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Morton ordering in PagedVolume
http://www.volumesoffun.com/phpBB3/viewtopic.php?f=14&t=634
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Author:  David Williams [ Sun Apr 05, 2015 4:00 pm ]
Post subject:  Morton ordering in PagedVolume

Hi all,

Over the last couple of weeks we have been continuing with PagedVolume improvements. As you probably know, the PagedVolume stores its data as a set of chunks with each chunk in turn containing a large number (e.g. 64*64*64) voxels. These voxels have always been stored in linear order inside the chunks, but we have now switched to use Morton ordering.

There are perhaps some small speed benefits to using Morton ordering (due to improved locality of voxel data), but the main benefits should be that the data is more compressible and also easier to subsample. For most people the change will be transparent as it is largely an implementation detail and is hidden by the chunk's Get/SetVoxel() functions, but if you are getting/filling/storing chunk data via the raw pointer then you will need to be aware that the voxel order has now changed. For convieniece we have provide the 'changeLinearOrderingToMorton()' and 'changeMortonOrderingToLinear()' functions to do the conversion. Have a look at these and ask if you have questions.

For further discussion about Morton ordering and our implementation choices you can read the discussion in the issue tracker: https://bitbucket.org/volumesoffun/poly ... g-of-voxel

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