commit 67e990c3c9577fa5ad34a87e0ab7250de5c97c37
parent 39fe23476b63769d369ea04f9d08d32caa15c658
Author: Hans Petter Selasky <hps@selasky.org>
Date: Sat, 4 Apr 2020 15:48:15 +0200
Convert all Microtonal frequency computations to be logarithmic power of two.
This makes many frequency computations easier, that we end up adding numbers
instead of multiplying numbers.
This change is part of a larger change to merge the basefreq and
log2_note_freq values being passed around in various parameter
structures, into a single log2_note_freq variable.
No functional change intended.
Signed-off-by: Hans Petter Selasky <hps@selasky.org>
Diffstat:
2 files changed, 146 insertions(+), 108 deletions(-)
diff --git a/src/Misc/Microtonal.cpp b/src/Misc/Microtonal.cpp
@@ -221,7 +221,7 @@ void Microtonal::defaults()
Pmapping[i] = i;
for(int i = 0; i < MAX_OCTAVE_SIZE; ++i) {
- octave[i].tuning = powf(2, (i % octavesize + 1) / 12.0f);
+ octave[i].tuning_log2 = (i % octavesize + 1) / 12.0f;
octave[i].type = 1;
octave[i].x1 = (i % octavesize + 1) * 100;
octave[i].x2 = 0;
@@ -255,110 +255,132 @@ unsigned char Microtonal::getoctavesize() const
}
/*
- * Get the frequency according the note number
+ * Update the logarithmic power of two frequency according the note number
*/
-float Microtonal::getnotefreq(float note_log2_freq, int keyshift) const
+bool Microtonal::updatenotefreq_log2(float ¬e_log2_freq, int keyshift) const
{
note_t note = roundf(12.0f * note_log2_freq);
+ float freq_log2 = note_log2_freq;
// in this function will appears many times things like this:
// var=(a+b*100)%b
// I had written this way because if I use var=a%b gives unwanted results when a<0
// This is the same with divisions.
- if((Pinvertupdown != 0) && ((Pmappingenabled == 0) || (Penabled == 0)))
+ if((Pinvertupdown != 0) && ((Pmappingenabled == 0) || (Penabled == 0))) {
note = (int) Pinvertupdowncenter * 2 - note;
+ freq_log2 = Pinvertupdowncenter * (2.0f / 12.0f) - freq_log2;
+ }
- //compute global fine detune
- float globalfinedetunerap =
- powf(2.0f, (Pglobalfinedetune - 64.0f) / 1200.0f); //-64.0f .. 63.0f cents
+ /* compute global fine detune, -64.0f .. 63.0f cents */
+ const float globalfinedetunerap_log2 = (Pglobalfinedetune - 64.0f) / 1200.0f;
- if(Penabled == 0) //12tET
- return powf(2.0f, note_log2_freq +
- ((keyshift - PAnote) / 12.0f)) * PAfreq * globalfinedetunerap;
+ if(Penabled == 0) { /* 12tET */
+ freq_log2 += (keyshift - PAnote) / 12.0f;
+ }
+ else { /* Microtonal */
+ const int scaleshift =
+ ((int)Pscaleshift - 64 + (int) octavesize * 100) % octavesize;
+
+ /* compute the keyshift */
+ float rap_keyshift_log2;
+ if(keyshift != 0) {
+ const int kskey = (keyshift + (int)octavesize * 100) % octavesize;
+ const int ksoct = (keyshift + (int)octavesize * 100) / octavesize - 100;
+
+ rap_keyshift_log2 =
+ ((kskey == 0) ? 0.0f : octave[kskey - 1].tuning_log2) +
+ (octave[octavesize - 1].tuning_log2 * ksoct);
+ }
+ else {
+ rap_keyshift_log2 = 0.0f;
+ }
- int scaleshift =
- ((int)Pscaleshift - 64 + (int) octavesize * 100) % octavesize;
+ /* if the mapping is enabled */
+ if(Pmappingenabled) {
