245 lines
9.8 KiB
C++
245 lines
9.8 KiB
C++
// velocity_curve.cpp — see velocity_curve.h. Pure eval + editing/clamp/inverse map; no host types.
|
|
|
|
#include "core/instrument/engine/velocity_curve.h"
|
|
|
|
#include <algorithm>
|
|
#include <cmath>
|
|
#include <utility>
|
|
|
|
namespace reasampler::instrument::engine {
|
|
|
|
namespace {
|
|
|
|
double clampVelocity(double v) { return std::clamp(v, kVelMin, kVelMax); }
|
|
double clampAmp(double a) { return std::clamp(a, kAmpMin, kAmpMax); }
|
|
|
|
// X spans the width for [0,127]; Y spans (height-1) rows for amp [0,1] with amp 1 at the TOP
|
|
// (pixel y increases downward, so this axis is inverted relative to amp).
|
|
double velPerPixel(const VelocityCurve::Box& box) {
|
|
const int w = std::max(0, box.width);
|
|
if (w <= 0) return 0.0;
|
|
return (kVelMax - kVelMin) / static_cast<double>(w);
|
|
}
|
|
double ampPerPixel(const VelocityCurve::Box& box) {
|
|
const int h = std::max(0, box.height);
|
|
if (h <= 1) return 0.0;
|
|
return (kAmpMax - kAmpMin) / static_cast<double>(h - 1);
|
|
}
|
|
int velToX(const VelocityCurve::Box& box, double velocity) {
|
|
const int w = std::max(0, box.width);
|
|
if (w <= 0) return box.left;
|
|
const double frac = (clampVelocity(velocity) - kVelMin) / (kVelMax - kVelMin);
|
|
return box.left + static_cast<int>(frac * static_cast<double>(w) + 0.5);
|
|
}
|
|
int ampToY(const VelocityCurve::Box& box, double amp) {
|
|
const int h = std::max(0, box.height);
|
|
if (h <= 1) return box.top;
|
|
const double frac = (clampAmp(amp) - kAmpMin) / (kAmpMax - kAmpMin);
|
|
return box.top + static_cast<int>((1.0 - frac) * static_cast<double>(h - 1) + 0.5);
|
|
}
|
|
|
|
} // namespace
|
|
|
|
VelocityCurve VelocityCurve::flat() {
|
|
VelocityCurve c;
|
|
c.points_ = {{kVelMin, kAmpMax}, {kVelMax, kAmpMax}};
|
|
return c;
|
|
}
|
|
|
|
VelocityCurve VelocityCurve::linear() {
|
|
VelocityCurve c;
|
|
c.points_ = {{kVelMin, kAmpMin}, {kVelMax, kAmpMax}};
|
|
return c;
|
|
}
|
|
|
|
VelocityCurve VelocityCurve::fromPoints(std::vector<VelocityPoint> pts) {
|
|
// Stable sort so coincident-X points keep their wire order (eval stays well-defined for
|
|
// duplicate-X knots).
|
|
for (VelocityPoint& p : pts) {
|
|
p.velocity = clampVelocity(p.velocity);
|
|
p.amp = clampAmp(p.amp);
|
|
}
|
|
std::stable_sort(pts.begin(), pts.end(),
|
|
[](const VelocityPoint& a, const VelocityPoint& b) {
|
|
return a.velocity < b.velocity;
|
|
});
|
|
if (pts.size() < 2) return flat();
|
|
if (pts.front().velocity > kVelMin) {
|
|
pts.insert(pts.begin(), VelocityPoint{kVelMin, pts.front().amp});
|
|
} else {
|
|
pts.front().velocity = kVelMin;
|
|
}
|
|
if (pts.back().velocity < kVelMax) {
|
|
pts.push_back(VelocityPoint{kVelMax, pts.back().amp});
|
|
} else {
|
|
pts.back().velocity = kVelMax;
|
|
}
|
|
VelocityCurve c;
|
|
c.points_ = std::move(pts);
|
|
return c;
|
|
}
|
|
|
|
namespace {
|
|
|
|
// Fritsch-Carlson monotone-cubic tangent: a sign change (or flat) neighbour is a local extremum,
|
|
// so the tangent pins to 0 to avoid overshoot; otherwise the weighted-harmonic-mean tangent,
|
|
// which for collinear knots (dPrev==dNext) reduces exactly to the shared secant — this is what
|
|
// makes the spline reproduce a straight line to ~1e-15 for linear()-style input.
