sub_texture.h

// Description: Rectangular subset of another texture
// Documentation: distortion_textures.txt

#ifndef PASTELGFX_SUB_TEXTURE_H
#define PASTELGFX_SUB_TEXTURE_H

#include "pastel/gfx/texture/texture.h"

#include "pastel/geometry/shape/alignedbox.h"

namespace Pastel
{

    template <typename Type, integer N = 2>
    class Sub_Texture
        : public Texture<Type, N>
    {
    public:
        Sub_Texture()
            : texture_(0)
            , window_(Vector<integer, N>(0), Vector<integer, N>(1))
        {
        }

        Sub_Texture(
            const Texture<Type, N>& texture,
            const AlignedBox<real, N>& window)
            : texture_(&texture)
            , window_(window)
        {
        }

        virtual ~Sub_Texture()
        {
        }

        virtual Type operator()(
            const Vector<real, N>& p,
            const Matrix<real>& m) const
        {
            Matrix<real> mNew(m);
            for (integer i = 0;i < mNew.height();++i)
            {
                mNew.column(i) *= window_.extent(i);
            }

            return (*texture_)(window_.at(p), mNew);
        }

        virtual std::string name() const
        {
            return std::string("Sub");
        }

        virtual std::string fullName() const
        {
            return std::string("Sub(") + texture_->fullName() + ")";
        }

    private:
        const Texture<Type, N>* texture_;
        AlignedBox<real, N> window_;
    };

    template <typename Type, integer N>
    Sub_Texture<Type, N> subTexture(
        const Texture<Type, N>& texture, 
        const AlignedBox<real, N>& window)
    {
        return Sub_Texture<Type, N>(texture, window);
    }

}

#endif