mirror of
https://github.com/TomHarte/CLK.git
synced 2024-11-26 08:49:37 +00:00
225 lines
8.0 KiB
C++
225 lines
8.0 KiB
C++
//
|
||
// Video.cpp
|
||
// Clock Signal
|
||
//
|
||
// Created by Thomas Harte on 12/10/2016.
|
||
// Copyright © 2016 Thomas Harte. All rights reserved.
|
||
//
|
||
|
||
#include "Video.hpp"
|
||
|
||
using namespace Oric;
|
||
|
||
namespace {
|
||
const unsigned int PAL50VSyncStartPosition = 256*64;
|
||
const unsigned int PAL60VSyncStartPosition = 234*64;
|
||
const unsigned int PAL50VSyncEndPosition = 259*64;
|
||
const unsigned int PAL60VSyncEndPosition = 238*64;
|
||
const unsigned int PAL50Period = 312*64;
|
||
const unsigned int PAL60Period = 262*64;
|
||
}
|
||
|
||
VideoOutput::VideoOutput(uint8_t *memory) :
|
||
ram_(memory),
|
||
crt_(new Outputs::CRT::CRT(64*6, 6, Outputs::CRT::DisplayType::PAL50, 2)),
|
||
v_sync_start_position_(PAL50VSyncStartPosition), v_sync_end_position_(PAL50VSyncEndPosition),
|
||
counter_period_(PAL50Period) {
|
||
crt_->set_rgb_sampling_function(
|
||
"vec3 rgb_sample(usampler2D sampler, vec2 coordinate, vec2 icoordinate)"
|
||
"{"
|
||
"uint texValue = texture(sampler, coordinate).r;"
|
||
"return vec3( uvec3(texValue) & uvec3(4u, 2u, 1u));"
|
||
"}");
|
||
crt_->set_composite_sampling_function(
|
||
"float composite_sample(usampler2D sampler, vec2 coordinate, vec2 icoordinate, float phase, float amplitude)"
|
||
"{"
|
||
"uint texValue = uint(dot(texture(sampler, coordinate).rg, uvec2(1, 256)));"
|
||
"uint iPhase = uint((phase + 3.141592654 + 0.39269908175) * 2.0 / 3.141592654) & 3u;"
|
||
"texValue = (texValue >> (4u*(3u - iPhase))) & 15u;"
|
||
"return (float(texValue) - 4.0) / 20.0;"
|
||
"}"
|
||
);
|
||
crt_->set_composite_function_type(Outputs::CRT::CRT::CompositeSourceType::DiscreteFourSamplesPerCycle, 0.0f);
|
||
|
||
set_output_device(Outputs::CRT::OutputDevice::Television);
|
||
crt_->set_visible_area(crt_->get_rect_for_area(53, 224, 16 * 6, 40 * 6, 4.0f / 3.0f));
|
||
}
|
||
|
||
void VideoOutput::set_output_device(Outputs::CRT::OutputDevice output_device) {
|
||
output_device_ = output_device;
|
||
crt_->set_output_device(output_device);
|
||
}
|
||
|
||
void VideoOutput::set_colour_rom(const std::vector<uint8_t> &rom) {
|
||
for(std::size_t c = 0; c < 8; c++) {
|
||
std::size_t index = (c << 2);
|
||
uint16_t rom_value = static_cast<uint16_t>((static_cast<uint16_t>(rom[index]) << 8) | static_cast<uint16_t>(rom[index+1]));
|
||
rom_value = (rom_value & 0xff00) | ((rom_value >> 4)&0x000f) | ((rom_value << 4)&0x00f0);
|
||
colour_forms_[c] = rom_value;
|
||
}
|
||
|
||
// check for big endianness and byte swap if required
|
||
uint16_t test_value = 0x0001;
|
||
if(*reinterpret_cast<uint8_t *>(&test_value) != 0x01) {
|
||
for(std::size_t c = 0; c < 8; c++) {
|
||
colour_forms_[c] = static_cast<uint16_t>((colour_forms_[c] >> 8) | (colour_forms_[c] << 8));
|
||
}
|
