Implement a mechanism for adding new extensions

[jjcasmar]

The exporter now looks for user defined extensions and call them when necesary. This way, its easy to implement new user defined extensions without the need to fork the exporter.

[CLAassistant]

All committers have signed the CLA.

[jjcasmar]

KHR_materials_unlit and KHR_lights_punctual have been implemented succesfuly using this mechanism

[jjcasmar]

@donmccurdy @julienduroure could you please have a look at this?

[julienduroure]

Activity is quite low during the summer, but I will definitively have a look on it when I can

[julienduroure]

Let's try to plan it for blender 2.82, it's too late for 2.81
Can you please update the PR against master?

[jjcasmar]

@julienduroure CI is failing in some tests that have nothing to do with my changes.

[julienduroure]

@jjcasmar CI is successful on current master, so your changes are probably the root cause of the failing.
Are you sure that your master merge was successful too?

Run 0:

AttributeError: 'PointLamp' object has no attribute 'use_custom_distance'

Maybe a merge issue ?

Run 1:

/extensions/KHR_lights_punctual/lights/2/spot/outerConeAngle - outerConeAngle (0.0872664600610733) is less than or equal to innerConeAngle (0.0872664600610733). (KHR_LIGHTS_PUNCTUAL_LIGHT_SPOT_ANGLES))

Maybe a merge issue, but is about extension data

Run 2 :

extensions["KHR_texture_transform"] = Extension("KHR_texture_transform", texture_transform)

TypeError: 'NoneType' object does not support item assignment

Definitively an issue in your code

Run 3:

extensions["KHR_texture_transform"] = Extension("KHR_texture_transform", texture_transform)
TypeError: 'NoneType' object does not support item assignment

Definitively an issue in your code

[emackey]

Moved to #732