {
            if (this.camera && sceneConfig.disableCameraControl) {
                this.camera.detachControl(canvas);
            } else if (this.camera && sceneConfig.disableCameraControl === false) {
                this.camera.attachControl(canvas);
            }
        }

        if (sceneConfig.defaultMaterial) {
            let conf = sceneConfig.defaultMaterial;
            if ((conf.materialType === 'standard' && this.scene.defaultMaterial.getClassName() !== 'StandardMaterial') ||
                (conf.materialType === 'pbr' && this.scene.defaultMaterial.getClassName() !== 'PBRMaterial')) {
                this.scene.defaultMaterial.dispose();
                if (conf.materialType === 'standard') {
                    this.scene.defaultMaterial = new StandardMaterial("defaultMaterial", this.scene);
                } else {
                    this.scene.defaultMaterial = new PBRMaterial("defaultMaterial", this.scene);
                }
            }
            extendClassWithConfig(this.scene.defaultMaterial, conf);
        }

        if (sceneConfig.flags) {
            extendClassWithConfig(this.scene, sceneConfig.flags);
        }

        this.onSceneConfiguredObservable.notifyObservers({
            sceneManager: this,
            object: this.scene,
            newConfiguration: sceneConfig
        });
    }

    /**
     * Configure the scene optimizer.
     * The existing scene optimizer will be disposed and a new one will be created.
     * @param optimizerConfig the (new) optimizer configuration
     */
    protected _configureOptimizer(optimizerConfig: ISceneOptimizerConfiguration | boolean) {
        if (typeof optimizerConfig === 'boolean') {
            if (this.sceneOptimizer) {
                this.sceneOptimizer.stop();
                this.sceneOptimizer.dispose();
                delete this.sceneOptimizer;
            }
            if (optimizerConfig) {
                this.sceneOptimizer = new SceneOptimizer(this.scene);
                this.sceneOptimizer.start();
            }
        } else {
            let optimizerOptions: SceneOptimizerOptions = new SceneOptimizerOptions(optimizerConfig.targetFrameRate, optimizerConfig.trackerDuration);
            // check for degradation
            if (optimizerConfig.degradation) {
                switch (optimizerConfig.degradation) {
                    case "low":
                        optimizerOptions = SceneOptimizerOptions.LowDegradationAllowed(optimizerConfig.targetFrameRate);
                        break;
                    case "moderate":
                        optimizerOptions = SceneOptimizerOptions.ModerateDegradationAllowed(optimizerConfig.targetFrameRate);
                        break;
                    case "hight":
                        optimizerOptions = SceneOptimizerOptions.HighDegradationAllowed(optimizerConfig.targetFrameRate);
                        break;
                }
            }
            if (this.sceneOptimizer) {
                this.sceneOptimizer.stop();
                this.sceneOptimizer.dispose();
            }
            if (optimizerConfig.custom) {
                let customOptimizer = getCustomOptimizerByName(optimizerConfig.custom, optimizerConfig.improvementMode);
                if (customOptimizer) {
                    optimizerOptions.addCustomOptimization(() => {
                        return customOptimizer(this);
                    }, () => {
                        return `Babylon Viewer ${optimizerConfig.custom} custom optimization`;
                    });
                }
            }
            this.sceneOptimizer = new SceneOptimizer(this.scene, optimizerOptions, optimizerConfig.autoGeneratePriorities, optimizerConfig.improvementMode);
            this.sceneOptimizer.start();
        }

        this.onSceneOptimizerConfiguredObservable.notifyObservers({
            sceneManager: this,
            object: this.sceneOptimizer,
            newConfiguration: optimizerConfig
        });
    }

    /**
     * configure all models using the configuration.
     * @param modelConfiguration the configuration to use to reconfigure the models
     */
    /*protected _configureModel(modelConfiguration: Partial<IModelConfiguration>) {
        this.models.forEach(model => {
            model.updateConfiguration(modelConfiguration);
        });

        this.onModelsConfiguredObservable.notifyObservers({
            sceneManager: this,
            object: this.models,
            newConfiguration: modelConfiguration
        });
    }*/

    protected _configureVR(vrConfig: IVRConfiguration) {
        if (vrConfig.disabled) {
            if (this._vrHelper) {
                if (this._vrHelper.isInVRMode) {
                    this._vrHelper.exitVR();
                }
                this._vrHelper.dispose();
                this._vrHelper = undefined;
            }
            return;
        }
        let vrOptions: VRExperienceHelperOptions = deepmerge({
            useCustomVRButton: true,
            createDeviceOrientationCamera: false,
            trackPosition: true
        }, vrConfig.vrOptions || {});

