Print a warning when importing a repeating NPOT texture in a GLES2 project

[Calinou]

Repeating NPOT textures are not guaranteed to be displayed correctly in GLES2, since the specification does not mandate support for it. The warning is displayed for both repeating and mirrored repeating textures.

The warning is also displayed in GLES3 projects that are configured to allow falling back to GLES2.

This closes #48807.

Testing project: test_npot.zip

Questions

• Should there be a project setting to disable this warning? It's only displayed when initially importing a texture or reimporting it, so I don't think it's that intrusive.
• Should the warning be extended to non-repeating textures?
• Could the wording be improved?

[lawnjelly]

Could possibly mention HTML5 as well as GLES2. It isn't necessary for non-wrapping textures as the limitation doesn't apply there. I can't remember the exact details of why it doesn't detect npot support on HTML5, it seems to run the detection for the extension but maybe it doesn't report correctly on that platform.

[lawnjelly]

Not sure what the CI failure is about, but yes this should be a big improvement as we continue to get issues posted about npot textures.

I don't think this should be that intrusive if it only happens on import. I suspect most users once they have seen this warning a couple of times, they will get the idea, so we may not need a runtime warning (when you start a project in GLES2 with npot wrapping textures).

[akien-mga]

 editor/import/resource_importer_texture.cpp: In member function 'virtual Error ResourceImporterTexture::import(const String&, const String&, const Map<StringName, Variant>&, List<String>*, List<String>*, Variant*)':
editor/import/resource_importer_texture.cpp:399:41: error: comparison of integer expressions of different signedness: 'int' and 'unsigned int' [-Werror=sign-compare]
  399 |   if (!min_gles3 && (image->get_width() != closest_power_of_2(image->get_width()) || image->get_height() != closest_power_of_2(image->get_height()))) {
      |                      ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
editor/import/resource_importer_texture.cpp:399:106: error: comparison of integer expressions of different signedness: 'int' and 'unsigned int' [-Werror=sign-compare]
  399 |   if (!min_gles3 && (image->get_width() != closest_power_of_2(image->get_width()) || image->get_height() != closest_power_of_2(image->get_height()))) {
      |                                                                                      ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

But maybe you could use Image.is_size_po2() instead of reinventing the wheel :P

[Calinou]

I updated the PR to use Image.is_size_po2() and mention HTML5 in the warning message.

[akien-mga]

Thanks!

[akien-mga]

Cherry-picked for 3.3.2.