Week 4 - Finalizing glTF loader

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.

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

  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.

Week 4: Camera animation, interpolation in GLSL, and a single Timeline!   Week 6 - Supporting Rotation of the Shapes from the Center