Seems to be an interesting read. Since Houdini is very heavily in OGL, I suppose someone might be interested.
http://www.opengl.org/pipeline/article/vol003_7/ [opengl.org]

Houdini is pure OpenGL, and not an OpenGL/GDI mix, so it passes at least the first hurdle. H8 and below may be a bit sluggish*, though, due to swapbuffers doing a double copy instead of a single buffer flip, and doing a user-kernel switch, at that. glReadPixels() also does a user-kernel switch, which H8 uses quite a bit of.

The one thing I've read about using OpenGL for numeric processing on Vista is that you have to break down your programs into smaller bits, otherwise long computations could be considered a video card hang and be shut down. However, Houdini doesn't currently have any fragment or pixel shaders that run anywhere close to that long.


EDIT: *by a bit sluggish, I mean in comparison to the same hardware running WinXP.

Aaah cool. I forgot that this was more of an issue pertaining to OGL/GDI mix… Thanks for the the insight as well.

twod
Houdini is pure OpenGL, and not an OpenGL/GDI mix, so it passes at least the first hurdle. H8 and below may be a bit sluggish*, though, due to swapbuffers doing a double copy instead of a single buffer flip, and doing a user-kernel switch, at that. glReadPixels() also does a user-kernel switch, which H8 uses quite a bit of.

Is there a hint here that H9 won't suffer from these issues or is that wishful thinking on my part?

any idea how sluggish Houdini should be? I'm not sure at this point if it's this issue or if it's my graphics/vista installation in general. I just installed vista and the 64bit driver for my video card

which is this
http://www.powercolor.com/global/main_product_detail_dis.asp?id=69 [powercolor.com]

seems my XP32 is much faster in the view than the vista64

anyone have a guess … I really like the memory now (I can use 4-gigs very good for chops with audio etc), but the cpu performance seems to really spike once I rotate the view.

on the 32bit vista I was seeing visible redraws of the parameters when selecting different nodes, but the viewport seemed quite normal. However it was on a laptop and I didn't push the viewer very hard, just a few spheres with the number of division pushed right up.
Definetely not usable in a production environment.

ah, it was my installation … Houdini works fine. I hate windows as much as the next guy but my audio programs only work on windows

Vista drivers are proving to be about 10% slower than the XP drivers right now, on average. Partly it's the new driver model, partly nVidia/ATI's brand new drivers for the model, and partly the fact that the driver model requires 100% virtualization of the driver (so that it can run several tasks at once, like the aero desktop and Houdini). Virtualization will be very useful, but does have overhead.

The rendering model in H8 and below does many partial updates to the screen rather that full window updates. With Vista OpenGL, this turns out to be very slow (each update must sync the OpenGL buffer with the Vista buffer). H9 does away with this, and so it should suffer much less of a performance penalty.

Also, laptop graphics, especially the lower end models, tend to be very poor performers. The ATI mobile graphics are borderline usable, and the Intel GMA can only be run reliably in software emulation mode. nVidia graphics fair better, though it's still recommended that you get their top-of-the-line mobile graphics chip.

I personally don't think the graphics drivers for Vista are quite ready yet. nVidia's OpenGL driver is much better than ATI's, but both are inferior to WinXP. I certainly wouldn't recommend anyone switching to Vista on the basis of graphics performance - you'd have to find other compelling reasons. That's just my opinion, though.

Thought others might be interested that I fixed my redraw slow down using the information in this thread

http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&p=38866#38866 [sidefx.com]


cheers to Nutman