Removed Geometry generators

[mrdoob]

Trying to remove THREE.Geometry.

[Mugen87]

Assuming Geometry is later moved to the examples and renamed to LegacyGeometry. And BufferGeometry is renamed to Geometry. Can we then rename the generators back to e.g. BoxGeometry?

By adding an alias for each geometry generator, names like BoxBufferGeometry should still work.

[mrdoob]

I'll give that a try tomorrow 👍

[Mugen87]

BTW: webgl_buffergeometry_constructed_from_geometry is failing in the E2E test since it's the last example that uses ExtrudeGeometry.

TBH, it makes no sense to convert it to BufferGeometry since its purpose is to show the construction of a BufferGeometry from Geometry. I think we can delete it 👍 .

[Mugen87]

Since #21021 is now in dev, I hope rebasing should fix unit and E2E tests.

[mrdoob]

Assuming Geometry is later moved to the examples and renamed to LegacyGeometry. And BufferGeometry is renamed to Geometry. Can we then rename the generators back to e.g. BoxGeometry?

Thinking more about this... I'm not sure we can do that.

If we rename BufferGeometry to Geometry then we'll also have to change all the .isBufferGeometry checks everywhere.

[Mugen87]

Couldn't we just add the isBufferGeometry property to Geometry (for backwards compatibility)?

[mrdoob]

I think that complicates things more...

I would rather keep BufferGeometry as the base and introduce something like MeshGeometry, LineGeometry, PointsGeometry and make them extend BufferGeometry.

That way we'll end up with BoxMeshGeometry, CircleMeshGeometry, etc

I'd also allow us to check geometry.isMeshGeometry in Line and warn the user that things are not likely to look right.

[Mugen87]

Okay, that's fine with me. I remember we discussed the introduction of specific geometry classes earlier.

[mrdoob]

Yeah... I'm still unsure about the approach, but feels way less scary than renaming BufferGeometry to Geometry 😅

[Mugen87]

I'm just a bit sad that the name Geometry is now somewhat reserved and not usable for the actual primal geometry class (which is BufferGeometry).

[mrdoob]

Yeah, I understand... 🤗

[Mugen87]

Maybe we can reconsider a rename later. When LegacyGeometry was part of the examples for a year or so.

[Mugen87]

Possible next steps:

• Move the class DirectGeometry into Geometry.js.
• Remove the following methods in BufferGeometry: fromGeometry(), fromDirectGeometry(), setFromObject() and updateFromObject(). Enhance THREE.Legacy.js and log console errors for the above methods.
• Introduce Geometry.toBufferGeometry().
• Stop rendering Geometry. This requires a small change in WebGLGeometries and WebGLObjects.
• Move Geometry.js to examples/js(m)/geometries.
• Remove all isGeometry checks in the code base. Instead, check for geometry.isBufferGeometry !== true.

[mrdoob]

I'll merge this for now and open another PR with these steps.

[mrdoob]

Follow-up: #21031