60 lines
2.1 KiB
C++
60 lines
2.1 KiB
C++
//---------------------------------------------------------------------------//
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// Copyright (c) 2013-2014 Kyle Lutz <kyle.r.lutz@gmail.com>
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//
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// Distributed under the Boost Software License, Version 1.0
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// See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt
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//
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// See http://boostorg.github.com/compute for more information.
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//---------------------------------------------------------------------------//
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#ifndef BOOST_COMPUTE_INTEROP_VTK_BOUNDS_HPP
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#define BOOST_COMPUTE_INTEROP_VTK_BOUNDS_HPP
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#include <vector>
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#include <iterator>
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#include <boost/compute/system.hpp>
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#include <boost/compute/command_queue.hpp>
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#include <boost/compute/algorithm/copy_n.hpp>
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#include <boost/compute/algorithm/reduce.hpp>
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#include <boost/compute/container/array.hpp>
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namespace boost {
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namespace compute {
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/// Calculates the bounds for the points in the range [\p first, \p last) and
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/// stores the result in \p bounds.
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///
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/// For example, this can be used to implement the GetBounds() method for a
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/// vtkMapper subclass.
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template<class PointIterator>
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inline void vtk_compute_bounds(PointIterator first,
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PointIterator last,
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double bounds[6],
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command_queue &queue = system::default_queue())
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{
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typedef typename std::iterator_traits<PointIterator>::value_type T;
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const context &context = queue.get_context();
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// compute min and max point
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array<T, 2> extrema(context);
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reduce(first, last, extrema.begin() + 0, min<T>(), queue);
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reduce(first, last, extrema.begin() + 1, max<T>(), queue);
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// copy results to host buffer
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std::vector<T> buffer(2);
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copy_n(extrema.begin(), 2, buffer.begin(), queue);
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// copy to vtk-style bounds
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bounds[0] = buffer[0][0]; bounds[1] = buffer[1][0];
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bounds[2] = buffer[0][1]; bounds[3] = buffer[1][1];
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bounds[4] = buffer[0][2]; bounds[5] = buffer[1][2];
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}
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} // end compute namespace
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} // end boost namespace
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#endif // BOOST_COMPUTE_INTEROP_VTK_BOUNDS_HPP
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