/[svn]/doc/docbase/instrument_scripts/nksp/01_nksp.html

Diff of /doc/docbase/instrument_scripts/nksp/01_nksp.html

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-revision 3608 by schoenebeck,
Wed Sep 18 13:24:28 2019 UTC
+revision 3887 by schoenebeck,
Sun May  9 18:00:00 2021 UTC
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        <img src="nksp_file.png" style="height:111px; margin-right:12px;">
        NKSP stands for "is <b>N</b>ot <b>KSP</b>", which denotes its distinction
        to an existing proprietary language called <i>KSP</i>.
-       NSKP is a script language specifically designed to write real-time capable
+       NKSP is a script language specifically designed to write real-time capable
        software extensions to LinuxSampler's sampler engines that can be bundled
        individually with sounds by sound designers themselves.
 Line 67 
 on ??event-name??
  end on
      </code>
      <p>
-       There are currently four events available:
+       There are currently six events available:
      </p>
        <table>
          <tr>
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            <td><code>on note</code></td> <td>This event handler is executed when a new note was triggered, i.e. when hitting a key on a MIDI keyboard.</td>
          </tr>
          <tr>
-           <td><code>on release</code></td> <td>This event handler is executed when a new note was released, i.e. when releasing a key on a MIDI keyboard.</td>
+           <td><code>on release</code></td> <td>This event handler is executed when a note was released, i.e. when releasing a key on a MIDI keyboard.</td>
          </tr>
          <tr>
            <td><code>on controller</code></td> <td>This event handler is executed when a MIDI control change event occurred. For instance when turning the modulation wheel at a MIDI keyboard.</td>
          </tr>
          <tr>
+           <td><code>on rpn</code></td> <td>This event handler is executed when a MIDI <i>RPN</i> event occurred.</td>
+         </tr>
+         <tr>
+           <td><code>on nrpn</code></td> <td>This event handler is executed when a MIDI <i>NRPN</i> event occurred.</td>
+         </tr>
+         <tr>
            <td><code>on init</code></td> <td>Executed only once, as very first event handler, right after the script had been loaded. This code block is usually used to initialize variables in your script with some initial, useful data.</td>
          </tr>
        </table>
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        Please note that you can hardly find MIDI keyboards which support release
        velocity. So with most keyboards this value will be 127.
      </p>
      <h3>Controller Events</h3>
      <p>
        Now let's extend the first script to not only show note-on and note-off
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+Line 186 
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      </p>
      <p>
        There is some special aspect you need to be aware about: in contrast to the MIDI standard,
-       monophonic aftertouch (a.k.a. channel pressure) and pitch beend wheel are
+       monophonic aftertouch (a.k.a. channel pressure) and pitch bend wheel are
        handled by NKSP as if they were regular MIDI controllers. So a value change
        of one of those two triggers a regular <code>controller</code> event handler
        to be executed. To obtain the current aftertouch value you can use
        <code>%CC[$VCC_MONO_AT]</code>, and to get the current pitch bend wheel
        value use <code>%CC[$VCC_PITCH_BEND]</code>.
      </p>
+     <h3 id="rpn_event">RPN / NRPN Events</h3>
+     <p>
+       There are also dedicated event handlers for
+       MIDI <i title="Registered Parameter Number">RPN</i> and
+       <i title="Non-Registered Parameter Number">NRPN</i>
+       events:
+     </p>
+     <code>
+ on rpn
+   message("RPN address msb=" & msb($RPN_ADDRESS) & ",lsb=" & lsb($RPN_ADDRESS) &
+           "-> value msb=" & msb($RPN_VALUE) & ",lsb="  & lsb($RPN_VALUE))
+   if ($RPN_ADDRESS = 2)
+     message("Standard Coarse Tuning RPN received")
+   end if
+ end on
+ on nrpn
+   message("NRPN address msb=" & msb($RPN_ADDRESS) & ",lsb=" & lsb($RPN_ADDRESS) &
+           "-> value msb=" & msb($RPN_VALUE) & ",lsb="  & lsb($RPN_VALUE))
+ end on
+     </code>
+     <p>
+       Since MIDI RPN and NRPN events are actually MIDI controller events,
+       you might as well handle these with the previous
+       <code>controller</code> event handler. But since RPN and NRPN messages
+       are not just one MIDI message, but rather always handled by a set of
+       individual MIDI messages, and since the
+       precise set and sequence of actual MIDI commands sent varies between
+       vendors and even among individual of their products, it highly makes sense to
+       use these two specialized event handlers for these instead, because the
+       sampler will already relief you from that burden to deal with all those
+       low-level MIDI event processing issues and all their wrinkles involved
+       when handling RPNs and NRPNs.
+     </p>
+     <note>
+       Even though there are two separate, dedicated event handlers for RPN and NRPN events,
+       they both share the same built-in variable names as you can see in the
+       example above.
+     </note>
+     <p>
+       So by reading <code>$RPN_ADDRESS</code> you get the RPN / NRPN parameter
+       number that had been changed, and <code>$RPN_VALUE</code> represents the
+       new value of that RPN / NRPN parameter. Note that these two built-in
+       variables are a 14-bit representation of the parameter number and new
+       value. So their possible value range is <code>0 .. 16383</code>. If you
+       rather want to use their (in MIDI world) more common separated two 7 bit
+       values instead, then you can easily do that by wrapping them into either
+       <code>msb()</code> or <code>lsb()</code> calls like also demonstrated above.
+     </p>
      <h3>Script Load Event</h3>
      <p>
-       As the last one of the four event types available with NKSP, the following
+       As the last one of the six event types available with NKSP, the following
        is an example of an <code>init</code> event handler.
      </p>
      <code>
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+Line 270 
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        had in mind when you wrote a certain script three years ago, and also if
        some other developer might need to continue working on your scripts one
        day, you should place as many comments into your scripts as possible. A
-       comment in NKSP is everything that is nested into a an opening and closing
+       comment in NKSP is everything that is nested into an opening and closing
        pair of curly braces.
      </p>
      <code>{ This is a comment. }</code>
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+Line 355 
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      <h3>Variable Types</h3>
