ViewNode

Introduction

a node within a VTK scene graph

This is the superclass for all nodes within a VTK scene graph. It contains
the API for a node. It supports the essential operations such as graph
creation, state storage and traversal. Child classes adapt this to VTK’s
major rendering classes. Grandchild classes adapt those to for APIs of
different rendering libraries.

Methods

addMissingNode

Add a child view node to this node, created from the renderable given as argument
If the node creation fails or the argument is falsy, returns undefined
Otherwise, returns the newly created node or the existing node

Argument	Type	Required	Description
dobj		Yes

addMissingNodes

Argument	Type	Required	Description
dataObjs		Yes

apply

Argument	Type	Required	Description
renderPass	vtkRenderPass	Yes
prepass		Yes

build

Builds myself.

Argument	Type	Required	Description
prepass		Yes

createViewNode

Argument	Type	Required	Description
dataObj		Yes

extend

Method used to decorate a given object (publicAPI+model) with vtkViewNode 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	IViewNodeInitialValues	No	(default: {})

getChildren

getChildrenByReference

getFirstAncestorOfType

Find the first parent/grandparent of the desired type

Argument	Type	Required	Description
type		Yes

getLastAncestorOfType

Find the last parent/grandparent of the desired type

Argument	Type	Required	Description
type		Yes

getMyFactory

getParent

getRenderable

Get The data object (thing to be rendered).

getViewNodeFor

Returns the view node that corresponding to the provided object
Will return NULL if a match is not found in self or descendents

Argument	Type	Required	Description
dataObject		Yes

getVisited

newInstance

Method used to create a new instance of vtkViewNode.

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

prepareNodes

removeNode

Removes a child view node
If the node is not found, returns false
Otherwise, removes the node from the children list and returns true

Argument	Type	Required	Description
dobj		Yes

removeUnusedNodes

render

Makes calls to make self visible.

Argument	Type	Required	Description
prepass		Yes

setMyFactory

Argument	Type	Required	Description
myFactory		Yes

setParent

Argument	Type	Required	Description
parent		Yes

setRenderable

Argument	Type	Required	Description
renderable		Yes

setVisited

Argument	Type	Required	Description
val		Yes

traverse

Traverse this node with the specified pass. If you want to traverse your
children in a specific order or way override this method

Argument	Type	Required	Description
renderPass	vtkRenderPass	Yes

Source

index.d.ts

import { vtkObject } from '../../../interfaces';
import vtkRenderPass from '../RenderPass';

export enum PASS_TYPES {
  'Build',
  'Render',
}

/**
 *
 */
export interface IViewNodeInitialValues {
  parent?: null;
  renderable?: null;
  myFactory?: null;
  children?: Array<any>;
  visited?: boolean;
}

export interface vtkViewNode extends vtkObject {
  /**
   * Add a child view node to this node, created from the renderable given as argument
   * If the node creation fails or the argument is falsy, returns undefined
   * Otherwise, returns the newly created node or the existing node
   * @param dobj
   */
  addMissingNode(dobj: any): vtkViewNode | undefined;

  /**
   * Removes a child view node
   * If the node is not found, returns false
   * Otherwise, removes the node from the children list and returns true
   * @param dobj
   */
  removeNode(dobj: any): boolean;

  /**
   *
   * @param dataObjs
   */
  addMissingNodes(dataObjs: any): void;

  /**
   *
   * @param {vtkRenderPass} renderPass
   * @param prepass
   */
  apply(renderPass: vtkRenderPass, prepass: boolean): void;

  /**
   * Builds myself.
   * @param prepass
   */
  build(prepass: any): void;

  /**
   *
   * @param dataObj
   */
  createViewNode(dataObj: any): void;

  /**
   *
   */
  getChildren(): any;

  /**
   *
   */
  getChildrenByReference(): any;

  /**
   * Find the first parent/grandparent of the desired type
   * @param type
   */
  getFirstAncestorOfType(type: any): void;

  /**
   * Find the last parent/grandparent of the desired type
   * @param type
   */
  getLastAncestorOfType(type: any): void;

