On 10/10/05, Marcel Moreaux <[EMAIL PROTECTED]> wrote: > On Sat, Oct 08, 2005 at 09:54:17AM -0400, Timothy Miller wrote: > > > Also maybe it would be an idea, if we use non-uniform sized packets, > > > to have a specialized packet to upload mouse pointer pixmap/masks. > > > On the other hand these can be stored in the card memory > > > and used by switching the pointing registers. > > > > Changing the mouse pointer is VERY infrequent (relatively speaking). > > It's also something asynchronous to other drawing operations that you > > want to happen immediately. As such, I've decided it's going to be > > all PIO. > > How would that scenario handle cursor animation? Many "The system is > busy now" type cursors are animated. Say cursor animation requires 15 > different images per second. > > Can the card store those images in its RAM, and just cycle through them? > Or is it required to PIO cursor image data to the card 15 times per > second? In the last case, would that be a problem?
Let's work this out. A 60fps animation means we reload the cursor every 16 milliseconds. We could make it a full-color cursor with alpha blending. That would be 1024 32-bit words to write via PIO. If each word takes 4 PCI clocks (all to the same address, no burst), that's 4096 clocks, and at 33MHz, that's about 124 microseconds. If you were to reload the cursor every frame, you would incur less than a 0.8% CPU and PCI bus load. Are my calculations right? _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
