HttpSceneLoader

Introduction

vtkHttpSceneLoader

Methods

applySettings

Argument	Type	Required	Description
sceneItem		Yes
settings		Yes

extend

Method used to decorate a given object (publicAPI+model) with vtkHttpSceneLoader characteristics.

Argument	Type	Required	Description
publicAPI		Yes	object on which methods will be bounds (public)
model		Yes	object on which data structure will be bounds (protected)
initialValues	IHttpSceneLoaderInitialValues	No	(default: {})

getAnimationHandler

getBaseURL

getFetchGzip

Argument	Type	Required	Description
fetchGzip	Boolean	Yes

getMetadata

getRenderer

getScene

getUrl

invokeReady

newInstance

Method used to create a new instance of vtkHttpSceneLoader

Argument	Type	Required	Description
initialValues	IHttpSceneLoaderInitialValues	No	for pre-setting some of its content

onReady

resetScene

setRenderer

Argument	Type	Required	Description
renderer	vtkRenderer	Yes	The vtkRenderer instance.

setUrl

Argument	Type	Required	Description
url	String	Yes

update

updateDatasetTypeMapping

Argument	Type	Required	Description
typeName		Yes
handler		Yes

Source

index.d.ts

import { vtkObject } from "../../../interfaces";
import vtkAnnotatedCubeActor from "../../../Rendering/Core/AnnotatedCubeActor";
import vtkAxesActor from "../../../Rendering/Core/AxesActor";
import vtkRenderer from "../../../Rendering/Core/Renderer";
import vtkRenderWindowInteractor from "../../../Rendering/Core/RenderWindowInteractor";

/**
 * 
 */
export interface IHttpSceneLoaderInitialValues {
	fetchGzip?: boolean,
	url?: string,
	baseURL?: string,
	animationHandler?: null,
	startLODLoaders?: boolean,
}

export interface vtkHttpSceneLoader extends vtkObject {

	/**
	 * 
	 */
	getAnimationHandler(): any; // vtkTimeStepBasedAnimationHandler

	/**
	 * 
	 */
	getBaseURL(): string;

	/**
	 * 
	 * @param {Boolean} fetchGzip 
	 */
	getFetchGzip(fetchGzip: boolean): boolean;

	/**
	 * 
	 */
	getMetadata(): any;

	/**
	 * 
	 */
	getRenderer(): vtkRenderer;

	/**
	 * 
	 */
	getScene(): object;

	/**
	 * 
	 */
	getUrl(): string;

	/**
	 * 
	 */
	invokeReady(): void;

	/**
	 * 
	 */
	onReady(): void;

	/**
	 * 
	 */
	resetScene(): void;

	/**
	 * 
	 * @param {vtkRenderer} renderer The vtkRenderer instance. 
	 */
	setRenderer(renderer: vtkRenderer): boolean;

	/**
	 * 
	 * @param {String} url 
	 */
	setUrl(url: string): void;

	/**
	 * 
	 */
	update(): void;
}

/**
 * Method used to decorate a given object (publicAPI+model) with vtkHttpSceneLoader characteristics.
 *
 * @param publicAPI object on which methods will be bounds (public)
 * @param model object on which data structure will be bounds (protected)
 * @param {IHttpSceneLoaderInitialValues} [initialValues] (default: {})
 */
export function extend(publicAPI: object, model: object, initialValues?: IHttpSceneLoaderInitialValues): void;

/**
 * Method used to create a new instance of vtkHttpSceneLoader
 * @param {IHttpSceneLoaderInitialValues} [initialValues] for pre-setting some of its content
 */
export function newInstance(initialValues?: IHttpSceneLoaderInitialValues): vtkHttpSceneLoader;

/**
 * 
 * @param sceneItem 
 * @param settings 
 */
export function applySettings(sceneItem: object, settings: object): void;

/**
 * 
 * @param typeName 
 * @param handler 
 */
export function updateDatasetTypeMapping(typeName: string, handler: any): void;