+ if((note < Pfirstkey) || (note > Plastkey))
+ goto failure;
+
+ /*
+ * Compute how many mapped keys are from middle note to reference note
+ * and find out the proportion between the freq. of middle note and "A" note
+ */
+ int tmp = PAnote - Pmiddlenote;
+ const bool minus = (tmp < 0);
+ if(minus)
+ tmp = -tmp;
+
+ int deltanote = 0;
+ for(int i = 0; i < tmp; ++i)
+ if(Pmapping[i % Pmapsize] >= 0)
+ deltanote++;
+
+ float rap_anote_middlenote_log2;
+ if(deltanote == 0) {
+ rap_anote_middlenote_log2 = 0.0f;
+ }
+ else {
+ rap_anote_middlenote_log2 =
+ octave[(deltanote - 1) % octavesize].tuning_log2 +
+ octave[octavesize - 1].tuning_log2 * ((deltanote - 1) / octavesize);
+ }
+ if(minus)
+ rap_anote_middlenote_log2 = -rap_anote_middlenote_log2;
+
+ /* Convert from note (midi) to degree (note from the tuning) */
+ int degoct =
+ (note - (int)Pmiddlenote + (int) Pmapsize
+ * 200) / (int)Pmapsize - 200;
+ int degkey = (note - Pmiddlenote + (int)Pmapsize * 100) % Pmapsize;
+ degkey = Pmapping[degkey];
+
+ /* check if key is not mapped */
+ if(degkey < 0)
+ goto failure;
+
+ /*
+ * Invert the keyboard upside-down if it is asked for
+ * TODO: do the right way by using Pinvertupdowncenter
+ */
+ if(Pinvertupdown != 0) {
+ degkey = octavesize - degkey - 1;
+ degoct = -degoct;
+ }
- //compute the keyshift
- float rap_keyshift = 1.0f;
- if(keyshift != 0) {
- int kskey = (keyshift + (int)octavesize * 100) % octavesize;
- int ksoct = (keyshift + (int)octavesize * 100) / octavesize - 100;
- rap_keyshift = (kskey == 0) ? (1.0f) : (octave[kskey - 1].tuning);
- rap_keyshift *= powf(octave[octavesize - 1].tuning, ksoct);
- }
+ degkey = degkey + scaleshift;
+ degoct += degkey / octavesize;
+ degkey %= octavesize;
- //if the mapping is enabled
- if(Pmappingenabled) {
- if((note < Pfirstkey) || (note > Plastkey))
- return -1.0f;
- //Compute how many mapped keys are from middle note to reference note
- //and find out the proportion between the freq. of middle note and "A" note
- int tmp = PAnote - Pmiddlenote, minus = 0;
- if(tmp < 0) {
- tmp = -tmp;
- minus = 1;
+ /* compute the logrithmic frequency of the note */
+ freq_log2 =
+ ((degkey == 0) ? 0.0f : octave[degkey - 1].tuning_log2) +
+ (octave[octavesize - 1].tuning_log2 * degoct) -
+ rap_anote_middlenote_log2;
}
- int deltanote = 0;
- for(int i = 0; i < tmp; ++i)
- if(Pmapping[i % Pmapsize] >= 0)
- deltanote++;
- float rap_anote_middlenote =
- (deltanote ==
- 0) ? (1.0f) : (octave[(deltanote - 1) % octavesize].tuning);
- if(deltanote)
- rap_anote_middlenote *=
- powf(octave[octavesize - 1].tuning,
- (deltanote - 1) / octavesize);
- if(minus)
- rap_anote_middlenote = 1.0f / rap_anote_middlenote;
-
- //Convert from note (midi) to degree (note from the tunning)
- int degoct =
- (note - (int)Pmiddlenote + (int) Pmapsize
- * 200) / (int)Pmapsize - 200;
- int degkey = (note - Pmiddlenote + (int)Pmapsize * 100) % Pmapsize;
- degkey = Pmapping[degkey];
- if(degkey < 0)
- return -1.0f; //this key is not mapped
-
- //invert the keyboard upside-down if it is asked for
- //TODO: do the right way by using Pinvertupdowncenter
