Week 4 - Finalizing glTF loader
===============================
.. post:: July 12 2022
   :author: Shivam Anand
   :tags: google
   :category: gsoc


What did you do this week?
--------------------------

This week I had to travel back to my college since the summer vacations have ended.
I had a coding session with Serge this week, we modified the exporter function and looked at some bugs I faced.

We managed to use the ``io.load_io`` function. There was a strange issue with loading png files. I had to convert the PIL ``Image`` to ``RGB`` format, and it fixed the issue, turns out png images are stored as ``P`` (pallet) mode.

I also added the ``glb`` format support to the importer. While loading a ``.glb`` model, I noticed that the image data is also stored in the buffer and there can be a ``bufferview`` index to get the buffer.

During this time, I also tested the glTF loader with all models in the ``KhronoosGroup/glTF-samples`` repository. Here's the table of models working well: `see file <https://github.com/xtanion/Blog-Items/blob/main/glTF-models-status.csv>`_.

+---------------------------------+---------+-------------------------------------------------------------------------------------+
| Model Name                      | Status  | Error Type                                                                          |
+=================================+=========+=====================================================================================+
| BoxInterleaved                  | No      | "BoxInterleaved.gltf: shapes (4,4) and (7,12) not aligned: 4 (dim 1) != 7 (dim 0)"  |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| Box                             | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| SpecularTest                    | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| AnimatedCube                    | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| NormalTangentMirrorTest         | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| AnimatedTriangle                | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| SpecGlossVsMetalRough           | No      | SpecGlossVsMetalRough.gltf: 'NoneType' object has no attribute 'baseColorTexture'   |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| CesiumMilkTruck                 | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| VC                              | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| WaterBottle                     | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| AnimatedMorphCube               | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| Sponza                          | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| SciFiHelmet                     | No      | SciFiHelmet.gltf: Python int too large to convert to C long                         |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| Triangle                        | No      | None: file not downloaded                                                           |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| IridescenceMetallicSpheres      | No      | None: file not downloaded                                                           |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| Corset                          | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| Cube                            | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| TextureLinearInterpolationTest  | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| SimpleMeshes                    | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| Lantern                         | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| TextureTransformMultiTest       | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| TextureSettingsTest             | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| LightsPunctualLamp              | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| DamagedHelmet                   | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| CesiumMan                       | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| Cameras                         | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| BarramundiFish                  | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| MetalRoughSpheresNoTextures     | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| EnvironmentTest                 | No      | None: file not downloaded                                                           |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| MosquitoInAmber                 | No      | MosquitoInAmber.gltf: buffer is smaller than requested size                         |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| BoxTexturedNonPowerOfTwo        | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| BrainStem                       | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| SimpleMorph                     | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| OrientationTest                 | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| BoxAnimated                     | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| StainedGlassLamp                | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| TextureTransformTest            | No      | None: file not downloaded                                                           |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| ClearCoatTest                   | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| IridescenceLamp                 | No      | None: file not downloaded                                                           |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| DragonAttenuation               | No      | DragonAttenuation.gltf: buffer is smaller than requested size                       |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| RecursiveSkeletons              | No      | RecursiveSkeletons.gltf: cannot reshape array of size 120 into shape (9)            |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| Suzanne                         | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| RiggedSimple                    | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| TextureEncodingTest             | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| 2CylinderEngine                 | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| NormalTangentTest               | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| MorphStressTest                 | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| IridescenceDielectricSpheres    | No      | None: file not downloaded                                                           |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| TextureCoordinateTest           | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| Duck                            | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| AlphaBlendModeTest              | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| TriangleWithoutIndices          | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| MultiUVTest                     | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| BoomBoxWithAxes                 | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| Box With Spaces                 | No      | Box%20With%20Spaces.gltf: 'NoneType' object has no attribute 'shape'                |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| SheenCloth                      | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| ToyCar                          | No      | None: file not downloaded                                                           |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| MaterialsVariantsShoe           | No      | MaterialsVariantsShoe.gltf: buffer is smaller than requested size                   |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| IridescentDishWithOlives        | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| VertexColorTest                 | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| SheenChair                      | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| Fox                             | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| AntiqueCamera                   | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| TransmissionTest                | No      | None: file not downloaded                                                           |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| TransmissionRoughnessTest       | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| BoxVertexColors                 | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| ReciprocatingSaw                | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| MorphPrimitivesTest             | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| MetalRoughSpheres               | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| GearboxAssy                     | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| TwoSidedPlane                   | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| Buggy                           | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| SimpleSparseAccessor            | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| BoxTextured                     | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| UnlitTest                       | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| SimpleSkin                      | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| FlightHelmet                    | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| Unicode❤♻Test                   | No      | Unicode%E2%9D%A4%E2%99%BBTest.gltf: 'NoneType' object has no attribute 'shape'      |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| Avocado                         | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| InterpolationTest               | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| GlamVelvetSofa                  | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| RiggedFigure                    | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| BoomBox                         | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| EmissiveStrengthTest            | No      | None: file not downloaded                                                           |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| AttenuationTest                 | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| AnimatedMorphSphere             | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+
| IridescenceSuzanne              | Yes     |                                                                                     |
+---------------------------------+---------+-------------------------------------------------------------------------------------+



What is coming up next week?
----------------------------

- Adding tests and merging export function PR.
- Start working on Simple Animations.


Did you get stuck anywhere?
---------------------------

- To create a texture, we needed the RGB values, However ``.png`` images were returning a 2D array when read using PIL. It is fixed by

   .. code-block :: python

         if pil_image.mode in ['P']:
            pil_image = pil_image.convert('RGB')


- pygltflib's ``load`` method does not handle glb files very well. It does not contain the buffer ``uri``. I used ``glb2gltf`` method as of now.