[Kstars-devel] XYZ Rotation matrix in 3.5.x

[James Bowlin]

On Thursday 15 June 2006 16:07, James Bowlin wrote:
> In the meantime, if we just skip rotating the labels for the equator and
> the horizon, we can probably save over 100 ms or so per draw cycle (on
> my 1.6 GHz laptop).

I commented out the psky.rotate() in the horizon code but drawing the horizon
still takes 36 ms on my system with AA turned off.  The funny thing is that
the time drops to 2 ms when showGround() is on.  If anything, I would have
expected the opposite behavior where it took longer to do the fill than to
do the outline.

What is even more strange is that sometimes the outlined horizon will draw
in 2 ms depending on the zoom factor.  I usually use the mouse wheel to
change the zoom in order to force a redraw.  But if I stick with one zoom
level and just hit "X", the timing seems pretty consistent, either 2 ms
or 36 ms depending on the zoom level.   The slow drawing seems to happen
when the horizon line on the bottom of the celestial sphere is partially
clipped by the bottom of the kstars window.

In summary:

  filled horizon:  always fast
outlined horizon:  sometimes slow depending on zoom level (clipping?). 


-- 
Peace, James