openCL

I'm aware I'm coming to the OpenCL party weeks after everyone else has (leaving me surrounded by empty beer bottles and the lingering smell of cigarettes and stale vomit), but OpenCL is GREAT.

I just managed to achieve something using OpenCL that I've been wrestling with (unsuccessfully) for ages using GLSL shaders- make a radially-displaced heightmap sphere, with working normals! My joy at this lasted until my machine locked up completely, about two minutes later, necessitating a force-shutdown.

Hopefully, future OS updates will make QC's OpenCL support a bit less flaky, and widen GPU support a little.

a|x

The Apple Developer Example N-Body.qtz simply doesn't work whatsoever at all in QC, even after applying the recently posted tip from Steve Elbows [thanks for that tip, Steve].

It may be a hardware related issue and I have posted the automatic crash report to Apple.

Just wondered if anyone else had experienced a similar problem with this item.

GT gave us a detailed many bases post about various aspects of QC4, and mentioned N-Body as being pretty active.

An experience I am as yet to share :-(

In QC, go into preferences whilst holding down alt, go to system section, tick 'QCDisableCLOpenGLSharing'.

Thats it really, reload QC and compositions that use openCL will now run on the CPU. It appears to work across the system, eg my itunes visualizer that uses 2D Fluid Simulation now works on my mac pro.

This trick can also be used on systems that do have a functioning OpenCL GPU, but you want to see how your CPU performs, because QC will now use your CPU instead (you can check this using the Context patch but it will be pretty obvious from high CPU use.)

Hope this is of use to some of you whilst waiting for Apple to fix bug or convince spouse that new computer is a good idea ;)