mirror of
https://github.com/TomHarte/CLK.git
synced 2024-08-16 16:28:59 +00:00
51 lines
1.6 KiB
C++
51 lines
1.6 KiB
C++
//
|
|
// CRTInputBufferBuilder.cpp
|
|
// Clock Signal
|
|
//
|
|
// Created by Thomas Harte on 08/03/2016.
|
|
// Copyright © 2016 Thomas Harte. All rights reserved.
|
|
//
|
|
|
|
#include "CRTInputBufferBuilder.hpp"
|
|
#include "CRTOpenGL.hpp"
|
|
#include <string.h>
|
|
|
|
using namespace Outputs::CRT;
|
|
|
|
CRTInputBufferBuilder::CRTInputBufferBuilder(size_t bytes_per_pixel) : bytes_per_pixel(bytes_per_pixel)
|
|
{
|
|
_next_write_x_position = _next_write_y_position = 0;
|
|
last_uploaded_line = 0;
|
|
}
|
|
|
|
void CRTInputBufferBuilder::allocate_write_area(size_t required_length)
|
|
{
|
|
_last_allocation_amount = required_length;
|
|
|
|
if(_next_write_x_position + required_length + 2 > InputBufferBuilderWidth)
|
|
{
|
|
move_to_new_line();
|
|
}
|
|
|
|
_write_x_position = _next_write_x_position + 1;
|
|
_write_y_position = _next_write_y_position;
|
|
_write_target_pointer = (_write_y_position * InputBufferBuilderWidth) + _write_x_position;
|
|
_next_write_x_position += required_length + 2;
|
|
}
|
|
|
|
void CRTInputBufferBuilder::reduce_previous_allocation_to(size_t actual_length, uint8_t *buffer)
|
|
{
|
|
// book end the allocation with duplicates of the first and last pixel, to protect
|
|
// against rounding errors when this run is drawn
|
|
memcpy( &buffer[(_write_target_pointer - 1) * bytes_per_pixel],
|
|
&buffer[_write_target_pointer * bytes_per_pixel],
|
|
bytes_per_pixel);
|
|
|
|
memcpy( &buffer[(_write_target_pointer + actual_length) * bytes_per_pixel],
|
|
&buffer[(_write_target_pointer + actual_length - 1) * bytes_per_pixel],
|
|
bytes_per_pixel);
|
|
|
|
// return any allocated length that wasn't actually used to the available pool
|
|
_next_write_x_position -= (_last_allocation_amount - actual_length);
|
|
}
|