147 lines
4.5 KiB
C++
Executable File
147 lines
4.5 KiB
C++
Executable File
/*
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* Software License Agreement (BSD License)
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*
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* Copyright (c) 2018, Locus Robotics
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials provided
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* with the distribution.
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* * Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <nav_grid_iterators/line/ray_trace.h>
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#include <cmath>
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#include <limits>
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namespace nav_grid_iterators
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{
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RayTrace::RayTrace(double x0, double y0, double x1, double y1, bool include_last_index)
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: AbstractLineIterator(), x0_(x0), y0_(y0), x1_(x1), y1_(y1), include_last_index_(include_last_index)
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{
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dx_ = std::abs(x1 - x0);
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dy_ = std::abs(y1 - y0);
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index_.x = static_cast<int>(floor(x0));
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index_.y = static_cast<int>(floor(y0));
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if (dx_ == 0)
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{
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loop_inc_x_ = 0;
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error_ = std::numeric_limits<double>::max();
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}
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else if (x1 > x0)
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{
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loop_inc_x_ = 1;
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error_ = (floor(x0) + 1 - x0) * dy_;
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}
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else
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{
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loop_inc_x_ = -1;
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error_ = (x0 - floor(x0)) * dy_;
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}
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if (dy_ == 0)
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{
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loop_inc_y_ = 0;
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error_ -= std::numeric_limits<double>::max();
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}
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else if (y1 > y0)
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{
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loop_inc_y_ = 1;
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error_ -= (floor(y0) + 1 - y0) * dx_;
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}
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else
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{
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loop_inc_y_ = -1;
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error_ -= (y0 - floor(y0)) * dx_;
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}
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/* Since we check if the index is equal to the second point in the line,
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* we have to check for this one edge case to ensure we don't get into a rounding
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* problem, resulting in an off-by-one error.
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*/
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if (!include_last_index && x1 < x0 && y1 - floor(y1) == 0.0)
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{
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error_ += 1e-10;
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}
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initial_error_ = error_;
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// Special use case when start and end point are the same AND we want to include that point
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if (include_last_index && loop_inc_x_ == 0 && loop_inc_y_ == 0)
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{
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loop_inc_x_ = 1;
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}
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}
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RayTrace::RayTrace(const nav_grid::SignedIndex& index,
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double x0, double y0, double x1, double y1, bool include_last_index,
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double dx, double dy, double initial_error, int loop_inc_x, int loop_inc_y)
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: AbstractLineIterator(index), x0_(x0), y0_(y0), x1_(x1), y1_(y1), include_last_index_(include_last_index),
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dx_(dx), dy_(dy), error_(initial_error), initial_error_(initial_error),
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loop_inc_x_(loop_inc_x), loop_inc_y_(loop_inc_y)
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{
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}
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RayTrace RayTrace::begin() const
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{
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return RayTrace(nav_grid::SignedIndex(x0_, y0_), x0_, y0_, x1_, y1_, include_last_index_,
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dx_, dy_, initial_error_, loop_inc_x_, loop_inc_y_);
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}
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RayTrace RayTrace::end() const
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{
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int x_diff = abs(static_cast<int>(x0_) - static_cast<int>(x1_));
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int y_diff = abs(static_cast<int>(y0_) - static_cast<int>(y1_));
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double final_error = initial_error_ - dx_ * y_diff + dy_ * x_diff;
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RayTrace end(nav_grid::SignedIndex(x1_, y1_), x0_, y0_, x1_, y1_, include_last_index_,
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dx_, dy_, final_error, loop_inc_x_, loop_inc_y_);
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// If we want the last_index, return an iterator that is whatever is one-past the end coordinates
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if (include_last_index_)
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end.increment();
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return end;
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}
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void RayTrace::increment()
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{
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if (error_ > 0.0)
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{
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index_.y += loop_inc_y_;
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error_ -= dx_;
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}
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else
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{
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index_.x += loop_inc_x_;
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error_ += dy_;
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}
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}
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nav_grid::SignedIndex RayTrace::getFinalIndex() const
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{
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return end().index_;
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}
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} // namespace nav_grid_iterators
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