Matrix4: Add note about non-uniform scale to decompose(). #20752
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Thanks! |
| Decomposes this matrix into it's [page:Vector3 position], [page:Quaternion quaternion] and | ||
| [page:Vector3 scale] components. | ||
| Decomposes this matrix into it's [page:Vector3 position], [page:Quaternion quaternion] and [page:Vector3 scale] components. | ||
| The method can't be used to decompose an object's world matrix if its parent has a non-uniform scale. |
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That statement is incorrect. You can't make such general statements based on a specific example.
It is better to say nothing.
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What would be a better description? Or do you think that it's better to not say anything and let users figure it out on their own?
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You can't make such general statements
TBH, I do not have the impression that it's a general statement. It's a specific note intended for Object3D.matrixWorld.
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@Mugen87 As I said, the statement is not true.
A simple counterexample is a non-uniformly scaled parent matrix with a child having the Identity as its matrix. The child's world matrix is decomposable in that case. There are infinitely many other examples.
@mrdoob I would say nothing. If you insist on saying something, you could say "Note: not all matrices can be decomposed in this manner."
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A bit of a delay but we finally got to discuss the statement "off-line".
@WestLangley suggested this one which I find educative:
Note: Not all matrices are decomposable in this way. For example, if an object has a non-uniformly scaled parent, then the object's world matrix may not be decomposable, and this method may not be appropriate.
I'll update the file directly.
Related issue: Fixed #20435.
Description
The PR adds a note about non-uniform scale to
.decompose().