||
}
|
||
}
|
||
|
||
Outputs::CRT::CRT *VideoOutput::get_crt() {
|
||
return crt_.get();
|
||
}
|
||
|
||
void VideoOutput::run_for(const Cycles cycles) {
|
||
// Vertical: 0–39: pixels; otherwise blank; 48–53 sync, 54–56 colour burst
|
||
// Horizontal: 0–223: pixels; otherwise blank; 256–259 sync
|
||
|
||
#define clamp(action) \
|
||
if(cycles_run_for <= number_of_cycles) { action; } else cycles_run_for = number_of_cycles;
|
||
|
||
int number_of_cycles = cycles.as_int();
|
||
while(number_of_cycles) {
|
||
int h_counter = counter_ & 63;
|
||
int cycles_run_for = 0;
|
||
|
||
if(counter_ >= v_sync_start_position_ && counter_ < v_sync_end_position_) {
|
||
// this is a sync line
|
||
cycles_run_for = v_sync_end_position_ - counter_;
|
||
clamp(crt_->output_sync(static_cast<unsigned int>(v_sync_end_position_ - v_sync_start_position_) * 6));
|
||
} else if(counter_ < 224*64 && h_counter < 40) {
|
||
// this is a pixel line
|
||
if(!h_counter) {
|
||
ink_ = 0x7;
|
||
paper_ = 0x0;
|
||
use_alternative_character_set_ = use_double_height_characters_ = blink_text_ = false;
|
||
set_character_set_base_address();
|
||
pixel_target_ = reinterpret_cast<uint16_t *>(crt_->allocate_write_area(240));
|
||
|
||
if(!counter_) {
|
||
frame_counter_++;
|
||
|
||
v_sync_start_position_ = next_frame_is_sixty_hertz_ ? PAL60VSyncStartPosition : PAL50VSyncStartPosition;
|
||
v_sync_end_position_ = next_frame_is_sixty_hertz_ ? PAL60VSyncEndPosition : PAL50VSyncEndPosition;
|
||
counter_period_ = next_frame_is_sixty_hertz_ ? PAL60Period : PAL50Period;
|
||
}
|
||
}
|
||
|
||
cycles_run_for = std::min(40 - h_counter, number_of_cycles);
|
||
int columns = cycles_run_for;
|
||
int pixel_base_address = 0xa000 + (counter_ >> 6) * 40;
|
||
int character_base_address = 0xbb80 + (counter_ >> 9) * 40;
|
||
uint8_t blink_mask = (blink_text_ && (frame_counter_&32)) ? 0x00 : 0xff;
|
||
|
||
while(columns--) {
|
||
uint8_t pixels, control_byte;
|
||
|
||
if(is_graphics_mode_ && counter_ < 200*64) {
|
||
control_byte = pixels = ram_[pixel_base_address + h_counter];
|
||
} else {
|
||
int address = character_base_address + h_counter;
|
||
control_byte = ram_[address];
|
||
int line = use_double_height_characters_ ? ((counter_ >> 7) & 7) : ((counter_ >> 6) & 7);
|
||
pixels = ram_[character_set_base_address_ + (control_byte&127) * 8 + line];
|
||
}
|
||
|
||
uint8_t inverse_mask = (control_byte & 0x80) ? 0x7 : 0x0;
|
||
pixels &= blink_mask;
|
||
|
||
if(control_byte & 0x60) {
|
||
if(pixel_target_) {
|
||
uint16_t colours[2];
|
||
if(output_device_ == Outputs::CRT::OutputDevice::Monitor) {
|
||
colours[0] = static_cast<uint8_t>(paper_ ^ inverse_mask);
|
||
colours[1] = static_cast<uint8_t>(ink_ ^ inverse_mask);
|
||
} else {
|
||
colours[0] = colour_forms_[paper_ ^ inverse_mask];
|
||
colours[1] = colour_forms_[ink_ ^ inverse_mask];
|
||
}
|
||
pixel_target_[0] = colours[(pixels >> 5)&1];