- if(Pinvertupdown != 0) {
- degkey = octavesize - degkey - 1;
- degoct = -degoct;
+ else { /* if the mapping is disabled */
+ const int nt = note - PAnote + scaleshift;
+ const int ntkey = (nt + (int)octavesize * 100) % octavesize;
+ const int ntoct = (nt - ntkey) / octavesize;
+
+ freq_log2 =
+ octave[(ntkey + octavesize - 1) % octavesize].tuning_log2 +
+ octave[octavesize - 1].tuning_log2 * (ntkey ? ntoct : (ntoct - 1));
}
- //compute the frequency of the note
- degkey = degkey + scaleshift;
- degoct += degkey / octavesize;
- degkey %= octavesize;
-
- float freq = (degkey == 0) ? (1.0f) : octave[degkey - 1].tuning;
- freq *= powf(octave[octavesize - 1].tuning, degoct);
- freq *= PAfreq / rap_anote_middlenote;
- freq *= globalfinedetunerap;
if(scaleshift)
- freq /= octave[scaleshift - 1].tuning;
- return freq * rap_keyshift;
- }
- else { //if the mapping is disabled
- int nt = note - PAnote + scaleshift;
- int ntkey = (nt + (int)octavesize * 100) % octavesize;
- int ntoct = (nt - ntkey) / octavesize;
-
- float oct = octave[octavesize - 1].tuning;
- float freq =
- octave[(ntkey + octavesize - 1) % octavesize].tuning * powf(oct,
- ntoct)
- * PAfreq;
- if(!ntkey)
- freq /= oct;
- if(scaleshift)
- freq /= octave[scaleshift - 1].tuning;
- freq *= globalfinedetunerap;
- return freq * rap_keyshift;
+ freq_log2 -= octave[scaleshift - 1].tuning_log2;
+ freq_log2 += rap_keyshift_log2;
}
+
+ /* common part */
+ freq_log2 += log2f(PAfreq);
+ freq_log2 += globalfinedetunerap_log2;
+
+ /* update value */
+ note_log2_freq = freq_log2;
+ return true;
+
+failure:
+ return false;
}
bool Microtonal::operator==(const Microtonal µ) const
@@ -395,7 +417,7 @@ bool Microtonal::operator!=(const Microtonal µ) const
MCREQ(Pmapping[i]);
for(int i = 0; i < octavesize; ++i) {
- FMCREQ(octave[i].tuning);
+ FMCREQ(octave[i].tuning_log2);
MCREQ(octave[i].type);
MCREQ(octave[i].x1);
MCREQ(octave[i].x2);
@@ -418,8 +440,11 @@ bool Microtonal::operator!=(const Microtonal µ) const
*/
int Microtonal::linetotunings(OctaveTuning &octave, const char *line)
{
- int x1 = -1, x2 = -1, type = -1;
- float x = -1.0f, tmp, tuning = 1.0f;
+ int x1 = -1, x2 = -1;
+ int type;
+ float tmp;
+ float x = -1.0f;
+ float tuning_log2 = 0.0f;
if(strstr(line, "/") == NULL) {
if(strstr(line, ".") == NULL) { // M case (M=M/1)
sscanf(line, "%d", &x1);
@@ -443,7 +468,7 @@ int Microtonal::linetotunings(OctaveTuning &octave, const char *line)
}
if(x1 <= 0)
- x1 = 1; //not allow zero frequency sounds (consider 0 as 1)
+ x1 = 1; //do not allow zero frequency sounds (consider 0 as 1)
//convert to float if the number are too big
if((type == 2)
@@ -455,16 +480,18 @@ int Microtonal::linetotunings(OctaveTuning &octave, const char *line)
case 1:
x1 = (int) floor(x);
tmp = fmod(x, 1.0f);
- x2 = (int) (floor(tmp * 1e6));
- tuning = powf(2.0f, x / 1200.0f);
+ x2 = (int) floor(tmp * 1e6);
+ tuning_log2 = x / 1200.0f;
break;
case 2:
x = ((float)x1) / x2;
- tuning = x;
+ tuning_log2 = log2f(x);
break;
+ default:
+ return 1;
}
- octave.tuning = tuning;
+ octave.tuning_log2 = tuning_log2;
octave.type = type;