  /**
   *
   */
  getMyFactory(): any;

  /**
   *
   */
  getParent(): any;

  /**
   * Get The data object (thing to be rendered).
   */
  getRenderable(): any;

  /**
   * Returns the view node that corresponding to the provided object
   * Will return NULL if a match is not found in self or descendents
   * @param dataObject
   */
  getViewNodeFor(dataObject: any): any;

  /**
   *
   */
  getVisited(): boolean;

  //invokeEvent
  //onEvent(callback: (instance: vtkObject) => any): vtkSubscription;

  /**
   *
   */
  prepareNodes(): void;

  /**
   *
   */
  removeUnusedNodes(): void;

  /**
   * Makes calls to make self visible.
   * @param prepass
   */
  render(prepass: any): void;

  /**
   *
   * @param myFactory
   */
  setMyFactory(myFactory: any): boolean;

  /**
   *
   * @param parent
   */
  setParent(parent: any): boolean;

  /**
   *
   * @param renderable
   */
  setRenderable(renderable: any): boolean;

  /**
   *
   * @param val
   */
  setVisited(val: boolean): void;

  /**
   * Traverse this node with the specified pass. If you want to traverse your
   * children in a specific order or way override this method
   * @param {vtkRenderPass} renderPass
   */
  traverse(renderPass: vtkRenderPass): void;
}

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

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

/**
 * a node within a VTK scene graph
 *
 * This is the superclass for all nodes within a VTK scene graph. It contains
 * the API for a node. It supports the essential operations such as graph
 * creation, state storage and traversal. Child classes adapt this to VTK's
 * major rendering classes. Grandchild classes adapt those to for APIs of
 * different rendering libraries.
 */
export declare const vtkViewNode: {
  newInstance: typeof newInstance;
  extend: typeof extend;
};
export default vtkViewNode;

index.js

import macro from 'vtk.js/Sources/macros';

const { vtkErrorMacro } = macro;

const PASS_TYPES = ['Build', 'Render'];

// ----------------------------------------------------------------------------
// vtkViewNode methods
// ----------------------------------------------------------------------------

function vtkViewNode(publicAPI, model) {
  // Set our className
  model.classHierarchy.push('vtkViewNode');

  // Builds myself.
  publicAPI.build = (prepass) => {};

  // Renders myself
  publicAPI.render = (prepass) => {};

  publicAPI.traverse = (renderPass) => {
    // we can choose to do special
    // traversal here based on pass
    const passTraversal = renderPass.getTraverseOperation();
    const fn = publicAPI[passTraversal];
    if (fn) {
      fn(renderPass);
      return;
    }

    // default traversal
    publicAPI.apply(renderPass, true);

    for (let index = 0; index < model.children.length; index++) {
      model.children[index].traverse(renderPass);
    }

    publicAPI.apply(renderPass, false);
  };

  publicAPI.apply = (renderPass, prepass) => {
    const customRenderPass = publicAPI[renderPass.getOperation()];
    if (customRenderPass) {
      customRenderPass(prepass, renderPass);
    }
  };

  publicAPI.getViewNodeFor = (dataObject) => {
    if (model.renderable === dataObject) {
      return publicAPI;
    }

    for (let index = 0; index < model.children.length; ++index) {
      const child = model.children[index];
      const vn = child.getViewNodeFor(dataObject);
      if (vn) {
        return vn;
      }
    }
    return undefined;
  };

  publicAPI.getFirstAncestorOfType = (type) => {
    if (!model._parent) {
      return null;
    }
    if (model._parent.isA(type)) {
      return model._parent;
    }
    return model._parent.getFirstAncestorOfType(type);
  };

  publicAPI.getLastAncestorOfType = (type) => {
    if (!model._parent) {
      return null;
    }
    const lastAncestor = model._parent.getLastAncestorOfType(type);
    if (lastAncestor) {
      return lastAncestor;
    }
    if (model._parent.isA(type)) {
      return model._parent;
    }
    return null;
  };

