From 05355d7ef514aac9e5981c29cc66598be3d78cf6 Mon Sep 17 00:00:00 2001
From: Raph Levien <raph@google.com>
Date: Thu, 30 May 2013 01:15:11 -0700
Subject: [PATCH] Pitch envelope

Adds implementation of pitch envelope. Also fixes a problem with
kLevelThresh.
---
 android/jni/Android.mk |  1 +
 cpp/src/core.gyp       |  1 +
 cpp/src/dx7note.cc     | 18 ++++++---
 cpp/src/dx7note.h      |  3 ++
 cpp/src/fm_core.cc     |  2 +
 cpp/src/pitchenv.cc    | 89 ++++++++++++++++++++++++++++++++++++++++++
 cpp/src/pitchenv.h     | 48 +++++++++++++++++++++++
 7 files changed, 157 insertions(+), 5 deletions(-)
 create mode 100644 cpp/src/pitchenv.cc
 create mode 100644 cpp/src/pitchenv.h

diff --git a/android/jni/Android.mk b/android/jni/Android.mk
index 676b606..c4a9db2 100644
--- a/android/jni/Android.mk
+++ b/android/jni/Android.mk
@@ -11,6 +11,7 @@ LOCAL_SRC_FILES := android_glue.cc \
                    fm_op_kernel.cc \
                    freqlut.cc \
                    patch.cc \
+                   pitchenv.cc \
                    resofilter.cc \
                    ringbuffer.cc \
                    sawtooth.cc \
diff --git a/cpp/src/core.gyp b/cpp/src/core.gyp
index cd0f8d1..7c6570d 100644
--- a/cpp/src/core.gyp
+++ b/cpp/src/core.gyp
@@ -12,6 +12,7 @@
         'freqlut.cc',
         'lfo.cc',
         'patch.cc',
+        'pitchenv.cc',
         'resofilter.cc',
         'ringbuffer.cc',
         'sawtooth.cc',
diff --git a/cpp/src/dx7note.cc b/cpp/src/dx7note.cc
index bddab1e..805b7b5 100644
--- a/cpp/src/dx7note.cc
+++ b/cpp/src/dx7note.cc
@@ -58,8 +58,7 @@ int32_t osc_freq(int midinote, int mode, int coarse, int fine, int detune) {
     logfreq = (4458616 * ((coarse & 3) * 100 + fine)) >> 3;
     logfreq += detune > 7 ? 13457 * (detune - 7) : 0;
   }
-  int32_t base_freq = Freqlut::lookup(logfreq);
-  return base_freq;
+  return logfreq;
 }
 
 const uint8_t velocity_data[64] = {
@@ -127,10 +126,10 @@ int ScaleLevel(int midinote, int break_pt, int left_depth, int right_depth,
 void Dx7Note::init(const char bulk[128], int midinote, int velocity) {
   char patch[156];
   UnpackPatch(bulk, patch);  // TODO: move this out, take unpacked patch
+  int rates[4];
+  int levels[4];
   for (int op = 0; op < 6; op++) {
     int off = op * 21;
-    int rates[4];
-    int levels[4];
     for (int i = 0; i < 4; i++) {
       rates[i] = patch[off + i];
       levels[i] = patch[off + 4 + i];
@@ -160,22 +159,30 @@ void Dx7Note::init(const char bulk[128], int midinote, int velocity) {
     int fine = patch[off + 19];
     int detune = patch[off + 20];
     int32_t freq = osc_freq(midinote, mode, coarse, fine, detune);
-    params_[op].freq = freq;
+    basepitch_[op] = freq;
     // cout << op << " freq: " << freq << endl;
     params_[op].phase = 0;
     params_[op].gain[1] = 0;
   }
+  for (int i = 0; i < 4; i++) {
+    rates[i] = patch[126 + i];
+    levels[i] = patch[130 + i];
+  }
+  pitchenv_.init(rates, levels);
   algorithm_ = patch[134];
   int feedback = patch[135];
   fb_shift_ = feedback != 0 ? 8 - feedback : 16;
 }
 
 void Dx7Note::compute(int32_t *buf) {
+  int32_t pitchenvlevel = pitchenv_.getsample();
   for (int op = 0; op < 6; op++) {
     params_[op].gain[0] = params_[op].gain[1];
     int32_t level = env_[op].getsample();
     int32_t gain = Exp2::lookup(level - (14 * (1 << 24)));
     //int32_t gain = pow(2, 10 + level * (1.0 / (1 << 24)));
+    // TODO: probably don't apply pitch env to fixed freq
+    params_[op].freq = Freqlut::lookup(basepitch_[op] + pitchenvlevel);
     params_[op].gain[1] = gain;
   }
   core_.compute(buf, params_, algorithm_, fb_buf_, fb_shift_);
@@ -184,6 +191,7 @@ void Dx7Note::compute(int32_t *buf) {
 void Dx7Note::keyup() {
   for (int op = 0; op < 6; op++) {
     env_[op].keydown(false);
+    pitchenv_.keydown(false);
   }
 }
 
diff --git a/cpp/src/dx7note.h b/cpp/src/dx7note.h
index da0bb1d..8e12159 100644
--- a/cpp/src/dx7note.h
+++ b/cpp/src/dx7note.h
@@ -24,6 +24,7 @@
 // and real-time control of parameters live here.
 
