Noise distortion / bulge map

[OnoSendai]

Hi FakeShamus,
Until recently, 32 bit EXRs were converted internally into 16 bit EXRs, which may cause the banding you're seeing there.

[Stromberg]

Ah, that might explain it, but why does indigo do that?
I mean if we load a 32 bit map, it's because we want to use on right

[FakeShamus]

Ah, yeah, ok.
there was also some mention in the past that 16-bit files were converted to 8-bit internally, is that still the case? I'll have to try some mountains again with a newer version. thanks, Ono.

[OnoSendai]

16 bit per channel PNGs and TIFs are converted to 8 bits on loading.

[OnoSendai]

Hi All,
I did some tests on a possible solution to this stepping issue, by changing the bump map format internally from 8 bit to 32 bit floating point, and then blurring the image, and it seems to work pretty well.
This fix should make it into the next Indigo version.

Cheers,
nik

[galinette]

Hi Ono,

Converting to 32 bit and then blurring slightly (saved under EXR format) is actually what I use for bump maps generated from 2D profilometer data and it works quite well. I'll show you some embossed glass material results soon.

However, doing this internally may be a problem as the blurring will sometimes erase small features of the bump map. Moreover, it will increase memory consumption. This should be an optional feature.

There is a possible trick implying no conversion to 32 bits which I used a long time ago for extracting normal map from a 8bit heightmap.
The trick consists in detecting cases where neighbor texels have the same exact height value. Then, you scan further along the axis, until you get a different value, and this in both directions. Then you just compute the slope as usual. This may be slower, though.

Etienne

[OnoSendai]

Hi Etienne,
The smoothing/blurring of the bump map will definitely be optional.

I also have considered modifying the sampling routine as you mentioned but I think it will generally be more efficient to pre-filter the bump map.

[OnoSendai]

Here are some results with the new code:
There is now a 'smooth' toggle for the texture that if enabled, will do the conversion to 32 bit and smoothing.
This will be available in the next Indigo release.

[dcm]

thank you master

[dakiru]

Here are some results with the new code:
There is now a 'smooth' toggle for the texture that if enabled, will do the conversion to 32 bit and smoothing.
This will be available in the next Indigo release.

This is great, thank you!

[ENSLAVER]

Awesome.

[zeitmeister]

Fantastic, Ono!