Algo 4-6 Feedback support

README.md

@@ -37,8 +37,11 @@ new version here but you see it in the change log, it's because this version is
 Changelog
 ---------
 #### Version 0.7.0 (current sprint)
-* DX Engine customizable bitrate engine
-* DX Engine AM implementation
+* Preliminary Algo 4 & 6 feedback support
+* DX Engine 'Dirty DX' emulation
+* DX Engine LFO amplitude - still buggy
+* Fixed stucked notes when programs where changed
+* Fixed engine envelop wrong timing if it was not 44100Khz - still buggy
 
 #### Version 0.6.1
 * Mouse over + LFO type fix + pitch eg values
@@ -71,7 +74,7 @@ you get something "not quite there". Yamaha did a lot of hacks to be able to squ
 musical and expressive. It is those 'hacks' that we need to recreate to be able to find that original
 DX sound.
 
-Dexed comes with 3 engine resolution.
+Dexed comes with 3 engine resolutions :
 * Modern : this is the original 24-bit music-synthesizer-for-android implementation.
 * Mark I : this is a pale implementation of the limitation of a Yamaha DX7 Mark I with the 12-bit (with the 4-bit attenuator hack) DAC.
 * OPL Series : this is a experimental implementation of Yamaha 4-ops that used the YM2151 chip. These chips were supposed to be even more limited to the DX7 but gave a very interesting distinctive sound.
@@ -145,6 +148,5 @@ TODO - Dexed
 
 TODO - msfa
 -----------
-* The sample rate should not change the response of the envelopes
 * Portamento implementation
-* Algo 4 & 6 feedback
+* Feedback tuning

Source/PluginParam.cpp

@@ -456,11 +456,8 @@ void DexedAudioProcessor::setCurrentProgram(int index) {
         return;
     }
     
-    for (int i = 0; i < MAX_ACTIVE_NOTES; i++) {
-        if (voices[i].keydown == false && voices[i].live == true) {
-            voices[i].live = false;
-        }
-    }
+    panic();
+    
     index = index > 31 ? 31 : index;
     unpackProgram(index);
     lfo.reset(data + 137);
@@ -473,6 +470,8 @@ void DexedAudioProcessor::setCurrentProgram(int index) {
         return;
     }
     editor->global.setParamMessage("");
+    
+    panic();
 }
 
 const String DexedAudioProcessor::getProgramName(int index) {

Source/PluginProcessor.cpp

@@ -26,6 +26,7 @@
 #include "msfa/freqlut.h"
 #include "msfa/sin.h"
 #include "msfa/exp2.h"
+#include "msfa/env.h"
 #include "msfa/pitchenv.h"
 #include "msfa/aligned_buf.h"
 #include "msfa/fm_op_kernel.h"
@@ -87,6 +88,7 @@ void DexedAudioProcessor::prepareToPlay(double sampleRate, int samplesPerBlock)
     Freqlut::init(sampleRate);
     Lfo::init(sampleRate);
     PitchEnv::init(sampleRate);
+    Env::init_sr(sampleRate);
     fx.init(sampleRate);
     
     for (int note = 0; note < MAX_ACTIVE_NOTES; ++note) {
@@ -364,6 +366,7 @@ void DexedAudioProcessor::keyup(uint8_t pitch) {
 void DexedAudioProcessor::panic() {
     for(int i=0;i<MAX_ACTIVE_NOTES;i++) {
         voices[i].keydown = false;
+        voices[i].live = false;
     }
     keyboardState.reset();
 }
@@ -438,7 +441,7 @@ void DexedAudioProcessor::setEngineResolution(int rs) {
             controllers.dacBitFilter = 0xFFFFF000;  // semi 14 bit
             break;
         case DEXED_RESO_OPL:
-            controllers.sinBitFilter = 0xFFFF8000;  // 9 bit
+            controllers.sinBitFilter = 0xFFFF0000;  // 9 bit
             controllers.dacBitFilter = 0xFFFF0000;
             break;
     }

Source/msfa/dx7note.cc

@@ -25,14 +25,6 @@ using namespace std;
 #include "controllers.h"
 #include "dx7note.h"
 