/**
 * vtkHttpSceneLoader
 */
export declare const vtkHttpSceneLoader: {
	newInstance: typeof newInstance;
	extend: typeof extend;
	applySettings: typeof applySettings;
	updateDatasetTypeMapping: typeof updateDatasetTypeMapping;
}
export default vtkHttpSceneLoader;

index.js

import macro from 'vtk.js/Sources/macros';
import vtkActor from 'vtk.js/Sources/Rendering/Core/Actor';
import vtkVolume from 'vtk.js/Sources/Rendering/Core/Volume';
import vtkHttpDataSetReader from 'vtk.js/Sources/IO/Core/HttpDataSetReader';
import vtkHttpDataSetSeriesReader from 'vtk.js/Sources/IO/Core/HttpDataSetSeriesReader';
import vtkMapper from 'vtk.js/Sources/Rendering/Core/Mapper';
import vtkTexture from 'vtk.js/Sources/Rendering/Core/Texture';
import vtkTextureLODsDownloader from 'vtk.js/Sources/Rendering/Misc/TextureLODsDownloader';
import vtkHttpDataSetLODsLoader from 'vtk.js/Sources/IO/Misc/HttpDataSetLODsLoader';
import vtkColorTransferFunction from 'vtk.js/Sources/Rendering/Core/ColorTransferFunction';
import vtkPiecewiseFunction from 'vtk.js/Sources/Common/DataModel/PiecewiseFunction';
import vtkVolumeMapper from 'vtk.js/Sources/Rendering/Core/VolumeMapper';
import vtkTimeStepBasedAnimationHandler from 'vtk.js/Sources/Interaction/Animations/TimeStepBasedAnimationHandler';
import DataAccessHelper from 'vtk.js/Sources/IO/Core/DataAccessHelper';

// Enable data soure for DataAccessHelper
import 'vtk.js/Sources/IO/Core/DataAccessHelper/LiteHttpDataAccessHelper'; // Just need HTTP
// import 'vtk.js/Sources/IO/Core/DataAccessHelper/HttpDataAccessHelper'; // HTTP + zip
// import 'vtk.js/Sources/IO/Core/DataAccessHelper/HtmlDataAccessHelper'; // html + base64 + zip
// import 'vtk.js/Sources/IO/Core/DataAccessHelper/JSZipDataAccessHelper'; // zip

const { vtkErrorMacro } = macro;

let itemCount = 1;

function applySettings(sceneItem, settings) {
  if (settings.actor) {
    sceneItem.actor.set(settings.actor);
  }

  if (settings.actorRotation) {
    sceneItem.actor.rotateWXYZ(
      settings.actorRotation[0],
      settings.actorRotation[1],
      settings.actorRotation[2],
      settings.actorRotation[3]
    );
  }

  if (settings.volumeRotation) {
    sceneItem.volume.rotateWXYZ(
      settings.volumeRotation[0],
      settings.volumeRotation[1],
      settings.volumeRotation[2],
      settings.volumeRotation[3]
    );
  }

  if (settings.property) {
    if (settings.volume) {
      const volumePropertySettings = { ...settings.property };
      delete volumePropertySettings.components;
      sceneItem.volume.getProperty().set(volumePropertySettings);
      if (settings.property.components) {
        const volumeProperty = sceneItem.volume.getProperty();
        sceneItem.volumeComponents.forEach((component, componentIndex) => {
          volumeProperty.setScalarOpacityUnitDistance(
            componentIndex,
            settings.property.components[componentIndex]
              .scalarOpacityUnitDistance
          );

          if (component.rgbTransferFunction) {
            volumeProperty.setRGBTransferFunction(
              componentIndex,
              component.rgbTransferFunction
            );
          }

          if (component.grayTransferFunction) {
            volumeProperty.setGrayTransferFunction(
              componentIndex,
              component.grayTransferFunction
            );
          }

          if (component.scalarOpacity) {
            volumeProperty.setScalarOpacity(
              componentIndex,
              component.scalarOpacity
            );
          }
        });
      }
    } else {
      sceneItem.actor.getProperty().set(settings.property);
    }
  }

  if (settings.mapper) {
    if (settings.mapper.colorByArrayName) {
      sceneItem.source.enableArray(
        settings.mapper.colorByArrayName,
        settings.mapper.colorByArrayName
      );
      sceneItem.source.loadData();
    }

