PcloudStimulusBuffer::produceFrameReq():
Now correctly produces into the stim frames for the
PcloudIntensityStimulusBuffer object that's attached to the
PcloudStimulusProducer. If there's no attached I stimbuff, then
the OpenCL kernel will simply not write out the intensity data.
This is the first moment when we actually use the SP-MC ringbuffer
properly and actually cycle through the frames, producing into
them one by one.
This ensures that we can avoid races when adding and removing
stimbuffs to a stimproducer.
At least in theory. I can think of some ways in which this current
design may result in races or other bad conditions.
We now allocate all the stimFrames for a StimBuffer using a
single StagingBuffer. This gives us all the benefits we're
looking for (pinning, alignment, etc).
hayodea