Odd behaviour with screen banks
Holger Palmroth (487) 115 posts |
While toying around with BASIC, I noticed that screen banks are not handled correctly:
BASIC isn’t to blame, if I use the ROOL interpreter on my RISC PC, the program works as intended. Martin Bazley’s game Magic Mushrooms illustrates this behavior, too. I use an BeagleBoard xM. This bug appears on the RISC OS builds of the 27th June 2011, the 28th February 2011 and some earlier build as well. |
Holger Palmroth (487) 115 posts |
To celebrate the 100th silent view of my post, I present two animations of the output of the above (slightly modified) program: This shows the correct output. Seriously, I wonder if the silence means that this bug doesn’t bother anyone or if my BeagleBoard is the only one experiencing it. EDIT: Here is the program for download |
Andrew Conroy (370) 725 posts |
I can confirm that I get very similar effects to you on my BB-xM too. |
Jeffrey Lee (213) 6048 posts |
Or possibly I forgot about this thread before finding the time to look into the bug :-) I’ve now checked in a fix for the bug (the OMAP video driver was doing the hardware accelerated copies/fills to the wrong screen bank), so assuming Steve hasn’t already started building the updated ROM that I asked him to build an hour or two ago, this fix should appear in an updated OMAP ROM download some time in the next day or two. And if he has already started the build then I guess I’ll have to hurry up and fix some more bugs just to justify me asking him to do two builds in one week ;-) Thanks for the animations & sample code, by the way – I was able to guess what the problem was even before I ran anything! |
Jeffrey Lee (213) 6048 posts |
Good news – the fix made it in to the ROM image that’s now available from the downloads page. |
Alan Peters (515) 51 posts |
Ah ha, this might explain a few odd things I was getting when running some tests on the BB XM using multiple display banks from BASIC. Excellent! |
Holger Palmroth (487) 115 posts |
Great, everything works as expected. Thanks, Jeffrey! |