pitchenv.h

/*
 * Copyright 2013 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
#pragma once
 
#include "env.h"
 
// Computation of the DX7 pitch envelope
 
class PitchEnv {
public:
    static void init(double sample_rate);
 
    // The rates and levels arrays are calibrated to match the Dx7 parameters
    // (ie, value 0..99).
    void set(const EnvParams& p);
 
    // Result is in Q24/octave
    int32_t getsample(const EnvParams& p, int n);
    void keydown(const EnvParams& p, bool down);
    void getPosition(char* step);
    bool isDown() const { return down_; }
 
private:
    static int unit_;
    int32_t level_;
    int targetlevel_;
    bool rising_;
    int ix_;
    int inc_;
 
    bool down_;
 
    void advance(const EnvParams& p, int newix);
};
 
extern const uint8_t pitchenv_rate[];
extern const int8_t pitchenv_tab[];