-void dexed_trace(const char *source, const char *fmt, ...);
-
-#ifdef _MSC_VER
-#define TRACE(fmt, ...) dexed_trace(__FUNCTION__,fmt,##__VA_ARGS__)
-#else
-#define TRACE(fmt, ...) dexed_trace(__PRETTY_FUNCTION__,fmt,##__VA_ARGS__)
-#endif
-
 int32_t midinote_to_logfreq(int midinote) {
   const int base = 50857777;  // (1 << 24) * (log(440) / log(2) - 69/12)
   const int step = (1 << 24) / 12;
@@ -134,9 +126,8 @@ static const uint8_t pitchmodsenstab[] = {
   0, 10, 20, 33, 55, 92, 153, 255
 };
 
-// PG: we need to find the real values
 static const uint8_t ampmodsenstab[] = {
-    0, 33, 153, 255
+    0, 66, 109, 255
 };
 
 void Dx7Note::init(const char patch[156], int midinote, int velocity) {
@@ -178,8 +169,6 @@ void Dx7Note::init(const char patch[156], int midinote, int velocity) {
     params_[op].phase = 0;
     params_[op].gain[1] = 0;
     ampmodsens_[op] = ampmodsenstab[patch[off + 14] & 3];
-      
-      TRACE("operator set: %d %d", op, ampmodsens_[op]);
   }
   for (int i = 0; i < 4; i++) {
     rates[i] = patch[126 + i];
@@ -253,6 +242,7 @@ void Dx7Note::update(const char patch[156], int midinote) {
     int fine = patch[off + 19];
     int detune = patch[off + 20];
     basepitch_[op] = osc_freq(midinote, mode, coarse, fine, detune);
+    ampmodsens_[op] = ampmodsenstab[patch[off + 14] & 3];
   }
   algorithm_ = patch[134];
   int feedback = patch[135];

Source/msfa/env.cc

@@ -21,6 +21,12 @@
 
 using namespace std;
 
+uint32_t Env::sr_multiplier = (1<<24);
+
+void Env::init_sr(double sampleRate) {
+    sr_multiplier = (44100 / sampleRate) * (1<<23);
+}
+
 void Env::init(const int r[4], const int l[4], int32_t ol, int rate_scaling) {
   for (int i = 0; i < 4; i++) {
     rates_[i] = r[i];
@@ -98,6 +104,9 @@ void Env::advance(int newix) {
     qrate += rate_scaling_;
     qrate = min(qrate, 63);
     inc_ = (4 + (qrate & 3)) << (2 + LG_N + (qrate >> 2));
+
+    // meh, this should be fixed elsewhere
+    inc_ = ((int64_t)inc_ * (int64_t)sr_multiplier) >> 23;
   }
 }
 

Source/msfa/env.h

@@ -43,7 +43,14 @@ class Env {
   void setparam(int param, int value);
   static int scaleoutlevel(int outlevel);
   void getPosition(char *step);
+    
+  static void init_sr(double sample_rate);
+    
  private:
+  // This code is normalized to 44100, need to put a multiplier
+  // if we are not using 44100.
+  static uint32_t sr_multiplier;
+    
   int rates_[4];
   int levels_[4];
   int outlevel_;

Source/msfa/fm_core.cc

@@ -23,7 +23,7 @@
 #include "fm_core.h"
 
 
-using namespace std;
+//using namespace std;
 
