jit.iter for driving RGB Leds?

You might also want to try jit.spill . Printing to the Max window can definitely be expensive for a lot of matrix data with jit.iter. I would try it with the board. If the performance still suffers, there are other options. From looking at your patch, I don't think it will be a problem.

Thanks!
Actually I am just preparing software. I dont have all the hardware to test it...
I will check jit.spill
Would it be faster?
But anyway - I am still little confused about how many bits the numbers occupy directly on the output to the serial object?
There are char values from 0-255. so just 8bit...
But maybe they are converted into int by int object? (it is there just for flip Right to left order).
Then it will by 32bit for each value ( even if will use numbers just in the range 0-255)?

Is there byte type of numbers in Max? I ve never seen that.... Even the char is new for me ( I ve used just int and float till today...)

I've been doing this for years for various size installations. There is a limit to how fast you can iterate through a frame of video though. For larger works, I split it across multiple processors or computers. At the size you're working with, you should be fine. I use [zl split 1] to lose the alpha channel and [zl group xxx] to capture a singe frame. See attached for a simple example.

Thanks Scott,

it looks fast. I hope I understand you how to work with iter this way.
But when I am checking it the order of R G B is changing. the first pixel shoul be always the same.
It is RGB than GBR than BRG etc... I have to think about it.

so basicly the main performance problem was because of using soo many rows in max window.
each pixel had its own row in my patch.
when the stream is "zl grouped" together the performance is perfect.
I know all this is probably unimportant when it will work without max window - just with microprocessor...

After a while a I've returned to this project. Now I have three testing RGB leds connected with WS2801 and all this with Teensy SPI.
I decided to use LEDstream patch for the Teensy board for the fast data transfer from Max to WS2801.
https://github.com/adafruit/Adalight/blob/master/Arduino/LEDstream/LEDstream.pde
The hardware works well - the testing pattern is ok.

Now I am quite confused about the data format that I must create in Max and send it to Teensy.
Please is there anybody who knows how to format this serial comunication?

The info about the comunication between Teensy and host is this:

// A 'magic word' (along with LED count & checksum) precedes each block
// of LED data; this assists the microcontroller in syncing up with the
// host-side software and properly issuing the latch (host I/O is
// likely buffered, making usleep() unreliable for latch). You may see
// an initial glitchy frame or two until the two come into alignment.
// The magic word can be whatever sequence you like, but each character
// should be unique, and frequent pixel values like 0 and 255 are
// avoided -- fewer false positives. The host software will need to
// generate a compatible header: immediately following the magic word
// are three bytes: a 16-bit count of the number of LEDs (high byte
// first) followed by a simple checksum value (high byte XOR low byte
// XOR 0x55). LED data follows, 3 bytes per LED, in order R, G, B,
// where 0 = off and 255 = max brightness.

I have just the LED data and I exactly dont know how to make that magic word, led count, checksum
beforem them.

Thanks a lot!!!

ah, you're using ws2801s and you want to send data to a string, you say?

use this instead:
http://ladyada.net/make/adavision/

It's the big brother of the adalight setup - it listens to your screen, so you can just pop up a matrix and show the data you want to project.

thanks Wetterberg.
I ve checked it and actually the arduino/teensy sketch looks exactly the same in both cases.
( “LEDstream.pde” sketch )
And both adavision and adalight are connected with processing. And I am not familiar with processing yet... so I prefer Max - also because I plan to do some sound processing in led patch too.

So my problem how to feed the LEDstream.pde from Max is still actual....

Actually I think that basic thing is how to declare that magic word, led count, checksum an than LEDdata exactly how it is expected by LEDstream.pde patch.

I know it is written in description but I am not so skilled to understand and write the proper patch right now.
( exactly this is quite unclear for me:

The host software will need to
// generate a compatible header: immediately following the magic word
// are three bytes: a 16-bit count of the number of LEDs (high byte
// first) followed by a simple checksum value (high byte XOR low byte
// XOR 0x55). LED data follows
)

Thanks a lot for any advice!

Has anyone got a patch they'd like to share which feeds LEDstream.pde from Max?

Or do I have to engage my brain?