visgl / deck.gl / 8985574679

import {COORDINATE_SYSTEM, Layer, LayerExtension, log} from '@deck.gl/core';

import mask from './shader-module';

import MaskEffect from './mask-effect';

const defaultProps = {

  maskId: '',

  maskByInstance: undefined,

  maskInverted: false

};

export type MaskExtensionProps = {

  /**

   * Id of the layer that defines the mask. The mask layer must use the prop `operation: 'mask'`.

   * Masking is disabled if `maskId` is empty or no valid mask layer with the specified id is found.

   */

  maskId?: string;

  /**

   * controls whether an object is clipped by its anchor (usually defined by an accessor called `getPosition`, e.g. icon, scatterplot) or by its geometry (e.g. path, polygon).

   * If not specified, it is automatically deduced from the layer.

   */

  maskByInstance?: boolean;

  /**

   * Inverts the masking operation

   */

  maskInverted?: boolean;

};

/** Allows layers to show/hide objects by a geofence. */

export default class MaskExtension extends LayerExtension {

  static defaultProps = defaultProps;

  static extensionName = 'MaskExtension';

  initializeState(this: Layer<MaskExtensionProps>) {

    this.context.deck?._addDefaultEffect(new MaskEffect());

  }

  getShaders(this: Layer<MaskExtensionProps>): any {

    // Infer by geometry if 'maskByInstance' prop isn't explictly set

    let maskByInstance = 'instancePositions' in this.getAttributeManager()!.attributes;

    // Users can override by setting the `maskByInstance` prop

    this.state.maskByInstance = maskByInstance;

    return {

      modules: [mask]

    };

  }

  /* eslint-disable camelcase */

  draw(this: Layer<Required<MaskExtensionProps>>, {uniforms, context, moduleParameters}: any) {

    uniforms.mask_maskByInstance = this.state.maskByInstance;

    const {maskId, maskInverted} = this.props;

    const {maskChannels} = moduleParameters;

    const {viewport} = context;

    if (maskChannels && maskChannels[maskId]) {

      const {index, bounds, coordinateOrigin: fromCoordinateOrigin} = maskChannels[maskId];

      let {coordinateSystem: fromCoordinateSystem} = maskChannels[maskId];

      uniforms.mask_enabled = true;

      uniforms.mask_channel = index;

      uniforms.mask_inverted = maskInverted;

      if (fromCoordinateSystem === COORDINATE_SYSTEM.DEFAULT) {

        fromCoordinateSystem = viewport.isGeospatial

      }

      const opts = {modelMatrix: null, fromCoordinateOrigin, fromCoordinateSystem};

      const bl = this.projectPosition([bounds[0], bounds[1], 0], opts);

      const tr = this.projectPosition([bounds[2], bounds[3], 0], opts);

      uniforms.mask_bounds = [bl[0], bl[1], tr[0], tr[1]];

  }

}