On 15 Feb '08, at 1:52 AM, Geert B. Clemmensen wrote:
The ViewFlip uses CATransform3DMakeRotation, but that isn't ideal as
described in the GeekGameBoard example.
From what I now know, I think it's OK to use that function, as long
as you only use it to generate the _intermediate_ transformations
during the rotation. The bugs it introduced into GeekGameBoard were
apparently due to roundoff errors: if you call it with a rotation of π
[180°] it doesn't give you an exact flip-about-y-axis matrix, but has
some tiny nonzero values left over in other cells. And that leads CA
to decide your layer/view still has a 3D transform, which affects the
way it does clipping, causing the glitches that I ran into in GGB.
So it should be OK to use CATransform3DMakeRotation to generate the
transformations during the flip, but at the end of the flip you should
construct your own matrix and use that.
