Use delayorama style buffering

Signed-off-by: Damien Zammit <damien@zamaudio.com>

2 files changed, 90 insertions, 49 deletions

diff --git a/plugins/ZamDelay/ZamDelayPlugin.cpp b/plugins/ZamDelay/ZamDelayPlugin.cpp
index f8ad0e1..141dffd 100644
--- a/plugins/ZamDelay/ZamDelayPlugin.cpp
+++ b/plugins/ZamDelay/ZamDelayPlugin.cpp
@@ -231,9 +231,23 @@ void ZamDelayPlugin::activate()
 		z[i] = 0.f;
 	}
 	posz = 0;
+	tap[0] = 0;
+	tap[1] = 0;
+	active = 0;
+	next = 1;
 	age = 0;
 	clearfilter();
 	fbstate = 0.f;
+
+	lpfold = 0.f;
+	divisorold = 0.f;
+	gainold = 0.f;
+	invertold = 0.f;
+	delaytimeold = 0.f;
+	syncold = 0.f;
+	drywetold = 0.f;
+	delaytimeoutold = 0.f;
+	delaysamplesold = 1.f;
 }
 
 
@@ -282,59 +296,25 @@ float ZamDelayPlugin::runfilter(float in)
 	return out;
 }
 
-float ZamDelayPlugin::getsample(float dline[], int pos, int a, int max)
-{
-	if (a < max) {
-		return 0.;
-	}
-	int p = pos + 1;
-	if (p >= max) {
-		p = 0;
-	}
-
-	return dline[p];
-}
-
-void ZamDelayPlugin::pushsample(float in, float dline[], int *pos, int *a, int max)
-{
-	static int oldmax = 1;
-	int i;
-	if (max != oldmax) {
-		clearfilter();
-		for (i = 0; i < MAX(max, oldmax); i++) {
-			dline[i] = 0.;
-		}
-		*a = 0;
-		fbstate = 0.;
-		oldmax = max;
-	}
-	(*pos)++;
-	if (*pos >= max) {
-		*pos = 0;
-	}
-	(*a)++;
-	if (*a >= max) {
-		*a = max;
-	}
-	dline[*pos] = in;
-}
-
 void ZamDelayPlugin::run(const float** inputs, float** outputs, uint32_t frames)
 {
 	uint32_t i;
-	float in;
+	float in, out;
 	float srate = getSampleRate();
 	TimePosition t = getTimePosition();
 	float bpm = 120.f;
 	int delaysamples;
+	unsigned int tmp;
 	float inv;
-	float filtered;
+	float xfade;
+	int recalc;
 	if (invert < 0.5) {
 		inv = -1.f;
 	} else {
 		inv = 1.f;
 	}
-
+	
+	recalc = 0;
 	delaytimeout = delaytime;
 	if (t.bbt.valid) {
 		bpm = t.bbt.beatsPerMinute;
@@ -345,14 +325,72 @@ void ZamDelayPlugin::run(const float** inputs, float** outputs, uint32_t frames)
 	}
 	delaysamples = (int)(delaytimeout * srate) / 1000;
 	
-	lpfRbj(lpf, srate);
+	if (lpf != lpfold) {
+		lpfRbj(lpf, srate);
+		recalc = 1;
+	}
+	if (divisor != divisorold) {
+		recalc = 1;
+	}
+	if (gain != gainold) {
+		recalc = 1;
+	}
+	if (invert != invertold) {
+		recalc = 1;
+	}
+	if (delaytime != delaytimeold) {
+		recalc = 1;
+	}
+	if (sync != syncold) {
+		recalc = 1;
+	}
+	if (drywet != drywetold) {
+		recalc = 1;
+	}
+	if (delaytimeout != delaytimeoutold) {
+		recalc = 1;
+	}
 	
+	if (recalc) {
+		tap[next] = delaysamples;
+		clearfilter();
+	}
+
+	xfade = 0.f;
 	for (i = 0; i < frames; i++) {
-		in = (1. - feedb) * inputs[0][i] + feedb * fbstate;
-		filtered = runfilter(getsample(&z[0], posz, age, delaysamples));
-		fbstate = ((1. - drywet) * in) + drywet * -inv * filtered;
-		outputs[0][i] = fbstate * from_dB(gain);
-		pushsample(in, &z[0], &posz, &age, delaysamples);
+		in = inputs[0][i];
+		z[posz] = in + feedb * fbstate;
+		out = 0.f;
+		int p = posz - tap[active]; // active line
+		if (p<0) p += MAX_DELAY;
+		out += runfilter(z[p]);
+		
+		if (recalc) {
+			xfade += 1.0f / (float)frames;
+			out *= (1.-xfade);
+			int p = posz - tap[next]; // next line
+			if (p<0) p += MAX_DELAY;
+			out += runfilter(z[p]) * xfade;
+		}
+		fbstate = from_dB(gain) * (((1. - drywet) * in) + drywet * -inv * out);
+		outputs[0][i] = fbstate;
+		if (++posz >= MAX_DELAY) {
+			posz = 0;
+		}
+	}
+	lpfold = lpf;
+	divisorold = divisor;
+	gainold = gain;
+	invertold = invert;
+	delaytimeold = delaytime;
+	syncold = sync;
+	drywetold = drywet;
+	delaytimeoutold = delaytimeout;
+	delaysamplesold = delaysamples;
+	if (recalc) {
+		tmp = active;
+		active = next;
+		next = tmp;
 	}
 }
 
diff --git a/plugins/ZamDelay/ZamDelayPlugin.hpp b/plugins/ZamDelay/ZamDelayPlugin.hpp
index 06a95ba..b9b61af 100644
--- a/plugins/ZamDelay/ZamDelayPlugin.hpp
+++ b/plugins/ZamDelay/ZamDelayPlugin.hpp
@@ -112,8 +112,6 @@ protected:
 
     void activate() override;
     void run(const float** inputs, float** outputs, uint32_t frames) override;
-    void pushsample(float in, float dline[], int *pos, int *a, int max);
-    float getsample(float dline[], int pos, int age, int max);
     void clearfilter(void);
     void lpfRbj(float fc, float srate);
     float runfilter(float in);
@@ -122,8 +120,13 @@ protected:
 
 private:
     float invert, feedb, delaytime, sync, lpf, divisor, gain, drywet, delaytimeout;
+    float invertold, feedbold, delaytimeold, syncold, lpfold, divisorold, gainold, drywetold, delaytimeoutold, delaysamplesold;
     float z[MAX_DELAY];
-    int posz, age;
+    unsigned int posz;
+    unsigned int tap[2];
+    int active;
+    int next;
+    int age;
     float A0, A1, A2, A3, A4, A5, B0, B1, B2, B3, B4, B5;
     float state[4];
     float fbstate;