Emitter area for ParticlesGPU 2D_Field

vvvv beta question
1

Hi guys
thanks lecloneur and other contributors there are few example how to texture-based deform
field of particles.
As jannis example http://youtu.be/RE5y085wL0w shows it’s possible to specify desire area to emit particles there.
my question how to via texture define the emitter area?
Is it possible to get "clean"emitter without emitting full quad?
or it’s only possible via making rest of the full quad with alpha =0?
I’ve tried to RGBA split the cycle texture, but cant get rid of the full quad building
I would like to achieve opposite of patch attached = silhouette filled with particles
Thx in adv, dimi

ParticlesGPU_2d_Emitter.zip (5.8 MB)

2

I got the the first step and have silhouette, thanks jannis tip to invert the texture. It looks bit ugly, there’s lots noise around. Any hints how can i clean it?
https://vvvv.org/sites/default/files/imagecache/large/images/Emitter.jpg

ParticlesGPU_2d_Emitter_v2.zip (5.8 MB)

3

my mistake Still everything there - Full quad emitted
any hlsl guru hints?https://vvvv.org/sites/default/files/imagecache/large/images/emitter.jpg

4

you need some basic keying, but prolly you lack some contrast on pre-pass

5

It sounds/looks like you want to play with the reset pos control texture. The field texture as I understand it is only affecting particles after they are already born.

So at the moment you are still emitting them everywhere, due to the reset pos texture not having anything to do with the actual dancer image.

Also the shader seems to be a bit modified from Dottore’s original, what’s different? I did not look inside it yet, just curious.

6

@antokhio: i tried to insert keying(and inverted too) pass between different passes but it doesnt change much in particles emitting
@everyoneishappy: i assume shader is adapted for the “displacementFX” - the field texture splited in two inputs. i will try to post the version with Dottore’s original. will see
thanks

7

Attached is the fake version of desire FX.
@antokhio: keying in post, but full particles quad still emitted and that’s actually not what i want
@everyoneishappy: I think the modified shader is OK for this case.
Generally I am not sure if it’s possible with this “Mesh Quad” approach to achieve specific area (defined by texture) emitting, not the full quad
https://vvvv.org/sites/default/files/imagecache/large/images/Emitter3.jpg

ParticlesGPU_2d_Emitter_v3.zip (5.8 MB)

8

Check your reset pos control texture- that is basically the emitter.

9

Thanks everyoneishappy.
got it. actually very simple: inverted texture goes to pipet to produce bunch of emitters. attached is basic, displacement is bad, should find better one

ParticlesGPU_2d_Emitter_v4.zip (5.8 MB)

10

Can someone point me please how to affect Lifetime of particles?

ParticlesGPU_2d_Emitter_v5.zip (5.8 MB)