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73 lines
1.8 KiB
C++
73 lines
1.8 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 12/10/2016.
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// Copyright © 2016 Thomas Harte. All rights reserved.
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//
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#include "Video.hpp"
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using namespace Oric;
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VideoOutput::VideoOutput(uint8_t *memory) :
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_ram(memory),
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_frame_counter(0), _counter(0),
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_state(Sync), _cycles_in_state(0)
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{
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_crt.reset(new Outputs::CRT::CRT(64*6, 6, Outputs::CRT::DisplayType::PAL50, 1));
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// TODO: this is a copy and paste from the Electron; factor out.
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_crt->set_rgb_sampling_function(
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"vec3 rgb_sample(usampler2D sampler, vec2 coordinate, vec2 icoordinate)"
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"{"
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"uint texValue = texture(sampler, coordinate).r;"
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"texValue >>= 4 - (int(icoordinate.x * 8) & 4);"
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"return vec3( uvec3(texValue) & uvec3(4u, 2u, 1u));"
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"}");
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}
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std::shared_ptr<Outputs::CRT::CRT> VideoOutput::get_crt()
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{
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return _crt;
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}
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void VideoOutput::run_for_cycles(int number_of_cycles)
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{
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// Vertical: 0–39: pixels; otherwise blank; 48–53 sync
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// Horizontal: 0–223: pixels; otherwise blank; 256–259 sync
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while(number_of_cycles--)
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{
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_counter = (_counter + 1)%(312 * 64); // TODO: NTSC
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State new_state = Blank;
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int h_counter =_counter & 63;
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if(
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(h_counter >= 48 && h_counter <= 53) ||
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(_counter >= 256*64 && _counter <= 259*64)) new_state = Sync;
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else if(_counter < 224*64 && h_counter < 40) new_state = Pixels;
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if(_state != new_state)
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{
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switch(_state)
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{
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case Sync: _crt->output_sync(_cycles_in_state * 6); break;
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case Blank: _crt->output_blank(_cycles_in_state * 6); break;
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case Pixels: _crt->output_data(_cycles_in_state * 6, 2); break;
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}
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_state = new_state;
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_cycles_in_state = 0;
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if(_state == Pixels) _pixel_target = _crt->allocate_write_area(120);
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}
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_cycles_in_state++;
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if(new_state == Pixels) {
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_pixel_target[0] = 0x70;
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_pixel_target[1] = 0x14;
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_pixel_target[2] = 0x23;
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_pixel_target += 3;
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}
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}
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}
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