Should samples favour using immutable textures?

[tsherif]

The spec suggests (section 3.7.6) that they should be preferred over mutable textures. If it's considered best practice, perhaps the samples should use them exclusively?

[kenrussell]

That'd be great. The memory savings on some platforms can be significant.

[tsherif]

Shannon Woods also mentioned that she saw reduced CPU overhead in ANGLE: https://twitter.com/ShannonIn3D/status/544915451940442112

Update should be straightforward, since I don't think any of the samples are resizing textures. It might be nice to have at least one example of generating mipmaps for an immutable texture, since it's a little more involved (here's the code that handles it in PicoGL).

[tsherif]

Just made an equivalent update to my WebGL 2 Examples: tsherif/webgl2examples@667f69e