sfizz/src/sfizz/Curve.h
Jean Pierre Cimalando b692377f7b Add the Flex EG
2020-09-12 01:46:00 +02:00

160 lines
4 KiB
C++

// SPDX-License-Identifier: BSD-2-Clause
// This code is part of the sfizz library and is licensed under a BSD 2-clause
// license. You should have receive a LICENSE.md file along with the code.
// If not, contact the sfizz maintainers at https://github.com/sfztools/sfizz
#pragma once
#include "absl/types/span.h"
#include "MathHelpers.h"
#include "SfzHelpers.h"
#include <array>
#include <vector>
#include <memory>
namespace sfz
{
struct Opcode;
/**
* @brief A value-mapping controller curve, built-in or user-defined.
*/
class Curve {
public:
enum { NumValues = 128 };
/**
* @brief Compute the curve for integral x in domain [0:127]
*/
float evalCC7(int value7) const
{
return _points[clamp(value7, 0, 127)];
}
/**
* @brief Compute the curve for real x in domain [0:127]
*/
float evalCC7(float value7) const
{
value7 = clamp(value7, 0.0f, 127.0f);
int i1 = static_cast<int>(value7);
int i2 = std::min(127, i1 + 1);
float mu = value7 - i1;
return _points[i1] + mu * (_points[i2] - _points[i1]);
}
/**
* @brief Compute the curve for real x in domain [0:1]
*/
float evalNormalized(float value) const
{
return evalCC7(value * 127.0f);
}
/**
* @brief Kind of curve interpolator
*/
enum class Interpolator {
Linear,
Spline,
};
/**
* @brief Build a curve based on contents of a <curve> header
*
* @param members contents of the <curve> header
* @param itp kind of interpolator to fill between values
* @param limit whether to force values in domain [-1:+1]
*/
static Curve buildCurveFromHeader(
absl::Span<const Opcode> members,
Interpolator itp = Interpolator::Linear, bool limit = false);
/**
* @brief Build a curve based on sfz v1 "amp_velcurve_&" points
*
* @param points the points vector
* @param itp kind of interpolator to fill between values
* @param invert whether to invert the curve
*/
static Curve buildFromVelcurvePoints(
absl::Span<const std::pair<uint8_t, float>> points,
Interpolator itp = Interpolator::Linear, bool invert = false);
/**
* @brief Number of predefined curves
*/
enum { NumPredefinedCurves = 7 };
/**
* @brief Build a predefined curve
*/
static Curve buildPredefinedCurve(int index);
/**
* @brief Build a linear curve from v1 to v2
*/
static Curve buildBipolar(float v1, float v2);
/**
* @brief Build a curve from a table of points
*/
static Curve buildFromPoints(const float points[NumValues]);
/**
* @brief Get a linear curve from 0 to 1
*/
static const Curve& getDefault();
private:
void fill(Interpolator itp, const bool fillStatus[NumValues]);
void lerpFill(const bool fillStatus[NumValues]);
void splineFill(const bool fillStatus[NumValues]);
private:
std::array<float, NumValues> _points {{}};
};
/**
* @brief A collection of curves organized by index.
*/
class CurveSet {
public:
/*
* @brief Create a curve set initialized with the default curves.
*/
static CurveSet createPredefined();
/*
* @brief Add a curve.
*
* @param curve a curve to add
* @param explicitIndex if not -1, the explicit index of the curve
*/
void addCurve(const Curve& curve, int explicitIndex = -1);
/**
* @brief Add a curve based on contents of a <curve> header
*
* @param members contents of the <curve> header
*/
void addCurveFromHeader(absl::Span<const Opcode> members);
/**
* @brief Get a curve given its index
*/
const Curve& getCurve(unsigned index) const;
/**
* @brief Get the number of slots.
*/
unsigned getNumCurves() const
{
return static_cast<unsigned>(_curves.size());
}
private:
std::vector<std::unique_ptr<Curve>> _curves;
bool _useExplicitIndexing = false;
};
} // namespace sfz