VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Fri Apr 14 2017 - 02:29:36 CDT

Josh,
  I have no idea what issue you're describing since I haven't seen it myself
It would be useful to get example images that display the problem so
I can have a look, but I wouldn't expect the old code to change much if
anything.

Cheers,
  John

On Fri, Apr 14, 2017 at 01:53:52AM +0000, Vermaas, Joshua wrote:
> Alright, I got fed up enough to try and fix this behavior. I failed
> miserably at correcting it myself, so instead I have a quickish hack for
> others that experience this: copy over OptiX* files from the src
> directory of a VMD 1.9.2 install to replace the same files in the src
> directory of VMD 1.9.3. This means you'll loose any of the VR-specific
> changes made for 1.9.3, since you are effectively going back to the
> 1.9.2 rendering path. You'll need to patch FileRenderList.C to
> accommodate this too.
>
> Instead of:
> if (optixdevcount > 0) {
> // Emit a console message during OptiX renderer instantiation
> // since the JIT compilation and linkage of the 256+ shaders may
> // take several seconds on machines with several GPUs...
> if (vmdapp->nodecount == 1) {
> msgInfo << " Compiling "
> << OptiXRenderer::material_shader_table_size()
> << " OptiX shaders on " << optixdevcount << " target GPU"
> << ((optixdevcount > 1) ? "s" : "") << "..." << sendmsg;
> }
>
> add(new OptiXDisplayDevice(vmdapp, 0));
> #if defined(VMDOPENGL) && defined(VMDOPTIX_INTERACTIVE_OPENGL)
> add(new OptiXDisplayDevice(vmdapp, 1, cluster_dev));
> #endif
>
> You go back to the simpler code from 1.9.2:
>
> if (optixdevcount > 0) {
> add(new OptiXDisplayDevice(vmdapp, 0));
> #if defined(VMDOPENGL) && defined(VMDOPTIX_INTERACTIVE_OPENGL)
> add(new OptiXDisplayDevice(vmdapp, 1));
> #endif
>
> After those changes are made, recompile. Rendering shadows then behaves
> correctly when calling the non-interactive renderer. As a happy
> accident, VMD startup times are reduced, since there isn't any shader
> compilation at startup.
>
> -Josh
>
> On 03/31/2017 01:25 PM, Vermaas, Joshua wrote:
> > Heya folks,
> >
> > Has anyone else noticed strange behavior when using ambient occlusion &
> > shadows coupled with the TachyonLOptiXInternal renderer in VMD 1.9.3?
> > Relative to the Interactive renderer (see screenshots attached), the
> > shadow edges look too straight, and are just wrong sometimes (compare
> > the edges on the bottom of the rightmost aromatic ring, for example).
> > The differences are huge compared to what they used to be in VMD 1.9.2.
> > Interestingly the render times have gone down in VMD 1.9.3 as well, so I
> > suspect internally its just a matter of not enough rays being cast in
> > the current version, but I haven't found the knob to turn to get the
> > look I want back. If I'm the only one experiencing this behavior, I can
> > just go back to VMD 1.9.2 when I need to render animations, but if I'm
> > not, I'd like to see what workarounds other folks have discovered.
> >
> > Thanks!
> >
> > -Josh Vermaas
> 

-- 
NIH Center for Macromolecular Modeling and Bioinformatics
Beckman Institute for Advanced Science and Technology
University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
http://www.ks.uiuc.edu/~johns/           Phone: 217-244-3349
http://www.ks.uiuc.edu/Research/vmd/