Hi,
I agree with Robert. The original osgParticle is very weird at some
points and would need a major rewrite. As found the structure and
facilities useful, I inherited from the ParticleSystem and overwrote the
render functionality to make it work better with geometry shaders and
some custom frame blending that I needed. But appart from this you can
control the values passed in the addDrawParticle implementation.
Cheers
Sebastian
Hi John,
It sounds like when you compute the position of the trail and when the
position of the emitter is updated is out of sync, what you need to do
is make sure your trail code is executed after the emiter update each
frame.
As a general comment, if I were to write a smoke trail right now I'd
just write from scratch and not use osgParticle. osgParticle was
original written for CPU based particle effects well before shaders
became available. There is modest support for using shaders in
osgParticle but the general design approach isn't conducive to a using
shaders.
For a modern smoke effect you should be able to do most of the effects
using a combination of vertex, geometry and fragment shaders. Use of
perlion noise in particle shaders can be a good way of generating
effective smoke effects as doesn't need an particle effects.
Robert.
On 28 July 2014 02:56, John Farrier <john.farr...@gmail.com
<mailto:john.farr...@gmail.com>> wrote:
Hi,
I am implementing my own smoke trail using osgParticle. I have it
just about where I want it, except for one thing: When I am
emitting the smoke trail from a fast moving object, the emitter
seems to "lag behind" the object. At some point, the faster the
object moves, the further the emitter seems to be. When moving
slowly, it looks perfect.
I am using an osgParticle::SegmentPlacer. The segment ends are
made up of the current position of the object and the previous
position of the object. My thought is that if I distributed
particles over the segment, it would fill in given a sufficient
number of particles generated. I set up my emitter's counter rate
range to a high and low both of 4096 particles (i.e. constant, no
rate.) Even with this, my particles are showing up well behind my
object when it is moving quickly. (The distance seems to be about
equal to the distance the object traveled in a single frame.)
Any thoughts or ideas would be appreciated!
Thank you!
Cheers,
John
------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=60474#60474
_______________________________________________
osg-users mailing list
osg-users@lists.openscenegraph.org
<mailto:osg-users@lists.openscenegraph.org>
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
_______________________________________________
osg-users mailing list
osg-users@lists.openscenegraph.org
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
_______________________________________________
osg-users mailing list
osg-users@lists.openscenegraph.org
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
