Add box shadow behind modules, tweak light fall times

include/app.hpp

@@ -89,6 +89,7 @@ struct ModuleWidget : OpaqueWidget {
 	virtual Menu *createContextMenu();
 
 	void draw(NVGcontext *vg) override;
+	void drawShadow(NVGcontext *vg);
 
 	Vec dragPos;
 	void onMouseDown(EventMouseDown &e) override;
@@ -213,6 +214,7 @@ struct ParamWidget : OpaqueWidget, QuantityWidget {
 
 	json_t *toJson();
 	void fromJson(json_t *rootJ);
+	virtual void reset();
 	virtual void randomize();
 	void onMouseDown(EventMouseDown &e) override;
 	void onChange(EventChange &e) override;

src/app/Knob.cpp

@@ -17,12 +17,12 @@ void Knob::onDragStart(EventDragStart &e) {
 }
 
 void Knob::onDragMove(EventDragMove &e) {
-	// Drag slower if Mod
 	float range = maxValue - minValue;
 	float delta = KNOB_SENSITIVITY * -e.mouseRel.y * speed;
 	if (std::isfinite(range))
 		delta *= range;
 
+	// Drag slower if Mod is held
 	if (guiIsModPressed())
 		delta /= 16.0;
 	dragValue += delta;

src/app/ModuleWidget.cpp

@@ -167,7 +167,7 @@ void ModuleWidget::_delete() {
 
 void ModuleWidget::reset() {
 	for (ParamWidget *param : params) {
-		param->setValue(param->defaultValue);
+		param->reset();
 	}
 	if (module) {
 		module->onReset();
@@ -189,6 +189,18 @@ void ModuleWidget::draw(NVGcontext *vg) {
 	nvgResetScissor(vg);
 }
 
+void ModuleWidget::drawShadow(NVGcontext *vg) {
+	nvgBeginPath(vg);
+	float r = 20; // Blur radius
+	float c = 20; // Corner radius
+	Vec b = Vec(-10, 30); // Offset from each corner
+	nvgRect(vg, b.x - r, b.y - r, box.size.x - 2*b.x + 2*r, box.size.y - 2*b.y + 2*r);
+	NVGcolor shadowColor = nvgRGBAf(0, 0, 0, 0.2);
+	NVGcolor transparentColor = nvgRGBAf(0, 0, 0, 0);
+	nvgFillPaint(vg, nvgBoxGradient(vg, b.x, b.y, box.size.x - 2*b.x, box.size.y - 2*b.y, c, r, shadowColor, transparentColor));
+	nvgFill(vg);
+}
+
 void ModuleWidget::onMouseDown(EventMouseDown &e) {
 	Widget::onMouseDown(e);
 	if (e.consumed)

src/app/ParamWidget.cpp

@@ -18,6 +18,10 @@ void ParamWidget::fromJson(json_t *rootJ) {
 		setValue(json_number_value(valueJ));
 }
 
+void ParamWidget::reset() {
+	setValue(defaultValue);
+}
+
 void ParamWidget::randomize() {
 	if (randomizable)
 		setValue(rescale(randomUniform(), 0.0, 1.0, minValue, maxValue));

src/app/RackWidget.cpp

@@ -12,6 +12,24 @@
 namespace rack {
 
 
+struct ModuleContainer : Widget {
+	void draw(NVGcontext *vg) override {
+		// Draw shadows behind each ModuleWidget first, so the shadow doesn't overlap the front.
+		for (Widget *child : children) {
+			if (!child->visible)
+				continue;
+			nvgSave(vg);
+			nvgTranslate(vg, child->box.pos.x, child->box.pos.y);
+			ModuleWidget *w = dynamic_cast<ModuleWidget*>(child);
+			w->drawShadow(vg);
+			nvgRestore(vg);
+		}
+
+		Widget::draw(vg);
+	}
+};
+
+
 RackWidget::RackWidget() {
 	rails = new FramebufferWidget();
 	rails->box.size = Vec();
@@ -23,7 +41,7 @@ RackWidget::RackWidget() {
 	}
 	addChild(rails);
 
-	moduleContainer = new Widget();
+	moduleContainer = new ModuleContainer();
 	addChild(moduleContainer);
 
 	wireContainer = new WireContainer();

src/engine.cpp

@@ -35,14 +35,14 @@ static float smoothValue;
 
 
 float Light::getBrightness() {
-	return sqrtf(fmaxf(0.0, value));
+	return sqrtf(fmaxf(0.f, value));
 }
 
 void Light::setBrightnessSmooth(float brightness) {
-	float v = (brightness > 0.0) ? brightness * brightness : 0.0;
+	float v = (brightness > 0.f) ? brightness * brightness : 0.f;
 	if (v < value) {
-		// Fade out light with lambda = 2 * framerate
-		value += (v - value) * sampleTime * (60.0 * 2.0);
+		// Fade out light with lambda = framerate
+		value += (v - value) * sampleTime * (60.f * 1.f);
 	}
 	else {
 		// Immediately illuminate light