DDS: Add support for loading layered textures

[BlueCube3310]

Adds support for loading layered DDS texture files.

Progress:

• 2D Arrays,
• Cubemaps,
• Cubemap arrays,
• 3D textures,
• Testing project.

MRP: ddslayered.zip

[fire]

There are some unused variables.

modules/dds/texture_loader_dds.cpp:648:14: error: unused variable 'dimension' [-Werror,-Wunused-variable]
                                uint32_t dimension = f->get_32();
                                         ^
modules/dds/texture_loader_dds.cpp:649:14: error: unused variable 'misc_flags_1' [-Werror,-Wunused-variable]
                                uint32_t misc_flags_1 = f->get_32();
                                         ^
modules/dds/texture_loader_dds.cpp:651:14: error: unused variable 'misc_flags_2' [-Werror,-Wunused-variable]
                                uint32_t misc_flags_2 = f->get_32();
                                         ^
Retrieved `modules/gdscript/gdscript_lambda_callable.android.editor.arm64.o' from cache
modules/dds/texture_loader_dds.cpp:579:11: error: unused variable 'caps_1' [-Werror,-Wunused-variable]
        uint32_t caps_1 = f->get_32();

[BlueCube3310]

There's an issue with the quick load menu where the dds files don't show up, since it narrows down the search range to a specific resource class (like Texture2D), and doesn't recognize them by their parent type (Texture in this case)

[Calinou]

Tested locally, it works as expected.

Testing project: test_dds_cubemap.zip

Before

Notice the resource type icon at the top. Here, it's loaded as a Texture2D. Only one face is imported.

Uncompressed	DXT5

After

The DDS file is now loaded as a Cubemap automatically. Memory usage is multiplied by 6 because it's now importing all faces, not just one.

Uncompressed	DXT5

PS: We should improve the Cubemap preview to allow choosing a face to view, or even have an interactive view like the material preview (except you'd be inside the box and the box would be unshaded, and with flipped faces).

[BlueCube3310]

PS: We should improve the Cubemap preview to allow choosing a face to view, or even have an interactive view like the material preview (except you'd be inside the box and the box would be unshaded, and with flipped faces).

This system is already in place, though it's not well-documented: left-click the cubemap preview and drag the cursor :)

[BlueCube3310]

I've added a testing project for every texture type. It seems to work correctly, though now thumbnails are not generated and the aforementioned issue with the quick search menu persists

[clayjohn]

Thank you!