        this._vrHelper = this.scene.createDefaultVRExperience(vrOptions);
        if (!vrConfig.disableInteractions) {
            this._vrHelper.enableInteractions();
        }
        if (!vrConfig.disableTeleportation) {
            let floorMeshName = vrConfig.overrideFloorMeshName || "BackgroundPlane";
            this._vrHelper.enableTeleportation({
                floorMeshName
            });
        }
        if (vrConfig.rotateUsingControllers) {
            let rotationOffset: Quaternion | null;
            this._vrHelper.onControllerMeshLoadedObservable.add((controller) => {
                controller.onTriggerStateChangedObservable.add((data) => {
                    if (controller.mesh && controller.mesh.rotationQuaternion) {
                        if (data.pressed) {
                            if (!rotationOffset) {
                                this.models[0].rootMesh.rotationQuaternion = this.models[0].rootMesh.rotationQuaternion || new Quaternion();
                                rotationOffset = controller.mesh.rotationQuaternion.conjugate().multiply(this.models[0].rootMesh.rotationQuaternion!);
                            }
                        } else {
                            rotationOffset = null;
                        }
                    }
                });
                this.scene.registerBeforeRender(() => {
                    if (this.models[0]) {
                        if (rotationOffset && controller.mesh && controller.mesh.rotationQuaternion) {
                            this.models[0].rootMesh.rotationQuaternion!.copyFrom(controller.mesh.rotationQuaternion).multiplyInPlace(rotationOffset);
                        } else {
                            this.models[0].rootMesh.rotationQuaternion = null;
                        }

                    }
                });
            });
        }
        this._vrHelper.onEnteringVRObservable.add(() => {
            if (this._observablesManager) {
                this._observablesManager.onEnteringVRObservable.notifyObservers(this);
            }
        });
        this._vrHelper.onExitingVRObservable.add(() => {
            if (this._observablesManager) {
                this._observablesManager.onExitingVRObservable.notifyObservers(this);
            }
        });
        this.onVRConfiguredObservable.notifyObservers({
            sceneManager: this,
            object: this._vrHelper,
            newConfiguration: vrConfig
        });
    }

    protected _configureEnvironmentMap(environmentMapConfiguration: IEnvironmentMapConfiguration): any {
        if (environmentMapConfiguration.texture) {
            this.scene.environmentTexture = new BABYLON.CubeTexture(this._getAssetUrl(environmentMapConfiguration.texture), this.scene);
        }

        //sanity check
        if (this.scene.environmentTexture) {
            let rotatquatRotationionY = Quaternion.RotationAxis(Axis.Y, environmentMapConfiguration.rotationY || 0);
            Matrix.FromQuaternionToRef(rotatquatRotationionY, this.scene.environmentTexture.getReflectionTextureMatrix());
        }

        // process mainColor changes:
        if (environmentMapConfiguration.mainColor) {
            this._configurationContainer.mainColor = this.mainColor || Color3.White();
            let mc = environmentMapConfiguration.mainColor;
            if (mc.r !== undefined) {
                this.mainColor.r = mc.r;
            }
            if (mc.g !== undefined) {
                this.mainColor.g = mc.g;
            }
            if (mc.b !== undefined) {
                this.mainColor.b = mc.b;
            }

            this.reflectionColor.copyFrom(this.mainColor);

            let environmentTint = getConfigurationKey("environmentMap.tintLevel", this._globalConfiguration) || 0;

            // reflection color
            this.reflectionColor.toLinearSpaceToRef(this.reflectionColor);
            this.reflectionColor.scaleToRef(1 / this.scene.imageProcessingConfiguration.exposure, this.reflectionColor);
            let tmpColor3 = Color3.Lerp(this._white, this.reflectionColor, environmentTint);
            this.reflectionColor.copyFrom(tmpColor3);

            //update the environment, if exists
            if (this.environmentHelper) {
                if (this.environmentHelper.groundMaterial) {
                    this.environmentHelper.groundMaterial._perceptualColor = this.mainColor;
                }

                if (this.environmentHelper.skyboxMaterial) {
                    this.environmentHelper.skyboxMaterial._perceptualColor = this.mainColor;
                }
            }
        }
    }

