Add SliderKnob as SVGSlider's superclass. Add logarithmic scaling too ParamQuantity

include/app/Knob.hpp

@@ -16,6 +16,7 @@ struct Knob : ParamWidget {
 	bool snap = false;
 	float snapValue = NAN;
 
+	void onHover(const event::Hover &e) override;
 	void onButton(const event::Button &e) override;
 	void onDragStart(const event::DragStart &e) override;
 	void onDragEnd(const event::DragEnd &e) override;

include/app/SVGSlider.hpp

@@ -1,6 +1,6 @@
 #pragma once
 #include "app/common.hpp"
-#include "app/Knob.hpp"
+#include "app/SliderKnob.hpp"
 #include "widgets/FramebufferWidget.hpp"
 #include "widgets/SVGWidget.hpp"
 
@@ -11,7 +11,7 @@ namespace rack {
 /** Behaves like a knob but linearly moves an SVGWidget between two points.
 Can be used for horizontal or vertical linear faders.
 */
-struct SVGSlider : Knob {
+struct SVGSlider : SliderKnob {
 	FramebufferWidget *fb;
 	SVGWidget *background;
 	SVGWidget *handle;

include/app/SliderKnob.hpp

@@ -0,0 +1,19 @@
+#pragma once
+#include "app/common.hpp"
+#include "app/Knob.hpp"
+
+
+namespace rack {
+
+
+struct SliderKnob : Knob {
+	void onHover(const event::Hover &e) override {
+		ParamWidget::onHover(e);
+	}
+	void onButton(const event::Button &e) override {
+		ParamWidget::onButton(e);
+	}
+};
+
+
+} // namespace rack

include/dsp/fft.hpp

@@ -19,7 +19,8 @@ void alignedDelete(T *p) {
 
 
 /** Real-valued FFT context
-Wraps PFFFT (https://bitbucket.org/jpommier/pffft/)
+Wrapper for PFFFT (https://bitbucket.org/jpommier/pffft/)
+`length` must be a multiple of 32.
 */
 struct RealFFT {
 	PFFFT_Setup *setup;
@@ -83,6 +84,9 @@ struct RealFFT {
 };
 
 
+/** Complex-valued FFT context
+`length` must be a multiple of 16.
+*/
 struct ComplexFFT {
 	PFFFT_Setup *setup;
 	int length;

include/ui/Slider.hpp

@@ -8,9 +8,6 @@
 namespace rack {
 
 
-static const float SLIDER_SENSITIVITY = 0.001f;
-
-
 struct Slider : OpaqueWidget {
 	BNDwidgetState state = BND_DEFAULT;
 	Quantity *quantity = NULL;

src/app/Knob.cpp

@@ -10,11 +10,18 @@ namespace rack {
 static const float KNOB_SENSITIVITY = 0.0015f;
 
 
+void Knob::onHover(const event::Hover &e) {
+	math::Vec c = box.size.div(2);
+	float dist = e.pos.minus(c).norm();
+	if (dist <= c.x) {
+		ParamWidget::onHover(e);
+	}
+}
+
 void Knob::onButton(const event::Button &e) {
-	float r = box.size.x / 2;
 	math::Vec c = box.size.div(2);
 	float dist = e.pos.minus(c).norm();
-	if (dist <= r) {
+	if (dist <= c.x) {
 		ParamWidget::onButton(e);
 	}
 }

src/app/ModuleWidget.cpp

@@ -286,7 +286,7 @@ void ModuleWidget::draw(NVGcontext *vg) {
 		nvgRect(vg,
 			0, box.size.y - 20,
 			65, 20);
-		nvgFillColor(vg, nvgRGBAf(0, 0, 0, 0.5));
+		nvgFillColor(vg, nvgRGBAf(0, 0, 0, 0.75));
 		nvgFill(vg);
 
 		std::string cpuText = string::f("%.2f μs", module->cpuTime * 1e6f);

src/app/ParamQuantity.cpp

@@ -58,34 +58,44 @@ float ParamQuantity::getDefaultValue() {
 float ParamQuantity::getDisplayValue() {
 	if (!module)
 		return Quantity::getDisplayValue();
-	if (getParam()->displayBase == 0.f) {
+	float displayBase = getParam()->displayBase;
+	if (displayBase == 0.f) {
 		// Linear
 		return getSmoothValue() * getParam()->displayMultiplier;
 	}
-	else if (getParam()->displayBase == 1.f) {
+	else if (displayBase == 1.f) {
 		// Fixed (special case of exponential)
 		return getParam()->displayMultiplier;
 	}
+	else if (displayBase < 0.f) {
+		// Logarithmic
+		return std::log(getSmoothValue()) / std::log(-displayBase) * getParam()->displayMultiplier;
+	}
 	else {
 		// Exponential
-		return std::pow(getParam()->displayBase, getSmoothValue()) * getParam()->displayMultiplier;
+		return std::pow(displayBase, getSmoothValue()) * getParam()->displayMultiplier;
 	}
 }
 
