Preet,
Perhaps the problem is lack of precision in your BillboardRotate uniform
(double - float).
Maybe you can try a different approach: transform your vertex into View
space (or Clip space) and then apply the ModelPosition offsets there. Just
an idea.
Glenn Waldron / @glennwaldron
On Sun, Jan 20, 2013 at 5:35 PM, Preet prismatic.proj...@gmail.com wrote:
Hiya,
This is somewhat related to my last thread (maybe I should have just
explained the situation from the beginning).
I'm trying to create a shader that does billboarding for hundreds of
objects at once (where using AutoTransform is too slow). I merge all these
objects together to reduce the number of draw calls, and pass along
specific vertex attribute data (specifically model-space relative vertex
data when I want the billboard center to be the model's center) and
uniforms (camera vectors) to do the required billboard transform in the
shader.
This kind of works, but the result is 'jittery' compared to AutoTransform.
I don't know whether its the way I specify the uniform update callback or
if its related to reduced shader precision (the coordinates I used are all
close to the origin though, so I hope that's not the case) or something
else entirely.
I created a minimal example that reproduces the issue [1]... (just
copy-past-compile). The example shows a square billboarded with
AutoTransform working perfectly, and my not so great example directly
behind it.
[1] https://gist.github.com/4582261
* Does anyone know why my example billboard implementation causes that
jitter/delay?
* Or, has anyone created a better shader that can do billboarding for
batched geometry (and if so, could they maybe share how)?
Preet
___
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