    /**
     * (Re) configure the camera. The camera will only be created once and from this point will only be reconfigured.
     * @param cameraConfig the new camera configuration
     * @param model optionally use the model to configure the camera.
     */
    protected _configureCamera(cameraConfig: ICameraConfiguration = {}) {
        if (!this.scene.activeCamera) {
            let attachControl = true;
            if (this._globalConfiguration.scene && this._globalConfiguration.scene.disableCameraControl) {
                attachControl = false;
            }
            this.scene.createDefaultCamera(true, true, attachControl);
            this.camera = <ArcRotateCamera>this.scene.activeCamera!;
            this.camera.setTarget(Vector3.Zero());
        }
        if (!this.camera) {
            this.camera = <ArcRotateCamera>this.scene.activeCamera!;
        }
        if (cameraConfig.position) {
            let newPosition = this.camera.position.clone();
            extendClassWithConfig(newPosition, cameraConfig.position);
            this.camera.setPosition(newPosition);
        }

        if (cameraConfig.target) {
            let newTarget = this.camera.target.clone();
            extendClassWithConfig(newTarget, cameraConfig.target);
            this.camera.setTarget(newTarget);
        } /*else if (this.models.length && !cameraConfig.disableAutoFocus) {
            this._focusOnModel(this.models[0]);
        }*/

        if (cameraConfig.rotation) {
            this.camera.rotationQuaternion = new Quaternion(cameraConfig.rotation.x || 0, cameraConfig.rotation.y || 0, cameraConfig.rotation.z || 0, cameraConfig.rotation.w || 0);
        }

        if (cameraConfig.behaviors) {
            for (let name in cameraConfig.behaviors) {
                if (cameraConfig.behaviors[name] !== undefined) {
                    this._setCameraBehavior(name, cameraConfig.behaviors[name]);
                }
            }
        }

        const sceneExtends = this.scene.getWorldExtends((mesh) => {
            return !this.environmentHelper || (mesh !== this.environmentHelper.ground && mesh !== this.environmentHelper.rootMesh && mesh !== this.environmentHelper.skybox);
        });
        const sceneDiagonal = sceneExtends.max.subtract(sceneExtends.min);
        const sceneDiagonalLength = sceneDiagonal.length();
        if (isFinite(sceneDiagonalLength)) {
            this.camera.upperRadiusLimit = sceneDiagonalLength * 4;
        }

        // sanity check!
        if (this.scene.imageProcessingConfiguration) {
            this.scene.imageProcessingConfiguration.colorCurvesEnabled = true;
            this.scene.imageProcessingConfiguration.vignetteEnabled = true;
            this.scene.imageProcessingConfiguration.toneMappingEnabled = !!getConfigurationKey("camera.toneMappingEnabled", this._globalConfiguration);
        }

        extendClassWithConfig(this.camera, cameraConfig);

        this.onCameraConfiguredObservable.notifyObservers({
            sceneManager: this,
            object: this.camera,
            newConfiguration: cameraConfig
        });
    }

    private _focusOnModel = (model: ViewerModel) => {
        const boundingInfo = model.rootMesh.getHierarchyBoundingVectors(true);
        const sizeVec = boundingInfo.max.subtract(boundingInfo.min);
        const halfSizeVec = sizeVec.scale(0.5);
        const center = boundingInfo.min.add(halfSizeVec);
        this.camera.setTarget(center);
        this.camera.alpha = (this._globalConfiguration.camera && this._globalConfiguration.camera.alpha) || this.camera.alpha;
        this.camera.beta = (this._globalConfiguration.camera && this._globalConfiguration.camera.beta) || this.camera.beta;
        this.camera.radius = (this._globalConfiguration.camera && this._globalConfiguration.camera.radius) || this.camera.radius;

        const sceneDiagonalLenght = sizeVec.length();
        if (isFinite(sceneDiagonalLenght)) {
            this.camera.upperRadiusLimit = sceneDiagonalLenght * 4;
        }

        if (this._configurationContainer.configuration) {
            this._configureEnvironment(this._configurationContainer.configuration.skybox, this._configurationContainer.configuration.ground);
        }
        /*this.scene.lights.filter(light => light instanceof ShadowLight).forEach(light => {
            // casting ais safe, due to the constraints tested before
            (<ShadowLight>light).setDirectionToTarget(center);
        });*/
    }

    protected _configureEnvironment(skyboxConifguration?: ISkyboxConfiguration | boolean, groundConfiguration?: IGroundConfiguration | boolean) {
        if (!skyboxConifguration && !groundConfiguration) {
            if (this.environmentHelper) {
                this.environmentHelper.dispose();
                this.environmentHelper = undefined;
            }
        } else {

            const options: Partial<IEnvironmentHelperOptions> = {
                createGround: !!groundConfiguration && this._groundEnabled,
                createSkybox: !!skyboxConifguration,
                setupImageProcessing: false, // will be done at the scene level!,
            };

