Christian Mayer writes:
> Really? I can't think of a reason why modern OpenGL accellerators take
> longer to display transparnet textures than solid ones (except of a
> harmless hardware optimized blending function).

? Transparency require a frame buffer read, a multiply, and a frame
buffer write. Opacity requires a frame buffer write. I've only done
software renderers, but I know a little bit about some of the issues
involved and there's quite a bit of cache contention that happens when
you start doing read/modify/write cycles, beyond the fact that you
have to do the read in the first place.

We like to think that our modern video hardware is infinitely fast,
but it ain't.

I don't know whether FlightGear is doing any of this stuff but back on
the main processor transparency also means that there's a whole level
of occlusion culling that can't occur.

Dan



_______________________________________________
Flightgear-users mailing list
[email protected]
http://mail.flightgear.org/mailman/listinfo/flightgear-users
2f585eeea02e2c79d7b1d8c4963bae2d

Reply via email to