Texture

Introduction

vtkTexture is an image algorithm that handles loading and binding of texture maps.
It obtains its data from an input image data dataset type.
Thus you can create visualization pipelines to read, process, and construct textures.
Note that textures will only work if texture coordinates are also defined, and if the rendering system supports texture.

Methods

extend

Method use to decorate a given object (publicAPI+model) with vtkTexture 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	ITextureInitialValues	No	(default: {})

generateMipmaps

Method used to create mipmaps from given texture data. Works best with textures that have a
width and a height that are powers of two.

Argument	Type	Required	Description
nativeArray		Yes	the array of data to create mipmaps from.
width		Yes	the width of the data
height		Yes	the height of the data
level		Yes	the level to which additional mipmaps are generated.

getEdgeClamp

getImage

getImageLoaded

getInterpolate

getMipLevel

getRepeat

newInstance

Method use to create a new instance of vtkTexture.

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

setEdgeClamp

Argument	Type	Required	Description
edgeClamp		Yes

setImage

Argument	Type	Required	Description
image		Yes

setInterpolate

Argument	Type	Required	Description
interpolate		Yes

setMipLevel

Argument	Type	Required	Description
level		Yes

setRepeat

Argument	Type	Required	Description
repeat		Yes

Source

index.d.ts

import { vtkAlgorithm } from "../../../interfaces";

/**
 * 
 * @param {boolean} [resizable] Must be set to true if texture can be resized at run time (default: false)
 */
export interface ITextureInitialValues {
	repeat?: boolean;
	interpolate?: boolean;
	edgeClamp?: boolean;
	imageLoaded?: boolean;
	mipLevel?: number;
	resizable?: boolean;
}

export interface vtkTexture extends vtkAlgorithm {

	/**
	 * 
	 */
	getRepeat(): boolean;

	/**
	 * 
	 */
	getEdgeClamp(): boolean;

	/**
	 * 
	 */
	getInterpolate(): boolean;

	/**
	 * 
	 */
	getImage(): any;

	/**
	 * 
	 */
	getImageLoaded(): boolean;

	/**
	 * 
	 */
	getMipLevel(): number;

	/**
	 * 
	 * @param repeat 
	 * @default false
	 */
	setRepeat(repeat: boolean): boolean;

	/**
	 * 
	 * @param edgeClamp 
	 * @default false
	 */
	setEdgeClamp(edgeClamp: boolean): boolean;

	/**
	 * 
	 * @param interpolate 
	 * @default false
	 */
	setInterpolate(interpolate: boolean): boolean;


	/**
	 * 
	 * @param image 
	 * @default null
	 */
	setImage(image: any): void;

	/**
	 * @param level
	 */
	setMipLevel(level: number): boolean;
}

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

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

/**
 * Method used to create mipmaps from given texture data. Works best with textures that have a 
 * width and a height that are powers of two.
 * 
 * @param nativeArray the array of data to create mipmaps from.
 * @param width the width of the data
 * @param height the height of the data
 * @param level the level to which additional mipmaps are generated.
 */
export function generateMipmaps(nativeArray: any, width: number, height: number, level: number): Array<Uint8ClampedArray>;

/** 
 * vtkTexture is an image algorithm that handles loading and binding of texture maps.
 * It obtains its data from an input image data dataset type. 
 * Thus you can create visualization pipelines to read, process, and construct textures. 
 * Note that textures will only work if texture coordinates are also defined, and if the rendering system supports texture.
 */
export declare const vtkTexture: {
	newInstance: typeof newInstance,
	extend: typeof extend,
};
export default vtkTexture;

index.js

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

// ----------------------------------------------------------------------------
// vtkTexture methods
// ----------------------------------------------------------------------------

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

  publicAPI.imageLoaded = () => {
    model.image.removeEventListener('load', publicAPI.imageLoaded);
    model.imageLoaded = true;
    publicAPI.modified();
  };

  publicAPI.setJsImageData = (imageData) => {
    if (model.jsImageData === imageData) {
      return;
    }

    // clear other entries
    if (imageData !== null) {
      publicAPI.setInputData(null);
      publicAPI.setInputConnection(null);
      model.image = null;
      model.canvas = null;
    }

    model.jsImageData = imageData;
    model.imageLoaded = true;
    publicAPI.modified();
  };

  publicAPI.setCanvas = (canvas) => {
    if (model.canvas === canvas) {
      return;
    }

    // clear other entries
    if (canvas !== null) {
      publicAPI.setInputData(null);
      publicAPI.setInputConnection(null);
      model.image = null;
      model.jsImageData = null;
    }

    model.canvas = canvas;
    publicAPI.modified();
  };

  publicAPI.setImage = (image) => {
    if (model.image === image) {
      return;
    }