|
|
double fritschCarlsonTangent(double dPrev, double dNext, double spanPrev, double spanNext) {
|
|
if (dPrev * dNext <= 0.0) return 0.0;
|
|
const double w1 = 2.0 * spanNext + spanPrev;
|
|
const double w2 = spanNext + 2.0 * spanPrev;
|
|
return (w1 + w2) / (w1 / dPrev + w2 / dNext);
|
|
}
|
|
|
|
} // namespace
|
|
|
|
double VelocityCurve::eval(double velocity) const {
|
|
if (points_.empty()) return kAmpMax;
|
|
if (points_.size() == 1) return clampAmp(points_[0].amp);
|
|
const double v = clampVelocity(velocity);
|
|
if (v <= points_.front().velocity) return clampAmp(points_.front().amp);
|
|
if (v >= points_.back().velocity) return clampAmp(points_.back().amp);
|
|
for (std::size_t i = 0; i + 1 < points_.size(); ++i) {
|
|
const VelocityPoint& a = points_[i];
|
|
const VelocityPoint& b = points_[i + 1];
|
|
if (v >= a.velocity && v <= b.velocity) {
|
|
const double span = b.velocity - a.velocity;
|
|
// Coincident-X neighbours (a step): zero-width segment, no interior to blend.
|
|
if (span <= 0.0) return clampAmp(b.amp);
|
|
|
|
// Monotone cubic Hermite (Fritsch-Carlson): provably stays within [a.amp, b.amp]
|
|
// between the two knots (no overshoot), reproducing a straight line for collinear input.
|
|
const double d = (b.amp - a.amp) / span;
|
|
|
|
double mA = d;
|
|
if (i > 0) {
|
|
const VelocityPoint& prev = points_[i - 1];
|
|
const double spanPrev = a.velocity - prev.velocity;
|
|
if (spanPrev > 0.0) {
|
|
const double dPrev = (a.amp - prev.amp) / spanPrev;
|
|
mA = fritschCarlsonTangent(dPrev, d, spanPrev, span);
|
|
} else {
|
|
mA = 0.0;
|
|
}
|
|
}
|
|
double mB = d;
|
|
if (i + 2 < points_.size()) {
|
|
const VelocityPoint& next = points_[i + 2];
|
|
const double spanNext = next.velocity - b.velocity;
|
|
if (spanNext > 0.0) {
|
|
const double dNext = (next.amp - b.amp) / spanNext;
|
|
mB = fritschCarlsonTangent(d, dNext, span, spanNext);
|
|
} else {
|
|
mB = 0.0;
|
|
}
|
|
}
|
|
|
|
const double t = (v - a.velocity) / span;
|
|
const double t2 = t * t;
|
|
const double t3 = t2 * t;
|
|
const double h00 = 2.0 * t3 - 3.0 * t2 + 1.0;
|
|
const double h10 = t3 - 2.0 * t2 + t;
|
|
const double h01 = -2.0 * t3 + 3.0 * t2;
|
|
const double h11 = t3 - t2;
|
|
const double y = h00 * a.amp + h10 * span * mA + h01 * b.amp + h11 * span * mB;
|
|
return clampAmp(y);
|
|
}
|
|
}
|
|
return clampAmp(points_.back().amp); // unreachable (v is between the endpoints)
|
|
}
|
|
|
|
std::size_t VelocityCurve::addPoint(double velocity, double amp) {
|
|
const VelocityPoint p{clampVelocity(velocity), clampAmp(amp)};
|
|
// First index strictly greater, so a duplicate-X point lands immediately after the existing one.
