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CLK/Machines/Apple/AppleII/Video.cpp
2021-06-13 19:46:47 -04:00

255 lines
10 KiB
C++

//
// Video.cpp
// Clock Signal
//
// Created by Thomas Harte on 14/04/2018.
// Copyright 2018 Thomas Harte. All rights reserved.
//
#include "Video.hpp"
using namespace Apple::II::Video;
VideoBase::VideoBase(bool is_iie, std::function<void(Cycles)> &&target) :
VideoSwitches<Cycles>(is_iie, Cycles(2), std::move(target)),
crt_(910, 1, Outputs::Display::Type::NTSC60, Outputs::Display::InputDataType::Luminance1),
is_iie_(is_iie) {
crt_.set_display_type(Outputs::Display::DisplayType::CompositeColour);
set_use_square_pixels(use_square_pixels_);
// TODO: there seems to be some sort of bug whereby switching modes can cause
// a signal discontinuity that knocks phase out of whack. So it isn't safe to
// use default_colour_bursts elsewhere, though it otherwise should be. If/when
// it is, start doing so and return to setting the immediate phase up here.
// crt_.set_immediate_default_phase(0.5f);
}
void VideoBase::set_use_square_pixels(bool use_square_pixels) {
use_square_pixels_ = use_square_pixels;
// HYPER-UGLY HACK. See correlated hack in the Macintosh.
#if defined(__APPLE__) && !defined(IGNORE_APPLE)
crt_.set_visible_area(Outputs::Display::Rect(0.128f, 0.122f, 0.75f, 0.77f));
#else
if(use_square_pixels) {
crt_.set_visible_area(Outputs::Display::Rect(0.128f, 0.09f, 0.75f, 0.77f));
} else {
crt_.set_visible_area(Outputs::Display::Rect(0.128f, 0.12f, 0.75f, 0.77f));
}
#endif
if(use_square_pixels) {
// From what I can make out, many contemporary Apple II monitors were
// calibrated slightly to stretch the Apple II's display slightly wider
// than it should be per the NTSC standards, for approximately square
// pixels. This reproduces that.
// 243 lines and 52µs are visible.
// i.e. to be square, 1 pixel should be: (1/243 * 52) * (3/4) = 156/972 = 39/243 µs
// On an Apple II each pixel is actually 1/7µs.
// Therefore the adjusted aspect ratio should be (4/3) * (39/243)/(1/7) = (4/3) * 273/243 = 1092/729 = 343/243 ~= 1.412
crt_.set_aspect_ratio(343.0f / 243.0f);
} else {
// Standard NTSC aspect ratio.
crt_.set_aspect_ratio(4.0f / 3.0f);
}
}
bool VideoBase::get_use_square_pixels() {
return use_square_pixels_;
}
void VideoBase::set_scan_target(Outputs::Display::ScanTarget *scan_target) {
crt_.set_scan_target(scan_target);
}
Outputs::Display::ScanStatus VideoBase::get_scaled_scan_status() const {
return crt_.get_scaled_scan_status() / 14.0f;
}
void VideoBase::set_display_type(Outputs::Display::DisplayType display_type) {
crt_.set_display_type(display_type);
}
Outputs::Display::DisplayType VideoBase::get_display_type() const {
return crt_.get_display_type();
}
void VideoBase::output_text(uint8_t *target, const uint8_t *const source, size_t length, size_t pixel_row) const {
for(size_t c = 0; c < length; ++c) {
const int character = source[c] & character_zones_[source[c] >> 6].address_mask;
const uint8_t xor_mask = character_zones_[source[c] >> 6].xor_mask;
const std::size_t character_address = size_t(character << 3) + pixel_row;
const uint8_t character_pattern = character_rom_[character_address] ^ xor_mask;
// The character ROM is output MSB to LSB rather than LSB to MSB.
