162 lines
4.8 KiB
C++
162 lines
4.8 KiB
C++
/*
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* This file is part of libgim.
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*
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* libgim is free software: you can redistribute it and/or modify it under the
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* terms of the GNU General Public License as published by the Free Software
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* Foundation, either version 3 of the License, or (at your option) any later
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* version.
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*
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* libgim is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License
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* along with libgim. If not, see <http://www.gnu.org/licenses/>.
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*
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* Copyright 2012-2015 Danny Robson <danny@nerdcruft.net>
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*/
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#ifndef __UTIL_COORD_HPP
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#define __UTIL_COORD_HPP
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#include "../platform.hpp"
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#include <algorithm>
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#include <iterator>
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#include <cstdlib>
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namespace util {
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namespace detail {
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// Disable GCC warnings about validity of anonyous structures in
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// unions. Push comes to shove I'll manually redsign everything to
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// keep this syntax anyway.
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#pragma GCC diagnostic push
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#if defined(COMPILER_GCC)
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#pragma GCC diagnostic ignored "-pedantic"
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#endif
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#if defined(COMPILER_CLANG)
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#pragma GCC diagnostic ignored "-Wgnu"
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#endif
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//---------------------------------------------------------------------
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// coord types are not really intended to have arbitrary dimension, so
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// don't add specialisations (or a general case) without a decent
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// reason.
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template <size_t S, typename T>
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struct coord_data;
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//---------------------------------------------------------------------
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template <typename T>
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struct coord_data<1, T>
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{
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coord_data () = default;
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coord_data (T v0):
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data { v0 }
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{ ; }
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union {
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T data[1];
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T x;
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};
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};
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//---------------------------------------------------------------------
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template <typename T>
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struct coord_data<2,T>
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{
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coord_data () = default;
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coord_data (T v0, T v1):
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data { v0, v1 }
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{ ; }
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union {
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T data[2];
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struct { T x, y; };
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struct { T s, t; };
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};
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};
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//---------------------------------------------------------------------
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template <typename T>
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struct coord_data<3,T>
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{
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coord_data () = default;
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coord_data (T v0, T v1, T v2):
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data { v0, v1, v2 }
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{ ; }
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union {
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T data[3];
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struct { T x, y, z; };
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struct { T s, t, p; };
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struct { T r, g, b; };
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};
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};
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//---------------------------------------------------------------------
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template <typename T>
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struct coord_data<4,T>
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{
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coord_data () = default;
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coord_data (T v0, T v1, T v2, T v3):
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data { v0, v1, v2, v3 }
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{ ; }
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union {
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T data[4];
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struct { T x, y, z, w; };
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struct { T s, t, p, q; };
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struct { T r, g, b, a; };
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};
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};
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//---------------------------------------------------------------------
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template <size_t S, typename T>
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struct coord : public coord_data<S,T> {
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static_assert (S > 0, "coord dimensions must be strictly positive");
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typedef T value_type;
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static constexpr size_t dimension = S;
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static constexpr size_t elements = S;
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using coord_data<S,T>::coord_data;
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coord () = default;
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explicit coord (T v)
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{ std::fill (std::begin (this->data), std::end (this->data), v); }
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coord (const coord<S,T> &rhs) = default;
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coord& operator= (const coord<S,T> &rhs) = default;
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T& operator[] (size_t i) { return this->data[i]; }
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T operator[] (size_t i) const { return this->data[i]; }
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};
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//---------------------------------------------------------------------
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// XXX: Unsure whether this should really be defined for arbitrary
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// types in a semantic sense, but practicality suggestes this is the
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// best option; point/vector dot product is too useful.
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template <size_t S, typename T>
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T dot (const coord<S,T> &a, const coord<S,T> &b)
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{
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return std::inner_product (std::begin (a.data),
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std::end (a.data),
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std::begin (b.data),
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T {0});
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}
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#pragma GCC diagnostic pop
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}
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}
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#endif
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