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Source File Description

Screentock component

A Screentock component for A-Frame, which allows you to take screenshots of your A-Frame scene.

Properties

Property Description Type Default Value
takeScreenshot A flag to take a screenshot of the scene when set to true boolean false
filename The name of the saved screenshot file string screenshot
type The file format of the saved screenshot (jpg, png, or img) string jpg
imgElementSelector A selector to specify the element for the screenshot image data to be copied to selector

Usage

HTML
<head>
  <title>My A-Frame Scene</title>
  <script src="https://aframe.io/releases/1.4.2/aframe.min.js"></script>
  <script src="path/to/aframe-screentock-component.min.js"></script>
</head>

<body>
  <a-scene screentock>
    <a-entity geometry="primitive: box" material="color: #C03546"></a-entity>
  </a-scene>
</body>
JavaScript
AFRAME.scenes[0].setAttribute('screentock', 'takeScreenshot', true);

index.js

  • The street component places a street in an A-Frame scene from a list of segments in a JSON blob. See the street component documentation for more details.
  • The streetmix-loader component uses a streetmix URL to supply a JSON blob for a street component on the same entity. See the streetmix-loader component documentation for more details.
  • This file also imports other libraries and functions partially described below.

assets.js

  • This file provides the street component with the ability to automatically load 3D models and other assets using the A-Frame asset loader. It does this by adding them to the scene's a-assets block and then defining mixins pointing to these assets. The street component itself simply places entities with appropriate mixin names. To change the visual appearance of items in a scene, you can modify mixin settings defined in this assets.js file, or point your scene to a new assets root URL, or both!
  • To set a custom URL for a scene's assets, add the following syntax to your a-assets block: <streetmix-assets url="./"></streetmix-assets>. Change "./" to your own path, or keep to use assets loaded from your local server.
  • How does this work? Getting assets to be dynamically injected into an A-Frame scene is tricky because a-assets gets created in the document body, after the streetmix javascript has been included in the header. The contents of this file is a scheme to try to intercept the creation of a-assets and get them to wait for 3DStreet assets just like assets defined in the document body. It's not perfect, but seems to work. There a Stack Overflow question and answer that goes into more detail on the original creation as well as a GitHub Issue with additional questions and answers.

aframe-streetmix-parsers.js

  • processSegments function - takes an array of streetmix segments and render them to the DOM - this is the "main" function of the entire application
  • processBuildings function - takes left, right and street width
  • Many other (untested) helper functions

tested/aframe-streetmix-parsers-tested.js - Now with tests!

  • isSidewalk function - for a streetmix segment name passed as string, tell me if the segment is on a sidewalk?
  • createBuildingsArray function - create an array of dictionaries that represent a psuedorandom block of buildings for use with create-from-json

tested/streetmix-utils.js

These are a handful of functions (and accompanying tests! that help deal with Streetmix URLs:

  • streetmixUserToAPI(userURL) takes a user facing Streetmix.net URL like https://streetmix.net/kfarr/3/a-frame-city-builder-street-only and turns it into the API redirect URL like https://streetmix.net/api/v1/streets?namespacedId=3&creatorId=kfarr
  • streetmixAPIToUser(APIURL) takes a Streetmix.net API redirect URL like https://streetmix.net/api/v1/streets?namespacedId=3&creatorId=kfarr and turns it into the user facing friendly Streetmix.net URL like https://streetmix.net/kfarr/3/a-frame-city-builder-street-only
  • calcStreetWidth takes an array of segments (data.streets.segments from a Streetmix API JSON String response) and returns the width in meters

components/create-from-json.js

  • create-from-json component creates child nodes beneath the component's entity from a JSON string of an array of dictionaries that represent entities, for example:
<a-entity create-from-json='jsonString:
  [
    {"tag":"a-entity","mixin":"SM3D_Bld_Mixed_Corner_4fl","position":"0 0 0"},
    {"tag":"a-entity","mixin":"SM3D_Bld_Mixed_Double_5fl","position":"0 0 5"}
  ]
  '>
</a-entity>

which after being parsed turns into

<a-entity create-from-json=''>
  <a-entity mixin="SM3D_Bld_Mixed_Corner_4fl" position=""></a-entity>
  <a-entity mixin="SM3D_Bld_Mixed_Double_5fl" position="0 0 5"></a-entity>
</a-entity>

Modified Components from Elsewhere

components/ocean-plane.js

This is a component originally written by Ada Rose from Samsung Internet, copied here to specify a local path for water normals.

aframe-ground-component

aframe-ground-component is a modified version of the awesome A-Frame Environment Component that removes environmental geometry and skybox while leaving just the ground. It also allows for reduction in triangle count by manually specifying ground elevation resolution. See more info here on the component doc page.

aframe-cubemap-component

aframe-cubemap-component is a local copy of this original cubemap sky component.

Unmodified Components

See src/lib/, included here to reduce fetching libraries remotely helpful for local development in bandwidth constricted environments.

Helpful Streetmix debugging information

Here are some tips and links from my experience "reverse engineering" Streetmix to get info out of their API.

I heavily referenced this Streetmix page which outlines all the possible segments: https://github.com/streetmix/streetmix/blob/master/assets/scripts/segments/info.json

I learned a few things:

More Notes

See DEV-NOTES for additional notes on future features and work in progress.