      <p>
-       There are currently three different variable types, which you can easily
+       There are currently five different variable types, which you can easily
        recognize upon their first character.
      </p>
      <table>
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+Line 369 
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          <td><code>%??variable-name??</code></td> <td>Integer Array</td> <td>Stores a certain amount of integer number values.</td>
        </tr>
        <tr>
+         <td><code>~??variable-name??</code></td> <td>Real Number Scalar</td> <td>Stores one single real (floating point) number value.</td>
+       </tr>
+       <tr>
+         <td><code>???variable-name??</code></td> <td>Real Number Array</td> <td>Stores a certain amount of real (floating point) number values.</td>
+       </tr>
+       <tr>
          <td><code>@??variable-name??</code></td> <td>String</td> <td>Stores one text string.</td>
        </tr>
      </table>
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+Line 475 
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      </p>
      <p>
        Let's assume you wanted to write an instrument script that shall resemble
-       a simple delay effect. You could do that by writing an note event handler
+       a simple delay effect. You could do that by writing a note event handler
        that automatically triggers several new notes for each note being
        triggered on a MIDI keyboard. The following example demonstrates how that
        could be achieved.
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        happening when executing that script exactly: Each time you play a note
        on your keyboard, a new instance of the <code>note</code> event handler
        will be spawned and executed by the sampler. In all our examples so far
-       our scripts were so simple, that in practice only one handler instance
+       our scripts were so simple, that in practice only one event handler instance
        was executed at a time. This is different in this case though. Because
        by calling the <code>wait()</code> function, the respective handler
        execution instance is paused for a while and in total each handler
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        you play multiple, successive notes on your keyboard in short time, you
        will have several instances of the <code>note</code> event handler running
        simultaniously. And that's where the problem starts. Because by default,
-       as said, all variables are global variables. So the handler instances
+       as said, all variables are global variables. So the event handler instances
        which are now running in parallel, are all reading and modifying the same
-       data. Thus the individual handler instances will modify the
+       data. Thus the individual event handler instances will modify the
        <code>$i</code> and <code>$velocity</code> variables of each other, causing
        an undesired misbehavior.
      </p>
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      </p>
      <p>
        Please note that the <i>polyphonic</i> qualifier only exists for integer
-       variables. So you cannot declare polyphonic string variables, nor can you
+       variables and real number variables (scalars).
+       So you cannot declare polyphonic string variables, nor can you
        declare polyphonic array variables. Like in the previous explanation,
        this is due to the fact that it would consume a huge amount of memory
        for such variables. And with string variables and array variables, the
-       required amount of memory would be much higher than with simple integer
+       required amount of memory would be much higher than with simple integer or
-       variables.
+       real number variables.
      </p>
      <p>
        As summary, the following are guideline rules describing when you should
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        execution of the script instance by calling <code>exit()</code>. The latter
        is important in this example, because otherwise the script execution instances would
        continue to run in this endless loop forever, even after the respectives
-       notes are gone. Which would let your CPU usage to increase with every new note
+       notes are gone. Which would let your CPU usage increase with every new note
        and would never decrease again.
        This behavior of the sampler is not a bug, it is intended, since there may
        also be cases where you want to do certain things by script even after the
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+Line 1197 
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      <p>
        If you are already familiar with some programming languages, then you
        might already have seen such synchronized code block concepts
-       in languages like i.e. Java. This technique really provides an easy way
+       in languages like e.g. Java. This technique really provides an easy way
        to protect certain sections of your script against concurrency issues.
      </p>
      <note class="important">
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+Line 1300 
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      </code>
      <p>
        All these operations yield in a <i>boolean</i> result which could then
-       be used i.e. with <code>if</code> or <code>while</code> loop statements.
+       be used e.g. with <code>if</code> or <code>while</code> loop statements.
      </p>
      <h3>String Operators</h3>
-Line 1325 
 RESET_CONDITION(??condition-name??)
+Line 1388 
 RESET_CONDITION(??condition-name??)
        You should only reset a preprocessor condition that way if you did set it
        with <code>SET_CONDITION(??condition-name??)</code> before. Trying to
        reset a condition that has not been set before, or trying to reset a
-       condition that has already been reset, will both be ignored by the samlper,
+       condition that has already been reset, will both be ignored by the sampler,
        but again you will get a warning, and you should take care about it.
      </p>
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+Line 1565 
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        previous example just to disable messages. There is actually a built-in
        preprocessor condition dedicated to perform that task much more conveniently for you.
        To disable all messages in your script, simply add <code>SET_CONDITION(NKSP_NO_MESSAGE)</code>
-       i.e. at the very beginning of your script.
+       e.g. at the very beginning of your script.
-       So the previous example can be simplified like this:
+       So the previous example can be simplified to this:
      </p>
      <code>
  { Enable debug mode, so show all debug messages. }

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