From c2ef13956710352267ae1583c11efbc745fecfd7 Mon Sep 17 00:00:00 2001
From: Grant Shangreaux <grant@unabridgedsoftware.com>
Date: Mon, 1 Nov 2021 19:45:51 -0500
Subject: Add: triangle and sawtooth waveforms

---
 klangfarb/main.gd      | 16 ++++++++++------
 klangfarbrs/src/lib.rs | 30 ++++++++++++++++++++++++++----
 2 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/klangfarb/main.gd b/klangfarb/main.gd
index 6552490..9735c5f 100644
--- a/klangfarb/main.gd
+++ b/klangfarb/main.gd
@@ -3,7 +3,7 @@ extends AudioStreamPlayer
 # controllable frequency interface
 export(float, 20, 8000, 5) var freq = 440.0
 # control wave form
-export(String, "sine", "square") var waveform = "sine"
+export(String, "sine", "square", "triangle", "sawtooth") var waveform = "sine"
 
 # load the GDNative script connected to the rust lib
 var Osc = preload("res://Osc.gdns")
@@ -26,12 +26,17 @@ func _fill_buffer() -> void:
 func _check_waveform():
 	if waveform == "square":
 		wave.square()
-	else:
+	elif waveform == "sine":
 		wave.sine()
+	elif waveform == "triangle":
+		wave.triangle()
+	elif waveform == "sawtooth":
+		wave.sawtooth()
 
 func _process(_delta):
-	_check_waveform()
-	_fill_buffer()
+	if self.is_playing():
+		_check_waveform()
+		_fill_buffer()
 
 func _ready() -> void:
 	# buffer length of 100ms gives us ~realtime response to input changes
@@ -41,6 +46,5 @@ func _ready() -> void:
 	# get our AudioStreamPlayback object
 	playback = self.get_stream_playback()
 	# prefill the stream's sample buffer (which feeds DAC)
+	_check_waveform()
 	_fill_buffer()
-	# start the audio
-	self.play()
diff --git a/klangfarbrs/src/lib.rs b/klangfarbrs/src/lib.rs
index 7954eb2..059d59f 100644
--- a/klangfarbrs/src/lib.rs
+++ b/klangfarbrs/src/lib.rs
@@ -26,23 +26,35 @@ pub struct Osc {
 pub enum Waveform {
     Sine,
     Square,
-    // Triangle,
-    // Saw,
+    Triangle,
+    Sawtooth,
     // Noise,
 }
 
 /// Generates the next sample for an oscillator based on its waveform.
 fn generate_sample(osc: &Osc) -> f32 {
+    let phase = osc.phase;
+
     match osc.waveform {
         Waveform::Sine => {
-            (TAU * osc.phase).sin()
+            (TAU * phase).sin()
         },
         Waveform::Square => {
-            if osc.phase < 0.5 {
+            if phase < 0.5 {
                 -1.0
             } else {
                 1.0
             }
+        },
+        Waveform::Triangle => {
+            if phase < 0.5 {
+                4.0 * phase - 1.0
+            } else {
+                4.0 * (1.0 - phase) - 1.0
+            }
+        },
+        Waveform::Sawtooth => {
+            2.0 * phase - 1.0
         }
     }
 }
@@ -95,6 +107,16 @@ impl Osc {
         self.waveform = Waveform::Square
     }
 
+    #[export]
+    fn triangle(&mut self, _owner: &Node) {
+        self.waveform = Waveform::Triangle
+    }
+
+    #[export]
+    fn sawtooth(&mut self, _owner: &Node) {
+        self.waveform = Waveform::Sawtooth
+    }
+
     #[export]
     pub fn set_sample_rate(&mut self, _owner: &Node, sample_rate: f32) {
         self.sample_rate = sample_rate;
-- 
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