Models with textures are not stored correctly in cache

[el-dee]

This is a regression introduced by 27ef4ae

If I load a .gltf model with textures twice, the second time there are errors in the log about texture not found and the models is rendered without any textures.

This is the output witht the BoomBox model from gLTF:

Known pipe types:
  glxGraphicsPipe
(all display modules loaded.)
:gobj(error): Texture::read() - couldn't read: BoomBox_baseColor.png
:gobj(error): Unable to find texture "BoomBox_baseColor.png" on model-path /home/ld/Projects/gltf/gltf:/usr/share/panda3d:/usr/share/panda3d/models
:gobj(error): Texture::read() - couldn't read: BoomBox_occlusionRoughnessMetallic.png
:gobj(error): Unable to find texture "BoomBox_occlusionRoughnessMetallic.png" on model-path /home/ld/Projects/gltf/gltf:/usr/share/panda3d:/usr/share/panda3d/models
:gobj(error): Texture::read() - couldn't read: BoomBox_normal.png
:gobj(error): Unable to find texture "BoomBox_normal.png" on model-path /home/ld/Projects/gltf/gltf:/usr/share/panda3d:/usr/share/panda3d/models
:gobj(error): Texture::read() - couldn't read: BoomBox_emissive.png
:gobj(error): Unable to find texture "BoomBox_emissive.png" on model-path /home/ld/Projects/gltf/gltf:/usr/share/panda3d:/usr/share/panda3d/models

The viewer does not show the issue as the cache is disabled and the directory containing the .gltf file is prepended to the model path list (which is something an actual app should not do as models could have textures using the same filename but with different content)

The fix seems trivial: the following line

panda3d-gltf/gltf/converter.py

Line 521 in cd8387f

texture.filename = texture.fullpath = uri

should be replaced by:

texture.filename = uri

but I fear any side effects or consequences on e.g. gltf2bam

[Moguri]

I went ahead and applied the fix. Tests are passing, and I ran into no issues with one of my projects that uses blend2bam/panda3d-gltf. Unfortunately, I do not remember why I originally needed to set fullpath there.

We'll see if someone complains about the change and then I can write a test case to catch it.