Correct WT and Window handling og 16 full range wt files

wt files with full-range 16 bit ints (so 16-is-16 or flag
0x8 + 0x4 = 0xC) was broken in a couple of ways, but most
importnatly, didn't survive a save/restore roundtrip.

This fixes it in three ways

1. When converting 16-as-16 to float scale accordingly with
   a different function and leave the ints untouched
2. Modify the window oscillator so if it gets a 16-as-16 it
   reduces the height of the ints to be consistent with a
   15 with an extra shift, making I15 WT vs Window and
   I16 WT vs Window consistent
3. Make sure it streams properly. No change required but
   tested.

Addresses surge-synthesizer#7694

Update wt-tool to allow int16 and int15 options both

scripts/wt-tool/wt-tool.py

@@ -40,7 +40,8 @@ def read_wt_header(fn):
     flags = {}
     flags["is_sample"] = (fl[0] & 0x01 != 0)
     flags["loop_sample"] = (fl[0] & 0x02 != 0)
-    flags["format"] = "int16" if (fl[0] & 0x04 != 0) else "float32"
+
+    flags["format"] = "int16-full-range" if (fl[0] == 0xC) else "int16" if (fl[0] & 0x04 != 0) else "float32"
     flags["samplebytes"] = 2 if (fl[0] & 0x04 != 0) else 4
 
     header["flags"] = flags
@@ -74,7 +75,7 @@ def explode(fn, wav_dir):
                 wav_file.writeframes(bdata)
 
 
-def create(fn, wavdir, norm):
+def create(fn, wavdir, norm, intform):
     onlyfiles = [f for f in listdir(wavdir) if (isfile(join(wavdir, f)) and f.endswith(".wav"))]
     onlyfiles.sort()
 
@@ -122,8 +123,8 @@ def create(fn, wavdir, norm):
                 newrec[2 * i + 1] = nms
             newdb.append(newrec)
         databuffer = newdb
-    elif (norm == "peak"):
-        print("Normalizing to peak")
+    elif (norm == "peak" or norm == "peak16"):
+        print("Normalizing to " + norm)
         peakp = 0
         peakm = 0
         for d in databuffer:
@@ -141,6 +142,11 @@ def create(fn, wavdir, norm):
             peakp = -peakm
         print("Peak value is ", peakp)
         newdb = []
+
+        den = 16384.0
+        if (norm == "peak16"):
+            den = den * 2
+
         for d in databuffer:
             newrec = bytearray(len(d))
 
@@ -149,7 +155,7 @@ def create(fn, wavdir, norm):
                 ms = d[2 * i + 1]
                 if(ms >= 128):
                     ms -= 256
-                r = int((ls + ms * 256) * 16384.0 / peakp)
+                r = int((ls + ms * 256) * den / peakp)
 
                 nls = int(r % 256)
                 nms = int(r / 256)
@@ -169,7 +175,7 @@ def create(fn, wavdir, norm):
         outf.write(b'vawt')
         outf.write(nf.to_bytes(4, byteorder='little'))
         outf.write((len(onlyfiles)).to_bytes(2, byteorder='little'))
-        outf.write(bytes([4, 0]))
+        outf.write(bytes([4 if (intform == "i15") else 12, 0]))
         for d in databuffer:
             outf.write(d)
 
@@ -199,7 +205,10 @@ def main():
 Modes are 'none' leave input untouched;
 'half' input wav are divided by 2 (so 2^16 range becomes 2^15 range);
 'peak' input wav are scanned and re-peaked to 2^15.
+'peak16' input wav are scanned and re-peaked to 2^15.
 """)
+    parser.add_option("-i", "--int-range", dest="intrange", default="i15", metavar="INTRANGE",
+                      help = "Int range for creating i16 files. Either i15 or i16")
     (options, args) = parser.parse_args()
 
     act = options.action
@@ -208,7 +217,7 @@ def main():
             parser.print_help()
             print("\nYou must specify a file and wav_dir for create")
         else:
-            create(options.file, options.wav_dir, options.normalize)
+            create(options.file, options.wav_dir, options.normalize, options.intrange)
     elif act == "explode":
         if(options.file is None or options.wav_dir is None):
             parser.print_help()

