Friday, June 27, 2008

Quick Update

After yesterday's monster post I thought I would take today off.  But as luck has it I was able to finish up a few good chunks of code that got Trimmed NURBS Surfaces back into mostly working order.  If you check out the code you should be able to create nice 3D Pads.  There are a couple of gotchas though.

First, much of the trimming process described yesterday as being on the GPU is still on the CPU.  I want to make sure I have the general algorithms correct before I put it onto the GPU, mostly because it is much harder to debug on the graphics card.

Second, LOD scaling is still a bit wonky.  Zoom way in and the trim texture gets denser, as it should.  But zoom way out and you typically only get down to 50x50 or so.  This is because I am using a method similar to the LOD for regular surface vertices.  I will be able to adjust this over time to optimize the amount of memory that the trim textures soak up.  Right now they eat a lot.

Next week I hope to move more onto the GPU and to optimize the LOD stuff, but for now trimmed surfaces are back.

Have a great weekend.
Cheers,
   Graham

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