444 lines
18 KiB
C
444 lines
18 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later
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* Copyright 2018 Blender Foundation. All rights reserved. */
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/** \file
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* \ingroup bke
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*/
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#include <math.h>
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#include "BKE_subdiv.h"
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#include "DNA_mesh_types.h"
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#include "DNA_meshdata_types.h"
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#include "DNA_modifier_types.h"
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#include "DNA_object_types.h"
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#include "BLI_math_vector.h"
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#include "BLI_utildefines.h"
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#include "BKE_customdata.h"
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#include "BKE_multires.h"
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#include "BKE_subdiv_eval.h"
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#include "MEM_guardedalloc.h"
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typedef struct PolyCornerIndex {
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int poly_index;
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int corner;
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} PolyCornerIndex;
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typedef struct MultiresDisplacementData {
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Subdiv *subdiv;
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int grid_size;
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/* Mesh is used to read external displacement. */
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Mesh *mesh;
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const MultiresModifierData *mmd;
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const MPoly *mpoly;
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const MDisps *mdisps;
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/* Indexed by ptex face index, contains polygon/corner which corresponds
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* to it.
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*
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* NOTE: For quad polygon this is an index of first corner only, since
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* there we only have one ptex. */
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PolyCornerIndex *ptex_poly_corner;
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/* Indexed by coarse face index, returns first ptex face index corresponding
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* to that coarse face. */
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int *face_ptex_offset;
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/* Sanity check, is used in debug builds.
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* Controls that initialize() was called prior to eval_displacement(). */
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bool is_initialized;
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} MultiresDisplacementData;
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/* Denotes which grid to use to average value of the displacement read from the
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* grid which corresponds to the ptex face. */
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typedef enum eAverageWith {
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AVERAGE_WITH_NONE,
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AVERAGE_WITH_ALL,
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AVERAGE_WITH_PREV,
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AVERAGE_WITH_NEXT,
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} eAverageWith;
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static int displacement_get_grid_and_coord(SubdivDisplacement *displacement,
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const int ptex_face_index,
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const float u,
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const float v,
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const MDisps **r_displacement_grid,
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float *grid_u,
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float *grid_v)
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{
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MultiresDisplacementData *data = displacement->user_data;
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const PolyCornerIndex *poly_corner = &data->ptex_poly_corner[ptex_face_index];
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const MPoly *poly = &data->mpoly[poly_corner->poly_index];
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const int start_grid_index = poly->loopstart + poly_corner->corner;
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int corner = 0;
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if (poly->totloop == 4) {
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float corner_u, corner_v;
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corner = BKE_subdiv_rotate_quad_to_corner(u, v, &corner_u, &corner_v);
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*r_displacement_grid = &data->mdisps[start_grid_index + corner];
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BKE_subdiv_ptex_face_uv_to_grid_uv(corner_u, corner_v, grid_u, grid_v);
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}
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else {
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*r_displacement_grid = &data->mdisps[start_grid_index];
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BKE_subdiv_ptex_face_uv_to_grid_uv(u, v, grid_u, grid_v);
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}
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return corner;
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}
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static const MDisps *displacement_get_other_grid(SubdivDisplacement *displacement,
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const int ptex_face_index,
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const int corner,
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const int corner_delta)
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{
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MultiresDisplacementData *data = displacement->user_data;
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const PolyCornerIndex *poly_corner = &data->ptex_poly_corner[ptex_face_index];
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const MPoly *poly = &data->mpoly[poly_corner->poly_index];
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const int effective_corner = (poly->totloop == 4) ? corner : poly_corner->corner;
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const int next_corner = (effective_corner + corner_delta + poly->totloop) % poly->totloop;
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return &data->mdisps[poly->loopstart + next_corner];
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}
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BLI_INLINE eAverageWith read_displacement_grid(const MDisps *displacement_grid,
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const int grid_size,
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const float grid_u,
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const float grid_v,
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float r_tangent_D[3])
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{
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if (displacement_grid->disps == NULL) {
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zero_v3(r_tangent_D);
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return AVERAGE_WITH_NONE;
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}
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const int x = roundf(grid_u * (grid_size - 1));
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const int y = roundf(grid_v * (grid_size - 1));
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copy_v3_v3(r_tangent_D, displacement_grid->disps[y * grid_size + x]);
