MutantQuartz

I’m back to poking around with OpenCL & QC a bit these days so hope to share some more compositions here at some point over the summer. In the meantime here is a video of something vaguely similar to EarFluid that I’ve been mucking around with in recent days.

Particles to fluid from Steve Watkins on Vimeo.

This is only going to work right if you have Snow Leopard, and a reasonable OpenCL-compatible GPU. Having said that, if you install Quartz Composer then you can get it running on the CPU using my tips from a previous post, but you probably wont get a useful framerate unless you have a mac pro, and even then it will use a silly amount of CPU power.

Instructions:

Unzip, put the file in ~/Library/Compositions and when you restart iTunes it should show up in the visualizer list.

Keys:

e to change effects

+ and – to cycle through various different speeds of fluid.

r to reset many of the parameters

h to switch to heightmap mode

s and d to adjust sensitivity to music

f to show framerate

x to enable a higher resolution version that may perform ok on better desktop GPU’s, I would love to know what framerate can be obtained with a GTX285 if anybody can comment on that. You probably need to press r to reset after switching to the higher res, x again will switch back.

There is probably much that could be improved about this visualizer, but it does some interesting things sometimes, so I will share it now. All of the clever stuff is done by quartz composer patches that come with snow leopard, I just wired it all up.  Use with caution as the technology is new to snow leopard and there could be bugs or memory leaks. Also note that quartz composer is not generally as efficient as writing code, so the performance of this visualizer should not be taken as being typical of openCL. If you have an OpenCL GPU then the framerate should be just about ok, and cpu use very low. If your cpu use is very high then it means OpenCL is using your CPU rather than GPU, and the experience probably wont be nice.

Download EarFluid 0.1 for Snow Leopard iTunes 8 or 9.

Apart from playing around with mesh stuff and the snow particle example, most of my time with QC4 has been spent playing around with the ‘2D Fluid Simulator’ patch that Apple provide with Snow Leopard. I doubt I am using it properly, others will do better, but I have knocked up a quick VDMX plugin effect using it anyway.

Read more about it here

Download the file here

I think it may only work on systems with suitable OpenCL GPU, so even if you use my CPU bug workaround that I mentioned in a previous post you may not get any joy.

itunes visualizer test based on the same concept coming soon.

In Snow Leopard, Quartz Composer has patches that enable the use of OpenCL, and this stuff is used to power the Mesh Filters and a few other things. If you dont have a graphics card that supports OpenCL in Snow Leopard, it is supposed to use your CPU instead, but unfortunately this functionality is broken in the intitial snow leopard release. Yesterday I stumbled on a workaround that can be used until Apple fix the underlying problem:

In QC, go into preferences whilst holding down alt, go to system section, tick ‘QCDisableCLOpenGLSharing’. Restart Quartz Composer.

Note that if you do this on a machine that has an OpenCL-capable GPU, it will be disabled, and OpenCL will just run on your CPU. In many instances this may give better framerate than mobile GPU’s, but you wont have much CPU left to do anything else!

Although this option is in the Quartz Composer editor it seems to apply system-wide, for example an OpenCL QC itunes visualiser that did not run on my Mac Pro due to lack of suitable GPU, now runs on the CPU when the above option is ticked. Shame it uses 600% CPU! (its based on the Apple-provided macro called 2D Fluid Simulatior that comes with Snow Leopard, and I will post it later)

There is some discussion of this on the kineme website

I had to wipe out my wordpress install and start again, so it may take a while before the video’s for my older 2008 posts show up.

I havent posted here for a long time, in part due to waiting for Snow Leopard to come out. New features are discussed in detail in an article by Vade on Create Digital Motion, so i wont go into too much detail here.

QC4 review

OpenCL in Quartz Composer, along with the Mesh stuff is what interests me most, although overall performance improvements are also welcome. I have been messing around with OpenCL a bit, mostly just playing with example stuff Apple included, and I will be posting more about this shortly, along with a few examples.

More of those pesky tubes, this time aranged differently and with 3D models passing through.

Anyways thats the last of todays silent videos. Im still working on some stuff that reacts to musical MIDI data, it may be optimistic to say that Monday will bring a musical video but it could happen I suppose.

I have begun to experiment with opacity of 3D objects, and slowly start to use some very simple textures here and there.

Made by accident, it sort of reminded me of some typical 90’s club flyer artwork. Again I will probably find a use for it as part of a larger 3D scene one day.

Something not altogether interesting, but that I’ll probably end up using as part of a larger composition sometime.