Pannellum: Image with alpha channel

[alketii]

Hi,
Is it possible to add an image with transparent parts ?
I want to use the background color to easily change the color.

Thanks.

[mpetroff]

No, it isn't.

[alketii]

Thanks.

[gregmatys]

@mpetroff …why? :)

[mpetroff]

Using a texture with an alpha channel increases memory usage and decreases performance.

[rose-maria]

Hello @mpetroff ,
It's true that the textures with alpha channels will lower the performance, but is it possible to overdrop a small rectangular texture over this 3D scene of pannellum ?
I need to have small subtitled image in the scene & also want that they transform accordingly, but can dissappear when user wants to hide them. (The image textures will be rectangular)

[rose-maria]

Or is it possible to reload the specific textures of a scene e.g. after 10 seconds ?

[mpetroff]

Pannellum generally doesn't use a 3D scene to render the panorama, so adding something in 3D space isn't possible. For equirectangular and cube map panoramas, the image is rendered using two triangles, to form a square, with the projection code residing in the fragment shader.

You can reload the current scene using the API via viewer.loadScene(viewer.getScene), where viewer is the Pannellum instance.

[rose-maria]

Thanks @mpetroff for your valuable support,
In case of a Cubemap, we have six textures. Is it possible that we reload only one of them(e.g. front), without reloading the full scene ???

[rose-maria]

Basically,
I am interested in a functionality that Pannellum video have but in Short SPAN like 2-3 frames only, since it gives us the power to practise the transition..

[mpetroff]

Now that you mentioned the video functionality, it made me realize that said functionality may be the ideal solution. You could pass an img element as an equirectangular image (or a canvas element if you want to be able to arbitrarily change things) and set the dynamic configuration option to true; any changes to the img element, e.g. changing the src, would then be automatically rendered (this is how the video functionality works). Something like this:

var image = document.createElement('img');
viewer = pannellum.viewer('panorama', {
    "type": "equirectangular",
    "panorama": image,
    "dynamic": true,
    "autoLoad": true
});
image.onload = function() {
    viewer.setUpdate(true);
}
image.src = 'test1.jpg';

Setting image.src to a different image URL would then cause the viewer to automatically update.