Kris Dale wrote:
Morning all,Okay, bear with me if this seems an extremely dumb question. I'm extremely new to OSG (heck, I'm new to 3D graphics in general, I've only made it through Chapter 5 of the OpenGL red book...), and I'm basically having to learn as much as fast as I can and what might seem obvious may be moderately difficult to me...Anyway, the question is this: I'm trying to simulate a jet stream emanating from a projectile in motion (ie. jet, rocket, space shuttle, etc.). I've managed to get through setting up a ParticleEffect and attaching it to the back of a Node model and everything, and in terms of where it's placed and such it actually looks pretty good, but it's in the details I'm a little bothered. While I've been able to change the actual size of the particles, I can't seem to figure out how to change the SHAPE of the particles. I'd like to try to round them out a little. I noticed the Particle object has the function setRadius but I've changed that to all sorts of extrema and don't see any difference... changing the size range works but they're still perfect squares. Is there no way to produce round (or even just rounded edge) particles?Thanks to anyone that can offer any help...
Particles are typically rendered as quads, just because it's efficient to do so. Generally rounded objects are expensive (in computation time) to do when you're dealing with polygonal rendering, as OpenGL and OSG do.
To make the particles "look" round, you typically just need to apply a texture map that is transparent near the corners of the quad. I attached an example image to give you an idea what I mean. When you apply this texture to your particles, they'll look round, even though they're still being drawn as quads.
--"J"
Kris ------------------ Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=14247#14247 _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
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