Wrong formula

[Leonid Petrunya]

The formula that is used to rotate the normals (inverse transpose matrix) is incorrect. An error occurs when scaling by a negative factor along one or three axes. Generally if the number of axes with a negative coefficient is odd. In this case, the vector rotates in the opposite direction from the desired. When deriving the formula, an error was made in logical reasoning.

If you don't believe me, you can check for yourself. I can be wrong too.

[Brandon Jones]

WebGL does not have any intrinsic support for normal rotations or inverse transpose matrices, those functions are all implemented by the developer, and thus will either come from a library you are using or code that you wrote, possibly from a tutorial. If there is an error in one of those sources you'll want to contact the library/tutorial/documentation authors about it. It's not something this group can help with, especially when you don't mention the source of the error.

[Leonid Petrunya]

I don't care at all. Just this error is present in threejs. This formula is used everywhere.

пт, 14 апр. 2023 г. в 19:23, 'Brandon Jones' via WebGL Dev List <webgl-d...@googlegroups.com>:

--
You received this message because you are subscribed to the Google Groups "WebGL Dev List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to webgl-dev-lis...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/webgl-dev-list/5fe207f6-05ae-46f9-8ba4-b961c81502e7n%40googlegroups.com.

[Richard Davey]

Report it to them then? This isn’t the place for it.

To view this discussion on the web visit https://groups.google.com/d/msgid/webgl-dev-list/CAOgjX-vpH9a8hhZ2Gr5PHqZ-6fxAHqBXAU7-tBOMd23yyMKXgw%40mail.gmail.com.

--

Photon Storm Ltd.

http://www.photonstorm.com

Twitter: @photonstorm

Registered in England and Wales.

Company ID: 8036404

VAT Number: 136 4333 27