text: // ----------------------------------------------------------------------------
  // -                        Open3D: www.open3d.org                            -
  // ----------------------------------------------------------------------------
  // The MIT License (MIT)
  //
  // Copyright (c) 2019 www.open3d.org
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  // IN THE SOFTWARE.
  // ----------------------------------------------------------------------------
  
  #pragma once
  
  #include <Eigen/Core>
  
  #include "open3d/visualization/rendering/RendererHandle.h"
  
  namespace open3d {
  namespace visualization {
  namespace rendering {
  
  struct TextureSamplerParameters {
      enum class MinFilter : uint8_t {
          Nearest = 0,  //!< No filtering. Nearest neighbor is used.
          Linear =
                  1,  //!< Box filtering. Weighted average of 4 neighbors is used.
          NearestMipmapNearest =
                  2,  //!< Mip-mapping is activated. But no filtering occurs.
          LinearMipmapNearest = 3,  //!< Box filtering within a mip-map level.
          NearestMipmapLinear = 4,  //!< Mip-map levels are interpolated, but no
                                    //!< other filtering occurs.
          LinearMipmapLinear = 5    //!< Both interpolated Mip-mapping and linear
                                    //!< filtering are used.
      };
  
      enum class MagFilter : uint8_t {
          Nearest = 0,  //!< No filtering. Nearest neighbor is used.
          Linear =
                  1,  //!< Box filtering. Weighted average of 4 neighbors is used.
      };
  
      enum class WrapMode : uint8_t {
          ClampToEdge,     //!< clamp-to-edge. The edge of the texture extends to
                           //!< infinity.
          Repeat,          //!< repeat. The texture infinitely repeats in the wrap
                           //!< direction.
          MirroredRepeat,  //!< mirrored-repeat. The texture infinitely repeats
                           //!< and mirrors in the wrap direction.
      };
  
      /* filterMag = MagFilter::Nearest
       * filterMin = MinFilter::Nearest
       * wrapU = WrapMode::ClampToEdge
       * wrapV = WrapMode::ClampToEdge
       * wrapW = WrapMode::ClampToEdge
       * anisotropy = 0
       */
      static TextureSamplerParameters Simple();
  
      /* filterMag = MagFilter::Linear
       * filterMin = MinFilter::Linear
       * wrapU = WrapMode::ClampToEdge
       * wrapV = WrapMode::ClampToEdge
       * wrapW = WrapMode::ClampToEdge
       * anisotropy = 4
       */
      static TextureSamplerParameters Pretty();
  
      TextureSamplerParameters() = default;
  
      // Creates a TextureSampler with the default parameters but setting the
      // filtering and wrap modes. 'minMag' is filtering for both minification and
      // magnification 'uvw' is wrapping mode for all texture coordinate axes
      explicit TextureSamplerParameters(MagFilter min_mag,
                                        WrapMode uvw = WrapMode::ClampToEdge);
  
      // Creates a TextureSampler with the default parameters but setting the
      // filtering and wrap modes. 'uvw' is wrapping mode for all texture
      // coordinate axes
      TextureSamplerParameters(MinFilter min,
                               MagFilter mag,
                               WrapMode uvw = WrapMode::ClampToEdge);
  
      TextureSamplerParameters(
              MinFilter min, MagFilter mag, WrapMode u, WrapMode v, WrapMode w);
  
      // \param a needs to be a power of 2
      void SetAnisotropy(std::uint8_t a);
  
      std::uint8_t GetAnisotropy() const { return anisotropy; }
  
      MagFilter filter_mag = MagFilter::Nearest;
      MinFilter filter_min = MinFilter::Nearest;
      WrapMode wrap_u = WrapMode::ClampToEdge;
      WrapMode wrap_v = WrapMode::ClampToEdge;
      WrapMode wrap_w = WrapMode::ClampToEdge;
  
  private:
      std::uint8_t anisotropy = 0;
  };
  
  class MaterialModifier {
  public:
      virtual ~MaterialModifier() = default;
  
      virtual MaterialModifier& SetParameter(const char* parameter,
                                             int value) = 0;
      virtual MaterialModifier& SetParameter(const char* parameter,
                                             float value) = 0;
      virtual MaterialModifier& SetParameter(const char* parameter,
                                             const Eigen::Vector3f& value) = 0;
      virtual MaterialModifier& SetColor(const char* parameter,
                                         const Eigen::Vector3f& value,
                                         bool srgb) = 0;
      virtual MaterialModifier& SetColor(const char* parameter,
                                         const Eigen::Vector4f& value,
                                         bool srgb) = 0;
      virtual MaterialModifier& SetTexture(
              const char* parameter,
              const TextureHandle& texture,
              const TextureSamplerParameters& sampler) = 0;
  
      virtual MaterialModifier& SetDoubleSided(bool doubleSided) = 0;
  
      virtual MaterialInstanceHandle Finish() = 0;
  };
  
  }  // namespace rendering
  }  // namespace visualization
  }  // namespace open3d
  