test/source/blender/geometry/GEO_uv_parametrizer.hh

/* SPDX-FileCopyrightText: 2023 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

#pragma once

#include "BLI_sys_types.h" /* for intptr_t support */

namespace slim {
struct MatrixTransfer;
}

/** \file
 * \ingroup geo
 */

struct GHash;
struct Heap;
struct MemArena;
struct RNG;

namespace blender::geometry {

struct PChart;
struct PHash;

using ParamKey = uintptr_t; /* Key (hash) for identifying verts and faces. */
#define PARAM_KEY_MAX UINTPTR_MAX

enum PHandleState {
  PHANDLE_STATE_ALLOCATED,
  PHANDLE_STATE_CONSTRUCTED,
  PHANDLE_STATE_LSCM,
  PHANDLE_STATE_STRETCH,
};

class ParamHandle {
 public:
  ParamHandle();
  ~ParamHandle();

  PHandleState state = PHANDLE_STATE_ALLOCATED;
  MemArena *arena = nullptr;
  MemArena *polyfill_arena = nullptr;
  Heap *polyfill_heap = nullptr;

  PChart *construction_chart = nullptr;
  PHash *hash_verts = nullptr;
  PHash *hash_edges = nullptr;
  PHash *hash_faces = nullptr;

  GHash *pin_hash = nullptr;
  int unique_pin_count = 0;

  PChart **charts = nullptr;
  int ncharts = 0;

  float aspect_y = 1.0f;

  RNG *rng = nullptr;
  float blend = 0.0f;

  /* SLIM uv unwrapping */
  slim::MatrixTransfer *slim_mt = nullptr;
};

/* -------------------------------------------------------------------- */
/** \name Chart Construction:
 *
 * Faces and seams may only be added between #ParamHandle::ParamHandle() and
 * #geometry::uv_parametrizer_construct_end.
 *
 * The pointers to `co` and `uv` are stored, rather than being copied. Vertices are implicitly
 * created.
 *
 * In #geometry::uv_parametrizer_construct_end the mesh will be split up according to the seams.
 * The resulting charts must be manifold, connected and open (at least one boundary loop). The
 * output will be written to the `uv` pointers.
 *
 * \{ */

void uv_parametrizer_aspect_ratio(ParamHandle *handle, float aspect_y);

void uv_prepare_pin_index(ParamHandle *handle, const int bmvertindex, const float uv[2]);

ParamKey uv_find_pin_index(ParamHandle *handle, const int bmvertindex, const float uv[2]);

void uv_parametrizer_face_add(ParamHandle *handle,
                              const ParamKey key,
                              const int nverts,
                              const ParamKey *vkeys,
                              const float **co,
                              float **uv, /* Output will eventually be written to `uv`. */
                              float *weight,
                              const bool *pin,
                              const bool *select);

void uv_parametrizer_edge_set_seam(ParamHandle *handle, ParamKey *vkeys);

void uv_parametrizer_construct_end(ParamHandle *handle,
                                   bool fill_holes,
                                   bool topology_from_uvs,
                                   int *r_count_failed = nullptr);

/** \} */

/* -------------------------------------------------------------------- */
/** \name SLIM:
 *
 * - begin: data is gathered into matrices and transferred to SLIM.
 * - solve: compute cheap initialization (if necessary) and refine iteratively.
 * - end: clean up.
 * \{ */

struct ParamSlimOptions {
  float weight_influence = 0.0f;
  int iterations = 0;
  bool no_flip = false;
  bool skip_init = false;
};

void uv_parametrizer_slim_solve(ParamHandle *phandle,
                                const ParamSlimOptions *slim_options,
                                int *count_changed,
                                int *count_failed);

void uv_parametrizer_slim_live_begin(ParamHandle *phandle, const ParamSlimOptions *slim_options);
void uv_parametrizer_slim_live_solve_iteration(ParamHandle *phandle);
void uv_parametrizer_slim_live_end(ParamHandle *phandle);
void uv_parametrizer_slim_stretch_iteration(ParamHandle *phandle, float blend);
bool uv_parametrizer_is_slim(const ParamHandle *phandle);

/** \} */

/* -------------------------------------------------------------------- */
/** \name Least Squares Conformal Maps:
 *
 * Charts with less than two pinned vertices are assigned two pins. LSCM is divided to three steps:
 *
 * 1. Begin: compute matrix and its factorization (expensive).
 * 2. Solve using pinned coordinates (cheap).
 * 3. End: clean up.
 *
 * UV coordinates are allowed to change within begin/end, for quick re-solving.
 *
 * \{ */

void uv_parametrizer_lscm_begin(ParamHandle *handle, bool live, bool abf);
void uv_parametrizer_lscm_solve(ParamHandle *handle, int *count_changed, int *count_failed);
void uv_parametrizer_lscm_end(ParamHandle *handle);

/** \} */

/* -------------------------------------------------------------------- */
/** \name Stretch
 * \{ */

void uv_parametrizer_stretch_begin(ParamHandle *handle);
void uv_parametrizer_stretch_blend(ParamHandle *handle, float blend);
void uv_parametrizer_stretch_iter(ParamHandle *handle);
void uv_parametrizer_stretch_end(ParamHandle *handle);

/** \} */

/* -------------------------------------------------------------------- */
/** \name Packing
 * \{ */

void uv_parametrizer_pack(ParamHandle *handle, float margin, bool do_rotate, bool ignore_pinned);

/** \} */

/* -------------------------------------------------------------------- */
/** \name Average area for all charts
 * \{ */

void uv_parametrizer_average(ParamHandle *handle, bool ignore_pinned, bool scale_uv, bool shear);

/** \} */

/* -------------------------------------------------------------------- */
/** \name Flushing
 * \{ */

void uv_parametrizer_flush(ParamHandle *handle);
void uv_parametrizer_flush_restore(ParamHandle *handle);

/** \} */

}  // namespace blender::geometry