            // will that cause problems with model ground configuration?
            /*if (model) {
                const boundingInfo = model.rootMesh.getHierarchyBoundingVectors(true);
                const sizeVec = boundingInfo.max.subtract(boundingInfo.min);
                const halfSizeVec = sizeVec.scale(0.5);
                const center = boundingInfo.min.add(halfSizeVec);
                options.groundYBias = -center.y;
            }*/

            if (groundConfiguration) {
                let groundConfig = (typeof groundConfiguration === 'boolean') ? {} : groundConfiguration;

                let groundSize = groundConfig.size || (typeof skyboxConifguration === 'object' && skyboxConifguration.scale);
                if (groundSize) {
                    options.groundSize = groundSize;
                }

                options.enableGroundShadow = groundConfig === true || groundConfig.receiveShadows;
                if (groundConfig.shadowLevel !== undefined) {
                    options.groundShadowLevel = groundConfig.shadowLevel;
                }
                options.enableGroundMirror = !!groundConfig.mirror && this.groundMirrorEnabled;
                if (groundConfig.texture) {
                    options.groundTexture = this._getAssetUrl(groundConfig.texture);
                }
                if (groundConfig.color) {
                    options.groundColor = new Color3(groundConfig.color.r, groundConfig.color.g, groundConfig.color.b);
                }

                if (groundConfig.opacity !== undefined) {
                    options.groundOpacity = groundConfig.opacity;
                }

                if (groundConfig.mirror) {
                    options.enableGroundMirror = true;
                    // to prevent undefines
                    if (typeof groundConfig.mirror === "object") {
                        if (groundConfig.mirror.amount !== undefined) {
                            options.groundMirrorAmount = groundConfig.mirror.amount;
                        }
                        if (groundConfig.mirror.sizeRatio !== undefined) {
                            options.groundMirrorSizeRatio = groundConfig.mirror.sizeRatio;
                        }
                        if (groundConfig.mirror.blurKernel !== undefined) {
                            options.groundMirrorBlurKernel = groundConfig.mirror.blurKernel;
                        }
                        if (groundConfig.mirror.fresnelWeight !== undefined) {
                            options.groundMirrorFresnelWeight = groundConfig.mirror.fresnelWeight;
                        }
                        if (groundConfig.mirror.fallOffDistance !== undefined) {
                            options.groundMirrorFallOffDistance = groundConfig.mirror.fallOffDistance;
                        }
                        if (this._defaultPipelineTextureType !== undefined) {
                            options.groundMirrorTextureType = this._defaultPipelineTextureType;
                        }
                    }
                }
            }

            let postInitSkyboxMaterial = false;
            if (skyboxConifguration) {
                let conf = skyboxConifguration === true ? {} : skyboxConifguration;
                if (conf.material && conf.material.imageProcessingConfiguration) {
                    options.setupImageProcessing = false; // will be configured later manually.
                }
                let skyboxSize = conf.scale;
                if (skyboxSize) {
                    options.skyboxSize = skyboxSize;
                }
                options.sizeAuto = !options.skyboxSize;
                if (conf.color) {
                    options.skyboxColor = new Color3(conf.color.r, conf.color.g, conf.color.b);
                }
                if (conf.cubeTexture && conf.cubeTexture.url) {
                    if (typeof conf.cubeTexture.url === "string") {
                        options.skyboxTexture = this._getAssetUrl(conf.cubeTexture.url);
                    } else {
                        // init later!
                        postInitSkyboxMaterial = true;
                    }
                }

                if (conf.material) {
                    postInitSkyboxMaterial = true;
                }
            }

            options.setupImageProcessing = false; // TMP

            if (!this.environmentHelper) {
                this.environmentHelper = this.scene.createDefaultEnvironment(options)!;
            } else {
                // unlikely, but there might be a new scene! we need to dispose.

                // get the scene used by the envHelper
                let scene: Scene = this.environmentHelper.rootMesh.getScene();
                // is it a different scene? Oh no!
                if (scene !== this.scene) {
                    this.environmentHelper.dispose();
                    this.environmentHelper = this.scene.createDefaultEnvironment(options)!;
                } else {
                    // recreate the ground
                    if (this.environmentHelper.ground) {
                        this.environmentHelper.ground.dispose();
                    }
                    // recreate the skybox
                    if (this.environmentHelper.skybox) {
                        this.environmentHelper.skybox.dispose();
                    }

                    this.environmentHelper.updateOptions(options)!;
                    // update doesn't change the size of the skybox and ground, so we have to recreate!
                    //this.environmentHelper.dispose();
                    //this.environmentHelper = this.scene.createDefaultEnvironment(options)!;
                }
            }