    sceneItem.mapper.set(settings.mapper);
    if (
      settings.mapper.colorByArrayName &&
      settings.luts[settings.mapper.colorByArrayName]
    ) {
      sceneItem.mapper.setLookupTable(
        settings.luts[settings.mapper.colorByArrayName]
      );
      sceneItem.mapper.setUseLookupTableScalarRange(true);
    }
  }

  if (settings.lookupTable) {
    sceneItem.mapper.getLookupTable().set(settings.lookupTable);
    sceneItem.mapper.getLookupTable().build();
  }

  if (settings.textureLODs) {
    sceneItem.textureLODs = settings.textureLODs;
  }

  if (settings.sourceLODs) {
    sceneItem.sourceLODs = settings.sourceLODs;
  }
}

// ----------------------------------------------------------------------------
// Global methods
// ----------------------------------------------------------------------------

function isImage(str) {
  const ext = str.split('.').pop().toLowerCase();
  return ['jpg', 'png', 'jpeg'].indexOf(ext) !== -1;
}

function loadColorTransferFunction(item) {
  const tf = vtkColorTransferFunction.newInstance(item);
  if (item.nodes) {
    tf.removeAllPoints();
    item.nodes.forEach(([x, r, g, b, midpoint, sharpness]) => {
      tf.addRGBPointLong(x, r, g, b, midpoint, sharpness);
    });
  }
  return tf;
}

function loadPiecewiseFunction(item) {
  const pwf = vtkPiecewiseFunction.newInstance(item);
  if (item.points) {
    pwf.removeAllPoints();

    item.points.forEach(([x, y, midpoint, sharpness]) =>
      pwf.addPointLong(x, y, midpoint, sharpness)
    );
  }
  return pwf;
}

function initializeVolumeComponents(components) {
  return components.map((component) => {
    const ret = {};
    if (component.rgbTransferFunction) {
      ret.rgbTransferFunction = loadColorTransferFunction(
        component.rgbTransferFunction
      );
    } else if (component.grayTransferFunction) {
      ret.grayTransferFunction = loadPiecewiseFunction(
        component.grayTransferFunction
      );
    }
    if (component.scalarOpacity) {
      ret.scalarOpacity = loadPiecewiseFunction(component.scalarOpacity);
    }
    return ret;
  });
}

// ----------------------------------------------------------------------------

function defineLoadFuctionForReader(type) {
  return (item, model, publicAPI) => {
    const source = type.newInstance({
      fetchGzip: model.fetchGzip,
      dataAccessHelper: model.dataAccessHelper,
    });
    let mapper;
    if (item.volume) {
      mapper = vtkVolumeMapper.newInstance();
    } else {
      mapper = vtkMapper.newInstance();
    }
    const sceneItem = {
      name: item.name || `Item ${itemCount++}`,
      source,
      mapper,
      defaultSettings: item,
    };

    if (item.volume) {
      const volume = vtkVolume.newInstance();
      sceneItem.volume = volume;
      if (model.renderer) {
        model.renderer.addVolume(volume);
      }
      if (item.property && item.property.components) {
        // initialize transfer functions
        sceneItem.volumeComponents = initializeVolumeComponents(
          item.property.components
        );
      }
      volume.setMapper(mapper);
    } else {
      const actor = vtkActor.newInstance();
      sceneItem.actor = actor;
      if (item.texture && item.texture in model.usedTextures) {
        // If this texture has already been used, re-use it
        actor.addTexture(model.usedTextures[item.texture]);
      } else if (item.texture) {
        const url = [model.baseURL, item.texture].join('/');
        const texture = vtkTexture.newInstance();
        texture.setInterpolate(true);
        texture.setRepeat(true);
        actor.addTexture(texture);
        sceneItem.texture = texture;
        model.usedTextures[item.texture] = texture;

        if (isImage(item.texture)) {
          // It's an image file
          model.dataAccessHelper
            .fetchImage({}, url, { crossOrigin: 'anonymous' })
            .then((img) => {
              texture.setImage(img);
            });
        } else {
          // Assume it's a dataset file
          const textureSource = type.newInstance({
            fetchGzip: model.fetchGzip,
            dataAccessHelper: model.dataAccessHelper,
          });
          textureSource.setUrl(url, { loadData: true }).then(() => {
            texture.setInputData(textureSource.getOutputData());
          });
        }
      }