octave.x1 = x1;
octave.x2 = x2;
@@ -504,7 +531,7 @@ int Microtonal::texttotunings(const char *text)
return -2; //the input is empty
octavesize = nl;
for(int i = 0; i < octavesize; ++i) {
- octave[i].tuning = tmpoctave[i].tuning;
+ octave[i].tuning_log2 = tmpoctave[i].tuning_log2;
octave[i].type = tmpoctave[i].type;
octave[i].x1 = tmpoctave[i].x1;
octave[i].x2 = tmpoctave[i].x2;
@@ -620,7 +647,7 @@ int Microtonal::loadscl(SclInfo &scl, const char *filename)
scl.octavesize = nnotes;
for(int i = 0; i < scl.octavesize; ++i) {
- scl.octave[i].tuning = tmpoctave[i].tuning;
+ scl.octave[i].tuning_log2 = tmpoctave[i].tuning_log2;
scl.octave[i].type = tmpoctave[i].type;
scl.octave[i].x1 = tmpoctave[i].x1;
scl.octave[i].x2 = tmpoctave[i].x2;
@@ -730,8 +757,8 @@ void Microtonal::add2XML(XMLwrapper& xml) const
for(int i = 0; i < octavesize; ++i) {
xml.beginbranch("DEGREE", i);
if(octave[i].type == 1)
- xml.addparreal("cents", octave[i].tuning);
- ;
+ xml.addparreal("cents", powf(2.0f, octave[i].tuning_log2));
+
if(octave[i].type == 2) {
xml.addpar("numerator", octave[i].x1);
xml.addpar("denominator", octave[i].x2);
@@ -780,7 +807,8 @@ void Microtonal::getfromXML(XMLwrapper& xml)
if(xml.enterbranch("DEGREE", i) == 0)
continue;
octave[i].x2 = 0;
- octave[i].tuning = xml.getparreal("cents", octave[i].tuning);
+ octave[i].tuning_log2 = log2f(xml.getparreal("cents",
+ powf(2.0f, octave[i].tuning_log2))) / log2(2.0f);
octave[i].x1 = xml.getpar127("numerator", octave[i].x1);
octave[i].x2 = xml.getpar127("denominator", octave[i].x2);
@@ -788,10 +816,10 @@ void Microtonal::getfromXML(XMLwrapper& xml)
octave[i].type = 2;
else {
octave[i].type = 1;
- //populate fields for display
- float x = logf(octave[i].tuning) / LOG_2 * 1200.0f;
- octave[i].x1 = (int) floor(x);
- octave[i].x2 = (int) (floor((x-octave[i].x1) * 1.0e6));
+ /* populate fields for display */
+ const float x = octave[i].tuning_log2 * 1200.0f;
+ octave[i].x1 = (int) floorf(x);
+ octave[i].x2 = (int) (floorf((x-octave[i].x1) * 1.0e6));
}
diff --git a/src/Misc/Microtonal.h b/src/Misc/Microtonal.h
@@ -41,9 +41,12 @@ struct KbmInfo
struct OctaveTuning {
unsigned char type; //1 for cents or 2 for division
- // the real tuning (eg. +1.05946f for one halftone)
- // or 2.0f for one octave
- float tuning;
+ /*
+ * The real tuning in logarithmic power of two.
+ * For example 1/12 for one halftone and
+ * 1 for one octave.
+ */
+ float tuning_log2;
//the real tunning is x1/x2
unsigned int x1, x2;
@@ -66,10 +69,17 @@ class Microtonal
/**Destructor*/
~Microtonal();
void defaults();
+ /**Updates the logarithmic power of two frequency for a given note
+ */
+ bool updatenotefreq_log2(float ¬e_log2_freq, int keyshift) const;
/**Calculates the frequency for a given note
*/
- float getnotefreq(float note_log2_freq, int keyshift) const;
-
+ float getnotefreq(float note_log2_freq, int keyshift) const {
+ if (updatenotefreq_log2(note_log2_freq, keyshift))
+ return powf(2.0f, note_log2_freq);
+ else
+ return -1.0f;
+ };
//Parameters
/**if the keys are inversed (the pitch is lower to keys from the right direction)*/
