On Sun, Oct 27, 2013 at 3:18 PM, Michael Fisher <mfisher31@gmail.com> wrote:

On Sun, Oct 27, 2013 at 2:25 PM, Aurélien Leblond <blablack@gmail.com> wrote:
Hi everyone,

In my lv2 plugin, I need to communicate information from the DSP to
the UI, but I don't want to break the DSP/UI separation principle (no
Instance or Data access). On top of that, I'm using LVTK.

The type of data I'm trying to move is a Vector of Float (buffer type
Sound in the ttl) - but even basic information on how to transfer a
Float from the DSP to the UI would be valuable.

he, he, yeah it can get a little confusing... maybe this will help.
 
    // you're sending things in an atom sequence so get the size information
    // from the port buffer

    LV2_Atom_Sequence* aseq = (LV2_Atom_Sequence*) p (p_notify);
    m_forge->set_buffer ((uint8_t*) aseq, aseq->atom.size);

    m_forge->sequence_head (m_notify_frame, 0);

    // sequences need a timestamp for each event added
    m_forge->frame_time (0);



Sorry, I prematurely pressed 'send' on the last message.

continuing on...  after forging a frame_time, just write a normal float (no blank object needed)

m_forge->write_float (1604);

And that should be it.  From a technical standpoint, whenever writing to a sequence you MUST write the time stamp  (forge->frame_time (a_timestamp_value)) before adding the 'next' event.

Your ttl file has  atom:Float  as the buffer type.  I've never used anything besides atom:Sequence.  I imagine this buffer type doesn't need a sequence head forged first.  Maybe David will jump in on how atom:Float  bufferType'd  ports are supposed to forged into and out of.

I recommend, if you want to use LVTK to do atom forging, that you subclass  lvtk::AtomForge and add appropriate methods to it...   

Here's a snippet that shows how to write  patch get/set messages with a subclassed AtomForge.  It also shows how to write raw midi.

http://pastebin.com/C1LYtXpv  --  the code in there uses small uses the nullptr macro.  just change those to "0"  if you're not using c++11


... and that should be it Plugin-Side.

 

    




In my UI, I just want to see if I receive this data
In the port_event method, at the moment the only thing I'm doing is:
    std::cout << port << " - " << format << std::endl;



The port is defined in the TTL as follows:
    a lv2:OutputPort, atom:AtomPort ;
    atom:bufferType atom:Float ;
    atom:supports <http://lv2plug.in/ns/ext/patch#Message> ;
    lv2:index 1 ;
    lv2:symbol "notify" ;
    lv2:name "Notify" ;




What I have do so far in the DSP (run method)
    m_forge->set_buffer((uint8_t*)p(p_notify), sizeof(float));
//p_notify being the atom port
    m_forge->sequence_head(m_notify_frame, 0);

    ForgeFrame p_frame;
    Atom p_msg = m_forge->write_blank(p_frame, 1, urids.atom_Float);
    m_forge->property_head(urids.atom_value, 0);
    m_forge->write_float(1604); //test data i'm trying to move
    m_forge->pop(p_frame);



In my UI, I just want to see if I receive this data
In the port_event method, at the moment the only thing I'm doing is:
    std::cout << port << " - " << format << std::endl;



The port is defined in the TTL as follows:
    a lv2:OutputPort, atom:AtomPort ;
    atom:bufferType atom:Float ;
    atom:supports <http://lv2plug.in/ns/ext/patch#Message> ;
    lv2:index 1 ;
    lv2:symbol "notify" ;
    lv2:name "Notify" ;



At the moment, the code compiles and runs without crashing (yeah!),
but nothing happens (boo!).
Would you guys have any ideas?

Thanks in advance,
Aurélien