/***************************************************************************
 *                                                                         *
 *   Copyright (C) 2005 Christian Schoenebeck                              *
 *   Copyright (C) 2011 Christian Schoenebeck and Grigor Iliev             *
 *                                                                         *
 *   This library is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU 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 General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this library; if not, write to the Free Software           *
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston,                 *
 *   MA  02111-1307  USA                                                   *
 ***************************************************************************/

#ifndef __LS_SAWLFO_H__
#define __LS_SAWLFO_H__

#include "LFOBase.h"

namespace LinuxSampler {

    /** @brief Saw LFO (int math implementation)
     *
     * This is a saw Low Frequency Oscillator which uses pure integer
     * math (without branches) to synthesize the saw wave.
     */
    template<range_type_t RANGE, bool SAWUP>
    class SawLFO : public LFOBase<RANGE> {
        public:

            /**
             * Constructor
             *
             * @param Max - maximum value of the output levels
             */
            SawLFO(float Max) : LFOBase<RANGE>::LFOBase(Max) {
            }

            /**
             * Calculates exactly one sample point of the LFO wave.
             *
             * @returns next LFO level
             */
            inline float render() {
                const unsigned int intLimit = (unsigned int) -1; // all 0xFFFF...
                
                uiLevel += c;
                if (RANGE == range_unsigned)
                    return normalizer * (float) (SAWUP ? uiLevel : intLimit - uiLevel);
                else /* signed range */
                    return normalizer * (float) (SAWUP ? uiLevel : intLimit - uiLevel) + offset;
            }

            /**
             * Update LFO depth with a new external controller value.
             *
             * @param ExtControlValue - new external controller value
             */
            inline void update(const uint16_t& ExtControlValue) {
                const unsigned int intLimit = (unsigned int) -1; // all 0xFFFF...
                const float max = this->InternalDepth + ExtControlValue * this->ExtControlDepthCoeff;
                if (RANGE == range_unsigned) {
                    normalizer = max / (float) intLimit;
                } else { // signed range
                    normalizer = max / (float) intLimit * 2.0f;
                    offset     = -max;
                }
            }
            
            /**
             * Will be called by the voice when the key / voice was triggered.
             *
             * @param Frequency       - frequency of the oscillator in Hz
             * @param StartLevel      - not implemented
             * @param InternalDepth   - firm, internal oscillator amplitude
             * @param ExtControlDepth - defines how strong the external MIDI
             *                          controller has influence on the
             *                          oscillator amplitude
             * @param FlipPhase       - not implemented
             * @param SampleRate      - current sample rate of the engines
             *                          audio output signal
             */
            virtual void trigger(float Frequency, start_level_t StartLevel, uint16_t InternalDepth, uint16_t ExtControlDepth, bool FlipPhase, unsigned int SampleRate) {
                this->InternalDepth        = (InternalDepth / 1200.0f) * this->Max;
                this->ExtControlDepthCoeff = (((float) ExtControlDepth / 1200.0f) / 127.0f) * this->Max;

                const unsigned int intLimit = (unsigned int) -1; // all 0xFFFF...
                const float r = Frequency / (float) SampleRate; // frequency alteration quotient
                c = (int) (intLimit * r);

                uiLevel = 0;
            }
            
            /**
             * Should be invoked after the LFO is triggered.
             * @param phase From 0 to 360 degrees.
             */
            void setPhase(float phase) {
                if (phase < 0) phase = 0;
                if (phase > 360) phase = 360;
                phase /= 360.0f;
                const unsigned int intLimit = (unsigned int) -1; // all 0xFFFF...
                uiLevel = intLimit * phase;
            }

        protected:
            unsigned int uiLevel;
            int   c;
            float offset; ///< only needed for signed range
            float normalizer;
    };
    
    
    template<range_type_t RANGE>
    class SawUpLFO : public SawLFO<RANGE, true> {
        public:
            SawUpLFO(float Max) : SawLFO<RANGE, true>::SawLFO(Max) { }
    };
    
    template<range_type_t RANGE>
    class SawDownLFO : public SawLFO<RANGE, false> {
        public:
            SawDownLFO(float Max) : SawLFO<RANGE, false>::SawLFO(Max) { }
    };

} // namespace LinuxSampler

#endif // __LS_SAWLFO_H__