 struct FmOperatorInfo {
   int in;
@@ -48,9 +48,9 @@ const FmAlgorithm algorithms[32] = {
   { { 0xc1, 0x11, 0x11, 0x14, 0x01, 0x14 } }, // 1
   { { 0x01, 0x11, 0x11, 0x14, 0xc1, 0x14 } }, // 2
   { { 0xc1, 0x11, 0x14, 0x01, 0x11, 0x14 } }, // 3
-  { { 0x41, 0x11, 0x94, 0x01, 0x11, 0x14 } }, // 4
+  { { 0xe1, 0x11, 0x94, 0x01, 0x11, 0x14 } }, // 4
   { { 0xc1, 0x14, 0x01, 0x14, 0x01, 0x14 } }, // 5
-  { { 0x41, 0x94, 0x01, 0x14, 0x01, 0x14 } }, // 6
+  { { 0xd1, 0x94, 0x01, 0x14, 0x01, 0x14 } }, // 6
   { { 0xc1, 0x11, 0x05, 0x14, 0x01, 0x14 } }, // 7
   { { 0x01, 0x11, 0xc5, 0x14, 0x01, 0x14 } }, // 8
   { { 0x01, 0x11, 0x05, 0x14, 0xc1, 0x14 } }, // 9
@@ -127,12 +127,31 @@ void FmCore::compute(int32_t *output, FmOpParams *params, int algorithm,
         add = false;
       }
       if (inbus == 0 || !has_contents[inbus]) {
-        // todo: more than one op in a feedback loop
+        // PG: this is my 'dirty' implementation of FB for 2 and 3 operators...
+        // still needs some tuning...
         if ((flags & 0xc0) == 0xc0 && feedback_shift < 16) {
-          // cout << op << " fb " << inbus << outbus << add << endl;
+          switch ( (flags >> 6) - 0xc ) {
+          // one operator feedback, normal process
+          case 0 :
+            //cout << "\t" << op << " fb " << inbus << outbus << add << endl;
             FmOpKernel::compute_fb(outptr, param.phase, param.freq,
                 gain1, gain2,
                 fb_buf, feedback_shift, add, controllers);
+            break;
+            // two operator feedback, process exception for ALGO 6
+          case 1 :
+            FmOpKernel::compute_fb2(outptr, params, fb_buf, feedback_shift, controllers);
+            params[1].phase += params[1].freq << LG_N;  // yuk, hack, we already processed op-5
+            op++; // ignore next operator;
+            break;
+            // three operator feedback, process exception for ALGO 4
+          case 2 :
+            FmOpKernel::compute_fb3(outptr, params, fb_buf, feedback_shift, controllers);
+            params[1].phase += params[1].freq << LG_N; // hack, we already processed op-5 - op-4
+            params[2].phase += params[2].freq << LG_N; // yuk yuk
+            op += 2; // ignore the 2 other operators
+            break;
+          }
         } else {
           // cout << op << " pure " << inbus << outbus << add << endl;
           FmOpKernel::compute_pure(outptr, param.phase, param.freq,

Source/msfa/fm_core.h

@@ -22,12 +22,6 @@
 #include "synth.h"
 #include "controllers.h"
 
-struct FmOpParams {
-  int32_t gain[2];
-  int32_t freq;
-  int32_t phase;
-};
-
 class FmCore {
  public:
   static void dump();

Source/msfa/fm_op_kernel.cc

@@ -159,6 +159,96 @@ void FmOpKernel::compute_fb(int32_t *output, int32_t phase0, int32_t freq,
   fb_buf[1] = y;
 }
 
