set.
The optimization is based on the observation that matrix matrix multiplication
with a dense matrix 4x4 is 4^3 Operations whereas multiplication with a
transform, or scale matrix is only 4^2 operations. Which is a gain of a
*FACTOR*4* for these special cases.
The change implements these special cases, provides a unit test for these
implementation and converts uses of the expensiver dense matrix matrix
routine with the specialized versions.
Depending on the transform nodes in the scenegraph this change gives a
noticable improovement.
For example the osgforest code using the MatrixTransform is about 20% slower
than the same codepath using the PositionAttitudeTransform instead of the
MatrixTransform with this patch applied.
If I remember right, the sse type optimizations did *not* provide a factor 4
improovement. Also these changes are totally independent of any cpu or
instruction set architecture. So I would prefer to have this current kind of
change instead of some hand coded and cpu dependent assembly stuff. If we
need that hand tuned stuff, these can go on top of this changes which must
provide than hand optimized additional variants for the specialized versions
to give a even better result in the end.
An other change included here is a change to rotation matrix from quaterion
code. There is a sqrt call which couold be optimized away. Since we divide in
effect by sqrt(length)*sqrt(length) which is just length ...
"
matrixd. It was returning the values of the diagonal
of the matrix, which only returns the scale if there
is not a rotation. I fixed this by returning the
length of the vectors that form the basis.
I also added a function to orthonormalize the
rotation component of the matrix. I seem to always run
into situations where non uniform (or even uniform)
scale complicate my calculations, and I thought other
members of the community could use this function as
well."
Made Matrix be a typedef to either Matrixf or Matrixd. Defaults to Matrixf.
Converted the osgGA::MatrixManipulators and osgProducer::Viewer/OsgCameraGroup
across to using exclusively Matrixd for internal computations and passing betwen
Manipulators, Producer and SceneView. Note, SceneView still uses Matrix internally
so will depend on what is set as the default in include/osg/Matrix.
Added the ability to osgProducer::setDone/getDone(), kept done() as the
method that the viewer main loop uses for detecting the exit condition.
