From bd39bbb34cfd646bfa4651bf8a4e5daf4a108e5f Mon Sep 17 00:00:00 2001
From: Andrew Belt <andrewpbelt@gmail.com>
Date: Fri, 9 Feb 2018 05:50:43 -0500
Subject: [PATCH] Remove low and high thresholds from SchmittTrigger, use 0 and
 1 as fixed defaults

---
 include/dsp/digital.hpp | 36 ++++++++++++++++++++----------------
 1 file changed, 20 insertions(+), 16 deletions(-)

diff --git a/include/dsp/digital.hpp b/include/dsp/digital.hpp
index 6b937491..4a90a5a5 100644
--- a/include/dsp/digital.hpp
+++ b/include/dsp/digital.hpp
@@ -6,35 +6,39 @@
 namespace rack {
 
 
-/** Turns high when value reaches the high threshold, turns low when value reaches the low threshold */
+/** Turns high when value reaches 1, turns low when value reaches 0 */
 struct SchmittTrigger {
 	// UNKNOWN is used to represent a stable state when the previous state is not yet set
-	enum {UNKNOWN, LOW, HIGH} state = UNKNOWN;
-	float low = 0.0;
-	float high = 1.0;
-	void setThresholds(float low, float high) {
-		this->low = low;
-		this->high = high;
-	}
-	/** Returns true if triggered */
+	enum State {
+		UNKNOWN,
+		LOW,
+		HIGH
+	};
+	State state = UNKNOWN;
+	/** Updates the state of the Schmitt Trigger given a value.
+	Returns true if triggered, i.e. the value increases from 0 to 1.
+	If different trigger thresholds are needed, use
+		process(rescale(in, low, high, 0.f, 1.f))
+	for example.
+	*/
 	bool process(float in) {
 		switch (state) {
 			case LOW:
-				if (in >= high) {
+				if (in >= 1.f) {
 					state = HIGH;
 					return true;
 				}
 				break;
 			case HIGH:
-				if (in <= low) {
+				if (in <= 0.f) {
 					state = LOW;
 				}
 				break;
 			default:
-				if (in >= high) {
+				if (in >= 1.f) {
 					state = HIGH;
 				}
-				else if (in <= low) {
+				else if (in <= 0.f) {
 					state = LOW;
 				}
 				break;
@@ -52,8 +56,8 @@ struct SchmittTrigger {
 
 /** When triggered, holds a high value for a specified time before going low again */
 struct PulseGenerator {
-	float time = 0.0;
-	float pulseTime = 0.0;
+	float time = 0.f;
+	float pulseTime = 0.f;
 	bool process(float deltaTime) {
 		time += deltaTime;
 		return time < pulseTime;
@@ -61,7 +65,7 @@ struct PulseGenerator {
 	void trigger(float pulseTime) {
 		// Keep the previous pulseTime if the existing pulse would be held longer than the currently requested one.
 		if (time + pulseTime >= this->pulseTime) {
-			time = 0.0;
+			time = 0.f;
 			this->pulseTime = pulseTime;
 		}
 	}