[Mod] Image Loader [0.1.0] [imageloader]

[bobomb]

we need a pure lua image handling library to make the opening of different image formats flawless for this and other mods. I need it for realterrain mod: https://forum.minetest.net/viewtopic.php?f=9&t=12666

[kaeza]

Update!

By popular demand (??), added PNG file support. One note though: please ensure PNG images are well-formed (i.e. not corrupted). Otherwise the PNG loader may get stuck in an endless loop or simply barf.

[Diamond knight]

cluck yea!!!!

i am soooo downloading this mod!!

[zak1975]

Just tested this mod in 0.4.13 and in 0.4.12. with loading a large png file. I can load the demo-png-file properly but my own png files do not work.
Ingame I get this message: Failed to load image: imageloader: unknown file type

In debug.txt:
21:44:44: WARNING: Assignment to undeclared global "ch" inside a function at ...netest-0.4.12/bin/../mods/imageloader/lib/pngLua/png.lua:251.
21:44:50: WARNING: Assignment to undeclared global "imStr" inside a function at ...netest-0.4.12/bin/../mods/imageloader/lib/pngLua/png.lua:266.
21:44:50: WARNING: Assignment to undeclared global "bpp" inside a function at ...netest-0.4.12/bin/../mods/imageloader/lib/pngLua/png.lua:136.
21:44:50: WARNING: Assignment to undeclared global "bpl" inside a function at ...netest-0.4.12/bin/../mods/imageloader/lib/pngLua/png.lua:137.

Edit:
Maybe the map isn't explored wide enough to insert a large image? What is the maximum resolution this mod can import?

[kaeza]

Thank you for the report about the undeclared globals. They can be safely ignored, but I will fix them so it does not generate those spurious warnings.

About max resolution, the short answer is "about 2000x2000".

The long answer: the max resolution is limited to either 2^32-1 columns by 2^32-1 lines (per the PNG spec), or the memory available to the Minetest executable, whichever is smaller. You are also limited by map size (to place the image in the world). In theory, you should be able to load 64000x64000 image and place it in the world. In practice, you should use a conservative limit (e.g. 2000x2000).

Finally, can you post an archive of some PNGs you find are failing? (if possible, keep them small) That error message is unrelated to map being loaded or not; it could be an unsupported compression method or indeed too big an image.

[Hybrid Dog]

What happens if l try to import an animated png file?

[benrob0329]

PNGs can't be animated, at least not in the official specks.

[Hybrid Dog]

PNGs can't be animated, at least not in the official specks.

https://en.wikipedia.org/wiki/APNG
lt has a wikipedia article, so l guess it's official.

[benrob0329]

That's a PNG add on, the official (as in the PNG website) specks say that PNG does not support it.

[zak1975]

@kaeza:
Now I found out that the images I tried to load were too big.
Trying a png with 100x100 px was able to load. Next try with a 250x250 px image ran about 1 hour and then failed.

Another thing is, the top of the image seems always to face south. I'm trying to import streetmaps into minetest and they have north at top of the image. After import north is south and the sun rises in the west ;)
This is not a big problem because I could rotate the images before loading.

My main Problem is that this mod can not import images above a certain resolution. Any idea?

[Hybrid Dog]

My main Problem is that this mod can not import images above a certain resolution. Any idea?

You could use mogrify to cut them.

[kaeza]

@kaeza:
Now I found out that the images I tried to load were too big.
Trying a png with 100x100 px was able to load. Next try with a 250x250 px image ran about 1 hour and then failed.

[...]

My main Problem is that this mod can not import images above a certain resolution. Any idea?

That is weird. I tested this locally, and a test image (640x640, shown in a spoiler below) loaded fine taking about a minute. Granted, the image was scaled down; the original (1500x1000) crashed minetest itself, probably due to out of memory conditions (I'll concede the loading algorithm is not very efficient, either CPU- or memory-wise).

Again, can you upload an image known to fail? Also, what are your system specs (mainly available memory)? For reference, I have a 3GHz dual core Intel E5700, with 4G of RAM.

+ Spoiler

URL: http://i.imgur.com/MrtaeOj.png

[zak1975]

That is weird. I tested this locally, and a test image (640x640, shown in a spoiler below) loaded fine taking about a minute. Granted, the image was scaled down; the original (1500x1000) crashed minetest itself, probably due to out of memory conditions (I'll concede the loading algorithm is not very efficient, either CPU- or memory-wise).

Again, can you upload an image known to fail? Also, what are your system specs (mainly available memory)? For reference, I have a 3GHz dual core Intel E5700, with 4G of RAM.

