fray.h

#pragma once
 
#include "fmat.h"
#include "fvec.h"
 
namespace cgv {
namespace math {
 
template <typename T, cgv::type::uint32_type N>
struct fray {
    fvec<T, N> origin;
    fvec<T, N> direction;
 
    fray() {
        origin = fvec<T, N>(0);
        direction = fvec<T, N>(0);
    }
 
    fray(const fvec<T, N>& origin, const fvec<T, N>& direction) : origin(origin), direction(direction) {}
 
    fvec<T, N> position(float t) const {
        return origin + t * direction;
    }
};
 
template <typename T>
struct fray<T, 3> {
    fvec<T, 3> origin;
    fvec<T, 3> direction;
 
    fray() {
        origin = fvec<T, 3>(0);
        direction = fvec<T, 3>(0);
    }
 
    fray(const fvec<T, 3>& origin, const fvec<T, 3>& direction) : origin(origin), direction(direction) {}
 
    fray(const fvec<T, 2>& screen_coord, const fvec<unsigned, 2>& viewport_size, const fvec<T, 3>& eye_position, const fmat<T, 4, 4>& view_projection_matrix) {
        fvec<T, 2> window_coord = T(2) * screen_coord / static_cast<fvec<T, 2>>(viewport_size) - T(1);
 
        fvec<T, 4> world_coord(window_coord.x(), window_coord.y(), T(1), T(1));
        world_coord = inverse(view_projection_matrix) * world_coord;
        world_coord /= world_coord.w();
 
        origin = eye_position;
        direction = normalize(fvec<T, 3>(world_coord) - eye_position);
    }
 
    fvec<T, 3> position(T t) const {
        return origin + t * direction;
    }
};
 
// Predefined ray types
typedef fray<unsigned, 2> uray2;
typedef fray<unsigned, 3> uray3;
typedef fray<unsigned, 3> uray4;
typedef fray<int, 2> iray2;
typedef fray<int, 3> iray3;
typedef fray<int, 3> iray4;
typedef fray<float, 2> ray2;
typedef fray<float, 3> ray3;
typedef fray<float, 3> ray4;
typedef fray<double, 2> dray2;
typedef fray<double, 3> dray3;
typedef fray<double, 3> dray4;
 
} // namespace math
} // namespace cgv