Grungy mesh fx

beginners
#1

Hello,
I would like to implement an effect like the one that is going on on the mesh in the first 10 seconds of this video
http://youtu.be/WZ5p-Xhe9qc
The fact that the mesh is 3d is unimportant… I just can’t figure out how to get an effect like that, even in 2d. When I wanted a grungy looking line, I’ve eventually used a grungy texture. But what I’d like to achieve is a sort of noisy cloud around the intersection points that could evolve in time, not something static. Any idea? Thank you in advance
alex

#2

A stroke with low opacity and using additive blending are the main things going on there I think. Let me see how one would do that in OF…

edit: try the following:

  
  
glEnable(GL_BLEND);  
glBlendFunc(GL_SRC_ALPHA, GL_ONE);
#3

If you are using 007, you can also do :

  
  
ofEnableBlendMode ( OF_BLENDMODE_ADD ) ;   
  
/// draw things   
  
ofDisableBlendMode( ) ;

You also have access too : OF_BLENDMODE_MULTIPLY, OF_BLENDMODE_SUBTRACT, OF_BLENDMODE_ALPHA, OF_BLENDMODE_SCREEN

I believe that :

  
  
ofEnableAlphaBlending() ;

and

  
  
ofEnableBlendMode ( OF_BLEND_ALPHA ) ;

will get you the same alpha blending result.

More info here : https://github.com/openframeworks/openFrameworks/pull/310

#4

I believe part of the effect is due to the linewidth changing according to the overall audio volume. Try it, especially don’t smooth your amplitude but just apply it to the linewidth immediately.

#5

Thank you for your advices. I have tried with additive blending and in fact the effect is similar. I am going to implement the rest with a shader to blur/glow proportionally to the luminosity of the line. already just blurrying a bit looks really fine. thank you!