 void ParamQuantity::setDisplayValue(float displayValue) {
 	if (!module)
 		return;
-	if (getParam()->displayBase == 0.f) {
+	float displayBase = getParam()->displayBase;
+	if (displayBase == 0.f) {
 		// Linear
 		setValue(displayValue / getParam()->displayMultiplier);
 	}
-	else if (getParam()->displayBase == 1.f) {
+	else if (displayBase == 1.f) {
 		// Fixed
 		setValue(getParam()->displayMultiplier);
 	}
+	else if (displayBase < 0.f) {
+		// Logarithmic
+		setValue(std::pow(displayBase, displayValue / getParam()->displayMultiplier));
+	}
 	else {
 		// Exponential
-		setValue(std::log(displayValue / getParam()->displayMultiplier) / std::log(getParam()->displayBase));
+		setValue(std::log(displayValue / getParam()->displayMultiplier) / std::log(displayBase));
 	}
 }
 

src/dsp/minblep.cpp

@@ -0,0 +1,81 @@
+#include "dsp/minblep.hpp"
+#include "dsp/fft.hpp"
+
+
+namespace rack {
+namespace dsp {
+
+
+void minBlepImpulse(int z, int o, float *output) {
+	// Symmetric sinc array with `z` zero-crossings on each side
+	int n = 2 * z * o;
+	float *x = alignedNew<float>(n);
+	for (int i = 0; i < n; i++) {
+		float p = math::rescale((float) i, 0.f, (float) (n - 1), (float) -z, (float) z);
+		x[i] = sinc(p);
+	}
+
+	// Apply window
+	blackmanHarrisWindow(x, n);
+
+	// Real cepstrum
+	float *fx = alignedNew<float>(2*n);
+	RealFFT rfft(n);
+	rfft.rfft(x, fx);
+	// fx = log(abs(fx))
+	fx[0] = std::log(std::abs(fx[0]));
+	for (int i = 1; i < n; i++) {
+		fx[2*i] = std::log(std::hypot(fx[2*i], fx[2*i+1]));
+		fx[2*i+1] = 0.f;
+	}
+	fx[1] = std::log(std::abs(fx[1]));
+	// Clamp values in case we have -inf
+	for (int i = 0; i < 2*n; i++) {
+		fx[i] = std::max(-30.f, fx[i]);
+	}
+	rfft.irfft(fx, x);
+	rfft.scale(x);
+
+	// Minimum-phase reconstruction
+	for (int i = 1; i < n / 2; i++) {
+		x[i] *= 2.f;
+	}
+	for (int i = (n + 1) / 2; i < n; i++) {
+		x[i] = 0.f;
+	}
+	rfft.rfft(x, fx);
+	// fx = exp(fx)
+	fx[0] = std::exp(fx[0]);
+	for (int i = 1; i < n; i++) {
+		float re = std::exp(fx[2*i]);
+		float im = fx[2*i+1];
+		fx[2*i] = re * std::cos(im);
+		fx[2*i+1] = re * std::sin(im);
+	}
+	fx[1] = std::exp(fx[1]);
+	rfft.irfft(fx, x);
+	rfft.scale(x);
+
+	// Integrate
+	float total = 0.f;
+	for (int i = 0; i < n; i++) {
+		total += x[i];
+		x[i] = total;
+	}
+
+	// Normalize
+	float norm = 1.f / x[n - 1];
+	for (int i = 0; i < n; i++) {
+		x[i] *= norm;
+	}
+
+	std::memcpy(output, x, n * sizeof(float));
+
+	// Cleanup
+	alignedDelete(x);
+	alignedDelete(fx);
+}
+
+
+} // namespace dsp
+} // namespace rack

src/ui/Slider.cpp

@@ -4,6 +4,9 @@
 namespace rack {
 
 
+static const float SENSITIVITY = 0.001f;
+
+
 Slider::Slider() {
 	box.size.y = BND_WIDGET_HEIGHT;
 }
@@ -26,7 +29,7 @@ void Slider::onDragStart(const event::DragStart &e) {
 
 void Slider::onDragMove(const event::DragMove &e) {
 	if (quantity) {
-		quantity->moveScaledValue(SLIDER_SENSITIVITY * e.mouseDelta.x);
+		quantity->moveScaledValue(SENSITIVITY * e.mouseDelta.x);
 	}
 }