World: r4wp

I'll just use write/append/binary with #{0A} as the terminator.

It's working now.  Thanks for all your detective work!  I don't know 
how you can find bugs so fast.

I didn't think it was very fast. :-) I had a hunch in the direction 
of corrupted printing all the time, but didn't think of CR

What I meant was "fast compared to me."

:-)

It still sucks to loose hours to this issue fourty years after it 
was perpetrated

I suppose it would be useful if I made read-file more like REBOL, 
like it already behaves on Windows. I'll look into that tomorrow

You're awesome!

Thanks

For anyone interested, I just published a JPG in the Files section 
under Misc called MotionDetect.jpg showing real-time motion detection 
performed by the Raspberry Pi running Red/System.  The top two frames 
are the actual camera video (shot at dusk) and the bottom frame highlights 
the areas of motion.  Thanks in huge part goes to Kaj for helping 
me finish this first project!

Cool to see it displayed like that

What do you mean by "displayed like that"?

By the way, the bottom image is completely built by Red/System.

Well, displayed at all. :-) So far I had only seen isolated code 
snippets

Have to protect my intellectual property. :-P

I really can't thank you enough, Kaj, for all your help!

Yes, but that's not what I mean. It's all very abstract and seems 
like any other code, but now it comes to life

I love the feeling that I get when I see my software working!  Especially 
something I've been struggling with for days/weeks/months.

My original prototype written in R2 was started 3-Aug-2012 and finished 
9-Sep-2012.  It's taken this long to get it running on the Pi natively.

Was that fast enough?

The development cycle?  Or the speed of the software?

R2

R2 couldn't do it nearly fast enough on the Pi.

However, it was fast enough on a powerful workstation.

R2 could even handle several cameras simultaneously on a powerful 
workstation (maybe 4 cameras at 1.3 megapixels @ 8fps).

Not bad, but not available on ARM

Right.

So can you do without the Broadcom specs now?

I've found a way around it for now, but I've had to make some concessions 
that I'm not very happy with.  My goal is to still get my hands on 
those Broadcom specs so I can get better performance and flexibility.

My motion detection executable on the Pi is 30KB.  The same executable 
compiled for Windows is 15KB (50% the size).

Yes, the ARM instruction set is optimised for speed at the expense 
of size

I've got plenty of room on the Pi, but not a lot of processing power.

So I'm thankful for that.

Another thing I've never tried in Red/System and can't seem to get 
to work:

	min-pixel-area-text: make-c-string 16

 min-pixel-area-text: read-file "config/motion-trigger-min-pixel-area.txt"
	print-line ["Minimum Pixel Area = " min-pixel-area-text]
	min-pixel-area: as-integer min-pixel-area-text
	print-line ["Minimum Pixel Area = " min-pixel-area]

Output:

	Minimum Pixel Area = 1
	Minimum Pixel Area = 3358672

@Bo 'read-file' will call 'fread' in libc, so it will return the 
total amount of bytes read.  I think 'Minimum Pixel Area = 3358672' 
is the number of bytes read from your file, but I have no idea why 
it print a '1'  in the first output.

Thanks for the suggestion.   I had the number "40" in the file before, 
and it printed "40", but gave me the same long number in the second 
'print-line.  So I don't think that is it.

I am with Arnold here, but I admit that it might be a psychological 
aspect, nothing more. Simply put - we have some low level stuff available, 
and I fear bulding higher (Rebol level) commands will be waste of 
time, as Doc will most probably rewrite it differently?

Let's take e.g. 'read function. Where will it be created? Red/System 
level? Red level? Both? E.g. Red/System does not allow refinements, 
so I expect some "natives" code will be done using R/S, and higher 
abstraction via routines in Red level?

Bo, congrats! Hope you'll demo it at the devcon.

btw - my brother ordered 3x Arduino kit for our friends, and for 
me he ordered BeagleBone Black. So I will see, if I can get Red programs 
running on it :-)

Red should run just fine on the BB Black.

My motion detection executable on the Pi is 30KB.  The same executable 
compiled for Windows is 15KB (50% the size).


Red currently emits only the standard ARM opcodes, so 32-bit per 
instruction. We'll add support in the future for Thumb mode (more 
compact instruction set). In the meantime, you can try to activate 
the literal pools by adding the following option to the Linux-ARM 
config block (in %config.r):

literal-pool?:	 yes


That should both reduce final binary size and give you a little speed 
improvement. But be sure to test is well as this mode has not been 
much used yet. Also, it might fail to compile if you use very big 
functions, or a lot of code in global context.

Bo, your make-c-string leaks memory. read-file will allocate memory 
of the size to fit the file contents

Xie, read-file is a Red/System function that does much more than 
fread. It returns the file content itself as a string, not the number 
of bytes read

fread is mapped directly to read-array

Bo, your file must contain "1". The second number is the address 
where it is read into memory

Remember that a c-string! is a pointer to a memory address. Much 
like a string! in REBOL is a reference to the storage of a series 
value that can be referenced by multiple string!s, each with their 
own index

If you want to convert the content of your text file to an integer, 
my C library binding provides to-integer, just like in REBOL

Petr, the Red/System READ functions and the higher Red abstractions 
on top of it are already here. As I said yesterday, Doc is free to 
use parts of it when he makes a more elaborate I/O framework in Red

You're not wasting any time on them, are you (except by talking about 
them)? I need them now, and so do others