Sprite based Billboards

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Cham M
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Sprite based Billboards

Post #1by Cham » 01.09.2011, 12:33

This morning, I had an idea which apparently was never used before (or maybe Fenerit did it once). I test it and it works perfectly ! :)

With sprites, we can add a billboard in space that will stay with the same orientation relative to the observer. This could be usefull to show the user some pictures with or without text explanations, diagrams, schematics, etc (it could even be some maths and physics equations from LaTeX, writen in white on a transparent background. That would look pretty, floating in space !). This is NOT the same as a "classic" billboard which will rotate while the user moves around it (pictures of nebulae, oriented toward Earth, for example).

Here's a stupid example : a simple picture (a single sprite !) floating on the side of a (fake) planet.
bill.jpg


And apparently, the billboards are all well depth sorted :
bill2.jpg


The addon here can very easily be edited and adapted to the user's needs :
Sprite_billboard.zip


At first, it may feel strange, but I think it may have a great pedagogical value. With several billboards in the same environment (or several billboards defined in the same CMOD file), it may even look like an art exhibition. :D

Of course, the sprite based billboard could be made invisible by default, and its visibility could be turned ON/OFF with a celx switch, like what I've done before with my "layers".
Last edited by Cham on 01.09.2011, 14:17, edited 1 time in total.
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Cham M
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Re: Sprite based Billboards

Post #2by Cham » 01.09.2011, 13:22

That idea is pretty cool, actually ! :mrgreen:

bill1.jpg
bill2.jpg


The user has a total control on the size and disposition of the billboards (SSC and DSC), and it's extremely easy to do.
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Re: Sprite based Billboards

Post #3by W0RLDBUILDER » 01.09.2011, 18:59

Image

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Re: Sprite based Billboards

Post #4by Cham » 02.09.2011, 01:23

? ?


I'm playing a bit with the billboard-sprites idea. The visual/graphical effect of a kind of 3D slideshow in space is realy fun. I may very well use it in my classroom as a "screen saver" while talking to the class or as a background field (the pictures are all moving around, in 3D). It's really impressive when projected with a wall projector, and also when you interact with them in 3D !

sprites.jpg


(is that Bob, in the upper-right ?)
Would probably add more pictures and equations, figures of Newton, Maxwell and Faraday. Maybe some Quantum Mechanics too...

Of course, the best would be to use some selected pictures and equations related to a particular topic, in a given place of space (gravitation around a black hole, electromagnetism around a pulsar, etc). Sky's the limit !
Last edited by Cham on 02.09.2011, 02:27, edited 1 time in total.
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Re: Sprite based Billboards

Post #5by Fenerit » 02.09.2011, 02:16

Such tecnique, the nebulae generator and few 3D meshes, if any, could be used for the stars' interiors.
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Cham M
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Re: Sprite based Billboards

Post #6by Cham » 02.09.2011, 02:26

Fenerit wrote:Such tecnique, the nebulae generator and few 3D meshes, if any, could be used for the stars' interiors.

I aready made something for our sun, a long time ago (never published, if I remember) :
sun.jpg


The billboard shown on the right is a standard flat one with some 3D CMOD curves on it.

The sprites gives us some new opportunities for "real" billboards in space (always face-on to the observer).
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Re: Sprite based Billboards

Post #7by Fenerit » 02.09.2011, 10:42

Cham wrote:I aready made something for our sun, a long time ago (never published, if I remember)

Maybe it shouldn't bad if you would publish that. 8) I wonder whether stars' shells can be done by nebulae method.

Cham wrote:The sprites gives us some new opportunities for "real" billboards in space (always face-on to the observer).

Yup. I was forgotting my atmospheres pie charts... :)

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Re: Sprite based Billboards

Post #8by Cham » 03.09.2011, 02:41

This experiment turns out to be really fascinating ! The depth sorting of each sprite is very good : even the magnetic field lines are intersecting the pictures in a nice way. There are lots of things to be done with this technique.

The pictures and equations are moving around the pulsar in a gentle way, and almost feel like an "accretion disk" ! :)
show.jpg
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Re: Sprite based Billboards

Post #9by MiR » 03.09.2011, 13:08

...And a very impressive picture, by the way...

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Re: Sprite based Billboards

Post #10by Cham » 03.09.2011, 19:04

An experiment which has a lot of potential :

I placed a single sprite in space to identify the center-of-mass of the local group of galaxies. The blue model was there since a long time ago, when I defined it as a part of a larger addon (WMAP, etc). I toggle it ON/OFF using a celx script.

The white text is a new sprite-based billboard. What is interesting is it's keeping its orientation relative to the user in front of its computer (so it's allways readable). Of course, the text is shrinking while the user is moving away of it.

local.jpg


This experiment is showing that we can do lots of new things in Celestia now... :mrgreen:

Please, share your thoughts, ideas and suggestions here, about how we could use the single-sprite billboards (its so easy to make, it's much easier than building a "classic" billboard with an absolute orientation in Celestia !).
"Well! I've often seen a cat without a grin", thought Alice; "but a grin without a cat! It's the most curious thing I ever saw in all my life!"


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