src/common/dsp/Wavetable.cpp

@@ -247,11 +247,14 @@ bool Wavetable::BuildWT(void *wdata, wt_header &wh, bool AppendSilence)
                                        &((short *)wdata)[this->size * j], this->size);
             if (this->flags & wtf_int16_is_16)
             {
-                i16toi15_block(&this->TableI16WeakPointers[0][j][FIRoffsetI16],
-                               &this->TableI16WeakPointers[0][j][FIRoffsetI16], this->size);
+                i162float_block(&this->TableI16WeakPointers[0][j][FIRoffsetI16],
+                                this->TableF32WeakPointers[0][j], this->size);
+            }
+            else
+            {
+                i152float_block(&this->TableI16WeakPointers[0][j][FIRoffsetI16],
+                                this->TableF32WeakPointers[0][j], this->size);
             }
-            i152float_block(&this->TableI16WeakPointers[0][j][FIRoffsetI16],
-                            this->TableF32WeakPointers[0][j], this->size);
         }
     }
     else

src/common/dsp/oscillators/WindowOscillator.cpp

@@ -196,7 +196,7 @@ inline unsigned int BigMULr16(unsigned int a, unsigned int b)
     return c >> 16u;
 }
 
-void WindowOscillator::ProcessWindowOscs(bool stereo, bool FM)
+template <bool FM, bool Full16> void WindowOscillator::ProcessWindowOscs(bool stereo)
 {
     const unsigned int M0Mask = 0x07f8;
     unsigned int SizeMask = (oscdata->wt.size << 16) - 1;
@@ -332,8 +332,9 @@ void WindowOscillator::ProcessWindowOscs(bool stereo, bool FM)
 #endif
 
                 iWin[0] = (iWin[0] + iWin[1] + iWin[2] + iWin[3]) >> 13;
-                iWave[0] = (iWave[0] + iWave[1] + iWave[2] + iWave[3]) >> 13;
-                iWaveP1[0] = (iWaveP1[0] + iWaveP1[1] + iWaveP1[2] + iWaveP1[3]) >> 13;
+                iWave[0] = (iWave[0] + iWave[1] + iWave[2] + iWave[3]) >> (13 + (Full16 ? 1 : 0));
+                iWaveP1[0] =
+                    (iWaveP1[0] + iWaveP1[1] + iWaveP1[2] + iWaveP1[3]) >> (13 + (Full16 ? 1 : 0));
 
                 iWave[0] = (int)((1.f - FTable) * iWave[0] + FTable * iWaveP1[0]);
 
@@ -414,7 +415,30 @@ void WindowOscillator::process_block(float pitch, float drift, bool stereo, bool
         }
     }
 
-    ProcessWindowOscs(stereo, FM);
+    bool is16 = oscdata->wt.flags & wtf_int16_is_16;
+
+    if (FM)
+    {
+        if (is16)
+        {
+            ProcessWindowOscs<true, true>(stereo);
+        }
+        else
+        {
+            ProcessWindowOscs<true, false>(stereo);
+        }
+    }
+    else
+    {
+        if (is16)
+        {
+            ProcessWindowOscs<false, true>(stereo);
+        }
+        else
+        {
+            ProcessWindowOscs<false, false>(stereo);
+        }
+    }
 
     // int32 -> float conversion
     __m128 scale = _mm_load1_ps(&OutAttenuation);

src/common/dsp/oscillators/WindowOscillator.h

@@ -77,7 +77,7 @@ class WindowOscillator : public Oscillator
     void applyFilter();
     template <bool is_init> void update_lagvals();
 
-    void ProcessWindowOscs(bool stereo, bool FM);
+    template <bool FM, bool Full16> void ProcessWindowOscs(bool stereo);
     lag<double> FMdepth[MAX_UNISON];
     lag<float> l_morph;
 

src/common/dsp/vembertech/basic_dsp.h

@@ -54,6 +54,15 @@ inline void i152float_block(short *s, float *f, int n)
     }
 }
 
+inline void i162float_block(short *s, float *f, int n)
+{
+    const float scale = 1.f / (16384.f * 2);
+    for (int i = 0; i < n; i++)
+    {
+        f[i] = (float)s[i] * scale;
+    }
+}
+
 inline void i16toi15_block(short *s, short *o, int n)
 {
     for (int i = 0; i < n; i++)