dj_flanger_1438.xml

<?xml version="1.0"?>
<!DOCTYPE ladspa SYSTEM "ladspa-swh.dtd">
<?xml-stylesheet href="ladspa.css" type="text/css"?>

<ladspa>
  <global>
    <meta name="maker" value="Steve Harris &lt;steve@plugin.org.uk&gt;"/>
    <meta name="copyright" value="GPL"/>
    <meta name="properties" value="HARD_RT_CAPABLE"/>
    <code><![CDATA[
      #include <sys/types.h>
      #include "ladspa-util.h"

      #define DELAY_TIME 0.005f
    ]]></code>
  </global>

  <plugin label="djFlanger" id="1438" class="FlangerPlugin">
    <name>DJ flanger</name>
    <p>This is a flanger which is more or less typical of DJ mixing desks. Requested by Patrick Shirkey.</p>

    <callback event="instantiate"><![CDATA[
      int buffer_size = 2048;

      fs = s_rate;
      while (buffer_size < fs * DELAY_TIME + 3.0f) {
	buffer_size *= 2;
      }
      buffer = calloc(buffer_size, sizeof(LADSPA_Data));
      buffer_mask = buffer_size - 1;
      buffer_pos = 0;
      x = 0.5f;
      y = 0.0f;
      last_sync = 0;
    ]]></callback>
      
    <callback event="activate"><![CDATA[
      memset(buffer, 0, (buffer_mask + 1) * sizeof(LADSPA_Data));
      last_sync = 0;
    ]]></callback>

    <callback event="run"><![CDATA[
      unsigned long pos;
      const float omega = 6.2831852f / (period * fs);
      const float dr = 0.001f * fs * depth;
      float fb;
      float d;
      float dout, out;
      unsigned int dof;

      if (feedback > 99.0f) {
	fb = 0.99f;
      } else if (feedback < -99.0f) {
	fb = -0.99f;
      } else {
	fb = feedback * 0.01f;
      }

      if (sync > 0) {
	if (!last_sync) {
          x = 0.5f;
          y = 0.0f;
        }
	plugin_data->last_sync = 1;
      } else {
	plugin_data->last_sync = 0;
      }

      for (pos = 0; pos < sample_count; pos++) {
	/* Write input into delay line */
	buffer[buffer_pos] = input[pos];

	/* Calcuate delay */
	d = (x + 0.5f) * dr;

	dof = f_round(d);
	//dout = buffer[(buffer_pos - f_round(d)) & buffer_mask];
	dout = cube_interp(d - floor(d),
			   buffer[(buffer_pos - dof - 3) & buffer_mask],
                           buffer[(buffer_pos - dof - 2) & buffer_mask],
                           buffer[(buffer_pos - dof - 1) & buffer_mask],
                           buffer[(buffer_pos - dof) & buffer_mask]);

	/* Write output */
	out = (buffer[buffer_pos] + dout) * 0.5f;
	buffer[buffer_pos] = input[pos] + out * fb;
	buffer_write(output[pos], out);

	/* Roll ringbuffer */
	buffer_pos = (buffer_pos + 1) & buffer_mask;

	/* Run LFO */
	x -= omega * y;
	y += omega * x;
      }

      plugin_data->x = x;
      plugin_data->y = y;
      plugin_data->buffer_pos = buffer_pos;
    ]]></callback>

    <callback event="cleanup"><![CDATA[
      free(plugin_data->buffer);
    ]]></callback>

    <port label="sync" dir="input" type="control" hint="default_0,toggled">
      <name>LFO sync</name>
      <p>When turned from off to on it resets the phase of the LFO back to the start of the cycle. Used to sync the LFO to the track.</p>
    </port>

    <port label="period" dir="input" type="control" hint="default_1">
      <name>LFO period (s)</name>
      <p>The cycle period of the LFO in seconds.</p>
      <range min="0.1" max="32.0"/>
    </port>

    <port label="depth" dir="input" type="control" hint="default_high">
      <name>LFO depth (ms)</name>
      <p>The maximum delay the LFO will use to flange, in milliseconds.</p>
      <range min="1" max="5"/>
    </port>

    <port label="feedback" dir="input" type="control" hint="default_0">
      <name>Feedback (%)</name>
      <p>The amount of the delays output that is mixed back into the delay.</p>
      <range min="-100" max="100"/>
    </port>

    <port label="input" dir="input" type="audio">
      <name>Input</name>
    </port>

    <port label="output" dir="output" type="audio">
      <name>Output</name>
    </port>

    <instance-data label="buffer" type="LADSPA_Data *" />
    <instance-data label="buffer_pos" type="unsigned int" />
    <instance-data label="buffer_mask" type="unsigned int" />
    <instance-data label="fs" type="float" />
    <instance-data label="x" type="float" />
    <instance-data label="y" type="float" />
    <instance-data label="last_sync" type="unsigned int" />
  </plugin>
</ladspa>