00001 #ifndef __SG_INTERPOLATOR_HXX 00002 #define __SG_INTERPOLATOR_HXX 00003 00004 // SGInterpolator 00005 // Subsystem that manages smooth linear interpolation of property 00006 // values across multiple data points and arbitrary time intervals. 00007 00008 // Written by Andrew J. Ross, started December 2003 00009 // 00010 // Copyright (C) 2003 Andrew J. Ross - andy@plausible.org 00011 // 00012 // This library is free software; you can redistribute it and/or 00013 // modify it under the terms of the GNU Library General Public 00014 // License as published by the Free Software Foundation; either 00015 // version 2 of the License, or (at your option) any later version. 00016 // 00017 // This library is distributed in the hope that it will be useful, 00018 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00019 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00020 // Library General Public License for more details. 00021 // 00022 // You should have received a copy of the GNU General Public License 00023 // along with this program; if not, write to the Free Software 00024 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 00025 00026 #include <simgear/props/props.hxx> 00027 #include <simgear/structure/subsystem_mgr.hxx> 00028 00029 // TODO: support a callback upon interpolation completion so that user 00030 // code can register another one immediately without worrying about 00031 // timer aliasing. 00032 00033 class SGInterpolator : public SGSubsystem { 00034 public: 00035 SGInterpolator() { _list = 0; } 00036 virtual void init() {} 00037 virtual void update(double delta_time_sec); 00038 00039 // Simple method that interpolates a double property value from 00040 // its current value (default of zero) to the specified target 00041 // over the specified time. 00042 void interpolate(SGPropertyNode* prop, double value, double dt_sec); 00043 00044 // More elaborate version that takes a pointer to lists of 00045 // arbitrary size. 00046 void interpolate(SGPropertyNode* prop, int nPoints, 00047 double* values, double* deltas); 00048 00049 // Cancels any interpolation of the specified property, leaving 00050 // its value at the current (mid-interpolation) state. 00051 void cancel(SGPropertyNode* prop); 00052 00053 private: 00054 struct Interp { 00055 SGPropertyNode_ptr target; 00056 int nPoints; 00057 double* curve; // time0, val0, time1, val1, ... 00058 Interp* next; 00059 00060 ~Interp() { delete[] curve; } 00061 double& dt(int i) { return curve[2*i]; } 00062 double& val(int i) { return curve[2*i + 1]; } 00063 }; 00064 Interp* _list; 00065 00066 bool interp(Interp* rec, double dt); 00067 void addNew(SGPropertyNode* prop, int nPoints); 00068 }; 00069 00070 #endif // __SG_INTERPOLATOR_HXX
1.6.1