ardour/libs/ardour/curve.cc
2006-10-25 20:11:42 +00:00

455 lines
9.3 KiB
C++

/*
Copyright (C) 2001-2003 Paul Davis
Contains ideas derived from "Constrained Cubic Spline Interpolation"
by CJC Kruger (www.korf.co.uk/spline.pdf).
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
$Id$
*/
#include <iostream>
#include <float.h>
#include <cmath>
#include <climits>
#include <cfloat>
#include <cmath>
#include <glibmm/thread.h>
#include <sigc++/bind.h>
#include "ardour/curve.h"
#include "i18n.h"
using namespace std;
using namespace ARDOUR;
using namespace sigc;
using namespace PBD;
sigc::signal<void, Curve*> Curve::CurveCreated;
Curve::Curve (double minv, double maxv, double canv, bool nostate)
: AutomationList (canv, nostate)
{
min_yval = minv;
max_yval = maxv;
CurveCreated(this);
}
Curve::Curve (const Curve& other)
: AutomationList (other)
{
min_yval = other.min_yval;
max_yval = other.max_yval;
CurveCreated(this);
}
Curve::Curve (const Curve& other, double start, double end)
: AutomationList (other, start, end)
{
min_yval = other.min_yval;
max_yval = other.max_yval;
CurveCreated(this);
}
Curve::~Curve ()
{
}
void
Curve::solve ()
{
uint32_t npoints;
if (!_dirty) {
return;
}
if ((npoints = events.size()) > 2) {
/* Compute coefficients needed to efficiently compute a constrained spline
curve. See "Constrained Cubic Spline Interpolation" by CJC Kruger
(www.korf.co.uk/spline.pdf) for more details.
*/
double x[npoints];
double y[npoints];
uint32_t i;
AutomationEventList::iterator xx;
for (i = 0, xx = events.begin(); xx != events.end(); ++xx, ++i) {
x[i] = (double) (*xx)->when;
y[i] = (double) (*xx)->value;
}
double lp0, lp1, fpone;
lp0 =(x[1] - x[0])/(y[1] - y[0]);
lp1 = (x[2] - x[1])/(y[2] - y[1]);
if (lp0*lp1 < 0) {
fpone = 0;
} else {
fpone = 2 / (lp1 + lp0);
}
double fplast = 0;
for (i = 0, xx = events.begin(); xx != events.end(); ++xx, ++i) {
CurvePoint* cp = dynamic_cast<CurvePoint*>(*xx);
if (cp == 0) {
fatal << _("programming error: ")
<< X_("non-CurvePoint event found in event list for a Curve")
<< endmsg;
/*NOTREACHED*/
}
double xdelta; /* gcc is wrong about possible uninitialized use */
double xdelta2; /* ditto */
double ydelta; /* ditto */
double fppL, fppR;
double fpi;
if (i > 0) {
xdelta = x[i] - x[i-1];
xdelta2 = xdelta * xdelta;
ydelta = y[i] - y[i-1];
}
/* compute (constrained) first derivatives */
if (i == 0) {
/* first segment */
fplast = ((3 * (y[1] - y[0]) / (2 * (x[1] - x[0]))) - (fpone * 0.5));
/* we don't store coefficients for i = 0 */
continue;
} else if (i == npoints - 1) {
/* last segment */
fpi = ((3 * ydelta) / (2 * xdelta)) - (fplast * 0.5);
} else {
/* all other segments */
double slope_before = ((x[i+1] - x[i]) / (y[i+1] - y[i]));
double slope_after = (xdelta / ydelta);
if (slope_after * slope_before < 0.0) {
/* slope changed sign */
fpi = 0.0;
} else {
fpi = 2 / (slope_before + slope_after);
}
}
/* compute second derivative for either side of control point `i' */
fppL = (((-2 * (fpi + (2 * fplast))) / (xdelta))) +
((6 * ydelta) / xdelta2);
fppR = (2 * ((2 * fpi) + fplast) / xdelta) -
((6 * ydelta) / xdelta2);
/* compute polynomial coefficients */
double b, c, d;
d = (fppR - fppL) / (6 * xdelta);
c = ((x[i] * fppL) - (x[i-1] * fppR))/(2 * xdelta);
double xim12, xim13;
double xi2, xi3;
xim12 = x[i-1] * x[i-1]; /* "x[i-1] squared" */
xim13 = xim12 * x[i-1]; /* "x[i-1] cubed" */
xi2 = x[i] * x[i]; /* "x[i] squared" */
xi3 = xi2 * x[i]; /* "x[i] cubed" */
b = (ydelta - (c * (xi2 - xim12)) - (d * (xi3 - xim13))) / xdelta;
/* store */
cp->coeff[0] = y[i-1] - (b * x[i-1]) - (c * xim12) - (d * xim13);
cp->coeff[1] = b;
cp->coeff[2] = c;
cp->coeff[3] = d;
fplast = fpi;
}
}
_dirty = false;
}
bool
Curve::rt_safe_get_vector (double x0, double x1, float *vec, int32_t veclen)
{
Glib::Mutex::Lock lm (lock, Glib::TRY_LOCK);
if (!lm.locked()) {
return false;
} else {
_get_vector (x0, x1, vec, veclen);
return true;
}
}
void
Curve::get_vector (double x0, double x1, float *vec, int32_t veclen)
{
Glib::Mutex::Lock lm (lock);