  // add a missing node/child for the passed in renderables. This should
  // be called only in between prepareNodes and removeUnusedNodes
  publicAPI.addMissingNode = (dobj) => {
    if (!dobj) {
      return undefined;
    }

    // if found just mark as visited
    const result = model._renderableChildMap.get(dobj);
    if (result !== undefined) {
      result.setVisited(true);
      return result;
    }

    // otherwise create a node
    const newNode = publicAPI.createViewNode(dobj);
    if (newNode) {
      newNode.setParent(publicAPI);
      newNode.setVisited(true);
      model._renderableChildMap.set(dobj, newNode);
      model.children.push(newNode);
      return newNode;
    }

    return undefined;
  };

  // add missing nodes/children for the passed in renderables. This should
  // be called only in between prepareNodes and removeUnusedNodes
  publicAPI.addMissingNodes = (dataObjs) => {
    if (!dataObjs || !dataObjs.length) {
      return;
    }

    for (let index = 0; index < dataObjs.length; ++index) {
      const dobj = dataObjs[index];
      publicAPI.addMissingNode(dobj);
    }
  };

  // ability to add children that have no renderable use in the same manner
  // as addMissingNodes This case is when a normal viewnode wants to
  // delegate passes to a helper or child that doeasn't map to a clear
  // renderable or any renderable
  publicAPI.addMissingChildren = (children) => {
    if (!children || !children.length) {
      return;
    }

    for (let index = 0; index < children.length; ++index) {
      const child = children[index];
      const cindex = model.children.indexOf(child);
      if (cindex === -1) {
        child.setParent(publicAPI);
        model.children.push(child);
        const childRenderable = child.getRenderable();
        if (childRenderable) {
          model._renderableChildMap.set(childRenderable, child);
        }
      }
      child.setVisited(true);
    }
  };

  publicAPI.removeNode = (child) => {
    const childIdx = model.children.findIndex((x) => x === child);
    if (childIdx < 0) {
      return false;
    }
    const renderable = child.getRenderable();
    if (renderable) {
      model._renderableChildMap.delete(renderable);
    }
    child.delete();
    model.children.splice(childIdx, 1);
    return true;
  };

  publicAPI.prepareNodes = () => {
    for (let index = 0; index < model.children.length; ++index) {
      model.children[index].setVisited(false);
    }
  };

  publicAPI.setVisited = (val) => {
    model.visited = val;
  };

  publicAPI.removeUnusedNodes = () => {
    let visitedCount = 0;
    for (let index = 0; index < model.children.length; ++index) {
      const child = model.children[index];
      const visited = child.getVisited();
      if (visited) {
        model.children[visitedCount++] = child;
        child.setVisited(false);
      } else {
        const renderable = child.getRenderable();
        if (renderable) {
          model._renderableChildMap.delete(renderable);
        }
        child.delete();
      }
    }

    model.children.length = visitedCount;
  };

  publicAPI.createViewNode = (dataObj) => {
    if (!model.myFactory) {
      vtkErrorMacro('Cannot create view nodes without my own factory');
      return null;
    }
    const ret = model.myFactory.createNode(dataObj);
    if (ret) {
      ret.setRenderable(dataObj);
    }
    return ret;
  };

  const parentDelete = publicAPI.delete;
  publicAPI.delete = () => {
    for (let i = 0; i < model.children.length; i++) {
      model.children[i].delete();
    }
    parentDelete();
  };
}

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

const DEFAULT_VALUES = {
  // _parent: null,
  renderable: null,
  myFactory: null,
  children: [],
  visited: false,
};

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

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

  // Build VTK API
  macro.obj(publicAPI, model);
  macro.event(publicAPI, model, 'event');

  model._renderableChildMap = new Map();

  macro.get(publicAPI, model, ['visited']);
  macro.setGet(publicAPI, model, ['_parent', 'renderable', 'myFactory']);
  macro.getArray(publicAPI, model, ['children']);
  macro.moveToProtected(publicAPI, model, ['parent']);

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

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

const newInstance = macro.newInstance(extend, 'vtkViewNode');

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

export default { newInstance, extend, PASS_TYPES };