Hugobox

Sorry if its common openGL knowledge, but couldn't find how to fade any 3d object (in my case: a text3D overlayed over a videoplane). I've tried with the alpha of the color of the text, but that disn't work, sadly. Any tips?

fading-3d-objects

post your patch and we'll help you fix it.

My patch is basically jit.gl.text3d.maxhelp, except I have more than 1 text3D and I use jit.gl.videoplane instead of a mesh and a texture. The effect wanted is to fade in and fade out the text in front of a video: to control the transparency/opacity of the 3D text, sorry if that wasn

set @depth_enable 0 and @blend_enable 1 on your jit.text3d.

adjust the alpha value of the @color attribute to fade.

set @depth_enable 0 and @blend_enable 1 on your jit.text3d.
adjust the alpha value of the @color attribute to fade.


Thanks, that's almost it, I can feel its coming along:

Setting the text to blend_enable 0 and depth_enable 0: text dissapears behind the videoplane.

Setting the text to blend_enable 1 and depth_enable 1: text blends with the grey background and not with the videoplane.

Setting the text to blend_enable 0 and depth_enable 1: alpha doesn't change the text opacity.

Setting the text to blend_enable 1 and depth_enable 0: text dissapears behind the videoplane.

Then I tried playing with the blending parameters of the videoplane itself, but cannot find the right killer combo...

Thanks, that's almost it, I can feel its coming along: 

Setting the text to blend_enable 1 and depth_enable 1: text blends with the grey background and not with the videoplane. 

Then I tried playing with the blending parameters of the videoplane itself, but cannot find the right killer combo...


robtherich wrote on Wed, 11 November 2009 12:41

robtherich wrote on Wed, 11 November 2009 12:41post your patch and we'll help you fix it.


It does work! I'm not sure why yet, but I'll meditate on your patch for awhile.

It does work! I'm not sure why yet, but I'll meditate on your patch for awhile.
Thanks a lot!


I finally had time to go back to this project, and now the problem is slightly different: is it possible to fade 3Dtext with depth and lighting so that it really looks like 3D text?

For now, its one or the other. I've played with blending modes, couldn't get it. here's the patch:

if you want depth_enable and blend_enable for transparency, you have to do depth sorting manually.

what this means is you must turn off @automatic mode for all gl objects in the scene.

then you manually send out bangs to the objects, in the order you want them drawn, after the "erase" message, and before the gl.render draw bang.

in your case you would bang the videoplane first, then bang the text3d.

if you want depth_enable and blend_enable for transparency, you have to do depth sorting manually.
what this means is you must turn off @automatic mode for all gl objects in the scene.
then you manually send out bangs to the objects, in the order you want them drawn, after the "erase" message, and before the gl.render draw bang.

in your case you would bang the videoplane first, then bang the text3d.


Thanks for your advice, will try it out!
Grateful Hugo.


Fading 3D objects