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123 lines
3.6 KiB
C++
123 lines
3.6 KiB
C++
//
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// Video.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 04/10/2019.
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// Copyright © 2019 Thomas Harte. All rights reserved.
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//
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#include "Video.hpp"
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#include <algorithm>
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using namespace Atari::ST;
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namespace {
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struct ModeParams {
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const int lines_per_frame;
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const int first_video_line;
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const int final_video_line;
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const int line_length;
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const int end_of_blank;
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const int start_of_display_enable;
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const int end_of_display_enable;
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const int start_of_output;
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const int end_of_output;
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const int start_of_blank;
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const int start_of_hsync;
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const int end_of_hsync;
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} modes[3] = {
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{313, 56, 256, 1024, 64, 116, 116+640, 116+48, 116+48+640, 904, 928, 1008 },
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{},
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{}
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};
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const ModeParams &mode_params_for_mode() {
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// TODO: rest of potential combinations, and accept mode as a paramter.
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return modes[0];
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}
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}
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Video::Video() :
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crt_(1024, 1, Outputs::Display::Type::PAL50, Outputs::Display::InputDataType::Red4Green4Blue4) {
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}
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void Video::set_scan_target(Outputs::Display::ScanTarget *scan_target) {
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crt_.set_scan_target(scan_target);
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}
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void Video::run_for(HalfCycles duration) {
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int integer_duration = duration.as_int();
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const auto mode_params = mode_params_for_mode();
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#define Period(lower, upper, type) \
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if(x >= lower && x < upper) { \
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const auto target = std::min(upper, final_x); \
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type(target - x); \
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x = target; \
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}
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while(integer_duration) {
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const int final_x = std::min(x + integer_duration, mode_params.line_length);
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integer_duration -= (final_x - x);
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if(y >= mode_params.first_video_line && y < mode_params.final_video_line) {
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// TODO: Prior to output: collect all necessary data, obeying start_of_display_enable and end_of_display_enable.
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Period(0, mode_params.end_of_blank, crt_.output_blank);
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Period(mode_params.end_of_blank, mode_params.start_of_output, output_border);
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if(x >= mode_params.start_of_output && x < mode_params.end_of_output) {
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const auto target = std::min(mode_params.end_of_output, final_x);
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x = target;
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if(x == mode_params.end_of_output) {
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uint16_t *colour_pointer = reinterpret_cast<uint16_t *>(crt_.begin_data(1));
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if(colour_pointer) *colour_pointer = 0xffff;
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crt_.output_level(mode_params.end_of_output - mode_params.start_of_output);
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}
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}
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Period(mode_params.end_of_output, mode_params.start_of_blank, output_border);
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Period(mode_params.start_of_blank, mode_params.start_of_hsync, crt_.output_blank);
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Period(mode_params.start_of_hsync, mode_params.start_of_blank, crt_.output_sync);
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Period(mode_params.start_of_blank, mode_params.line_length, crt_.output_blank);
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} else {
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// Hard code the first three lines as vertical sync.
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if(y < 3) {
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Period(0, mode_params.start_of_hsync, crt_.output_sync);
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Period(mode_params.start_of_hsync, mode_params.end_of_hsync, crt_.output_blank);
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Period(mode_params.end_of_hsync, mode_params.line_length, crt_.output_sync);
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} else {
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Period(0, mode_params.end_of_blank, crt_.output_blank);
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Period(mode_params.end_of_blank, mode_params.start_of_blank, output_border);
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Period(mode_params.start_of_blank, mode_params.start_of_hsync, crt_.output_blank);
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Period(mode_params.start_of_hsync, mode_params.start_of_blank, crt_.output_sync);
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Period(mode_params.start_of_blank, mode_params.line_length, crt_.output_blank);
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}
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}
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if(x == mode_params.line_length) {
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x = 0;
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y = (y + 1) % mode_params.lines_per_frame;
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}
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}
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#undef Period
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}
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void Video::output_border(int duration) {
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uint16_t *colour_pointer = reinterpret_cast<uint16_t *>(crt_.begin_data(1));
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if(colour_pointer) *colour_pointer = 0x333;
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crt_.output_level(duration);
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}
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