      const { textureLODs } = item;
      if (textureLODs && textureLODs.files && textureLODs.files.length !== 0) {
        // If this texture LOD has already been used, re-use it
        const textureLODsStr = JSON.stringify(textureLODs);
        if (textureLODsStr in model.usedTextureLODs) {
          actor.addTexture(model.usedTextureLODs[textureLODsStr]);
        } else {
          // Set it on the scene item so it can be accessed later, for
          // doing things like setting a callback function.
          sceneItem.textureLODsDownloader =
            vtkTextureLODsDownloader.newInstance();
          const textureDownloader = sceneItem.textureLODsDownloader;

          const texture = vtkTexture.newInstance();
          texture.setInterpolate(true);
          actor.addTexture(texture);
          model.usedTextureLODs[textureLODsStr] = texture;

          textureDownloader.setTexture(texture);
          textureDownloader.setCrossOrigin('anonymous');
          textureDownloader.setBaseUrl(textureLODs.baseUrl);
          textureDownloader.setFiles(textureLODs.files);

          if (model.startLODLoaders) {
            textureDownloader.startDownloads();
          }
        }
      }
      if (model.renderer) {
        model.renderer.addActor(actor);
      }
      actor.setMapper(mapper);
    }

    mapper.setInputConnection(source.getOutputPort());

    source
      .setUrl([model.baseURL, item[item.type].url].join('/'), {
        loadData: true,
      })
      .then(() => publicAPI.invokeReady());

    applySettings(sceneItem, item);
    model.scene.push(sceneItem);

    const { sourceLODs } = item;
    if (sourceLODs && sourceLODs.files && sourceLODs.files.length !== 0) {
      // Set it on the scene item so it can be accessed later, for
      // doing things like setting a callback function.
      sceneItem.dataSetLODsLoader = vtkHttpDataSetLODsLoader.newInstance();
      const { dataSetLODsLoader } = sceneItem;

      dataSetLODsLoader.setMapper(mapper);
      dataSetLODsLoader.setSceneItem(sceneItem);
      dataSetLODsLoader.setBaseUrl(sourceLODs.baseUrl);
      dataSetLODsLoader.setFiles(sourceLODs.files);

      if (model.startLODLoaders) {
        dataSetLODsLoader.startDownloads();
      }
    }

    return sceneItem;
  };
}

function loadTimeStepBasedAnimationHandler(data, model) {
  model.animationHandler = vtkTimeStepBasedAnimationHandler.newInstance({
    scene: model.scene,
    originalMetadata: model.metadata,
    applySettings,
  });
  if (model.animationHandler && model.renderer) {
    model.animationHandler.addRenderer(model.renderer);
  }
  model.animationHandler.setData(data);
}

// ----------------------------------------------------------------------------
// Note: keeping both types (with and without 'vtk' prefix) for backwards compatibility
// see https://gitlab.kitware.com/paraview/paraview/-/merge_requests/4628#note_876772

const TYPE_MAPPING = {
  httpDataSetReader: defineLoadFuctionForReader(vtkHttpDataSetReader),
  vtkHttpDataSetReader: defineLoadFuctionForReader(vtkHttpDataSetReader),
  httpDataSetSeriesReader: defineLoadFuctionForReader(
    vtkHttpDataSetSeriesReader
  ),
  vtkHttpDataSetSeriesReader: defineLoadFuctionForReader(
    vtkHttpDataSetSeriesReader
  ),
};

const ANIMATION_TYPE_MAPPING = {
  timeStepBasedAnimationHandler: loadTimeStepBasedAnimationHandler,
  vtkTimeStepBasedAnimationHandler: loadTimeStepBasedAnimationHandler,
};

// ----------------------------------------------------------------------------

function updateDatasetTypeMapping(typeName, handler) {
  TYPE_MAPPING[typeName] = handler;
}

// ----------------------------------------------------------------------------
// vtkHttpSceneLoader methods
// ----------------------------------------------------------------------------

function vtkHttpSceneLoader(publicAPI, model) {
  const originalSceneParameters = {};

