/*
 * Copyright 2011-2020 Blender Foundation
 *
 * 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.
 */

#ifndef __HAIR_H__
#define __HAIR_H__

#include "render/geometry.h"

CCL_NAMESPACE_BEGIN

class Hair : public Geometry {
 public:
  NODE_DECLARE

  /* Hair Curve */
  struct Curve {
    int first_key;
    int num_keys;

    int num_segments() const
    {
      return num_keys - 1;
    }

    void bounds_grow(const int k,
                     const float3 *curve_keys,
                     const float *curve_radius,
                     BoundBox &bounds) const;
    void bounds_grow(float4 keys[4], BoundBox &bounds) const;
    void bounds_grow(const int k,
                     const float3 *curve_keys,
                     const float *curve_radius,
                     const Transform &aligned_space,
                     BoundBox &bounds) const;

    void motion_keys(const float3 *curve_keys,
                     const float *curve_radius,
                     const float3 *key_steps,
                     size_t num_curve_keys,
                     size_t num_steps,
                     float time,
                     size_t k0,
                     size_t k1,
                     float4 r_keys[2]) const;
    void cardinal_motion_keys(const float3 *curve_keys,
                              const float *curve_radius,
                              const float3 *key_steps,
                              size_t num_curve_keys,
                              size_t num_steps,
                              float time,
                              size_t k0,
                              size_t k1,
                              size_t k2,
                              size_t k3,
                              float4 r_keys[4]) const;

    void keys_for_step(const float3 *curve_keys,
                       const float *curve_radius,
                       const float3 *key_steps,
                       size_t num_curve_keys,
                       size_t num_steps,
                       size_t step,
                       size_t k0,
                       size_t k1,
                       float4 r_keys[2]) const;
    void cardinal_keys_for_step(const float3 *curve_keys,
                                const float *curve_radius,
                                const float3 *key_steps,
                                size_t num_curve_keys,
                                size_t num_steps,
                                size_t step,
                                size_t k0,
                                size_t k1,
                                size_t k2,
                                size_t k3,
                                float4 r_keys[4]) const;
  };

  array<float3> curve_keys;
  array<float> curve_radius;
  array<int> curve_first_key;
  array<int> curve_shader;

  /* BVH */
  size_t curvekey_offset;

  /* Constructor/Destructor */
  Hair();
  ~Hair();

  /* Geometry */
  void clear() override;

  void resize_curves(int numcurves, int numkeys);
  void reserve_curves(int numcurves, int numkeys);
  void add_curve_key(float3 loc, float radius);
  void add_curve(int first_key, int shader);

  void copy_center_to_motion_step(const int motion_step);

  void compute_bounds() override;
  void apply_transform(const Transform &tfm, const bool apply_to_motion) override;

  /* Curves */
  Curve get_curve(size_t i) const
  {
    int first = curve_first_key[i];
    int next_first = (i + 1 < curve_first_key.size()) ? curve_first_key[i + 1] : curve_keys.size();

    Curve curve = {first, next_first - first};
    return curve;
  }

  size_t num_keys() const
  {
    return curve_keys.size();
  }

  size_t num_curves() const
  {
    return curve_first_key.size();
  }

  size_t num_segments() const
  {
    return curve_keys.size() - curve_first_key.size();
  }

  /* UDIM */
  void get_uv_tiles(ustring map, unordered_set<int> &tiles) override;

  /* BVH */
  void pack_curves(Scene *scene, float4 *curve_key_co, float4 *curve_data, size_t curvekey_offset);
};

CCL_NAMESPACE_END

#endif /* __HAIR_H__ */