Problem setting up multiple 3D models using a url as source with ar.js and A-frame

Question

I'm just recently learning to code for A-frame projects. When trying to set up a scene with multiple targets in A-fram, the 3D model that was supposed to be displayed by one of them doesn´t appear. The model, like the marker, uses an URL as the original but only the latter works.

Separating the ar.js and A-frame proved that the problem was apparently on ar.js, however, I may be mistaken.

You can find my code in this link since it is giving me too much trouble to post here due to the URL in the code. The file's name is "Problem code":

https://github.com/BrandexGlobal/ARDuratex/tree/master

Please copy a code snippet you are asking about to the question. Most people will not bother going to your Github repository. — sesm, Apr 25 '19 at 19:42

Jack G · Answer 1 · 2019-04-25T21:28:03.797

In HTML, you can use base64 data uris OR blobs for turning raw content into a viable url. This url should work in any place that any other url would work. I say should because I am not familiar with the framework that you are using (I'm anti-framework and pro-vanilla), so there is a slight chance that your framework might mess something up.

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Example of plain ordinary image:

(function(mainImage) {
    mainImage.title = mainImage.src;
})(document.getElementById("mainImage"));

<img src="https://i.stack.imgur.com/Lr5Kg.jpg" id="mainImage"/>

Example of using base64 data URI (notice how the url is the image itself). Also, see Jpillora's base64 encoder and this demo page.

(function(mainImage) {
    mainImage.title = mainImage.src;
})(document.getElementById("mainImage"));

<img src="data:image/jpeg;base64,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" id="mainImage"/>

Example of using a Blob URI. Notice how the url is dynamically generated similar to a memory address pointer.

(function(){
    var rawData = atob("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");
    var rawDataLength = rawData.length;
    var typedArrayView = new Uint8Array(rawDataLength);
    for (var i=0; i<rawDataLength; i=i+1|0)
        typedArrayView[i] = rawData.charCodeAt(i);
    var img = document.body.appendChild(document.createElement("img"));
    img.src = img.title = URL.createObjectURL(new Blob([
        typedArrayView
    ], {type: "image/jpeg"}));
})();

Another example is that we can encode the image as a Base64 data URI, then use an XMLHttpRequest to HTTP-get the data URI's contents, but set the returnType property of the XMLHttpRequest to Blob so that we get a blob from the base64 data URI.

(function(){
    var xhr = new XMLHttpRequest;
    xhr.responseType = "blob";
    xhr.open("GET", document.getElementById("base64DataURIImage").src);
    xhr.onload = function(){
       var img=document.body.appendChild(document.createElement("img"));
       img.src = img.title = URL.createObjectURL(xhr.response);
    }
    xhr.send();
})();
(function(mainImage) {
    mainImage.title = mainImage.src;
})(document.getElementById("base64DataURIImage"));

As a base64 URI: <img id="base64DataURIImage" src="data:image/jpeg;base64,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" />
<br /><br />
Then turned into a blob:

Resources:

For base64 data URIs, see this MDN page

For my own library for correctly encoding base64 URIs with high unicode characters, see this Github repository

For blobs, see this MDN page

Problem setting up multiple 3D models using a url as source with ar.js and A-frame

1 Answers1

Resources: