Updated test code in init.srp, made changes to overdrive.srp and ugens.md

apps/test/dspmanifest.txt

@@ -28,7 +28,8 @@ spectralcentroid
 spectralrolloff
 o2audioio
 sttest
-# zitarev
+zitarev
 tableosc*
 blend*
 stdistr
+monodistortion

apps/test/init.srp

@@ -294,6 +294,9 @@ def arco_ready():
     Checkbox(win, "supersaw", 'S', 'D', WIDTH, 'S', 'supersawcheckbox')
     supersawcheckbox.add_target_method(nil, 'supersawtest')
 
+    Checkbox(win, "Overdrive Test", 'S', 'D', WIDTH, 'S', 'overdrivecheckbox')
+    overdrivecheckbox.add_target_method(nil, 'overdrivetest')
+
     ui_initialized = true
     default_window.fit_to_children()
 
@@ -1374,6 +1377,33 @@ def supersawtest(obj, event, x, y):
         return
         sss.mute()
 
+########## Overdrive Test ##############
+
+ovd = nil
+
+def overdrivetest(obj, event, x, y):
+    display "overdrivetest", x
+    if x:
+
+        var left_tone = sine(220, 0.3)  // 220 Hz (A3)
+        var right_tone = sine(275, 0.3) // 275 Hz (~C#4)
+
+        var env = pweb(0.2, 0.5, 1)
+        var left_env = mult(left_tone, env)
+        var right_env = mult(right_tone, env)
+
+        // Mix left and right signals into a single mono signal before distortion
+        var mono_input = add(left_env, right_env)
+
+        // Apply distortion
+        ovd = monodistortion(mono_input, 0.85, 0.85, 0.8) // snd, gain, tone, volume
+        ovd.play()
+    else:
+        // Fade out and stop processing
+        ovd.set('snd', zero_ugen)
+        sched_select(rtsched)
+        sched_cause(6, ovd, 'mute')
+        ovd = nil
 
 
 ########## Main Initialization ################

doc/ugens.md

@@ -1942,3 +1942,49 @@ zero()
 
 `/arco/zero/new id` - Create a signal consisting of all-zeros.
 
+### monodistortion 
+'''
+monodistortion(input, gain, tone, volume)
+'''
+The input signal can have multiple channels, which are first summed into 
+a mono signal and scaled by `gain`. After processing in mono, the signal 
+is fanned out and blended with the original input signal using `wetdry` 
+to control the balance from pure input (`wetdry` = 0) to pure effect 
+(`wetdry` = 1).
+
+The processing chain contains a first-order high-pass filter set at 720 Hz,
+which removes low-frequency components. The filtered signal is then passed
+through a cubic nonlinear distortion function, which shapes the
+signal by introducing harmonic content and saturation. After
+distortion, the signal is passed through a low-pass filter with a cutoff
+frequency determined by the `tone` parameter (in Hz), allowing for control
+over the brightness or warmth of the effect. Finally, the signal is
+multiplied by the `volume` parameter, controlling the output gain.
+
+After the signal is processed, the `wetdry` parameter is used to blend the
+distorted signal with the original input. When `wetdry` is set to 0, the
+output consists entirely of the original input signal. When set to 1, the
+output consists only of the distorted signal. Values in between allow for a
+balance between the dry and processed signals
+
+`/arco/monodistortion/new id chans gain tone volume` - Create a new 
+monodistortion unit generator with `gain`, `tone`, and `volume` control 
+inputs, along with an audio input and output.
+
+`/arco/monodistortion/repl_gain id gain_id` - Set gain to object with id 
+`gain_id`.
+
+`/arco/monodistortion/set_gain id chan gain` - Set gain of channel `chan` to
+float value `gain`.
+
+`/arco/monodistortion/repl_tone id tone_id` - Set tone to object with id 
+`tone_id`.
+
+`/arco/monodistortion/set_tone id chan tone` - Set tone of channel `chan` to 
+float value `tone`.
+
+`/arco/monodistortion/repl_volume id volume_id` - Set volume to object with 
+id `volume_id`.
+
+`/arco/monodistortion/set_volume id chan volume` - Set volume of channel 
+`chan` to float value `volume`.

