In order to better facilitate the change from block stream order to non-block stream order,
a lot of changes were introduced to the way that we feed texture data to the compressors. This
data is embodied in the CompressionJob struct. We have made it so that the compression job
points to both the in and out pointers for our compressed and uncompressed data. Furthermore,
we have made sure that the struct also contains the format that its compressing for, so that if
any threading programs would like to chop up a compression job into smaller chunks based on the
format, it doesn't need to know the format explicitly, it just needs to know certain properties
about the format.
Moreover, the user can now define the start and end pixels from which we would like to compress
to. We can compress subsets of data by changing the in and out pointers and the width and height
values. The compressors will read data linearly until they reach the out pixels based on the width
of the given pixel.
In general, we want to use this algorithm only with self-contained compression
lists. As such, we've added all of the proper synchronization primitives in
the list object itself. That way, different threads that are working on the
same list will be able to communicate. Ideally, this should eliminate the
number of user-space context switches that happen. Whether or not this is
faster than the other synchronization algorithms that we've tried remains
to be seen...
In order to develop a threadsafe texture compression function, we will need
to preempt threads in order to not kill performance while we initialzie everything...