  // These are here to re-use the same textures when possible
  if (!model.usedTextures) {
    model.usedTextures = {};
  }
  if (!model.usedTextureLODs) {
    model.usedTextureLODs = {};
  }

  // Set our className
  model.classHierarchy.push('vtkHttpSceneLoader');

  // Create scene container
  if (!model.scene) {
    model.scene = [];
  }

  function setCameraParameters(params) {
    if (model.renderer) {
      const camera = model.renderer.getActiveCamera();
      if (camera) {
        camera.set(params);
      } else {
        vtkErrorMacro('No active camera to update');
      }
    }
  }

  function setBackground(color) {
    if (model.renderer) {
      model.renderer.setBackground(color);
    }
  }

  // Create default dataAccessHelper if not available
  if (!model.dataAccessHelper) {
    model.dataAccessHelper = DataAccessHelper.get('http');
  }

  publicAPI.update = () => {
    model.dataAccessHelper.fetchJSON(publicAPI, model.url).then(
      (data) => {
        if (data.fetchGzip !== undefined) {
          model.fetchGzip = data.fetchGzip;
        }
        if (data.background && model.renderer) {
          setBackground(data.background);
        }
        if (data.camera) {
          originalSceneParameters.camera = data.camera;
          setCameraParameters(data.camera);
        }
        const luts = {};
        if (data.lookupTables) {
          Object.keys(data.lookupTables).forEach((fieldName) => {
            const config = data.lookupTables[fieldName];
            const lookupTable = loadColorTransferFunction(config);
            luts[fieldName] = lookupTable;
          });
        }
        if (data.scene) {
          data.scene.forEach((item) => {
            const builder = TYPE_MAPPING[item.type];
            if (builder) {
              builder({ luts, ...item }, model, publicAPI);
            }
          });
          global.scene = model.scene;

          // Clear these
          model.usedTextures = {};
          model.usedTextureLODs = {};
        }

        // Capture index.json into meta
        model.metadata = data;

        if (data.animation) {
          const animationLoader = ANIMATION_TYPE_MAPPING[data.animation.type];
          animationLoader(
            { ...data.animation },
            model,
            publicAPI,
            setCameraParameters,
            setBackground
          );
        }
      },
      (error) => {
        vtkErrorMacro(`Error fetching scene ${error}`);
      }
    );
  };

  publicAPI.resetScene = () => {
    if (originalSceneParameters.camera) {
      setCameraParameters(originalSceneParameters.camera);
    }
  };

  // Set DataSet url
  publicAPI.setUrl = (url) => {
    if (url.indexOf('index.json') === -1) {
      model.baseURL = url;
      model.url = `${url}/index.json`;
    } else {
      model.url = url;

      // Remove the file in the URL
      const path = url.split('/');
      path.pop();
      model.baseURL = path.join('/');
    }

    // Fetch data
    return publicAPI.update();
  };
}

// ----------------------------------------------------------------------------
// Object factory
// ----------------------------------------------------------------------------

const DEFAULT_VALUES = {
  fetchGzip: false,
  url: null,
  baseURL: null,
  animationHandler: null,
  // Whether or not to automatically start texture LOD and poly LOD
  // downloads when they are read.
  startLODLoaders: true,
};

// ----------------------------------------------------------------------------

export function extend(publicAPI, model, initialValues = {}) {
  Object.assign(model, DEFAULT_VALUES, initialValues);

  // Build VTK API
  macro.obj(publicAPI, model);
  macro.get(publicAPI, model, [
    'fetchGzip',
    'url',
    'baseURL',
    'scene',
    'metadata',
    'animationHandler',
  ]);
  macro.setGet(publicAPI, model, ['renderer']);
  macro.event(publicAPI, model, 'ready');

  // Object methods
  vtkHttpSceneLoader(publicAPI, model);
}

// ----------------------------------------------------------------------------

export const newInstance = macro.newInstance(extend, 'vtkHttpSceneLoader');

// ----------------------------------------------------------------------------

export default { newInstance, extend, applySettings, updateDatasetTypeMapping };