1 /*************************************************************************** 2 * * 3 * Copyright (C) 2005 - 2019 Christian Schoenebeck * 4 * * 5 * This library is free software; you can redistribute it and/or modify * 6 * it under the terms of the GNU General Public License as published by * 7 * the Free Software Foundation; either version 2 of the License, or * 8 * (at your option) any later version. * 9 * * 10 * This library is distributed in the hope that it will be useful, * 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of * 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * 13 * GNU General Public License for more details. * 14 * * 15 * You should have received a copy of the GNU General Public License * 16 * along with this library; if not, write to the Free Software * 17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, * 18 * MA 02111-1307 USA * 19 ***************************************************************************/ 20 21 #ifndef __LS_LFOBASE_H__ 22 #define __LS_LFOBASE_H__ 23 24 #include "../LFO.h" 25 #include "../../common/RTMath.h" 26 27 #include <math.h> 28 #include <stdint.h> 29 30 namespace LinuxSampler { 31 32 /** @brief POD base for all LFO implementations. 33 * 34 * This structure acts as POD (Plain Old Data structure) base for all LFO 35 * implementations. For efficiency reasons all our LFOs are C++ template 36 * classes. By deriving all those LFO C++ templase classes from this 37 * POD structure, it allows us to at least do a unified @code delete for 38 * any LFO object, which would not work on @code void* pointers (correctly). 39 * 40 * ATM this is actually only used in LFO.cpp. 41 */ 42 struct LFOPOD { 43 }; 44 45 /** @brief LFO (abstract base class) 46 * 47 * Abstract base class for all Low Frequency Oscillator implementations. 48 */ 49 template<LFO::range_type_t RANGE> 50 class LFOBase : public LFOPOD { 51 public: 52 53 // *************** attributes *************** 54 // * 55 56 uint8_t ExtController; ///< MIDI control change controller number if the LFO is controlled by an external controller, 0 otherwise. 57 58 59 // *************** methods *************** 60 // * 61 62 /** 63 * Constructor 64 * 65 * @param Max - maximum value of the output levels 66 */ LFOBase(float Max)67 LFOBase(float Max) { 68 this->ExtController = 0; 69 this->Max = Max; 70 this->InternalDepth = 0; 71 this->Frequency = 20.f; 72 this->ExtControlValue = 0; 73 this->ExtControlDepthCoeff = 0; 74 this->ScriptDepthFactor = 1.f; 75 this->ScriptFrequencyFactor = 1.f; 76 this->pFinalDepth = NULL; 77 this->pFinalFrequency = NULL; 78 } 79 80 /** 81 * Calculates exactly one sample point of the LFO wave. This 82 * inline method has to be implemented by the descendant. 83 * 84 * @returns next LFO level 85 */ 86 //abstract inline float render(); //< what a pity that abstract inliners are not supported by C++98 (probably by upcoming C++0x?) 87 88 /** 89 * Update LFO depth with a new external controller value. This 90 * inline method has to be implemented by the descendant. 91 * 92 * @param ExtControlValue - new external controller value 93 */ 94 //abstract inline void updateByMIDICtrlValue(const uint16_t& ExtControlValue); //< what a pity that abstract inliners are not supported by C++98 (probably by upcoming C++0x?) 95 96 /** 97 * Will be called by the voice when the key / voice was triggered. 98 * 99 * @param Frequency - frequency of the oscillator in Hz 100 * @param StartLevel - on which level the wave should start 101 * @param InternalDepth - firm, internal oscillator amplitude 102 * @param ExtControlDepth - defines how strong the external MIDI 103 * controller has influence on the 104 * oscillator amplitude 105 * @param FlipPhase - inverts the oscillator wave against 106 * a horizontal axis 107 * @param SampleRate - current sample rate of the engines 108 * audio output signal 109 */ 110 virtual void trigger(float Frequency, LFO::start_level_t StartLevel, uint16_t InternalDepth, uint16_t ExtControlDepth, bool FlipPhase, unsigned int SampleRate) = 0; 111 112 protected: 113 float Max; 114 float InternalDepth; 115 float Frequency; ///< Internal base frequency for this LFO. 116 float ExtControlValue; ///< The current external MIDI controller value (0-127). 117 float ExtControlDepthCoeff; ///< A usually constant factor used to convert a new MIDI controller value from range 0-127 to the required internal implementation dependent value range. 118 float ScriptDepthFactor; ///< Usually neutral (1.0), only altered by external RT instrument script functions. 119 float ScriptFrequencyFactor; ///< Usually neutral (1.0), only altered by external RT instrument script functions. 120 float* pFinalDepth; ///< Usually NULL; it may be set to one of above's member variables in order to process that and ignore all other sources for LFO depth. 121 float* pFinalFrequency; ///< Usually NULL; it may be set to one of above's member variables in order to process that and ignore all other sources for LFO frequency. 122 }; 123 124 } // namespace LinuxSampler 125 126 #endif // __LS_LFOBASE_H__ 127