<?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 "ladspa-util.h"
    ]]></code>
  </global>

  <plugin label="valve" id="1209" class="DistortionPlugin,SimulatorPlugin">
    <name>Valve saturation</name>
    <p>A model of valve (tube) distortion, lacking some of the harmonics you would get in a real tube amp, but sounds good nonetheless.</p>
    <p>Taken from Ragnar Bendiksen's thesis: \url{https://web.archive.org/web/20050212034404/http://www.notam02.no/~rbendiks/Diplom/Innhold.html}.</p>

    <callback event="activate"><![CDATA[
      itm1 = 0.0f;
      otm1 = 0.0f;
    ]]></callback>

    <callback event="run"><![CDATA[
unsigned long pos;
LADSPA_Data fx;

const float q = q_p - 0.999f;
const float dist = dist_p * 40.0f + 0.1f;

if (q == 0.0f) {
	for (pos = 0; pos < sample_count; pos++) {
		if (input[pos] == q) {
			fx = 1.0f / dist;
		} else {
			fx = input[pos] / (1.0f - f_exp(-dist * input[pos]));
		}
		otm1 = 0.999f * otm1 + fx - itm1;
		round_to_zero(&otm1);
		itm1 = fx;
		buffer_write(output[pos], otm1);
	}
} else {
	for (pos = 0; pos < sample_count; pos++) {
		if (input[pos] == q) {
			fx = 1.0f / dist + q / (1.0f - f_exp(dist * q));
		} else {
			fx = (input[pos] - q) /
			 (1.0f - f_exp(-dist * (input[pos] - q))) +
			 q / (1.0f - f_exp(dist * q));
		}
		otm1 = 0.999f * otm1 + fx - itm1;
		round_to_zero(&otm1);
		itm1 = fx;
		buffer_write(output[pos], otm1);
	}
}

plugin_data->itm1 = itm1;
plugin_data->otm1 = otm1;
    ]]></callback>

    <port label="q_p" dir="input" type="control" hint="default_0">
      <name>Distortion level</name>
      <p>How hard the signal is driven against the limit of the amplifier.</p>
      <range min="0" max="1"/>
    </port>

    <port label="dist_p" dir="input" type="control" hint="default_0">
      <name>Distortion character</name>
      <p>The hardness of the sound, low for soft, high for hard.</p>
      <range min="0" max="1"/>
    </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="itm1" type="LADSPA_Data"/>
    <instance-data label="otm1" type="LADSPA_Data"/>

  </plugin>
</ladspa>