target[0] = target[1] = character_pattern & 0x40;
target[2] = target[3] = character_pattern & 0x20;
target[4] = target[5] = character_pattern & 0x10;
target[6] = target[7] = character_pattern & 0x08;
target[8] = target[9] = character_pattern & 0x04;
target[10] = target[11] = character_pattern & 0x02;
target[12] = target[13] = character_pattern & 0x01;
graphics_carry_ = character_pattern & 0x01;
target += 14;
}
}
void VideoBase::output_double_text(uint8_t *target, const uint8_t *const source, const uint8_t *const auxiliary_source, size_t length, size_t pixel_row) const {
for(size_t c = 0; c < length; ++c) {
const std::size_t character_addresses[2] = {
size_t(
(auxiliary_source[c] & character_zones_[auxiliary_source[c] >> 6].address_mask) << 3
) + pixel_row,
size_t(
(source[c] & character_zones_[source[c] >> 6].address_mask) << 3
) + pixel_row
};
const uint8_t character_patterns[2] = {
uint8_t(
character_rom_[character_addresses[0]] ^ character_zones_[auxiliary_source[c] >> 6].xor_mask
),
uint8_t(
character_rom_[character_addresses[1]] ^ character_zones_[source[c] >> 6].xor_mask
)
};
// The character ROM is output MSB to LSB rather than LSB to MSB.
target[0] = character_patterns[0] & 0x40;
target[1] = character_patterns[0] & 0x20;
target[2] = character_patterns[0] & 0x10;
target[3] = character_patterns[0] & 0x08;
target[4] = character_patterns[0] & 0x04;
target[5] = character_patterns[0] & 0x02;
target[6] = character_patterns[0] & 0x01;
target[7] = character_patterns[1] & 0x40;
target[8] = character_patterns[1] & 0x20;
target[9] = character_patterns[1] & 0x10;
target[10] = character_patterns[1] & 0x08;
target[11] = character_patterns[1] & 0x04;
target[12] = character_patterns[1] & 0x02;
target[13] = character_patterns[1] & 0x01;
graphics_carry_ = character_patterns[1] & 0x01;
target += 14;
}
}
void VideoBase::output_low_resolution(uint8_t *target, const uint8_t *const source, size_t length, int column, int row) const {
const int row_shift = row&4;
for(size_t c = 0; c < length; ++c) {
// Low-resolution graphics mode shifts the colour code on a loop, but has to account for whether this
// 14-sample output window is starting at the beginning of a colour cycle or halfway through.
if((column + int(c))&1) {
target[0] = target[4] = target[8] = target[12] = (source[c] >> row_shift) & 4;
target[1] = target[5] = target[9] = target[13] = (source[c] >> row_shift) & 8;
target[2] = target[6] = target[10] = (source[c] >> row_shift) & 1;
target[3] = target[7] = target[11] = (source[c] >> row_shift) & 2;
graphics_carry_ = (source[c] >> row_shift) & 8;
} else {
target[0] = target[4] = target[8] = target[12] = (source[c] >> row_shift) & 1;
target[1] = target[5] = target[9] = target[13] = (source[c] >> row_shift) & 2;
target[2] = target[6] = target[10] = (source[c] >> row_shift) & 4;
target[3] = target[7] = target[11] = (source[c] >> row_shift) & 8;
graphics_carry_ = (source[c] >> row_shift) & 2;
}
target += 14;
}
}
void VideoBase::output_fat_low_resolution(uint8_t *target, const uint8_t *const source, size_t length, int, int row) const {
const int row_shift = row&4;
for(size_t c = 0; c < length; ++c) {
// Fat low-resolution mode appears not to do anything to try to make odd and
// even columns compatible.