_get_vector (x0, x1, vec, veclen);
}
void
Curve::_get_vector (double x0, double x1, float *vec, int32_t veclen)
{
double rx, dx, lx, hx, max_x, min_x;
int32_t i;
int32_t original_veclen;
int32_t npoints;
if ((npoints = events.size()) == 0) {
for (i = 0; i < veclen; ++i) {
vec[i] = default_value;
}
return;
}
/* events is now known not to be empty */
max_x = events.back()->when;
min_x = events.front()->when;
lx = max (min_x, x0);
if (x1 < 0) {
x1 = events.back()->when;
}
hx = min (max_x, x1);
original_veclen = veclen;
if (x0 < min_x) {
/* fill some beginning section of the array with the
initial (used to be default) value
*/
double frac = (min_x - x0) / (x1 - x0);
int32_t subveclen = (int32_t) floor (veclen * frac);
subveclen = min (subveclen, veclen);
for (i = 0; i < subveclen; ++i) {
vec[i] = events.front()->value;
}
veclen -= subveclen;
vec += subveclen;
}
if (veclen && x1 > max_x) {
/* fill some end section of the array with the default or final value */
double frac = (x1 - max_x) / (x1 - x0);
int32_t subveclen = (int32_t) floor (original_veclen * frac);
float val;
subveclen = min (subveclen, veclen);
val = events.back()->value;
i = veclen - subveclen;
for (i = veclen - subveclen; i < veclen; ++i) {
vec[i] = val;
}
veclen -= subveclen;
}
if (veclen == 0) {
return;
}
if (npoints == 1 ) {
for (i = 0; i < veclen; ++i) {
vec[i] = events.front()->value;
}
return;
}
if (npoints == 2) {
/* linear interpolation between 2 points */
/* XXX I'm not sure that this is the right thing to
do here. but its not a common case for the envisaged
uses.
*/
if (veclen > 1) {
dx = (hx - lx) / (veclen - 1) ;
} else {
dx = 0; // not used
}
double slope = (events.back()->value - events.front()->value)/
(events.back()->when - events.front()->when);
double yfrac = dx*slope;
vec[0] = events.front()->value + slope * (lx - events.front()->when);
for (i = 1; i < veclen; ++i) {
vec[i] = vec[i-1] + yfrac;
}
return;
}
if (_dirty) {
solve ();
}
rx = lx;
if (veclen > 1) {
dx = (hx - lx) / veclen;
for (i = 0; i < veclen; ++i, rx += dx) {
vec[i] = multipoint_eval (rx);
}
}
}
double
Curve::unlocked_eval (double x)
{
if (_dirty) {
solve ();
}
return shared_eval (x);
}
double
Curve::multipoint_eval (double x)
{
pair<AutomationEventList::iterator,AutomationEventList::iterator> range;
if ((lookup_cache.left < 0) ||
((lookup_cache.left > x) ||
(lookup_cache.range.first == events.end()) ||
((*lookup_cache.range.second)->when < x))) {
TimeComparator cmp;
ControlEvent cp (x, 0.0);
lookup_cache.range = equal_range (events.begin(), events.end(), &cp, cmp);
}
range = lookup_cache.range;
/* EITHER
a) x is an existing control point, so first == existing point, second == next point
OR
b) x is between control points, so range is empty (first == second, points to where
to insert x)
*/
if (range.first == range.second) {
/* x does not exist within the list as a control point */
lookup_cache.left = x;
if (range.first == events.begin()) {
/* we're before the first point */
// return default_value;
events.front()->value;
}
if (range.second == events.end()) {
/* we're after the last point */
return events.back()->value;
}
double x2 = x * x;
CurvePoint* cp = dynamic_cast<CurvePoint*> (*range.second);
return cp->coeff[0] + (cp->coeff[1] * x) + (cp->coeff[2] * x2) + (cp->coeff[3] * x2 * x);
}
/* x is a control point in the data */
/* invalidate the cached range because its not usable */
lookup_cache.left = -1;
return (*range.first)->value;
}
ControlEvent*
Curve::point_factory (double when, double val) const
{
return new CurvePoint (when, val);
}
ControlEvent*
Curve::point_factory (const ControlEvent& other) const
{
return new CurvePoint (other.when, other.value);
}
#ifdef STATE_MANAGER
Change
Curve::restore_state (StateManager::State& state)
{
mark_dirty ();
return AutomationList::restore_state (state);
}
#endif
extern "C" {
void
curve_get_vector_from_c (void *arg, double x0, double x1, float* vec, int32_t vecsize)
{
static_cast<Curve*>(arg)->get_vector (x0, x1, vec, vecsize);
}
}