> I'm almost certain the errors aren't caused by bugs to any significant
> extent, but are caused as I said in my earlier post by using an 8-bit
rather
> than a 16-bit height map. The attached image shows two almost identical
> height fields - the left hand one is 8-bit, and the right-hand one is a
> 16-bit version of exactly the same height field. The resolution of the
> heightfield is 500x500 in both cases, and the smooth keyword is used for
> both images.

Yes, the differences between the 16- and 8-bit images are significant,
obviously. In the images you gave, the difference is caused 99% by the bit
depth of the images. However, Noe Falzon's image, you'll notice, doesn't
have large, flat areas. Rather, it has lots of small, flat areas, which sort
of look like rounded squares which correspond to the grid of the height
field.

> The reason I think this is the problem is that the artifacts in your image
> are very similar to the ones in my 8-bit height-field image.

The bug I mentioned *is* displayed (slightly) in your 8-bit image. Since the
8-bit image has lots of flat areas, you can see that the edges of the flat
areas appear to be too "square." It's hardly, if at all, a problem in your
16-bit image, since that one doesn't have any significantly flat areas. I
would not be surprised if the greater bit depth helps to hide the bug I
mentioned.

The presence of the rounded-square artifacts in Falzon's image convinces me
that the majority of the problem he's having is due to the normal-smoothing
bug. If it were caused by bit depth problems, I would expect something more
like contour-line flatness, as displayed in your first image.

 - Slime
 [ http://www.slimeland.com ]

Post a reply to this message