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if (x == 0 && y == 0) {
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return AVERAGE_WITH_ALL;
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}
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if (x == 0) {
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return AVERAGE_WITH_PREV;
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}
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if (y == 0) {
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return AVERAGE_WITH_NEXT;
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}
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return AVERAGE_WITH_NONE;
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}
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static void average_convert_grid_coord_to_ptex(const MPoly *poly,
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const int corner,
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const float grid_u,
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const float grid_v,
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float *r_ptex_face_u,
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float *r_ptex_face_v)
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{
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if (poly->totloop == 4) {
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BKE_subdiv_rotate_grid_to_quad(corner, grid_u, grid_v, r_ptex_face_u, r_ptex_face_v);
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}
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else {
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BKE_subdiv_grid_uv_to_ptex_face_uv(grid_u, grid_v, r_ptex_face_u, r_ptex_face_v);
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}
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}
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static void average_construct_tangent_matrix(Subdiv *subdiv,
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const MPoly *poly,
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const int ptex_face_index,
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const int corner,
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const float u,
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const float v,
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float r_tangent_matrix[3][3])
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{
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const bool is_quad = (poly->totloop == 4);
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const int quad_corner = is_quad ? corner : 0;
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float dummy_P[3], dPdu[3], dPdv[3];
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BKE_subdiv_eval_limit_point_and_derivatives(subdiv, ptex_face_index, u, v, dummy_P, dPdu, dPdv);
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BKE_multires_construct_tangent_matrix(r_tangent_matrix, dPdu, dPdv, quad_corner);
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}
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static void average_read_displacement_tangent(MultiresDisplacementData *data,
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const MDisps *other_displacement_grid,
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const float grid_u,
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const float grid_v,
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float r_tangent_D[3])
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{
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read_displacement_grid(other_displacement_grid, data->grid_size, grid_u, grid_v, r_tangent_D);
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}
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static void average_read_displacement_object(MultiresDisplacementData *data,
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const MDisps *displacement_grid,
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const float grid_u,
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const float grid_v,
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const int ptex_face_index,
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const int corner_index,
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float r_D[3])
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{
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const PolyCornerIndex *poly_corner = &data->ptex_poly_corner[ptex_face_index];
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const MPoly *poly = &data->mpoly[poly_corner->poly_index];
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/* Get (u, v) coordinate within the other ptex face which corresponds to
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* the grid coordinates. */
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float u, v;
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average_convert_grid_coord_to_ptex(poly, corner_index, grid_u, grid_v, &u, &v);
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/* Construct tangent matrix which corresponds to partial derivatives
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* calculated for the other ptex face. */
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float tangent_matrix[3][3];
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average_construct_tangent_matrix(
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data->subdiv, poly, ptex_face_index, corner_index, u, v, tangent_matrix);
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/* Read displacement from other grid in a tangent space. */
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float tangent_D[3];
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average_read_displacement_tangent(data, displacement_grid, grid_u, grid_v, tangent_D);
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/* Convert displacement to object space. */
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mul_v3_m3v3(r_D, tangent_matrix, tangent_D);
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}
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static void average_get_other_ptex_and_corner(MultiresDisplacementData *data,
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const int ptex_face_index,
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const int corner,
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const int corner_delta,
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int *r_other_ptex_face_index,
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int *r_other_corner_index)
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{
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const PolyCornerIndex *poly_corner = &data->ptex_poly_corner[ptex_face_index];
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const MPoly *poly = &data->mpoly[poly_corner->poly_index];
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const int num_corners = poly->totloop;
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const bool is_quad = (num_corners == 4);
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const int poly_index = poly - data->mpoly;
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const int start_ptex_face_index = data->face_ptex_offset[poly_index];
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*r_other_corner_index = (corner + corner_delta + num_corners) % num_corners;
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*r_other_ptex_face_index = is_quad ? start_ptex_face_index :
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start_ptex_face_index + *r_other_corner_index;
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}
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/* NOTE: Grid coordinates are relatiev to the other grid already. */
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static void average_with_other(SubdivDisplacement *displacement,
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const int ptex_face_index,
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const int corner,
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const float grid_u,
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const float grid_v,
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const int corner_delta,
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float r_D[3])
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{
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MultiresDisplacementData *data = displacement->user_data;