 #include "env.h"
+#include "pitchenv.h"
 #include "fm_core.h"
 
 class Dx7Note {
@@ -50,6 +51,8 @@ class Dx7Note {
   FmCore core_;
   Env env_[6];
   FmOpParams params_[6];
+  PitchEnv pitchenv_;
+  int32_t basepitch_[6];
   int32_t fb_buf_[2];
   int32_t fb_shift_;
 
diff --git a/cpp/src/fm_core.cc b/cpp/src/fm_core.cc
index 3c95cb0..52383ac 100644
--- a/cpp/src/fm_core.cc
+++ b/cpp/src/fm_core.cc
@@ -143,6 +143,8 @@ void FmCore::compute(int32_t *output, FmOpParams *params, int algorithm,
                             param.phase, param.freq, gain1, gain2, add);
       }
       has_contents[outbus] = true;
+    } else if (!add) {
+      has_contents[outbus] = false;
     }
     param.phase += param.freq << LG_N;
   }
diff --git a/cpp/src/pitchenv.cc b/cpp/src/pitchenv.cc
new file mode 100644
index 0000000..146421f
--- /dev/null
+++ b/cpp/src/pitchenv.cc
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2012 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "synth.h"
+#include "pitchenv.h"
+
+using namespace std;
+
+void PitchEnv::init(const int r[4], const int l[4]) {
+  for (int i = 0; i < 4; i++) {
+    rates_[i] = r[i];
+    levels_[i] = l[i];
+  }
+  level_ = 0;
+  down_ = true;
+  advance(0);
+}
+
+int32_t PitchEnv::getsample() {
+  if (ix_ < 3 || (ix_ < 4) && !down_) {
+    if (rising_) {
+      level_ += inc_;
+      if (level_ >= targetlevel_) {
+        level_ = targetlevel_;
+        advance(ix_ + 1);
+      }
+    } else {  // !rising
+      level_ -= inc_;
+      if (level_ <= targetlevel_) {
+        level_ = targetlevel_;
+        advance(ix_ + 1);
+      }
+    }
+  }
+  return level_;
+}
+
+void PitchEnv::keydown(bool d) {
+  if (down_ != d) {
+    down_ = d;
+    advance(d ? 0 : 3);
+  }
+}
+
+static uint8_t ratetab[] = {
+  1, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12,
+  12, 13, 13, 14, 14, 15, 16, 16, 17, 18, 18, 19, 20, 21, 22, 23, 24,
+  25, 26, 27, 28, 30, 31, 33, 34, 36, 37, 38, 39, 41, 42, 44, 46, 47,
+  49, 51, 53, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 79, 82,
+  85, 88, 91, 94, 98, 102, 106, 110, 115, 120, 125, 130, 135, 141, 147,
+  153, 159, 165, 171, 178, 185, 193, 202, 211, 232, 243, 254, 255
+};
+
+static int8_t pitchtab[] = {
+  -128, -116, -104, -95, -85, -76, -68, -61, -56, -52, -49, -46, -43,
+  -41, -39, -37, -35, -33, -32, -31, -30, -29, -28, -27, -26, -25, -24,
+  -23, -22, -21, -20, -19, -18, -17, -16, -15, -14, -13, -12, -11, -10,
+  -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
+  11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
+  28, 29, 30, 31, 32, 33, 34, 35, 38, 40, 43, 46, 49, 53, 58, 65, 73,
+  82, 92, 103, 115, 127
+};
+
+void PitchEnv::advance(int newix) {
+  ix_ = newix;
+  if (ix_ < 4) {
+    int newlevel = levels_[ix_];
+    targetlevel_ = pitchtab[newlevel] << 19;
+    rising_ = (targetlevel_ > level_);
+
+    // TODO: adapt to sample rate
+    // const is 1<<12 / 0.0104 * 44100
+    inc_ = ratetab[rates_[ix_]] * (8 * N);
+  }
+}
+
diff --git a/cpp/src/pitchenv.h b/cpp/src/pitchenv.h
new file mode 100644
index 0000000..65893db
--- /dev/null
+++ b/cpp/src/pitchenv.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2013 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __PITCHENV_H
+#define __PITCHENV_H
+
+// Computation of the DX7 pitch envelope
+
+class PitchEnv {
+ public:
+
+  // The rates and levels arrays are calibrated to match the Dx7 parameters
+  // (ie, value 0..99).
+  void init(const int rates[4], const int levels[4]);
+
+  // Result is in Q24/octave
+  int32_t getsample();
+
+  void keydown(bool down);
+ private:
+  int rates_[4];
+  int levels_[4];
+  int32_t level_;
+  int targetlevel_;
+  bool rising_;
+  int ix_;
+  int inc_;
+
+  bool down_;
+
+  void advance(int newix);
+};
+
+#endif  // __PITCHENV_H
+