kepler.gl/src/shaderlib/picking-module.js

kepler.gl is a webgl based application to visualize large scale location data in the browser

// Copyright (c) 2018 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 {picking} from 'luma.gl';

// add picking_uHighlightScale to fs uniform
const fs = `\
uniform bool picking_uActive; // true during rendering to offscreen picking buffer
uniform vec3 picking_uSelectedColor;
uniform vec4 picking_uHighlightColor;
uniform float picking_uHighlightScale;

varying vec4 picking_vRGBcolor_Aselected;

const float COLOR_SCALE = 1. / 255.;

/*
 * Returns highlight color if this item is selected.
 */
vec4 picking_filterHighlightColor(vec4 color) {
  bool selected = bool(picking_vRGBcolor_Aselected.a);
  // return selected ? (picking_uHighlightColor * COLOR_SCALE) : color;
  return selected ? (
   (bool(picking_uHighlightScale > 0.0) ? color * picking_uHighlightScale : picking_uHighlightColor * COLOR_SCALE)
  ) : color;
}

/*
 * Returns picking color if picking enabled else unmodified argument.
 */
vec4 picking_filterPickingColor(vec4 color) {
  vec3 pickingColor = picking_vRGBcolor_Aselected.rgb;
  if (picking_uActive && length(pickingColor) < 0.001) {
    discard;
  }
  return picking_uActive ? vec4(pickingColor, 1.0) : color;
}

/*
 * Returns picking color if picking is enabled if not
 * highlight color if this item is selected, otherwise unmodified argument.
 */
vec4 picking_filterColor(vec4 color) {
  vec4 highightColor = picking_filterHighlightColor(color);
  return picking_filterPickingColor(highightColor);
}
`;

export default {
  ...picking,
  fs
};