This png file doesn't load: http://we.tl/2yZkTHJwKg
While testing, I converted my png files to bitmap and with bmp I could load files up to 2000x2000.

250.png is a 250x250 px image that I have cut out of my large map. It was created with Maperitive (a tool for generating images from openstreetmap data). With gimp I extracted this piece and saved it over export menu to a new png. While doing this I recognized that there are several options in gimp for exporting to png, but I used the default settings.

When I loaded the bmp files, your mod worked very fast and I just had to wait a few seconds, even with high resolutions. My system is a notebook with 8GB Ram and i5-3230m cpu. OS ist Kubuntu 14.04. Minetest and ImageLoader are latest git versions.

[kaeza]

I first tested your image, and it locked up. I killed the process after about a minute or so, but an image this size should not take that long given that a much larger image takes about 5 seconds.

Something I noticed is that your image (which is 32bpp (*)), when converted to 8bpp, loads in about a second here. So I'm guessing there's something wrong in pngLua, but haven't had time to track the bug down.

So I suggest converting your images to 8bpp that as a workaround in the meantime.

(*) The image I posted is also 32bpp and it loads fine, so this puzzles me.

[Hybrid Dog]

Is it possible to use the loadlib function to use some given library for importing images?

[kaeza]

Is it possible to use the loadlib function to use some given library for importing images?

It is, but see the IRC mod for problems with this.

Long story short, I want the mod to be usable without having to hack around with native libs.

[Hybrid Dog]

Is it possible to use the loadlib function to use some given library for importing images?

It is, but see the IRC mod for problems with this.

Long story short, I want the mod to be usable without having to hack around with native libs.

thanks, and does the mod also work for windows? Somewhere l read that on windows \ is used for paths instead of /
https://github.com/kaeza/minetest-image ... lua#L4-L10
https://github.com/kaeza/minetest-image ... png.lua#L4

[kaeza]

Yes, it works on Windows.

And I don't know why are you asking about the slashes, given that 100% of the mods out there use forward slashes and none of them fail on Windows.

[Sokomine]

And I don't know why are you asking about the slashes, given that 100% of the mods out there use forward slashes and none of them fail on Windows.

I thought so as well. Until I encountered the problem that minetest.get_worldpath returns a path using backslashes instead of slashes.

[kaeza]

Yes, but mod do things like

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all

dofile(minetest.get_modpath("foo").."/bar.lua")

which translates to C:\whatever\minetest\mods\foo/bar.lua

It still doesn't fail.

[Sokomine]

which translates to C:\whatever\minetest\mods\foo/bar.lua

...unless the mod deliberately searches for the slashes in order to act as a file browser. Lua just doesn't seem to be very consistent here. If all you're doing is loading some files with dofile, it's not relevant. But the pahts are just not the way they might be expected.

[kaeza]

If you need to manipulate paths, feel free to implement all the functionality required. In this particular case, the question was whether or not this mod would work under Windows, citing an unfounded fear that it might cause problems due to different directory separators. The C lib under windows (MSVCRT) supports using forward slashes as separators, so why should I concern myself with these details? It makes the code portable to all platforms currently supported by minetest. If it ever causes problems, it will be fixed. Until then, no more discussion on this subject from my part.

[bobomb]

inspired by this mod I wanted to show some work I did today on the realterrain mod, now allowing you to map a greyscale image as a heightmap and the same image in color as a color overlay. this map is 640x480

while the intent is to overlay satellite imagery onto elevation maps, it is fun for this kind of thing.
of course realterrain requires a lot of external libraries... and introduces 216 new textures to accomplish this.

viewtopic.php?f=9&t=12666

[lordfingle]

If you'd like to create load images vertically instead of flat on the ground, change this routine in imageloader.lua:

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all

function imageloader.to_schematic(bmp, pal)
   local data = { }
   local datai = 1
   for y = bmp.h, 1, -1 do
      for x = 1, bmp.w do
         local c = bmp.pixels[y][bmp.w + 1 - x]
         local i = palette.bestfit_color(pal, c)
         if (i == 1) and ((c.r ~= 255) or (c.g ~= 0) or (c.r ~= 255)) then
            print("WARNING: wrong color taken as transparency:"
               ..(("at (%d,%d): [R=%d,G=%d,B=%d]"):format(x, y, c.r, c.g, c.b))
            )
         end
         local node = pal[i].node
         data[datai] = { name=node }
         datai = datai + 1
      end
   end
   return {
      size = { x=bmp.w, y=bmp.h, z=1 },
      data = data,
   }
end

[azekill_DIABLO]

great! but we need a better color render :/