    // clear other entries
    if (image !== null) {
      publicAPI.setInputData(null);
      publicAPI.setInputConnection(null);
      model.canvas = null;
      model.jsImageData = null;
    }

    model.image = image;
    model.imageLoaded = false;

    if (image.complete) {
      publicAPI.imageLoaded();
    } else {
      image.addEventListener('load', publicAPI.imageLoaded);
    }

    publicAPI.modified();
  };

  publicAPI.getDimensionality = () => {
    let width = 0;
    let height = 0;
    let depth = 1;

    if (publicAPI.getInputData()) {
      const data = publicAPI.getInputData();
      width = data.getDimensions()[0];
      height = data.getDimensions()[1];
      depth = data.getDimensions()[2];
    }
    if (model.jsImageData) {
      width = model.jsImageData.width;
      height = model.jsImageData.height;
    }
    if (model.canvas) {
      width = model.canvas.width;
      height = model.canvas.height;
    }
    if (model.image) {
      width = model.image.width;
      height = model.image.height;
    }
    const dimensionality = (width > 1) + (height > 1) + (depth > 1);
    return dimensionality;
  };

  publicAPI.getInputAsJsImageData = () => {
    if (!model.imageLoaded || publicAPI.getInputData()) return null;

    if (model.jsImageData) {
      return model.jsImageData();
    }
    if (model.canvas) {
      const context = model.canvas.getContext('2d');
      const imageData = context.getImageData(
        0,
        0,
        model.canvas.width,
        model.canvas.height
      );
      return imageData;
    }
    if (model.image) {
      const canvas = document.createElement('canvas');
      canvas.width = model.image.width;
      canvas.height = model.image.height;
      const context = canvas.getContext('2d');
      context.translate(0, canvas.height);
      context.scale(1, -1);
      context.drawImage(
        model.image,
        0,
        0,
        model.image.width,
        model.image.height
      );
      const imageData = context.getImageData(0, 0, canvas.width, canvas.height);
      return imageData;
    }

    return null;
  };
}

// Use nativeArray instead of self
const generateMipmaps = (nativeArray, width, height, level) => {
  // TODO: FIX UNEVEN TEXTURE MIP GENERATION:
  // When textures don't have standard ratios, higher mip levels
  // result in their color chanels getting messed up and shifting
  // 3x3 gaussian kernel
  const g3m = [1, 2, 1]; // eslint-disable-line
  const g3w = 4; // eslint-disable-line
  // 5x5 gaussian kernel
  const g5m = [1, 2, 4, 2, 1]; // eslint-disable-line
  const g5w = 10; // eslint-disable-line
  // 7x7 gaussian kernel
  const g7m = [1, 2, 6, 8, 6, 2, 1]; // eslint-disable-line
  const g7w = 26; // eslint-disable-line

  const kernel = g3m;
  const kernelWeight = g3w;

  const hs = nativeArray.length / (width * height); // TODO: support for textures with depth more than 1
  let currentWidth = width;
  let currentHeight = height;
  let imageData = nativeArray;
  const maps = [imageData];

  for (let i = 0; i < level; i++) {
    const oldData = [...imageData];
    currentWidth /= 2;
    currentHeight /= 2;
    imageData = new Uint8ClampedArray(currentWidth * currentHeight * hs);
    const vs = hs * currentWidth;

    // Scale down
    let shift = 0;
    for (let p = 0; p < imageData.length; p += hs) {
      if (p % vs === 0) {
        shift += 2 * hs * currentWidth;
      }

      for (let c = 0; c < hs; c++) {
        let sample = oldData[shift + c];
        sample += oldData[shift + hs + c];
        sample += oldData[shift - 2 * vs + c];
        sample += oldData[shift - 2 * vs + hs + c];
        sample /= 4;
        imageData[p + c] = sample;
      }

      shift += 2 * hs;
    }

    // Horizontal Pass
    let dataCopy = [...imageData];
    for (let p = 0; p < imageData.length; p += hs) {
      for (let c = 0; c < hs; c++) {
        let x = -(kernel.length - 1) / 2;
        let kw = kernelWeight;
        let value = 0.0;
        for (let k = 0; k < kernel.length; k++) {
          let index = p + c + x * hs;
          const lineShift = (index % vs) - ((p + c) % vs);
          if (lineShift > hs) index += vs;
          if (lineShift < -hs) index -= vs;
          if (dataCopy[index]) {
            value += dataCopy[index] * kernel[k];
          } else {
            kw -= kernel[k];
          }
          x += 1;
        }
        imageData[p + c] = value / kw;
      }
    }
    // Vertical Pass
    dataCopy = [...imageData];
    for (let p = 0; p < imageData.length; p += hs) {
      for (let c = 0; c < hs; c++) {
        let x = -(kernel.length - 1) / 2;
        let kw = kernelWeight;
        let value = 0.0;
        for (let k = 0; k < kernel.length; k++) {
          const index = p + c + x * vs;
          if (dataCopy[index]) {
            value += dataCopy[index] * kernel[k];
          } else {
            kw -= kernel[k];
          }
          x += 1;
        }
        imageData[p + c] = value / kw;
      }
    }

    maps.push(imageData);
  }
  return maps;
};

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

const DEFAULT_VALUES = {
  image: null,
  canvas: null,
  jsImageData: null,
  imageLoaded: false,
  repeat: false,
  interpolate: false,
  edgeClamp: false,
  mipLevel: 0,
  resizable: false, // must be set at construction time if the texture can be resizable
};

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

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

  // Build VTK API
  macro.obj(publicAPI, model);
  macro.algo(publicAPI, model, 6, 0);

  macro.get(publicAPI, model, [
    'canvas',
    'image',
    'jsImageData',
    'imageLoaded',
    'resizable',
  ]);

  macro.setGet(publicAPI, model, [
    'repeat',
    'edgeClamp',
    'interpolate',
    'mipLevel',
  ]);

  vtkTexture(publicAPI, model);
}

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

export const newInstance = macro.newInstance(extend, 'vtkTexture');
export const STATIC = { generateMipmaps };

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

export default { newInstance, extend, ...STATIC };