text: // Copyright (c) 2015 - 2017 Uber Technologies, Inc.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  
  import {LayerExtension, mergeShaders} from '@deck.gl/core';
  import {dashShaders} from './shaders.glsl';
  
  const defaultProps = {
    getDashArray: {type: 'accessor', value: [0, 0]},
    dashJustified: false
  };
  
  export default class PathStyleExtension extends LayerExtension {
    constructor({dash = false} = {}) {
      super({dash});
    }
  
    isEnabled(layer) {
      return layer.state.pathTesselator;
    }
  
    getShaders(extension) {
      if (!extension.isEnabled(this)) {
        return null;
      }
  
      // Merge shader injection
      let result = {};
      if (extension.opts.dash) {
        result = mergeShaders(result, dashShaders);
      }
  
      return result;
    }
  
    initializeState(context, extension) {
      const attributeManager = this.getAttributeManager();
      if (!attributeManager || !extension.isEnabled(this)) {
        // This extension only works with the PathLayer
        return;
      }
  
      extension.enabled = true;
  
      if (extension.opts.dash) {
        attributeManager.add({
          instanceDashArrays: {size: 2, accessor: 'getDashArray'}
        });
      }
    }
  
    updateState(params, extension) {
      if (!extension.isEnabled(this)) {
        return;
      }
  
      const uniforms = {};
  
      if (extension.opts.dash) {
        uniforms.dashAlignMode = this.props.dashJustified ? 1 : 0;
      }
  
      this.state.model.setUniforms(uniforms);
    }
  }
  
  PathStyleExtension.extensionName = 'PathStyleExtension';
  PathStyleExtension.defaultProps = defaultProps;
  