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CLK/Machines/AtariST/Video.hpp
2019-11-08 22:18:47 -05:00

127 lines
2.6 KiB
C++

//
// Video.hpp
// Clock Signal
//
// Created by Thomas Harte on 04/10/2019.
// Copyright © 2019 Thomas Harte. All rights reserved.
//
#ifndef Atari_ST_Video_hpp
#define Atari_ST_Video_hpp
#include "../../Outputs/CRT/CRT.hpp"
#include "../../ClockReceiver/ClockReceiver.hpp"
namespace Atari {
namespace ST {
enum class FieldFrequency {
Fifty = 0, Sixty = 1, SeventyTwo = 2
};
class Video {
public:
Video();
/*!
Sets the target device for video data.
*/
void set_scan_target(Outputs::Display::ScanTarget *scan_target);
/*!
Produces the next @c duration period of pixels.
*/
void run_for(HalfCycles duration);
/*!
@returns the number of cycles until there is next a change in the hsync,
vsync or display_enable outputs.
*/
HalfCycles get_next_sequence_point();
bool hsync();
bool vsync();
bool display_enabled();
void set_ram(uint16_t *, size_t size);
uint16_t read(int address);
void write(int address, uint16_t value);
private:
Outputs::CRT::CRT crt_;
uint16_t raw_palette_[16];
uint16_t palette_[16];
int base_address_ = 0;
int current_address_ = 0;
uint16_t *ram_;
uint16_t line_buffer_[256];
int x_ = 0, y_ = 0, next_y_ = 0;
void output_border(int duration);
uint16_t video_mode_ = 0;
uint16_t sync_mode_ = 0;
FieldFrequency field_frequency_ = FieldFrequency::Fifty;
enum class OutputBpp {
One, Two, Four
} output_bpp_;
void update_output_mode();
struct HorizontalState {
bool enable = false;
bool blank = false;
bool sync = false;
} horizontal_;
struct VerticalState {
bool enable = false;
bool blank = false;
enum class SyncSchedule {
/// No sync events this line.
None,
/// Sync should begin during this horizontal line.
Begin,
/// Sync should end during this horizontal line.
End,
} sync_schedule = SyncSchedule::None;
bool sync = false;
} vertical_, next_vertical_;
int line_length_ = 1024;
int data_latch_position_ = 0;
uint16_t data_latch_[4];
union {
uint64_t output_shifter_;
uint32_t shifter_halves_[2];
};
void shift_out(int length);
void latch_word();
struct PixelBufferState {
uint16_t *pixel_pointer;
int pixels_output = 0;
int cycles_output = 0;
OutputBpp output_bpp;
void flush(Outputs::CRT::CRT &crt) {
if(cycles_output) {
crt.output_data(cycles_output, size_t(pixels_output));
pixels_output = cycles_output = 0;
pixel_pointer = nullptr;
}
}
void allocate(Outputs::CRT::CRT &crt) {
flush(crt);
pixel_pointer = reinterpret_cast<uint16_t *>(crt.begin_data(328));
}
} pixel_buffer_;
};
}
}
#endif /* Atari_ST_Video_hpp */