/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Copyright 2015-2018 Danny Robson <danny@nerdcruft.net>
 */

#include "ray.hpp"

#include "iostream.hpp"
#include "ops.hpp"
#include "../coord/iostream.hpp"
#include "../debug.hpp"

using util::geom::ray;


///////////////////////////////////////////////////////////////////////////////
/// returns the closest parameter along the ray to a given point
template <size_t S, typename T>
T
ray<S,T>::closest (point<S,T> q) const
{
    // project the origin-point difference onto the direction
    return dot (origin - q, direction);
}


//-----------------------------------------------------------------------------
template <size_t S, typename T>
util::point<S,T>
ray<S,T>::at (T t) const
{
    return origin + direction * t;
}


///////////////////////////////////////////////////////////////////////////////
util::geom::ray3f
util::geom::operator* (util::matrix4f lhs, ray3f rhs)
{
    return {
        (lhs * rhs.origin.homog<4>    ()).redim<3> (),
        normalised (
            (lhs * rhs.direction.homog<4> ()).redim<3> ()
        )
    };
}


///////////////////////////////////////////////////////////////////////////////
template <size_t S, typename T>
std::ostream&
util::geom::operator<< (std::ostream &os, ray<S,T> r)
{
    return os << "ray(" << r.origin << ',' << r.direction << ')';
}


///////////////////////////////////////////////////////////////////////////////
template <size_t S, typename T>
struct util::debug::validator<ray<S,T>> {
    static bool
    is_valid (ray<S,T> const& val)
    {
        return util::debug::is_valid (val.origin) &&
               util::debug::is_valid (val.direction) &&
               is_normalised (val.direction);
    }
};


///////////////////////////////////////////////////////////////////////////////
#define INSTANTIATE_S_T(S,T) \
template std::ostream& util::geom::operator<< (std::ostream&, ray<S,T>); \
template struct util::debug::validator<ray<S,T>>; \
template struct util::geom::ray<S,T>;


INSTANTIATE_S_T(2,float)
INSTANTIATE_S_T(3,float)