|
|
std::size_t i = 0;
|
|
while (i < points_.size() && points_[i].velocity <= p.velocity) ++i;
|
|
points_.insert(points_.begin() + static_cast<std::ptrdiff_t>(i), p);
|
|
return i;
|
|
}
|
|
|
|
VelocityPoint VelocityCurve::movePoint(std::size_t index, double velocity, double amp) {
|
|
if (index >= points_.size()) return VelocityPoint{}; // no-op (out of range)
|
|
const bool isFirst = (index == 0);
|
|
const bool isLast = (index + 1 == points_.size());
|
|
|
|
double newAmp = clampAmp(amp);
|
|
double newVel;
|
|
if (isFirst) {
|
|
newVel = kVelMin;
|
|
} else if (isLast) {
|
|
newVel = kVelMax;
|
|
} else {
|
|
const double lo = points_[index - 1].velocity;
|
|
const double hi = points_[index + 1].velocity;
|
|
newVel = std::clamp(clampVelocity(velocity), lo, hi);
|
|
}
|
|
points_[index] = VelocityPoint{newVel, newAmp};
|
|
return points_[index];
|
|
}
|
|
|
|
bool VelocityCurve::deletePoint(std::size_t index) {
|
|
if (index >= points_.size()) return false;
|
|
if (index == 0 || index + 1 == points_.size()) return false; // endpoints are not deletable
|
|
points_.erase(points_.begin() + static_cast<std::ptrdiff_t>(index));
|
|
return true;
|
|
}
|
|
|
|
VelocityCurve::CurvePixel VelocityCurve::pixelFromPoint(const Box& box, const VelocityPoint& p) {
|
|
return CurvePixel{velToX(box, p.velocity), ampToY(box, p.amp)};
|
|
}
|
|
|
|
VelocityPoint VelocityCurve::pointFromPixel(const Box& box, int x, int y) {
|
|
// Exact inverse of velToX/ampToY (within one pixel); degenerate dims collapse the same way.
|
|
VelocityPoint p;
|
|
const int w = std::max(0, box.width);
|
|
const int h = std::max(0, box.height);
|
|
p.velocity = (w <= 0)
|
|
? kVelMin
|
|
: clampVelocity(kVelMin + static_cast<double>(x - box.left) / static_cast<double>(w) *
|
|
(kVelMax - kVelMin));
|
|
p.amp = (h <= 1)
|
|
? kAmpMax
|
|
: clampAmp(kAmpMax - static_cast<double>(y - box.top) / static_cast<double>(h - 1) *
|
|
(kAmpMax - kAmpMin));
|
|
return p;
|
|
}
|
|
|
|
int VelocityCurve::pointAtPixel(const Box& box, int x, int y) const {
|
|
for (std::size_t i = 0; i < points_.size(); ++i) {
|
|
const int px = velToX(box, points_[i].velocity);
|
|
const int py = ampToY(box, points_[i].amp);
|
|
if (std::abs(x - px) <= kCurveNodeGrabRadius && std::abs(y - py) <= kCurveNodeGrabRadius) {
|
|
return static_cast<int>(i);
|
|
}
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
VelocityCurve VelocityCurve::resolvePointDrag(const VelocityCurve& grabCurve, std::size_t index,
|
|
const Box& box, int dxPixels, int dyPixels) {
|
|
VelocityCurve out = grabCurve;
|
|
if (index >= out.points_.size()) return out; // out of range -> no motion
|
|
const double velPerPx = velPerPixel(box);
|
|
const double ampPerPx = ampPerPixel(box);
|
|
if (velPerPx <= 0.0 || ampPerPx <= 0.0) return out; // degenerate box -> no motion
|
|
|
|
const VelocityPoint& grab = grabCurve.points_[index];
|
|
const double newVel = grab.velocity + static_cast<double>(dxPixels) * velPerPx;
|
|
// Y increases downward but amp increases upward, so a downward drag (positive dy) LOWERS amp.
|
|
const double newAmp = grab.amp - static_cast<double>(dyPixels) * ampPerPx;
|
|
out.movePoint(index, newVel, newAmp); // applies box + neighbour-X + endpoint-pin clamps
|
|
return out;
|
|
}
|
|
|
|
bool VelocityCurve::equals(const VelocityCurve& other, double eps) const {
|
|
if (points_.size() != other.points_.size()) return false;
|
|
for (std::size_t i = 0; i < points_.size(); ++i) {
|
|
if (std::fabs(points_[i].velocity - other.points_[i].velocity) > eps) return false;
|
|
if (std::fabs(points_[i].amp - other.points_[i].amp) > eps) return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
} // namespace reasampler::instrument::engine
|