Saving & reloading precedurally generated textures

[supagu]

Godot 3.0
commit 187c40d
Linux Manjaro

I have a height map, which my game will then take and generate a normal map from. This normal map is then saved to disk so that next time the user plays the map, the normal map does not need to be generated again.

I can save out the normal map as a png just fine, but when it tries to load the png the next time I hit the error:

ERROR: _load_data: Condition ' header[0] != 'G' || header[1] != 'D' || header[2] != 'S' || header[3] != 'T' ' is true. returned: ERR_FILE_CORRUPT
At: scene/resources/texture.cpp:430.

I suspect this has to do with godot using its own intermediate texture format.

[ghost]

What are the functions you use? Image.load(path) and ImageTexture.create_from_image(Image)?
Or ImageTexture.load(path)? or something else?

[supagu]

Ref< StreamTexture > n;
n.instance();
Error error = n->load(path);
if (error != OK)
return error;

[ghost]

IIRC, load uses ResourceLoader, which can only load imported resources. Try loading it as Image and set it to ImageTexture.

Edit: might be related to #14879

Also just saw that you use StreamTexture. Try using ResourceSaver::save("... .tres") to save it instead of png.

[supagu]

The technique you suggested works

[supagu]

This is now causing me another problem, The Image and ImageTexture I create is being saved into my scene making it bloat out to like 200mb!

Seems I need to emulate what EditorFileSystem::get_singleton()->reimport_files(reimports); is doing
it casues the file to be processed into a stex file in the cache and can then be loaded using ResourceLoader::load,

but i can only do this in the editor

doing it this way stops some image being saved into my scene.

[vnen]

But if it's generated, why are you adding it to the scene? You can create an ImageTexture, save it with ResourceSaver somewhere (so it's not part of your scene), then load it when needed,

[supagu]

I generate a normal map from a height map then save it. Then I load it and apply it to the terrain material so there map maker can see the normals.
Somehow in this chain of events and ImageTexture is saved into the map unless I use a StreamTexture

[supagu]

Right after a good sleep I have this almost working using the following steps:

1. create a temporary ImageTexture fill it with the normal map image and call ResourceSaver::save, then ImageTexture can be released.

1a. if in the editor, I tell the editor to re-import the texture so I can load it ASAP:
if (EditorFileSystem::get_singleton()) { // cause the image to be "imported" Vector<String> reimports; reimports.push_back(path); EditorFileSystem::get_singleton()->reimport_files(reimports); }

2. Image can then be loaded with:
   Ref n = ResourceLoader::load(path);

There is a 'gotcha' here in that because I am applying the procedural texture in the editor, it is being saved into the scene. So If I want to ship the map without this texture (as it is generated procedurally) then I would need to work around this last issue. The map won't load with a missing texture.

Is there a way I can force the level to load with missing dependencies as the editor somehow does?

[akien-mga]

What's the status on this issue? If there's still a problem, could you provide a minimal reproduction project?

[supagu]

Sorry I have no idea if this is possible yet. I have just changed things so the texture is generated each time I load onto a level which is slow but works for me. Which is a better solution in my case.

The ideal solution is to be able to cache the generated texture on the end users machine by the game but at this stage editor code is compiled out AFAIK (ie ability to save out assets).

[Xrayez]

In theory you can bypass this by implementing your own custom EditorImportPlugin to import your normal maps alongside original textures, or find a way to override StreamTexture import, which might not be as trivial to do in comparison, these kind of limitations of ImageTexture vs StreamTexture are also expressed in #24222, I'm not sure what would be the recommended solution for this, but implementing custom editor plugins seems to be the most "straightforward" way to do this, of course that's up to a tutorial and the problem is more or less specific to the project.

What Godot could do at the core is possibly exposing some StreamTexture internal methods which are used to import textures in the same way, but that's probably up to a proposal anyway, for which you can open an issue at GIP repository.

[RedMser]

I think this issue should be closed. It had no activity for years and to me looks unactionable / better fit for a proposal.