+
+// exclusively used for ALGO 6 with feedback
+void FmOpKernel::compute_fb2(int32_t *output, FmOpParams *parms, int32_t *fb_buf, int fb_shift, const Controllers *cont) {
+    int32_t dgain[2];
+    int32_t gain[2];
+    int32_t phase[2];
+    int32_t y0 = fb_buf[0];
+    int32_t y = fb_buf[1];
+    
+    phase[0] = parms[0].phase;
+    phase[1] = parms[1].phase;
+    
+    dgain[0] = (parms[0].gain[1] - parms[0].gain[0] + (N >> 1)) >> LG_N;
+    dgain[1] = (parms[1].gain[1] - parms[1].gain[1] + (N >> 1)) >> LG_N;
+    
+    gain[0] = parms[0].gain[0];
+    gain[1] = parms[1].gain[1];
+    
+    for (int i = 0; i < N; i++) {
+        // op 0
+        gain[0] += dgain[0];
+        int32_t scaled_fb = (y0 + y) >> (fb_shift + 1);
+        y0 = y;
+        y = Sin::lookup(phase[0] + scaled_fb);
+        y = ((int64_t)y * (int64_t)gain) >> 24;
+        phase[0] += parms[0].freq;
+        
+        // op 1
+        gain[1] += dgain[1];
+        //scaled_fb = (y0 + y) >> (fb_shift + 1);
+        y0 = y;
+        y = Sin::lookup(phase[1] + scaled_fb + y);
+        y = ((int64_t)y * (int64_t)gain) >> 24;
+        output[i] = y;
+        phase[1] += parms[1].freq;
+    }
+    fb_buf[0] = y0;
+    fb_buf[1] = y;
+}
+
+// exclusively used for ALGO 4 with feedback
+void FmOpKernel::compute_fb3(int32_t *output, FmOpParams *parms, int32_t *fb_buf, int fb_shift, const Controllers *conts) {
+    int32_t dgain[3];
+    int32_t gain[3];
+    int32_t phase[3];
+    int32_t y0 = fb_buf[0];
+    int32_t y = fb_buf[1];
+    
+    phase[0] = parms[0].phase;
+    phase[1] = parms[1].phase;
+    phase[2] = parms[2].phase;
+    
+    dgain[0] = (parms[0].gain[1] - parms[0].gain[0] + (N >> 1)) >> LG_N;
+    dgain[1] = (parms[1].gain[1] - parms[1].gain[0] + (N >> 1)) >> LG_N;
+    dgain[2] = (parms[2].gain[1] - parms[2].gain[0] + (N >> 1)) >> LG_N;
+    
+    gain[0] = parms[0].gain[0];
+    gain[1] = parms[1].gain[0];
+    gain[2] = parms[2].gain[0];
+    
+    for (int i = 0; i < N; i++) {
+        // op 0
+        gain[0] += dgain[0];
+        int32_t scaled_fb = (y0 + y) >> (fb_shift + 1);
+        y0 = y;
+        y = Sin::lookup(phase[0] + scaled_fb);
+        y = ((int64_t)y * (int64_t)gain) >> 24;
+        phase[0] += parms[0].freq;
+        
+        // op 1
+        gain[1] += dgain[1];
+        scaled_fb = (y0 + y) >> (fb_shift + 1);
+        y0 = y;
+        y = Sin::lookup(phase[1] + scaled_fb + y);
+        y = ((int64_t)y * (int64_t)gain) >> 24;
+        phase[1] += parms[1].freq;
+        
+        // op 2
+        gain[2] += dgain[2];
+        scaled_fb = (y0 + y) >> (fb_shift + 1);
+        y0 = y;
+        y = Sin::lookup(phase[2] + scaled_fb + y);
+        y = ((int64_t)y * (int64_t)gain) >> 24;
+        output[i] = y;
+        phase[2] += parms[2].freq;      
+    }
+    fb_buf[0] = y0;
+    fb_buf[1] = y;
+}
+
 ////////////////////////////////////////////////////////////////////////////////////
 ////////////////////////////////////////////////////////////////////////////////////
 ////////////////////////////////////////////////////////////////////////////////////

Source/msfa/fm_op_kernel.h

@@ -19,6 +19,12 @@
 
 #include "controllers.h"
 
+struct FmOpParams {
+    int32_t gain[2];
+    int32_t freq;
+    int32_t phase;
+};
+
 class FmOpKernel {
  public:    
   // gain1 and gain2 represent linear step: gain for sample i is
@@ -37,6 +43,12 @@ class FmOpKernel {
   static void compute_fb(int32_t *output, int32_t phase0, int32_t freq,
                          int32_t gain1, int32_t gain2,
                          int32_t *fb_buf, int fb_gain, bool add, const Controllers *controllers);
+    
+  static void compute_fb2(int32_t *output, FmOpParams *params, int32_t *fb_buf, int fb_shift,
+                          const Controllers *controllers);
+    
+  static void compute_fb3(int32_t *output, FmOpParams *params, int32_t *fb_buf, int fb_shift,
+                          const Controllers *controllers);
 };
 
 #endif

Source/msfa/synth.h

@@ -57,4 +57,14 @@ inline static T max(const T& a, const T& b) {
     return a > b ? a : b;
 }
 
+
+void dexed_trace(const char *source, const char *fmt, ...);
+
+#ifdef _MSC_VER
+#define TRACE(fmt, ...) dexed_trace(__FUNCTION__,fmt,##__VA_ARGS__)
+#else
+#define TRACE(fmt, ...) dexed_trace(__PRETTY_FUNCTION__,fmt,##__VA_ARGS__)
+#endif
+
+
 #endif  // __SYNTH_H