glsl-georender-style-texture

glslify module to read from a georender style texture

example

var glsl = require('glslify')
var regl = require('regl')()
var draw = regl({
  frag: glsl`
    precision highp float;
    varying vec4 v_color;
    void main() {
      gl_FragColor = vec4(v_color);
    }
  `,
  vert: glsl`
    precision highp float;
    #pragma glslify: Area = require('glsl-georender-style-texture/area.h');
    #pragma glslify: readArea = require('glsl-georender-style-texture/area.glsl');
    uniform sampler2D texture;
    attribute vec2 position;
    varying vec4 v_color;
    void main() {
      float zoom = 10.0;
      float featureCount = 50.0;
      float featureType = 6.0;
      Area area = readArea(texture, featureType, zoom, featureCount);
      v_color = area.color;
      gl_Position = vec4(position,0,1);
    }
  `,
  uniforms: {
    texture: regl.prop('texture')
  },
  attributes: {
    position: [-0.8,-0.8,+0.0,+0.8,+0.8,-0.8]
  },
  elements: [0,1,2]
})

require('resl')({
  manifest: {
    texture: {
      type: 'image',
      src: './example/texture.png',
      parser: function (data) { return regl.texture({ data }) }
    }
  },
  onDone: function ({texture}) {
    regl.frame(function () {
      regl.poll()
      regl.clear({ color: [0,0,0,1], depth: true })
      draw({texture})
    })
  }
})

to run example:

• clone the repo from https://github.com/peermaps/glsl-georender-style-texture
• navigate to the folder where the package was cloned and do npm install.
• do npm run example. you should see output like Server running at http://192.168.129.29:9966/.
• in the browser, navigate to that url. you should see a large blue triangle.

(the directions above assume that you have node.js and npm installed. instructions are for usage on the command line.)

in the example code, if you change the featureType value, the color of the triangle should change. try values like 1.0, 18.0, 40.0.

if you'd like to generate your own texture.png, you can use georender-style2png.

api

#pragma glslify: Point = require('glsl-georender-style-texture/point.h');
#pragma glslify: readPoint = require('glsl-georender-style-texture/point.glsl');
#pragma glslify: Line = require('glsl-georender-style-texture/line.h');
#pragma glslify: readLine = require('glsl-georender-style-texture/line.glsl');
#pragma glslify: Area = require('glsl-georender-style-texture/area.h');
#pragma glslify: readArea = require('glsl-georender-style-texture/area.glsl');

Point readPoint(sampler2D styleTexture, float featureType, float zoom, float featureCount)

return a Point from a style texture, for a given feature type, zoom, and total number of features (featureCount).

Point

• vec4 color - rgba
• float size - point size in pixels
• float zindex - stacking order from 0-100 where 0 is on bottom

Line readLine(sampler2D styleTexture, float featureType, float zoom, float featureCount)

return a Line from a style texture, for a given feature type, zoom, and total number of features (featureCount).

Line

• vec4 fillColor - rgba
• vec4 strokeColor - rgba
• float fillStyle - float representing fill style.
  • if solid, 10.
  • if dot, 6.
  • if dash, default is 10.
  • if line-fill-dash-length is short, 10.
  • if line-fill-dash-length is medium, 15.
  • if line-fill-dash-length is long, 20.
• float strokeStyle - float representing stroke style.
  • if solid, 10.
  • if dot, 6.
  • if dash, default is 10.
  • if line-stroke-dash-length is short, 10.
  • if line-stroke-dash-length is medium, 15.
  • if line-stroke-dash-length is long, 20.
• float fillDashGap - float for the gap between dashes when the line-fill-style is dash. values from 0-100. default is 50 (dash and dash gap are equal length).
• float strokeDashGap - float for the gap between dashes when the line-stroke-style is dash. values from 0-100. default is 50 (dash and dash gap are equal length).
• float fillWidth - line fill width in pixels
• float strokeWidth - line stroke width in pixels
• float zindex - stacking order from 0-100 where 0 is on bottom

Area readArea(sampler2D styleTexture, float featureType, float zoom, float featureCount)

return an Area from a style texture, for a given feature type, zoom, and total number of features (featureCount).

Area

• vec4 color - rgba
• float zindex - stacking order from 0-100 where 0 is on bottom

install

npm install glsl-georender-style-texture

license

MIT