Some features are not working with F3D web

[Meakk]

Here is the exhaustive list of rendering features not working with F3D web:

Point sprites

The gaussian mapper seems to be dysfunctional with WebGL. Nothing is displayed.
Here are the related options:

• model.point_sprites.enable
• model.point_sprites.type
• model.point_sprites.size

Temporal anti-aliasing

No antialiasing is applied.
I suspect the internal event loop is not running

Related option:

• render.effect.antialiasing.mode set to taa

Solid background color

Since the render result is blended into the HTML page, the pixels having an alpha value equal to zero are still transparent.
We should have an option to make the result opaque.

Related option:

• render.background.color

Blur background

The blur background pass seems to be dysfunctional.
When the option is enabled, the resulting background is completely black.
It's most likely a shader issue.

Related option:

• render.background.blur.enable

Loader progress bar

The internal loader progress bar is not showing up.

Related option:

• ui.loader_progress

Armature visibility

When the feature is enabled, the armature is not visible.

Related option:

• render.armature.enable

[Meakk]

Update the issue description with all the rendering features not working with webassembly.
Note that some features have not been tested because webassembly is not enabling the module: F3D_MODULE_RAYTRACING and F3D_MODULE_UI