/* SPDX-License-Identifier: GPL-2.0-or-later
 * Copyright 2021 Blender Foundation. All rights reserved. */

/** \file
 * \ingroup bke
 */

#pragma once

#include "BKE_subdiv.h"

#include "BLI_sys_types.h"

#ifdef __cplusplus
extern "C" {
#endif

/* Hardcoded for until GPU shaders are automatically generated, then we will have a more
 * programmatic way of detecting this. */
#define MAX_GPU_SUBDIV_SSBOS 12

struct Mesh;
struct Object;
struct Scene;
struct Subdiv;
struct SubdivSettings;
struct SubsurfModifierData;

/* Runtime subsurf modifier data, cached in modifier on evaluated meshes. */
typedef struct SubsurfRuntimeData {
  /* Subdivision settings, exists before descriptor or mesh wrapper is created. */
  SubdivSettings settings;

  /* Cached subdivision surface descriptor, with topology and settings. */
  struct Subdiv *subdiv;
  bool set_by_draw_code;

  /* Cached mesh wrapper data, to be used for GPU subdiv or lazy evaluation on CPU. */
  bool has_gpu_subdiv;
  int resolution;
  bool use_optimal_display;
  bool calc_loop_normals;
  bool use_loop_normals;

  /* Cached from the draw code for stats display. */
  int stats_totvert;
  int stats_totedge;
  int stats_totpoly;
  int stats_totloop;
} SubsurfRuntimeData;

bool BKE_subsurf_modifier_runtime_init(struct SubsurfModifierData *smd, bool use_render_params);

bool BKE_subsurf_modifier_use_custom_loop_normals(const struct SubsurfModifierData *smd,
                                                  const struct Mesh *mesh);

/**
 * Return true if GPU subdivision evaluation is disabled by force due to incompatible mesh or
 * modifier settings. This will only return true if GPU subdivision is enabled in the preferences
 * and supported by the GPU. It is mainly useful for showing UI messages.
 */
bool BKE_subsurf_modifier_force_disable_gpu_evaluation_for_mesh(
    const struct SubsurfModifierData *smd, const struct Mesh *mesh);
/**
 * \param skip_check_is_last: When true, we assume that the modifier passed is the last enabled
 * modifier in the stack.
 */
bool BKE_subsurf_modifier_can_do_gpu_subdiv(const struct Scene *scene,
                                            const struct Object *ob,
                                            const struct Mesh *mesh,
                                            const struct SubsurfModifierData *smd,
                                            int required_mode);

bool BKE_subsurf_modifier_has_gpu_subdiv(const struct Mesh *mesh);

extern void (*BKE_subsurf_modifier_free_gpu_cache_cb)(struct Subdiv *subdiv);

/**
 * Main goal of this function is to give usable subdivision surface descriptor
 * which matches settings and topology.
 */
struct Subdiv *BKE_subsurf_modifier_subdiv_descriptor_ensure(
    struct SubsurfRuntimeData *runtime_data, const struct Mesh *mesh, bool for_draw_code);

/**
 * Return the #ModifierMode required for the evaluation of the subsurf modifier,
 * which should be used to check if the modifier is enabled.
 */
int BKE_subsurf_modifier_eval_required_mode(bool is_final_render, bool is_edit_mode);

#ifdef __cplusplus
}
#endif