serpent/srp/overdrive.srp

@@ -0,0 +1,19 @@
+# overdrive.srp -- overdrive unit generator
+#
+# Vivek Mohan
+# February 2025
+
+class Overdrive(Instrument):
+    def init(input, gain, tone, volume, wetdry):
+
+        mono_input = route(1)
+        for i = 0 to input.chans:
+            mono_input.ins(input, i, 0)
+
+        scale_factor = 1.0 / sqrt(input.chans)
+
+        processed = monodistortion(mono_input, gain, tone, volume * scale_factor)
+
+        final_output = add(mult(input, mult(scale_factor,subb(1, wetdry))), mult(processed, mult(scale_factor,wetdry)))
+
+        super.init("Overdrive", final_output)

ugens/monodistortion/monodistortion.cpp

@@ -0,0 +1,179 @@
+/* monodistortion -- unit generator for arco
+ *
+ * generated by f2a.py
+ */
+
+#include "arcougen.h"
+#include "monodistortion.h"
+
+const char *Monodistortion_name = "Monodistortion";
+
+/* O2SM INTERFACE: /arco/monodistortion/new int32 id, int32 chans, int32 snd, int32 gain, int32 tone, int32 volume;
+ */
+void arco_monodistortion_new(O2SM_HANDLER_ARGS)
+{
+    // begin unpack message (machine-generated):
+    int32_t id = argv[0]->i;
+    int32_t chans = argv[1]->i;
+    int32_t snd = argv[2]->i;
+    int32_t gain = argv[3]->i;
+    int32_t tone = argv[4]->i;
+    int32_t volume = argv[5]->i;
+    // end unpack message
+
+    ANY_UGEN_FROM_ID(snd_ugen, snd, "arco_monodistortion_new");
+    ANY_UGEN_FROM_ID(gain_ugen, gain, "arco_monodistortion_new");
+    ANY_UGEN_FROM_ID(tone_ugen, tone, "arco_monodistortion_new");
+    ANY_UGEN_FROM_ID(volume_ugen, volume, "arco_monodistortion_new");
+
+    new Monodistortion(id, chans, snd_ugen, gain_ugen, tone_ugen, volume_ugen);
+}
+
+
+/* O2SM INTERFACE: /arco/monodistortion/repl_snd int32 id, int32 snd_id;
+ */
+static void arco_monodistortion_repl_snd(O2SM_HANDLER_ARGS)
+{
+    // begin unpack message (machine-generated):
+    int32_t id = argv[0]->i;
+    int32_t snd_id = argv[1]->i;
+    // end unpack message
+
+    UGEN_FROM_ID(Monodistortion, monodistortion, id, "arco_monodistortion_repl_snd");
+    ANY_UGEN_FROM_ID(snd, snd_id, "arco_monodistortion_repl_snd");
+    monodistortion->repl_snd(snd);
+}
+
+
+/* O2SM INTERFACE: /arco/monodistortion/set_snd int32 id, int32 chan, float val;
+ */
+static void arco_monodistortion_set_snd (O2SM_HANDLER_ARGS)
+{
+    // begin unpack message (machine-generated):
+    int32_t id = argv[0]->i;
+    int32_t chan = argv[1]->i;
+    float val = argv[2]->f;
+    // end unpack message
+
+    UGEN_FROM_ID(Monodistortion, monodistortion, id, "arco_monodistortion_set_snd");
+    monodistortion->set_snd(chan, val);
+}
+
+
+/* O2SM INTERFACE: /arco/monodistortion/repl_gain int32 id, int32 gain_id;
+ */
+static void arco_monodistortion_repl_gain(O2SM_HANDLER_ARGS)
+{
+    // begin unpack message (machine-generated):
+    int32_t id = argv[0]->i;
+    int32_t gain_id = argv[1]->i;
+    // end unpack message
+
+    UGEN_FROM_ID(Monodistortion, monodistortion, id, "arco_monodistortion_repl_gain");
+    ANY_UGEN_FROM_ID(gain, gain_id, "arco_monodistortion_repl_gain");
+    monodistortion->repl_gain(gain);
+}
+
+
+/* O2SM INTERFACE: /arco/monodistortion/set_gain int32 id, int32 chan, float val;
+ */
+static void arco_monodistortion_set_gain (O2SM_HANDLER_ARGS)
+{
+    // begin unpack message (machine-generated):
+    int32_t id = argv[0]->i;
+    int32_t chan = argv[1]->i;
+    float val = argv[2]->f;
+    // end unpack message
+
