simgear/simgear/misc/interpolator.hxx

76 lines
2.6 KiB
C++

#ifndef __SG_INTERPOLATOR_HXX
#define __SG_INTERPOLATOR_HXX
// SGInterpolator
// Subsystem that manages smooth linear interpolation of property
// values across multiple data points and arbitrary time intervals.
// Written by Andrew J. Ross, started December 2003
//
// Copyright (C) 2003 Andrew J. Ross - andy@plausible.org
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library 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
// Library 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#include <simgear/props/props.hxx>
#include <simgear/structure/subsystem_mgr.hxx>
// TODO: support a callback upon interpolation completion so that user
// code can register another one immediately without worrying about
// timer aliasing.
class SGInterpolator : public SGSubsystem
{
public:
SGInterpolator() { _list = 0; }
// Subsystem API.
void update(double delta_time_sec) override;
// Subsystem identification.
static const char* staticSubsystemClassId() { return "interpolator"; }
// Simple method that interpolates a double property value from
// its current value (default of zero) to the specified target
// over the specified time.
void interpolate(SGPropertyNode* prop, double value, double dt_sec);
// More elaborate version that takes a pointer to lists of
// arbitrary size.
void interpolate(SGPropertyNode* prop, int nPoints,
double* values, double* deltas);
// Cancels any interpolation of the specified property, leaving
// its value at the current (mid-interpolation) state.
void cancel(SGPropertyNode* prop);
private:
struct Interp {
SGPropertyNode_ptr target;
int nPoints;
double* curve; // time0, val0, time1, val1, ...
Interp* next;
~Interp() { delete[] curve; }
double& dt(int i) { return curve[2*i]; }
double& val(int i) { return curve[2*i + 1]; }
};
Interp* _list;
bool interp(Interp* rec, double dt);
void addNew(SGPropertyNode* prop, int nPoints);
};
#endif // __SG_INTERPOLATOR_HXX