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84 lines
1.9 KiB
C++
84 lines
1.9 KiB
C++
//
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// CRTInputBufferBuilder.hpp
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// Clock Signal
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//
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// Created by Thomas Harte on 08/03/2016.
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// Copyright © 2016 Thomas Harte. All rights reserved.
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//
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#ifndef CRTInputBufferBuilder_hpp
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#define CRTInputBufferBuilder_hpp
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#include <stdint.h>
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#include <stdarg.h>
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#include <stddef.h>
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#include "CRTConstants.hpp"
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#include "OpenGL.hpp"
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namespace Outputs {
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namespace CRT {
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struct CRTInputBufferBuilder {
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CRTInputBufferBuilder(size_t bytes_per_pixel);
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void allocate_write_area(size_t required_length);
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bool reduce_previous_allocation_to(size_t actual_length, uint8_t *buffer);
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inline uint16_t get_and_finalise_current_line()
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{
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uint16_t result = _write_y_position;
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if(!_is_full)
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{
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_next_write_x_position = 0;
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_next_write_y_position++;
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}
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_next_write_y_position %= InputBufferBuilderHeight;
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_is_full = false;
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return result;
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}
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inline uint8_t *get_write_target(uint8_t *buffer)
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{
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return _is_full ? nullptr : &buffer[_write_target_pointer * _bytes_per_pixel];
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}
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inline uint16_t get_last_write_x_position()
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{
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return _write_x_position;
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}
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inline uint16_t get_last_write_y_position()
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{
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return _write_y_position % InputBufferBuilderHeight;
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}
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inline size_t get_bytes_per_pixel()
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{
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return _bytes_per_pixel;
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}
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private:
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// where pixel data will be put to the next time a write is requested
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uint16_t _next_write_x_position, _next_write_y_position;
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// the most recent position returned for pixel data writing
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uint16_t _write_x_position, _write_y_position;
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// details of the most recent allocation
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size_t _write_target_pointer;
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size_t _last_allocation_amount;
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// the buffer size
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size_t _bytes_per_pixel;
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// Storage for the amount of buffer uploaded so far; initialised correctly by the buffer
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// builder but otherwise entrusted to the CRT to update.
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unsigned int _last_uploaded_line;
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bool _is_full;
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};
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}
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}
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#endif /* CRTInputBufferBuilder_hpp */
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