+    UGEN_FROM_ID(Monodistortion, monodistortion, id, "arco_monodistortion_set_gain");
+    monodistortion->set_gain(chan, val);
+}
+
+
+/* O2SM INTERFACE: /arco/monodistortion/repl_tone int32 id, int32 tone_id;
+ */
+static void arco_monodistortion_repl_tone(O2SM_HANDLER_ARGS)
+{
+    // begin unpack message (machine-generated):
+    int32_t id = argv[0]->i;
+    int32_t tone_id = argv[1]->i;
+    // end unpack message
+
+    UGEN_FROM_ID(Monodistortion, monodistortion, id, "arco_monodistortion_repl_tone");
+    ANY_UGEN_FROM_ID(tone, tone_id, "arco_monodistortion_repl_tone");
+    monodistortion->repl_tone(tone);
+}
+
+
+/* O2SM INTERFACE: /arco/monodistortion/set_tone int32 id, int32 chan, float val;
+ */
+static void arco_monodistortion_set_tone (O2SM_HANDLER_ARGS)
+{
+    // begin unpack message (machine-generated):
+    int32_t id = argv[0]->i;
+    int32_t chan = argv[1]->i;
+    float val = argv[2]->f;
+    // end unpack message
+
+    UGEN_FROM_ID(Monodistortion, monodistortion, id, "arco_monodistortion_set_tone");
+    monodistortion->set_tone(chan, val);
+}
+
+
+/* O2SM INTERFACE: /arco/monodistortion/repl_volume int32 id, int32 volume_id;
+ */
+static void arco_monodistortion_repl_volume(O2SM_HANDLER_ARGS)
+{
+    // begin unpack message (machine-generated):
+    int32_t id = argv[0]->i;
+    int32_t volume_id = argv[1]->i;
+    // end unpack message
+
+    UGEN_FROM_ID(Monodistortion, monodistortion, id, "arco_monodistortion_repl_volume");
+    ANY_UGEN_FROM_ID(volume, volume_id, "arco_monodistortion_repl_volume");
+    monodistortion->repl_volume(volume);
+}
+
+
+/* O2SM INTERFACE: /arco/monodistortion/set_volume int32 id, int32 chan, float val;
+ */
+static void arco_monodistortion_set_volume (O2SM_HANDLER_ARGS)
+{
+    // begin unpack message (machine-generated):
+    int32_t id = argv[0]->i;
+    int32_t chan = argv[1]->i;
+    float val = argv[2]->f;
+    // end unpack message
+
+    UGEN_FROM_ID(Monodistortion, monodistortion, id, "arco_monodistortion_set_volume");
+    monodistortion->set_volume(chan, val);
+}
+
+
+static void monodistortion_init()
+{
+    // O2SM INTERFACE INITIALIZATION: (machine generated)
+    o2sm_method_new("/arco/monodistortion/new", "iiiiii",
+                    arco_monodistortion_new, NULL, true, true);
+    o2sm_method_new("/arco/monodistortion/repl_snd", "ii",
+                    arco_monodistortion_repl_snd, NULL, true, true);
+    o2sm_method_new("/arco/monodistortion/set_snd", "iif",
+                    arco_monodistortion_set_snd, NULL, true, true);
+    o2sm_method_new("/arco/monodistortion/repl_gain", "ii",
+                    arco_monodistortion_repl_gain, NULL, true, true);
+    o2sm_method_new("/arco/monodistortion/set_gain", "iif",
+                    arco_monodistortion_set_gain, NULL, true, true);
+    o2sm_method_new("/arco/monodistortion/repl_tone", "ii",
+                    arco_monodistortion_repl_tone, NULL, true, true);
+    o2sm_method_new("/arco/monodistortion/set_tone", "iif",
+                    arco_monodistortion_set_tone, NULL, true, true);
+    o2sm_method_new("/arco/monodistortion/repl_volume", "ii",
+                    arco_monodistortion_repl_volume, NULL, true, true);
+    o2sm_method_new("/arco/monodistortion/set_volume", "iif",
+                    arco_monodistortion_set_volume, NULL, true, true);
+    // END INTERFACE INITIALIZATION
+
+    // class initialization code from faust:
+}
+
+Initializer monodistortion_init_obj(monodistortion_init);