|
||
pixel_target_[1] = colours[(pixels >> 4)&1];
|
||
pixel_target_[2] = colours[(pixels >> 3)&1];
|
||
pixel_target_[3] = colours[(pixels >> 2)&1];
|
||
pixel_target_[4] = colours[(pixels >> 1)&1];
|
||
pixel_target_[5] = colours[(pixels >> 0)&1];
|
||
}
|
||
} else {
|
||
switch(control_byte & 0x1f) {
|
||
case 0x00: ink_ = 0x0; break;
|
||
case 0x01: ink_ = 0x4; break;
|
||
case 0x02: ink_ = 0x2; break;
|
||
case 0x03: ink_ = 0x6; break;
|
||
case 0x04: ink_ = 0x1; break;
|
||
case 0x05: ink_ = 0x5; break;
|
||
case 0x06: ink_ = 0x3; break;
|
||
case 0x07: ink_ = 0x7; break;
|
||
|
||
case 0x08: case 0x09: case 0x0a: case 0x0b:
|
||
case 0x0c: case 0x0d: case 0x0e: case 0x0f:
|
||
use_alternative_character_set_ = (control_byte&1);
|
||
use_double_height_characters_ = (control_byte&2);
|
||
blink_text_ = (control_byte&4);
|
||
set_character_set_base_address();
|
||
break;
|
||
|
||
case 0x10: paper_ = 0x0; break;
|
||
case 0x11: paper_ = 0x4; break;
|
||
case 0x12: paper_ = 0x2; break;
|
||
case 0x13: paper_ = 0x6; break;
|
||
case 0x14: paper_ = 0x1; break;
|
||
case 0x15: paper_ = 0x5; break;
|
||
case 0x16: paper_ = 0x3; break;
|
||
case 0x17: paper_ = 0x7; break;
|
||
|
||
case 0x18: case 0x19: case 0x1a: case 0x1b:
|
||
case 0x1c: case 0x1d: case 0x1e: case 0x1f:
|
||
is_graphics_mode_ = (control_byte & 4);
|
||
next_frame_is_sixty_hertz_ = !(control_byte & 2);
|
||
break;
|
||
|
||
default: break;
|
||
}
|
||
if(pixel_target_) {
|
||
pixel_target_[0] = pixel_target_[1] =
|
||
pixel_target_[2] = pixel_target_[3] =
|
||
pixel_target_[4] = pixel_target_[5] =
|
||
(output_device_ == Outputs::CRT::OutputDevice::Monitor) ? paper_ ^ inverse_mask : colour_forms_[paper_ ^ inverse_mask];
|
||
}
|
||
}
|
||
if(pixel_target_) pixel_target_ += 6;
|
||
h_counter++;
|
||
}
|
||
|
||
if(h_counter == 40) {
|
||
crt_->output_data(40 * 6, 1);
|
||
}
|
||
} else {
|
||
// this is a blank line (or the equivalent part of a pixel line)
|
||
if(h_counter < 48) {
|
||
cycles_run_for = 48 - h_counter;
|
||
clamp(
|
||
int period = (counter_ < 224*64) ? 8 : 48;
|
||
crt_->output_blank(static_cast<unsigned int>(period) * 6);
|
||
);
|
||
} else if(h_counter < 54) {
|
||
cycles_run_for = 54 - h_counter;
|
||
clamp(crt_->output_sync(6 * 6));
|
||
} else if(h_counter < 56) {
|
||
cycles_run_for = 56 - h_counter;
|
||
clamp(crt_->output_default_colour_burst(2 * 6));
|
||
} else {
|
||
cycles_run_for = 64 - h_counter;
|
||
clamp(crt_->output_blank(8 * 6));
|
||
}
|
||
}
|
||
|
||
counter_ = (counter_ + cycles_run_for)%counter_period_;
|
||
number_of_cycles -= cycles_run_for;
|
||
}
|
||
}
|
||
|
||
void VideoOutput::set_character_set_base_address() {
|
||
if(is_graphics_mode_) character_set_base_address_ = use_alternative_character_set_ ? 0x9c00 : 0x9800;
|
||
else character_set_base_address_ = use_alternative_character_set_ ? 0xb800 : 0xb400;
|
||
}
|