[x3d-public] VariationPhysicsModel for ParticleSystem using programmable shaders

[John Carlson]

My thought is to add a new input variable in to shader,

in float[] myVariable;

Then provide

<field name=“myVariable” type=“MFFloat” accessType=“inputOnly” value=“…”/>

In the ComposedShader.

But I don’t know currently how to tie a particle physics model to a
composed shader, nor how to address instances of geometry.  The work I’ve
done so far addresses all instances, and uses scripts, not wind.

So I need to look into source code a bit.

It would seem that naming individual floats might provide better
documentation.  I guess an MFFloat is less wordy, and a single float
MFFloat can serve as an SFFloat.

John

On Mon, Apr 22, 2024 at 7:53 PM John Carlson <yottzumm at gmail.com> wrote:

> Also, one could provide Variational Physics Models that apply to all
> particles or one particle.
>
> WindPhysicsModel already does this, but the 6 variational physics models
> I’m imagining affects each particle.
>
> I’ll probably start coding this up tonight, if no one else volunteers.
>
> I don’t know if I need a Script per particle or not.  I’m thinking I need
> to provide toNode and toField (ROUTEs), but on a particle level, so perhaps
> I need a specialized ROUTE.
>
> How might we combine this with InstancedShape?  Can we add
> ParticleSystems’ PhysicsModels to InstancedShape?
>
> I’m looking for more collaboration on reducing the number of Scripts I use.
>
> I’m now seeing that float arrays are a thing in custom shaders, so perhaps
> for my 6 shader parameters, a single variational physics model is all that
> is required, with 2 MFFloats, one for values, and one for variation of
> values.
>
> Thanks!
>
> John
>
> On Mon, Apr 22, 2024 at 7:24 PM John Carlson <yottzumm at gmail.com> wrote:
>
>> Holger, I would like to provide 2 sets of (SFVec3f of values as well as
>> an SFVec3f of variation corresponding to the values).  My thought is to use
>> PhysicsModels in the ParticleSystems.  These are not emitters, but
>> something more like a WindPhysicsModel, they parametrically alter the shape
>> of geometry over time in a ComposedShader.  There are actually 6 individual
>> SFFloats of values, so technically, I might use 6 WindPhysicsModels,
>> sending speed into the programmable shader, and providing gustiness for
>> variation.  But this is not wind, and AFAIK, X_ITE and Sunrize does wind
>> with the WindPhysicsModel.  Is there another PhysicsModel available, or
>> should I write my own?
>>
>> Would it be better to use 2 MFFloats, and how do I send an MFFloat to the
>> ComposedShader?
>>
>> Thanks!
>>
>> John
>>
>
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