Support for texStorage

[skbizport]

Can we please add support for texStorage2D & texStorage3D for more efficient uploading of data (not images).

WebGL 2.0 spec has a comment on this topic in section 3.7.6 Texture objects: "texStorage2D should be considered a preferred alternative to texImage2D. It may have lower memory costs than texImage2D in some implementations."

This is also mentioned in MDN.

https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/WebGL_best_practices.
https://www.khronos.org/registry/webgl/specs/latest/2.0/

Some discussion on this on stackoverflow
https://stackoverflow.com/questions/63353873/how-to-handle-3d-texture-on-webgl2

Describe the solution you'd like

Describe alternatives you've considered

Additional context

[mrdoob]

Interesting...

How do you propose the API for it to look like?

[skbizport]

One possibility is DataStorageTexture, DataStorageTexture3D, DataStorageTexture2DArray. Another could be to pass additional parameters to existing class. E.g.

DataTexture( data, width, height, format, type, mapping, wrapS, wrapT, magFilter, minFilter, anisotropy, encoding, storage (true|false)).

Thx

[Mugen87]

Would it be possible to use texStorage2D() automatically with a WebGL 2 rendering context? It's easy to check for a WebGL 2 rendering context in the renderer classes (via capabilities.isWebGL2).

[mrdoob]

@Mugen87 You mean when using DataTexture?

[Mugen87]

I thought the method could always be used when mipmaps are defined.

[mrdoob]

Right... After reading greggman's explanation, seems to me that we should use texStorage2D and texStorage3D when possible indeed.

[mrdoob]

@DavidPeicho @mbredif do you guys agree?

[DavidPeicho]

Using texStorage* API whenever WebGL2 is used is the way to go I believe 👌

[mrdoob]

Something to be aware of is that, Chrome currently doesn't have optimised support of texStorage* for video textures.

[Mugen87]

I've started to experiment with texStorage2D today and want to clarify one thing that confused be at the beginning:

texStorage2D is no 1:1 replacement for texImage2D. A call of texImage2D for uploading a single texture has to be replaced with a combination of texStorage2D and texSubImage2D. texStorage2D only allocates the memory whereas texSubImage2D actually defines the data. texImage2D does this all in one method call.

Besides, the approach looks different depending on the use case in WebGLTexture. A texture with manual mipmaps just needs a single call of texStorage2D but multiple ones with texSubImage2D. With texImage2D, one can treat all API calls uniformly. That makes the introduction of texStorage2D a bit trickier.