WebGLRenderer: LuminanceFormat does not seem to work

[gkjohnson]

Description

Using LuminanceFormat with a texture results in WebGL warning when trying to render whether it be with a Float or Uint8 data type. Swapping RedFormat in, however, works.

Is there a non standard way to LuminanceFormat? I don't see it used anywhere in examples or anything.

Reproduction steps

1. Create a data texture with LuminanceFormat and mark "needsUpdate" to true
2. Try to render with the texture
3. See that the texture is not rendered with the following warnings the console:

[.WebGL-0x10800a89600] GL_INVALID_ENUM: Invalid internal format 0x1909.Understand this warning
[.WebGL-0x10800a89600] GL_INVALID_OPERATION: Level of detail outside of range.

Code

const map = new THREE.DataTexture(
  new Uint8Array( [ 255 ] ), 1, 1,
  LuminanceFormat, UnsignedByteType,
);
map.needsUpdate = true;

Live example

https://jsfiddle.net/u3zjxk1p/3/

Screenshots

When rendering with LuminanceFormat - this should be white

When rendering with RedFormat

Version

r175

Device

Desktop

Browser

Chrome

OS

MacOS

[Mugen87]

Should be a duplicate of #23824.

Solution is indeed the usage of THREE.RedFormat: #23824 (comment)

We probably should remove LuminanceFormat and LuminanceAlphaFormat to avoid further confusion.

[gkjohnson]

That's disappointing - unfortunately shader modifications aren't an option and expanding to larger formats naturally results in ballooning memory usage. The more flexible node materials would be the better way to deal with this. But it looks like WebGPU doesn't support this kind of format, anyway, so it's probably a good change. Babylon has removed support for the format in WebGPU, as well.

We probably should remove LuminanceFormat and LuminanceAlphaFormat to avoid further confusion.

Done in #30934.