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Wire envelope amplitude shaping.

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Signed-off-by: Adrian.Conlon <adrian.conlon@gmail.com>
This commit is contained in:
Adrian.Conlon 2017-09-23 00:07:30 +01:00
parent 09f7fe5dfe
commit 5084d85e49
2 changed files with 37 additions and 19 deletions
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16
LR35902/inc/Audio.h
View File

@ -19,20 +19,24 @@ namespace EightBit {
void reset();
bool zeroed() const;
int default() const;
void setDefault(int value);
int volume() const;
void setVolume(int value);
Direction direction() const;
void setDirection(int value);
void setDirection(Direction value);
int stepLength() const;
void setStepLength(int value);
int period() const;
void setPeriod(int value);
void step();
private:
int m_defaultValue;
int m_volume;
int m_direction;
int m_stepLength;
int m_period;
int m_position;
};
class Sweep final {

40
LR35902/src/Audio.cpp
View File

@ -6,19 +6,19 @@
EightBit::GameBoy::Envelope::Envelope() {}
void EightBit::GameBoy::Envelope::reset() {
m_defaultValue = m_direction = m_stepLength = 0;
m_position = m_volume = m_direction = m_period = 0;
}
bool EightBit::GameBoy::Envelope::zeroed() const {
return (default() == 0) && (stepLength() == 0) && (direction() == Attenuate);
return (volume() == 0) && (period() == 0) && (direction() == Attenuate);
}
int EightBit::GameBoy::Envelope::default() const {
return m_defaultValue;
int EightBit::GameBoy::Envelope::volume() const {
return m_volume;
}
void EightBit::GameBoy::Envelope::setDefault(int value) {
m_defaultValue = value;
void EightBit::GameBoy::Envelope::setVolume(int value) {
m_volume = value;
}
EightBit::GameBoy::Envelope::Direction EightBit::GameBoy::Envelope::direction() const {
@ -33,12 +33,23 @@ void EightBit::GameBoy::Envelope::setDirection(Direction value) {
setDirection((int)value);
}
int EightBit::GameBoy::Envelope::stepLength() const {
return m_stepLength;
int EightBit::GameBoy::Envelope::period() const {
return m_period;
}
void EightBit::GameBoy::Envelope::setStepLength(int value) {
m_stepLength = value;
void EightBit::GameBoy::Envelope::setPeriod(int value) {
m_position = m_period = value;
}
void EightBit::GameBoy::Envelope::step() {
if (m_period != 0) {
if (--m_position == 0) {
auto volume = m_volume + (m_direction == Amplify ? +1 : -1);
if (volume >= 0 || volume <= 15)
m_volume = volume;
m_position == m_period;
}
}
}
//
@ -495,15 +506,15 @@ void EightBit::GameBoy::Audio::fromNRx1(int i, uint8_t value) {
uint8_t EightBit::GameBoy::Audio::toNRx2(int i) {
auto voice = (EnvelopedRectangularVoice*)m_voices[i].get();
auto& envelope = voice->envelope();
return (envelope.default() << 4) | (envelope.direction() << 3) | envelope.stepLength();
return (envelope.volume() << 4) | (envelope.direction() << 3) | envelope.period();
}
void EightBit::GameBoy::Audio::fromNRx2(int i, uint8_t value) {
auto voice = (EnvelopedRectangularVoice*)m_voices[i].get();
auto& envelope = voice->envelope();
envelope.setDefault((value >> 4) & Processor::Mask4); // Bits 4-7
envelope.setVolume((value >> 4) & Processor::Mask4); // Bits 4-7
envelope.setDirection((value >> 3) & Processor::Mask1); // Bit 3
envelope.setStepLength(value & Processor::Mask3); // Bits 0-2
envelope.setPeriod(value & Processor::Mask3); // Bits 0-2
}
uint8_t EightBit::GameBoy::Audio::toNRx3(int i) {
@ -776,6 +787,9 @@ void EightBit::GameBoy::Audio::Sequencer_LengthStep(const int step) {
}
void EightBit::GameBoy::Audio::Sequencer_VolumeStep(const int step) {
voice1()->envelope().step();
voice2()->envelope().step();
voice4()->envelope().step();
}
void EightBit::GameBoy::Audio::Sequencer_SweepStep(const int step) {