1
0
mirror of https://github.com/TomHarte/CLK.git synced 2024-11-26 08:49:37 +00:00
CLK/Components/KonamiSCC/KonamiSCC.hpp
Thomas Harte 48737a32a7 Introduces formal setting of the output volume to SampleSource.
Previously every output device was making its own decision. Which is increasingly less sustainable due to the CompoundSource.
2018-03-09 13:23:18 -05:00

75 lines
1.8 KiB
C++

//
// KonamiSCC.hpp
// Clock Signal
//
// Created by Thomas Harte on 06/01/2018.
// Copyright © 2018 Thomas Harte. All rights reserved.
//
#ifndef KonamiSCC_hpp
#define KonamiSCC_hpp
#include "../../Outputs/Speaker/Implementation/SampleSource.hpp"
#include "../../Concurrency/AsyncTaskQueue.hpp"
namespace Konami {
/*!
Provides an emulation of Konami's Sound Creative Chip ('SCC').
The SCC is a primitive wavetable synthesis chip, offering 32-sample tables,
and five channels of output. The original SCC uses the same wave for channels
four and five, the SCC+ supports different waves for the two channels.
*/
class SCC: public ::Outputs::Speaker::SampleSource {
public:
/// Creates a new SCC.
SCC(Concurrency::DeferringAsyncTaskQueue &task_queue);
/// As per ::SampleSource; provides a broadphase test for silence.
bool is_zero_level();
/// As per ::SampleSource; provides audio output.
void get_samples(std::size_t number_of_samples, std::int16_t *target);
void set_sample_volume_range(std::int16_t range);
/// Writes to the SCC.
void write(uint16_t address, uint8_t value);
/// Reads from the SCC.
uint8_t read(uint16_t address);
private:
Concurrency::DeferringAsyncTaskQueue &task_queue_;
// State from here on down is accessed ony from the audio thread.
int master_divider_ = 0;
std::int16_t master_volume_ = 0;
int16_t transient_output_level_ = 0;
struct Channel {
int period = 0;
int amplitude = 0;
int tone_counter = 0;
int offset = 0;
} channels_[5];
struct Wavetable {
std::uint8_t samples[32];
} waves_[4];
std::uint8_t channel_enable_ = 0;
std::uint8_t test_register_ = 0;
void evaluate_output_volume();
// This keeps a copy of wave memory that is accessed from the
// main emulation thread.
std::uint8_t ram_[128];
};
}
#endif /* KonamiSCC_hpp */