These properties look like they were intended to be internal but they were missing the `PROPERTY_USAGE_INTERNAL` flag.
- `PackedScene::_bundled`
- `PortableCompressedTexture2D::_data`
- `ImporterMesh::_data`
When importing images, we store a compressed version of the image to a .ctex file with ResourceImporterTexture::save_to_ctex_format. When importing many large images at once, this can use a large amount of memory, especially when the .ctex file uses WebP format.
This change is for ResourceImporterTexture::save_to_ctex_format to use the original Image object instead of p_image->get_image_from_mipmap(0), to avoid creating a copy of the full uncompressed image when looping through the base Image and mipmaps. This reduces the import memory usage for large images by around 10% when using WebP, and 35-40% when Project Settings/Rendering/Textures/Lossless Compression/Force PNG is enabled, may vary depending on the image and number of import threads running. Same change applied to PortableCompressedTexture2D::create_from_image, which has similar logic.
This helps with #92084, but does not fully resolve the issue on its own, as compressing with WebP on many threads can still use a large amount of memory - this just lowers that amount, and makes it more likely that enabling "Force PNG" will reduce memory usage enough to import the files.
Raul Santos
aaronp64
jsjtxietian
nklbdev
Bastiaan Olij
Hendrik Brucker