            if (this.environmentHelper.rootMesh && this._globalConfiguration.scene && this._globalConfiguration.scene.environmentRotationY !== undefined) {
                this.environmentHelper.rootMesh.rotation.y = this._globalConfiguration.scene.environmentRotationY;
            }

            let groundConfig = (typeof groundConfiguration === 'boolean') ? {} : groundConfiguration;
            if (this.environmentHelper.groundMaterial && groundConfig) {
                this.environmentHelper.groundMaterial._perceptualColor = this.mainColor;
                if (groundConfig.material) {
                    extendClassWithConfig(this.environmentHelper.groundMaterial, groundConfig.material);
                }

                if (this.environmentHelper.groundMirror) {
                    const mirrorClearColor = this.environmentHelper.groundMaterial._perceptualColor.toLinearSpace();
                    // TODO user camera exposure value to set the mirror clear color
                    let exposure = Math.pow(2.0, -this.scene.imageProcessingConfiguration.exposure) * Math.PI;
                    mirrorClearColor.scaleToRef(1 / exposure, mirrorClearColor);

                    this.environmentHelper.groundMirror.clearColor.r = Scalar.Clamp(mirrorClearColor.r);
                    this.environmentHelper.groundMirror.clearColor.g = Scalar.Clamp(mirrorClearColor.g);
                    this.environmentHelper.groundMirror.clearColor.b = Scalar.Clamp(mirrorClearColor.b);
                    this.environmentHelper.groundMirror.clearColor.a = 1;

                    if (!this.groundMirrorEnabled) {
                        this.environmentHelper.groundMaterial.reflectionTexture = null;
                    }
                }
            }

            let skyboxMaterial = this.environmentHelper.skyboxMaterial;
            if (skyboxMaterial) {
                skyboxMaterial._perceptualColor = this.mainColor;

                if (postInitSkyboxMaterial) {
                    if (typeof skyboxConifguration === 'object' && skyboxConifguration.material) {
                        extendClassWithConfig(skyboxMaterial, skyboxConifguration.material);
                    }
                }
            }

        }

        this._observablesManager && this._observablesManager.onModelLoadedObservable.add((model) => {
            this._updateGroundMirrorRenderList(model);
        });

        this.onEnvironmentConfiguredObservable.notifyObservers({
            sceneManager: this,
            object: this.environmentHelper!,
            newConfiguration: {
                skybox: skyboxConifguration,
                ground: groundConfiguration
            }
        });
    }

    /**
     * configure the lights.
     *
     * @param lightsConfiguration the (new) light(s) configuration
     * @param model optionally use the model to configure the camera.
     */
    protected _configureLights(lightsConfiguration: { [name: string]: ILightConfiguration | boolean | number } = {}) {

        // sanity check!
        let lightKeys = Object.keys(lightsConfiguration).filter((name) => name !== 'globalRotation');

        if (!lightKeys.length) {
            if (!this.scene.lights.length) {
                this.scene.createDefaultLight(true);
            }
        } else {

            let lightsAvailable: Array<string> = this.scene.lights.map((light) => light.name);
            // compare to the global (!) configuration object and dispose unneeded:
            let lightsToConfigure = Object.keys(this._globalConfiguration.lights || []);
            if (Object.keys(lightsToConfigure).length !== lightsAvailable.length) {
                lightsAvailable.forEach((lName) => {
                    if (lightsToConfigure.indexOf(lName) === -1) {
                        this.scene.getLightByName(lName)!.dispose();
                    }
                });
            }

            lightKeys.forEach((name, idx) => {
                let lightConfig: ILightConfiguration = { type: 0 };
                if (typeof lightsConfiguration[name] === 'object') {
                    lightConfig = <ILightConfiguration>lightsConfiguration[name];
                }
                if (typeof lightsConfiguration[name] === 'number') {
                    lightConfig.type = <number>lightsConfiguration[name];
                }

                lightConfig.name = name;

                let light: Light;
                // light is not already available
                if (lightsAvailable.indexOf(name) === -1) {
                    let constructor = Light.GetConstructorFromName(lightConfig.type, lightConfig.name, this.scene);
                    if (!constructor) { return; }
                    light = constructor();
                } else {
                    // available? get it from the scene
                    light = <Light>this.scene.getLightByName(name);
                    if (typeof lightsConfiguration[name] === 'boolean') {
                        lightConfig.type = light.getTypeID();
                    }
                    lightsAvailable = lightsAvailable.filter((ln) => ln !== name);
                    if (lightConfig.type !== undefined && light.getTypeID() !== lightConfig.type) {
                        light.dispose();
                        let constructor = Light.GetConstructorFromName(lightConfig.type, lightConfig.name, this.scene);
                        if (!constructor) { return; }
                        light = constructor();
                    }
                }

