/***************************************************************************
 *                                                                         *
 *   LinuxSampler - modular, streaming capable sampler                     *
 *                                                                         *
 *   Copyright (C) 2003 by Benno Senoner and Christian Schoenebeck         *
 *                                                                         *
 *   This program 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 program 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 program; if not, write to the Free Software           *
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston,                 *
 *   MA  02111-1307  USA                                                   *
 ***************************************************************************/

#include "eg_d.h"

EG_D::EG_D(ModulationSystem::destination_t ModulationDestination) {
    this->ModulationDestination = ModulationDestination;
}

/**
 * Will be called by the voice for every audio fragment to let the EG
 * queue it's modulation changes for the current audio fragment.
 *
 * @param Samples - total number of sample points to be rendered in this
 *                  audio fragment cycle by the audio engine
 */
void EG_D::Process(uint Samples) {
    if (!DecayStepsLeft) return;

    int iSample     = TriggerDelay;
    int to_process  = Min(Samples - iSample, DecayStepsLeft);
    int process_end = iSample + to_process;
    DecayStepsLeft -= to_process;
    while (iSample < to_process) {
        ModulationSystem::pDestinationParameter[ModulationDestination][iSample++] *= Level;
        Level += DecayCoeff;
    }
    TriggerDelay = 0;
}

/**
 * Will be called by the voice when the key / voice was triggered.
 *
 * @param Depth     - Initial level of the envelope
 * @param DecayTime - Decay time of the envelope (0.000 - 10.000s)
 * @param Delay     - Number of sample points triggering should be delayed.
 */
void EG_D::Trigger(float Depth, double DecayTime, uint Delay) {
    this->TriggerDelay = Delay;
    this->Level        = Depth;

    // calculate decay parameters (lin. curve)
    DecayStepsLeft = (long) (DecayTime * ModulationSystem::SampleRate());
    DecayCoeff     = (1.0 - Depth) / DecayStepsLeft;

    dmsg(4,("Depth=%d, DecayTime=%f\n", Depth, DecayTime));
}