coord.hpp

#pragma once

#include "../type.hpp"

namespace gli{
namespace detail
{
        template <typename T, precision P, template <typename, precision> class vecType>
        inline vecType<bool, P> in_interval(vecType<T, P> const& Value, vecType<T, P> const& Min, vecType<T, P> const& Max)
        {
                return greaterThanEqual(Value, Min) && lessThanEqual(Value, Max);
        }

        template <typename extent_type, typename normalized_type>
        struct coord_nearest
        {
                extent_type Texel;
                typename extent_type::bool_type UseTexel;
        };

        template <typename extent_type, typename normalized_type>
        inline coord_nearest<extent_type, normalized_type> make_coord_nearest(extent_type const& TexelExtent, normalized_type const& SampleCoord)
        {
                normalized_type const TexelLast(normalized_type(TexelExtent) - normalized_type(1));

                coord_nearest<extent_type, normalized_type> Coord;
                Coord.Texel = extent_type(round(SampleCoord * TexelLast));
                Coord.UseTexel = in_interval(Coord.Texel, extent_type(0), TexelExtent - 1);
                return Coord;
        }

        template <typename extent_type, typename normalized_type>
        struct coord_linear
        {
                extent_type TexelFloor;
                extent_type TexelCeil;
                normalized_type Blend;
        };

        template <typename extent_type, typename normalized_type>
        struct coord_linear_border : public coord_linear<extent_type, normalized_type>
        {
                typename extent_type::bool_type UseTexelFloor;
                typename extent_type::bool_type UseTexelCeil;
        };

        template <typename extent_type, typename normalized_type>
        GLI_FORCE_INLINE coord_linear<extent_type, normalized_type> make_coord_linear(extent_type const& TexelExtent, normalized_type const& SampleCoord)
        {
                coord_linear<extent_type, normalized_type> Coord;

                normalized_type const TexelExtentF(TexelExtent);
                normalized_type const TexelLast = TexelExtentF - normalized_type(1);
                normalized_type const ScaledCoord(SampleCoord * TexelLast);
                normalized_type const ScaledCoordFloor = normalized_type(extent_type(ScaledCoord));
                normalized_type const ScaledCoordCeil = normalized_type(extent_type(ScaledCoord + normalized_type(0.5)));
                //normalized_type const ScaledCoordFloor(floor(ScaledCoord));
                //normalized_type const ScaledCoordCeil(ceil(ScaledCoord));

                Coord.Blend = ScaledCoord - ScaledCoordFloor;
                Coord.TexelFloor = extent_type(ScaledCoordFloor);
                Coord.TexelCeil = extent_type(ScaledCoordCeil);

                return Coord;
        }

        template <typename extent_type, typename normalized_type>
        GLI_FORCE_INLINE coord_linear_border<extent_type, normalized_type> make_coord_linear_border(extent_type const& TexelExtent, normalized_type const& SampleCoord)
        {
                coord_linear_border<extent_type, normalized_type> Coord;

                normalized_type const TexelExtentF(TexelExtent);
                normalized_type const TexelLast = TexelExtentF - normalized_type(1);
                normalized_type const ScaledCoord(SampleCoord * TexelLast);
                normalized_type const ScaledCoordFloor(floor(ScaledCoord));
                normalized_type const ScaledCoordCeil(ceil(ScaledCoord));

                Coord.Blend = ScaledCoord - ScaledCoordFloor;
                Coord.TexelFloor = extent_type(ScaledCoordFloor);
                Coord.TexelCeil = extent_type(ScaledCoordCeil);
                Coord.UseTexelFloor = in_interval(Coord.TexelFloor, extent_type(0), TexelExtent - 1);
                Coord.UseTexelCeil = in_interval(Coord.TexelCeil, extent_type(0), TexelExtent - 1);

                return Coord;
        }
}//namespace detail
}//namespace gli