                // if config set the light to false, dispose it.
                if (lightsConfiguration[name] === false) {
                    light.dispose();
                    return;
                }

                //enabled
                var enabled = lightConfig.enabled !== undefined ? lightConfig.enabled : !lightConfig.disabled;
                light.setEnabled(enabled);

                extendClassWithConfig(light, lightConfig);

                //position. Some lights don't support shadows
                if (light instanceof ShadowLight) {
                    // set default values
                    light.shadowMinZ = light.shadowMinZ || 0.2;
                    light.shadowMaxZ = Math.min(10, light.shadowMaxZ || 10); //large far clips reduce shadow depth precision

                    if (lightConfig.target) {
                        if (light.setDirectionToTarget) {
                            let target = Vector3.Zero().copyFrom(lightConfig.target as Vector3);
                            light.setDirectionToTarget(target);
                        }
                    } else if (lightConfig.direction) {
                        let direction = Vector3.Zero().copyFrom(lightConfig.direction as Vector3);
                        light.direction = direction;
                    }

                    let isShadowEnabled = false;
                    if (light.getTypeID() === BABYLON.Light.LIGHTTYPEID_DIRECTIONALLIGHT) {
                        (<BABYLON.DirectionalLight>light).shadowFrustumSize = lightConfig.shadowFrustumSize || 2;
                        isShadowEnabled = true;
                    }
                    else if (light.getTypeID() === BABYLON.Light.LIGHTTYPEID_SPOTLIGHT) {
                        let spotLight: BABYLON.SpotLight = <BABYLON.SpotLight>light;
                        if (lightConfig.spotAngle !== undefined) {
                            spotLight.angle = lightConfig.spotAngle * Math.PI / 180;
                        }
                        if (spotLight.angle && lightConfig.shadowFieldOfView) {
                            spotLight.shadowAngleScale = lightConfig.shadowFieldOfView / spotLight.angle;
                        }
                        isShadowEnabled = true;
                    }
                    else if (light.getTypeID() === BABYLON.Light.LIGHTTYPEID_POINTLIGHT) {
                        if (lightConfig.shadowFieldOfView) {
                            (<BABYLON.PointLight>light).shadowAngle = lightConfig.shadowFieldOfView * Math.PI / 180;
                        }
                        isShadowEnabled = true;
                    }

                    let shadowGenerator = <BABYLON.ShadowGenerator>light.getShadowGenerator();
                    if (isShadowEnabled && lightConfig.shadowEnabled && this._maxShadows) {
                        let bufferSize = lightConfig.shadowBufferSize || 256;

                        if (!shadowGenerator) {
                            shadowGenerator = new ShadowGenerator(bufferSize, light);
                        }

                        var blurKernel = this.getBlurKernel(light, bufferSize);
                        shadowGenerator.bias = this._shadowGeneratorBias;
                        shadowGenerator.blurKernel = blurKernel;
                        //override defaults
                        extendClassWithConfig(shadowGenerator, lightConfig.shadowConfig || {});

                        // add the focues meshes to the shadow list
                        this._observablesManager && this._observablesManager.onModelLoadedObservable.add((model) => {
                            this._updateShadowRenderList(shadowGenerator, model);
                        });

                        //if (model) {
                        this._updateShadowRenderList(shadowGenerator);
                        //}
                    } else if (shadowGenerator) {
                        shadowGenerator.dispose();
                    }
                }
            });

            // render priority
            let globalLightsConfiguration = this._globalConfiguration.lights || {};
            Object.keys(globalLightsConfiguration).sort().forEach((name, idx) => {
                let configuration = globalLightsConfiguration[name];
                let light = this.scene.getLightByName(name);
                // sanity check
                if (!light) { return; }
                light.renderPriority = -idx;
            });
        }

        this.onLightsConfiguredObservable.notifyObservers({
            sceneManager: this,
            object: this.scene.lights,
            newConfiguration: lightsConfiguration
        });
    }

    private _shadowGroundPlane: Nullable<AbstractMesh>;

