Mesen-X/Core/ApuEnvelope.h

62 lines
945 B
C++

#pragma once
#include "stdafx.h"
#include "ApuLengthCounter.h"
class ApuEnvelope : public ApuLengthCounter
{
private:
bool _constantVolume = false;
uint8_t _volume = 0;
uint8_t _envelope = 0;
uint8_t _envelopeCounter = 0;
bool _start = false;
int8_t _divider = 0;
uint8_t _counter = 0;
protected:
void InitializeEnvelope(uint8_t regValue)
{
_constantVolume = (regValue & 0x10) == 0x10;
_volume = regValue & 0x0F;
}
void ResetEnvelope()
{
_start = true;
}
uint32_t GetVolume()
{
if(_lengthCounter > 0) {
if(_constantVolume) {
return _volume;
} else {
return _counter;
}
} else {
return 0;
}
}
public:
void TickEnvelope()
{
if(!_start) {
_divider--;
if(_divider < 0) {
_divider = _volume;
if(_counter > 0) {
_counter--;
} else if(_lengthCounterHalt) {
_counter = 15;
}
}
} else {
_start = false;
_counter = 15;
_divider = _volume;
}
}
};