target[0] = target[1] = target[8] = target[9] = (source[c] >> row_shift) & 1;
target[2] = target[3] = target[10] = target[11] = (source[c] >> row_shift) & 2;
target[4] = target[5] = target[12] = target[13] = (source[c] >> row_shift) & 4;
target[6] = target[7] = (source[c] >> row_shift) & 8;
graphics_carry_ = (source[c] >> row_shift) & 4;
target += 14;
}
}
void VideoBase::output_double_low_resolution(uint8_t *target, const uint8_t *const source, const uint8_t *const auxiliary_source, size_t length, int column, int row) const {
const int row_shift = row&4;
for(size_t c = 0; c < length; ++c) {
if((column + int(c))&1) {
target[0] = target[4] = (auxiliary_source[c] >> row_shift) & 4;
target[1] = target[5] = (auxiliary_source[c] >> row_shift) & 8;
target[2] = target[6] = (auxiliary_source[c] >> row_shift) & 1;
target[3] = (auxiliary_source[c] >> row_shift) & 2;
target[8] = target[12] = (source[c] >> row_shift) & 8;
target[9] = target[13] = (source[c] >> row_shift) & 1;
target[10] = (source[c] >> row_shift) & 2;
target[7] = target[11] = (source[c] >> row_shift) & 4;
graphics_carry_ = (source[c] >> row_shift) & 8;
} else {
target[0] = target[4] = (auxiliary_source[c] >> row_shift) & 1;
target[1] = target[5] = (auxiliary_source[c] >> row_shift) & 2;
target[2] = target[6] = (auxiliary_source[c] >> row_shift) & 4;
target[3] = (auxiliary_source[c] >> row_shift) & 8;
target[8] = target[12] = (source[c] >> row_shift) & 2;
target[9] = target[13] = (source[c] >> row_shift) & 4;
target[10] = (source[c] >> row_shift) & 8;
target[7] = target[11] = (source[c] >> row_shift) & 1;
graphics_carry_ = (source[c] >> row_shift) & 2;
}
target += 14;
}
}
void VideoBase::output_high_resolution(uint8_t *target, const uint8_t *const source, size_t length) const {
for(size_t c = 0; c < length; ++c) {
// High resolution graphics shift out LSB to MSB, optionally with a delay of half a pixel.
// If there is a delay, the previous output level is held to bridge the gap.
// Delays may be ignored on a IIe if Annunciator 3 is set; that's the state that
// high_resolution_mask_ models.
if(source[c] & high_resolution_mask_ & 0x80) {
target[0] = graphics_carry_;
target[1] = target[2] = source[c] & 0x01;
target[3] = target[4] = source[c] & 0x02;
target[5] = target[6] = source[c] & 0x04;
target[7] = target[8] = source[c] & 0x08;
target[9] = target[10] = source[c] & 0x10;
target[11] = target[12] = source[c] & 0x20;
target[13] = source[c] & 0x40;
} else {
target[0] = target[1] = source[c] & 0x01;
target[2] = target[3] = source[c] & 0x02;
target[4] = target[5] = source[c] & 0x04;
target[6] = target[7] = source[c] & 0x08;
target[8] = target[9] = source[c] & 0x10;
target[10] = target[11] = source[c] & 0x20;
target[12] = target[13] = source[c] & 0x40;
}
graphics_carry_ = source[c] & 0x40;
target += 14;
}
}
void VideoBase::output_double_high_resolution(uint8_t *target, const uint8_t *const source, const uint8_t *const auxiliary_source, size_t length) const {
for(size_t c = 0; c < length; ++c) {
target[0] = auxiliary_source[c] & 0x01;
target[1] = auxiliary_source[c] & 0x02;
target[2] = auxiliary_source[c] & 0x04;
target[3] = auxiliary_source[c] & 0x08;
target[4] = auxiliary_source[c] & 0x10;
target[5] = auxiliary_source[c] & 0x20;
target[6] = auxiliary_source[c] & 0x40;
target[7] = source[c] & 0x01;
target[8] = source[c] & 0x02;
target[9] = source[c] & 0x04;
target[10] = source[c] & 0x08;
target[11] = source[c] & 0x10;
target[12] = source[c] & 0x20;
target[13] = source[c] & 0x40;
graphics_carry_ = auxiliary_source[c] & 0x40;
target += 14;
}
}