Cesium

WebGL Virtual Globe and Map Engine

Requirements

In Gemfile file add line:

gem "cesium"

Run the bundle command to install it.

This gem relies on ‘requirejs-rails’ gem.

Make sure you follow the instruction from:

https://github.com/jwhitley/requirejs-rails

and you understand the concept of RequireJS:

http://requirejs.org

Now you are ready to use this gem :-)

Examples

Example 1:

For the convenience there is prepared route that will show you the globe. All you need to do is to modify your route.rb and add:

get 'cesium', to: 'cesium#index'

Now you can see the WebGL globe by visiting:

http://localhost:3000/cesium

Example 2:

Usage of this gem inside your own Rails application.

I presume you have a canvas tag in your view with id “globe”:

<div class="fullSize">
  <canvas id="globe" class="fullSize"></canvas>
</div>

You should have some CSS to define canvas size.

Here is an example that shows how to display the globe and cover 100% width & height of the wrapper

html, body {
    height: 100%;
    margin: 0;
    padding: 0;
    overflow: hidden;
}

.fullSize {
    width: 100%;
    height: 100%;
}

In the javascript module that is related to the view

Here I use application.js (coffee):

require [
  'jquery'
  'Cesium'
], ($, Cesium) ->

  $ ->

    canvas = $('#globe')[0]  # change this to match your needs!!!

    @scene = new Cesium.Scene canvas
    @scene.skyAtmosphere = new Cesium.SkyAtmosphere

    skyBoxBaseUrl = '/assets/Assets/Textures/SkyBox/tycho2t3_80'
    @scene.skyBox = new Cesium.SkyBox
      positiveX: skyBoxBaseUrl + '_px.jpg'
      negativeX: skyBoxBaseUrl + '_mx.jpg'
      positiveY: skyBoxBaseUrl + '_py.jpg'
      negativeY: skyBoxBaseUrl + '_my.jpg'
      positiveZ: skyBoxBaseUrl + '_pz.jpg'
      negativeZ: skyBoxBaseUrl + '_mz.jpg'

    primitives = @scene.getPrimitives()

    bing = new Cesium.BingMapsImageryProvider(
      url: 'http://dev.virtualearth.net'
      mapStyle: Cesium.BingMapsStyle.AERIAL
      proxy: if Cesium.FeatureDetection.supportsCrossOriginImagery() then undefined else new Cesium.DefaultProxy('/proxy/')
    )

    ellipsoid = Cesium.Ellipsoid.WGS84
    centralBody = new Cesium.CentralBody(ellipsoid)
    centralBody.getImageryLayers().addImageryProvider(bing)
    primitives.setCentralBody(centralBody)

    new Cesium.SceneTransitioner(@scene, ellipsoid)

    ##################################################################
    #   INSERT CODE HERE to create graphics primitives in the scene.
    ##################################################################

    animate = =>
      # INSERT CODE HERE to update primitives based on changes to animation time, camera parameters, etc.

    tick = =>
      @scene.initializeFrame()
      animate()
      @scene.render()
      Cesium.requestAnimationFrame(tick)

    tick()

    canvas.oncontextmenu = =>
      false

    onResize = =>
      width = canvas.clientWidth
      height = canvas.clientHeight
      return if canvas.width == width and canvas.height == height
      canvas.width = width
      canvas.height = height
      @scene.getCamera().frustum.aspectRatio = width / height

    $(window).on('resize', onResize)
    onResize()

Contribution

To write new feature or fix a bug:

We follow git-flow branching model which means:

“master” branch should be more less stable
“develop” branch is the place to integrate features & bug fixes

More about git-flow: github.com/nvie/gitflow

Fork it
Clone it
*Check out “develop” branch*
Create locally feature/fix branch
Write code & test it
Merge it back into local “develop” branch *as one commit*
Test it!
Send “pull request” against “develop” branch on github

To report an issue/bug:

Please check that the issue you are about to report is not already reported

Report it on GitHub Issues:

https://github.com/bogwro/cesium/issues

Maintainers

Bogumil Wrona (github.com/bogwro)

License

Rails’ Engine & all code which is part of this gem AND not part of the Cesium WebGL Globe:
```
MIT License.
```
All of the code that is part of Cesium WebGL:
```
Apache License, Version 2.0
```

Please check the Cesium website for details:

http://cesium.agi.com
https://raw.github.com/AnalyticalGraphicsInc/cesium/master/LICENSE.md