    private _updateShadowRenderList(shadowGenerator: ShadowGenerator, model?: ViewerModel, resetList?: boolean) {
        let focusMeshes = model ? model.meshes : this.scene.meshes;
        // add the focues meshes to the shadow list
        let shadownMap = shadowGenerator.getShadowMap();
        if (!shadownMap) { return; }
        if (resetList && shadownMap.renderList) {
            shadownMap.renderList.length = 0;
        } else {
            shadownMap.renderList = shadownMap.renderList || [];
        }
        for (var index = 0; index < focusMeshes.length; index++) {
            let mesh = focusMeshes[index];
            if (Tags.MatchesQuery(mesh, 'castShadow') && shadownMap.renderList.indexOf(mesh) === -1) {
                shadownMap.renderList.push(mesh);
            }
        }

        if (!this._shadowGroundPlane) {
            if (shadowGenerator.useBlurCloseExponentialShadowMap) {
                let shadowGroundPlane = Mesh.CreatePlane("shadowGroundPlane", 100, this.scene, false);
                shadowGroundPlane.useVertexColors = false;
                //material isn't ever used in rendering, just used to set back face culling
                shadowGroundPlane.material = new StandardMaterial('shadowGroundPlaneMaterial', this.scene);
                shadowGroundPlane.material.backFaceCulling = false;
                shadowGroundPlane.rotation.x = Math.PI * 0.5;
                shadowGroundPlane.freezeWorldMatrix();
                this._shadowGroundPlane = shadowGroundPlane;
                this.scene.removeMesh(shadowGroundPlane);
            }
        } else {
            if (!shadowGenerator.useBlurCloseExponentialShadowMap) {
                this._shadowGroundPlane.dispose();
                this._shadowGroundPlane = null;
            }
        }

        if (this._shadowGroundPlane && shadownMap.renderList.indexOf(this._shadowGroundPlane) === -1) {
            shadownMap.renderList.push(this._shadowGroundPlane);
        }
    }

    private _updateGroundMirrorRenderList(model?: ViewerModel, resetList?: boolean) {
        if (this.environmentHelper && this.environmentHelper.groundMirror && this.environmentHelper.groundMirror.renderList) {
            let focusMeshes = model ? model.meshes : this.scene.meshes;
            let renderList = this.environmentHelper.groundMirror.renderList;
            if (resetList) {
                renderList.length = 0;
            }
            for (var index = 0; index < focusMeshes.length; index++) {
                let mesh = focusMeshes[index];
                if (renderList.indexOf(mesh) === -1) {
                    renderList.push(mesh);
                }
            }
        }
    }

    /**
     * Gets the shadow map blur kernel according to the light configuration.
     * @param light The light used to generate the shadows
     * @param bufferSize The size of the shadow map
     * @return the kernel blur size
     */
    public getBlurKernel(light: BABYLON.IShadowLight, bufferSize: number): number {
        var normalizedBlurKernel = 0.05; // TODO Should come from the config.
        if (light.getTypeID() === BABYLON.Light.LIGHTTYPEID_DIRECTIONALLIGHT) {
            normalizedBlurKernel = normalizedBlurKernel / (<BABYLON.DirectionalLight>light).shadowFrustumSize;
        }
        else if (light.getTypeID() === BABYLON.Light.LIGHTTYPEID_POINTLIGHT) {
            normalizedBlurKernel = normalizedBlurKernel / (<BABYLON.PointLight>light).shadowAngle;
        }
        else if (light.getTypeID() === BABYLON.Light.LIGHTTYPEID_SPOTLIGHT) {
            normalizedBlurKernel = normalizedBlurKernel / ((<BABYLON.SpotLight>light).angle * (<BABYLON.SpotLight>light).shadowAngleScale);
        }

        let minimumBlurKernel = 5 / (bufferSize / 256); //magic number that aims to keep away sawtooth shadows

        var blurKernel = Math.max(bufferSize * normalizedBlurKernel, minimumBlurKernel);
        return blurKernel;
    }

    /**
     * Alters render settings to reduce features based on hardware feature limitations
     * @param enableHDR Allows the viewer to run in HDR mode.
     */
    protected _handleHardwareLimitations(enableHDR = true) {
        //flip rendering settings switches based on hardware support
        let maxVaryingRows = this._engine.getCaps().maxVaryingVectors;
        let maxFragmentSamplers = this._engine.getCaps().maxTexturesImageUnits;

        //shadows are disabled if there's not enough varyings for a single shadow
        if ((maxVaryingRows < 8) || (maxFragmentSamplers < 8)) {
            this._maxShadows = 0;
        } else {
            this._maxShadows = 3;
        }

