mwhitak2++at++csc.com
Wed, 18 Aug 1999 12:12:04 +1000
I have been using clipgen to generate small cliptextures with some success. I am
now attempting to use it to build larger, more complex cliptextures and seem to
have hit a serious performance problem.
Any assistance you can provide will be appreciated, as the alternatives that I
am considering appear to be extremely labour intensive. Although at the moment I
am attempting to construct a cliptexture from a single image file, in the future
this image file will form a higher resolution inset to a low res. satellite
image covering a large area, and will itself be the parent of an even higher
resolution inset. For this reason, I much perfer to be able to use a tool that
can construct such a hierarchy, rather than build the thing by hand.
Here is the clipgen parameters file that I am using:
(See attached file: copy_of_Nowra.cp)
This attempts to create a clip texture from a single inset file (Nowra.rgb,
approx 4.0Gb), the details of which are given below:
lionel 13:31:12 35> imginfo Nowra.rgb
Image file: Nowra.rgb
File format: Classic SGI image
Dimensions (w,h,z,c): 34858, 41972, 1, 3
Page Size (w,h,z,c): 34858, 1312, 1, 3
Data type: unsigned char
Dimension order: interleaved
Color model: RGB
Coordinate space: lower-left
Statistical Min/Max: 0 - 255
Display Min/Max: 0 - 255
I have generated the highest resolution level (L65536), and using icache this
seems to be complete and correct.
This level consists of a total of 16384 tiles and took approximately 5 days to
generate using an O2 (approx 30s /tile), However the next level down (L32768)
appears to be running extremely slow, taking approximately 10m /tile.
With roughly 5000 tiles remaining before the texture is completed, I am faced
with an apparent wait of 1 month, which is obviously unacceptable!
Am I doing something wrong? Or is there some algorithmic compromise that
accounts for these delays?
As well as running clipgen on my O2, I have also tried running it as root on a 4
CPU Onyx2 with 512Mb RAM and 5Gb swap. Even here, there does not appear to be
any significant improvement in performance and all system resources appear to be
under-utilised, i.e. it does not appear to be I/O or CPU bound.
Both machines are running IRIX 6.5 and performer v2.2.1
As I said before, any useful advice is appreciated!!
Regards,
Matthew Whitaker
__________________________________________________
3D Database Modeller - ANZAC Ship Helicopter Project
CSC
460 Pacific Hwy, St Leonards NSW 2065 Australia
Ph: +61-2-9901-1633 Fax: +61-2-9901-1110 Email: mwhitak2++at++csc.com.au
This archive was generated by hypermail 2.0b2 on Wed Aug 18 1999 - 11:25:40 PDT