Subject:
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Extending the firmware through DrawGraphic()
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Newsgroups:
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lugnet.robotics.nxt
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Date:
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Wed, 21 Feb 2007 13:17:39 GMT
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Viewed:
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13608 times
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Having made an earlier suggestion about using file names to extend the
capabilities, I've looked into it a little further and found something very
useful.
The 'NXTDrawPicture', or 'DrawGraphic' command can take an arbitrary array of
variables. The explanation from LEGO hints at various versions of the RIC file
format that can hold extra capabilites. These variables would work with these
extra features. But at the moment they go unused.
I can think of one obvious usage - store multiple graphics in the RIC file, and
use extra parameters to tell it which one to display. The NXT firmware already
uses something like this internally - the font is a single rectangular bitmap,
but with a grid applied to it. The system is able to extract one part of the
grid given the X and Y position of the character it wants to display.
I don't have any details of the RIC file format itself (anyone?) but could this
scheme be cracked ahead of any upgrade from LEGO? Now we can see the data
structure for internal bitmaps, does that clarify anything in the RIC file
format?
Anyway, my main point is that this is also an avenue to pass an arbitrary list
of input parameters (that may also be used as outputs) into a function. You
could call the 'DrawGraphic' function with an unusable filename character (e.g.
'?') followed by a single word command, and your input and output parameters
would be handled through the 'variables' array.
Jason R
P.S. Talking of graphics, I can confirm that grey on the NXT screen is
possible... :-)
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Message has 2 Replies:
 | | Re: Extending the firmware through DrawGraphic()
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| (...) These variables do get used by the existing RIC format. I could tell you what they mean but then I'd have to kill you. :-) It definitely is not a good idea to try to use them for something completely different. It seems better to just add a (...) (18 years ago, 21-Feb-07, to lugnet.robotics.nxt)
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