Half-baked API (Camera position)
pavel.safrata at oracle.com
Wed Oct 16 01:04:27 PDT 2013
it looks like we can't help releasing a not-fully-baked piece of API
with FX8. We've added bunch of new APIs for 3D and did our best to make
them work well. Unfortunately, there's been not enough time&priority to
fine-tune their behavior in 2D world. Right now I'm concerned about
camera position in scene. It is inherent in the 3D perspective camera
that it has its specific position in world, but the 2D parallel camera
as we have it projects everything to the XY plane basically by ignoring
the Z coordinate, so the camera position doesn't matter all that much.
However, some of the newly added APIs depend on it:
1. Near/far clip on camera. This obviously cannot work without knowing
where the camera is. Right now the parallel camera does no clipping
though, so I guess we are OK to go with it as a "known limitation".
2. PickResult on events which reports "intersectedDistance" between the
camera and the picked point. This is worse because we can't just "not
support" it - there will be some value and once somebody uses it we'll
have a backward compatibility issue. The state right now is that the
camera is (tentatively, by my arbitrary decision) at [0, 0, -1] and
reports distances from there (note that as the camera renders
everything, for nodes "in front of Z=-1" it reports negative distances).
This may change when the camera position is properly discussed and
Note that this post is *not* meant to discuss the camera position. Even
if we could find the answer quickly (which I doubt), it's most probably
too late to apply the change for FX8.
So finally here is my question: do you think it's OK to solve this by
keeping the current behavior and documenting the "intersectedDistance"
in a way that for parallel camera the numbers are unspecified and
subject to change in future versions? Or would you prefer something more
drastic like throwing an UnsupportedOperationException (losing the
possibility to compare the distances)?
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