Help making good maps in Gimp ?

[RorrKonn]

[attachment=3049][attachment=3049]If I paint a texture in Gimp. Save 8 bit I get the odd lines,
but if I save in 32 bit I do not get the odd lines.
But if I take the 32 bit gimp image and make maps with Bounding Box Materialize. I get the odd lines again.

So I'm thinking I'm not saving the Gimp image correctly.
Does anyone know how to make textures correctly in Gimp ? or any app ?
I've been fighting with this for days n not really sure where to ask this.
but there has to be a answer some where.
Thanks for any and all help

[Blighty]

I have no idea what Bounding Box Materialize is; not the relevance of 8 bit 32 bit in this situation.

What is apparent is that your texture pattern is not seamless. This will account for lines where the pattern edges touch.

Take your image and do:
Layer > Transform > Offset > W/2,H/2
The harsh lines are immediately visible.

There are various ways to make seamless patterns. One way is to use Filters > Map > Tile Seamless. But this does not work very well with this particular pattern. Could be made better by cloning. Or G'MIC has some Make Seamless filters, they could be better on this pattern.

[Ofnuts]

If you mean the things that look like contour lines, this is due to color quantization (only 256 values in an 8-bit channel). So you can have uniform area between which the value jumps by more that a couple of units and your eyes are very sensitive to this (in other words it a bit like an optical illusion). This can be checked wit the Histogram dialog: in the image below, the histogram corresponds to the little selected strip at the top (that is drew perpendicular to the "contour lines"). Visually, your eyes mostly see the jumps between the spikes.

   

If you need to remain in 8-bit you can mitigate the problem using "Spread noise" (`Filters>Noise>Spread). Despite the name th is more like a blur, it swaps pixels with neighboring pixels, so the value jumps are spread over a wider area and are less visible.

   

[rich2005]

This is a games texture, a map? http://boundingboxsoftware.com/materialize/ - no linux version and the video tutorials are too long so guessing at requirements.

Taking the posted RGB jpeg and a color cube analysis Colors -> Info -> Color Cube Analysis, only shows 86 shades. Did this originally come from a greyscale image?

As examples of differences, taking (roughly) the lightest and darkest shade in the jpeg, A gradient in 32 bit RGB has 477 shades but so does a 8 bit RGB so it is not bit depth.. Convert to greyscale gives something like the jpeg and down to 69 shades and banding. example: https://i.imgur.com/7onoIbt.jpg

Try the previous mentioned fixes, also a gaussian blur might help but you are still stuck with those 86 shades of grey and you need more. You probably need to go back to beginnings and look at how you are making the map in the first place.

[rich2005]

I got a screenshot of "Bounding Box Materialize" and it makes all sorts of maps from a source file (jpeg in example)  https://i.imgur.com/2INkJGi.jpg

Not as comprehensive but there is a Gimp plugin InsaneBump that will make some of those: height map - normal map  and the result might / might-not be an improvement. https://i.imgur.com/V3yJHxj.jpg

Then of course it might be nothing to do with the image, could be the game rendering engine producing that effect.

notes:
InsaneBump Gimp plugin is old. Maybe not so easy to find these days, the attached Windows 64 bit version is 1.0.5 It does work with Gimp 2.10.12. Might throw up errors but still renders the maps. Base image has to be on disk. Maps rendered to the same place.  Find in Filters -> Map -> Insanebump 
There are also various other versions on GitHub if you search.

If you decide to try it, the usual, Unzip. put the file gimp-plugin-insanebump.exe in C:\Users\"yourname"\AppData\Roaming\GIMP\2.10\plug-ins

[RorrKonn]

Thanks for all the help.
Is there some tool that can make the Histogram line flat ?