        //can we render to any >= 16-bit targets (required for HDR)
        let caps = this._engine.getCaps();
        let linearHalfFloatTargets = caps.textureHalfFloatRender && caps.textureHalfFloatLinearFiltering;
        let linearFloatTargets = caps.textureFloatRender && caps.textureFloatLinearFiltering;

        this._hdrSupport = enableHDR && !!(linearFloatTargets || linearHalfFloatTargets);

        if (linearHalfFloatTargets) {
            this._defaultHighpTextureType = Engine.TEXTURETYPE_HALF_FLOAT;
            this._shadowGeneratorBias = 0.002;
        } else if (linearFloatTargets) {
            this._defaultHighpTextureType = Engine.TEXTURETYPE_FLOAT;
            this._shadowGeneratorBias = 0.001;
        } else {
            this._defaultHighpTextureType = Engine.TEXTURETYPE_UNSIGNED_INT;
            this._shadowGeneratorBias = 0.001;
        }

        this._defaultPipelineTextureType = this._hdrSupport ? this._defaultHighpTextureType : Engine.TEXTURETYPE_UNSIGNED_INT;
    }

    /**
     * Dispoe the entire viewer including the scene and the engine
     */
    public dispose() {

        // this.onCameraConfiguredObservable.clear();
        this.onEnvironmentConfiguredObservable.clear();
        this.onLightsConfiguredObservable.clear();
        this.onModelsConfiguredObservable.clear();
        this.onSceneConfiguredObservable.clear();
        this.onSceneInitObservable.clear();
        this.onSceneOptimizerConfiguredObservable.clear();
        this.onVRConfiguredObservable.clear();

        if (this.sceneOptimizer) {
            this.sceneOptimizer.stop();
            this.sceneOptimizer.dispose();
        }

        if (this.environmentHelper) {
            this.environmentHelper.dispose();
        }

        this.models.forEach((model) => {
            model.dispose();
        });

        if (this._defaultRenderingPipeline) {
            this._defaultRenderingPipeline.dispose();
        }

        this.models.length = 0;

        if (this.scene) {
            this.scene.dispose();
        }
    }

    /**
     * Get an environment asset url by using the configuration if the path is not absolute.
     * @param url Asset url
     * @returns The Asset url using the `environmentAssetsRootURL` if the url is not an absolute path.
     */
    private _getAssetUrl(url: string): string {
        let returnUrl = url;
        if (url && url.toLowerCase().indexOf("//") === -1) {
            if (!this._assetsRootURL) {
                // Tools.Warn("Please, specify the root url of your assets before loading the configuration (labs.environmentAssetsRootURL) or disable the background through the viewer options.");
                return url;
            }

            returnUrl = this._assetsRootURL + returnUrl;
        }

        return returnUrl;
    }

    private _cameraBehaviorMapping: { [name: string]: number } = {};

    private _setCameraBehavior(name: string, behaviorConfig: boolean | number | {
        type: number;
        [propName: string]: any;
    }, payload?: any) {

        let behavior: Behavior<ArcRotateCamera> | null;
        let type: number;
        if (typeof behaviorConfig === 'object') {
            type = behaviorConfig.type;
        } else if (typeof behaviorConfig === 'number') {
            type = behaviorConfig;
        } else {
            type = this._cameraBehaviorMapping[name];
        }

        if (type === undefined) { return; }

        let config: { [propName: string]: any } = (typeof behaviorConfig === "object") ? behaviorConfig : {};

        let enabled = true;
        if (typeof behaviorConfig === 'boolean') {
            enabled = behaviorConfig;
        }

        // constructing behavior
        switch (type) {
            case CameraBehavior.AUTOROTATION:
                this.camera.useAutoRotationBehavior = enabled;
                behavior = this.camera.autoRotationBehavior;
                break;
            case CameraBehavior.BOUNCING:
                this.camera.useBouncingBehavior = enabled;
                behavior = this.camera.bouncingBehavior;
                break;
            case CameraBehavior.FRAMING:
                this.camera.useFramingBehavior = enabled;
                behavior = this.camera.framingBehavior;
                break;
            default:
                behavior = null;
                break;
        }

        if (behavior) {
            this._cameraBehaviorMapping[name] = type;

            if (typeof behaviorConfig === "object") {
                extendClassWithConfig(behavior, behaviorConfig);
            }
        }

        // post attach configuration. Some functionalities require the attached camera.
        switch (type) {
            case CameraBehavior.AUTOROTATION:
                break;
            case CameraBehavior.BOUNCING:
                break;
            case CameraBehavior.FRAMING:
                this._observablesManager && this._observablesManager.onModelLoadedObservable.add((model) => {
                    if (config.zoomOnBoundingInfo) {
                        (<FramingBehavior>behavior).zoomOnMeshHierarchy(model.rootMesh);
                    }
                });
                break;
        }
    }
}