BKE_subdiv_eval.hh

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/* SPDX-FileCopyrightText: 2018 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#pragma once
 
#include "BLI_math_vector_types.hh"
#include "BLI_span.hh"
#include "BLI_sys_types.h"
 
struct Mesh;
struct OpenSubdiv_EvaluatorCache;
struct OpenSubdiv_EvaluatorSettings;
 
namespace blender::bke::subdiv {
 
struct Subdiv;
 
enum eSubdivEvaluatorType {
  SUBDIV_EVALUATOR_TYPE_CPU,
  SUBDIV_EVALUATOR_TYPE_GPU,
};
 
/* Returns true if evaluator is ready for use. */
bool eval_begin(Subdiv *subdiv,
                eSubdivEvaluatorType evaluator_type,
                OpenSubdiv_EvaluatorCache *evaluator_cache,
                const OpenSubdiv_EvaluatorSettings *settings);
 
/* coarse_vertex_cos is an optional argument which allows to override coordinates of the coarse
 * mesh. */
bool eval_begin_from_mesh(Subdiv *subdiv,
                          const Mesh *mesh,
                          Span<float3> coarse_vert_positions,
                          eSubdivEvaluatorType evaluator_type,
                          OpenSubdiv_EvaluatorCache *evaluator_cache);
bool eval_refine_from_mesh(Subdiv *subdiv, const Mesh *mesh, Span<float3> coarse_vert_positions);
 
/* Makes sure displacement evaluator is initialized.
 *
 * NOTE: This function must be called once before evaluating displacement or
 * final surface position. */
void eval_init_displacement(Subdiv *subdiv);
 
/* Single point queries. */
 
/* Evaluate point at a limit surface, with optional derivatives and normal. */
 
void eval_limit_point(Subdiv *subdiv, int ptex_face_index, float u, float v, float r_P[3]);
void eval_limit_point_and_derivatives(Subdiv *subdiv,
                                      int ptex_face_index,
                                      float u,
                                      float v,
                                      float r_P[3],
                                      float r_dPdu[3],
                                      float r_dPdv[3]);
void eval_limit_point_and_normal(
    Subdiv *subdiv, int ptex_face_index, float u, float v, float r_P[3], float r_N[3]);
 
/* Evaluate smoothly interpolated vertex data (such as ORCO). */
void eval_vertex_data(Subdiv *subdiv,
                      const int ptex_face_index,
                      const float u,
                      const float v,
                      float r_vertex_data[]);
 
/* Evaluate face-varying layer (such as UV). */
void eval_face_varying(Subdiv *subdiv,
                       int face_varying_channel,
                       int ptex_face_index,
                       float u,
                       float v,
                       float r_face_varying[2]);
 
/* NOTE: Expects derivatives to be correct.
 *
 * TODO(sergey): This is currently used together with
 * eval_final_point() which can easily evaluate derivatives.
 * Would be nice to have displacement evaluation function which does not require
 * knowing derivatives ahead of a time. */
void eval_displacement(Subdiv *subdiv,
                       int ptex_face_index,
                       float u,
                       float v,
                       const float dPdu[3],
                       const float dPdv[3],
                       float r_D[3]);
 
/* Evaluate point on a limit surface with displacement applied to it. */
void eval_final_point(Subdiv *subdiv, int ptex_face_index, float u, float v, float r_P[3]);
 
}  // namespace blender::bke::subdiv