Compact image-generation texture modifier

[appgurueu]

• Goal of the PR: Allowing larger mod-generated images by implementing a more compact texture modifier
• How does the PR work? Takes width and height & colors as hex-string-RGBA-array
• Does it resolve any reported issue? Closes Allow more complex texture modifiers #6821

Status

This PR is Ready for Review.

How to test

minetest.register_craftitem("testmod:testitem", {
	inventory_image = "[image:2x2:".."FF0000FF".."00FF00FF".."0000FFFF".."FFFFFF00",
	description = "Test Item"
})

Results in this:

[sfan5]

I wonder if there isn't a better solution to dynamically generated images.

[appgurueu]

I wonder if there isn't a better solution to dynamically generated images.

There most likely is, but not without much effort.

[rubenwardy]

I suggest having PNG data in the same way that data URLs work, constructed with a helper on the server

It would be nice to fix texture caching to not cache everything when doing stuff like this, though

[nerzhul]

raw_image sounds better than image for me, as we are low level here

[appgurueu]

I suggest having PNG data in the same way that data URLs work, constructed with a helper on the server

So propose minetest.raw_image(data) returns base64-compressed PNG data, with data being a Lua list of RGBA byte strings. Accordingly, the raw_image modifier would take that data.

[SmallJoker]

👎 this PR should either implement a modifier for raw image data, or image data encoded as base64.

[appgurueu]

Closing this in favor of @sfan5's PR.

[sorcerykid]

Unless i missed something, I wasn't aware that the other PR allowed for programmatic generation of textures. From my reading, it implements pushing of already existing media files to the client, which is completely different.

[v-rob]

I believe this PR still can serve a purpose. This allows highly customizable textures, working for things like e.g. painting or sign mods. You could, I suppose, create a PPM image, save it with a cryptic name like mymod_generated_###.ppm where the number increments every time you create a new image, and load that -- not an ideal solution. Neither is tons of ^combine[s with intermediate caching.

Personally, I think using a hexadecimal color string for each pixel is overkill though. Offering a palette modifier would also be a good solution, like ^palette[2x2:#F00#0F0#00F#0000:0123 (the same as the example picture) would offer a good compromise, since many really dynamic things won't need that many colors but will need many pixels. It could go from 0-9, then A-Z, and finally a-z for a total of 62 palette colors.