1720176 - Matrix4x4Typed::Decompose() is not properly typed

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Botond Ballo [:botond]]

The signature of Matrix4x4Typed::Decompose() is as follows:

template <class SourceUnits, class TargetUnits, class T>
class Matrix4x4Typed {
  ...
  bool Decompose(Point3DTyped<UnknownUnits, T>& translation,
                 BaseQuaternion<T>& rotation,
                 Point3DTyped<UnknownUnits, T>& scale) const {
};

Note the use of UnknownUnits in the signature.

Moreover, even if you pass in inputs of the specified (unknown) types, a call to this function does not compile if the matrix itself is not unknown-typed, because of this call:

rotation.SetFromRotationMatrix(*this);

Here, BaseQuaternion::SetFromRotationMatrix() is not templated on any unit types and expects an unknown matrix as input.

So, the only way to call this function is to convert to an unknown matrix first:

matrix.ToUnknownMatrix().Decompose(...)

which is probably not what's intended.

Comment 1

[Botond Ballo [:botond]]

It's not immediately obvious how to convert the signature into a fully typed one:

• The translation applies after the other transforms, so that could be changed to Point3DTyped<TargetUnits>
• BaseQuaternion is not parameterized on types (which is fine, it can be left alone)
• For the scale, it's not clear how it could be typed. We usually use ScaleFactors2D<Source, Target> for typed scales, but we don't have a "3D" scale representation.

So, I think for now I'll just leave the signature alone, and tweak the implementation so that it compiles for non-Unknown matrix objects as well.

Comment 2

[Botond Ballo [:botond]]

Attachment: Bug 1720176 - Get To/FromUnknownMatrix() to respect the matrix's representation type. r=jrmuizel

Prior to this patch, ToUnknownMatrix() on a Matrix4x4Typed<A, B, double>
would return a Matrix4x4Typed<Unknown, Unknown, float>.

After this patch, it returns a Matrix4x4Typed<Unknown, Unknown, double>.

Comment 3

[Botond Ballo [:botond]]

Attachment: Bug 1720176 - Get Matrix4x4Typed::Decompose() to compile for non-Unknown matrix types. r=jrmuizel,hiro

Depends on D119696

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/f95bf7ce00ee
Get To/FromUnknownMatrix() to respect the matrix's representation type. r=jrmuizel
https://hg.mozilla.org/integration/autoland/rev/9079b87aeba1
Get Matrix4x4Typed::Decompose() to compile for non-Unknown matrix types. r=jrmuizel

Comment 5

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/mozilla-central/rev/f95bf7ce00ee
https://hg.mozilla.org/mozilla-central/rev/9079b87aeba1