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const MDisps *other_displacement_grid = displacement_get_other_grid(
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displacement, ptex_face_index, corner, corner_delta);
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int other_ptex_face_index, other_corner_index;
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average_get_other_ptex_and_corner(
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data, ptex_face_index, corner, corner_delta, &other_ptex_face_index, &other_corner_index);
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/* Get displacement in object space. */
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float other_D[3];
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average_read_displacement_object(data,
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other_displacement_grid,
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grid_u,
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grid_v,
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other_ptex_face_index,
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other_corner_index,
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other_D);
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/* Average result with the other displacement vector. */
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add_v3_v3(r_D, other_D);
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mul_v3_fl(r_D, 0.5f);
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}
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static void average_with_all(SubdivDisplacement *displacement,
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const int ptex_face_index,
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const int corner,
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const float UNUSED(grid_u),
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const float UNUSED(grid_v),
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float r_D[3])
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{
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MultiresDisplacementData *data = displacement->user_data;
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const PolyCornerIndex *poly_corner = &data->ptex_poly_corner[ptex_face_index];
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const MPoly *poly = &data->mpoly[poly_corner->poly_index];
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const int num_corners = poly->totloop;
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for (int corner_delta = 1; corner_delta < num_corners; corner_delta++) {
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average_with_other(displacement, ptex_face_index, corner, 0.0f, 0.0f, corner_delta, r_D);
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}
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}
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static void average_with_next(SubdivDisplacement *displacement,
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const int ptex_face_index,
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const int corner,
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const float grid_u,
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const float UNUSED(grid_v),
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float r_D[3])
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{
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average_with_other(displacement, ptex_face_index, corner, 0.0f, grid_u, 1, r_D);
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}
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static void average_with_prev(SubdivDisplacement *displacement,
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const int ptex_face_index,
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const int corner,
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const float UNUSED(grid_u),
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const float grid_v,
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float r_D[3])
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{
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average_with_other(displacement, ptex_face_index, corner, grid_v, 0.0f, -1, r_D);
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}
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static void average_displacement(SubdivDisplacement *displacement,
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eAverageWith average_with,
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const int ptex_face_index,
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const int corner,
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const float grid_u,
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const float grid_v,
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float r_D[3])
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{
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switch (average_with) {
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case AVERAGE_WITH_ALL:
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average_with_all(displacement, ptex_face_index, corner, grid_u, grid_v, r_D);
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break;
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case AVERAGE_WITH_PREV:
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average_with_prev(displacement, ptex_face_index, corner, grid_u, grid_v, r_D);
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break;
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case AVERAGE_WITH_NEXT:
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average_with_next(displacement, ptex_face_index, corner, grid_u, grid_v, r_D);
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break;
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case AVERAGE_WITH_NONE:
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break;
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}
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}
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static int displacement_get_face_corner(MultiresDisplacementData *data,
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const int ptex_face_index,
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const float u,
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const float v)
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{
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const PolyCornerIndex *poly_corner = &data->ptex_poly_corner[ptex_face_index];
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const MPoly *poly = &data->mpoly[poly_corner->poly_index];
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const int num_corners = poly->totloop;
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const bool is_quad = (num_corners == 4);
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if (is_quad) {
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float dummy_corner_u, dummy_corner_v;
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return BKE_subdiv_rotate_quad_to_corner(u, v, &dummy_corner_u, &dummy_corner_v);
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}
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return poly_corner->corner;
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}
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static void initialize(SubdivDisplacement *displacement)
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{
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MultiresDisplacementData *data = displacement->user_data;
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multiresModifier_ensure_external_read(data->mesh, data->mmd);
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data->is_initialized = true;
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}
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static void eval_displacement(SubdivDisplacement *displacement,
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const int ptex_face_index,
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const float u,
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const float v,
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const float dPdu[3],
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const float dPdv[3],
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float r_D[3])
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{
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MultiresDisplacementData *data = displacement->user_data;
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BLI_assert(data->is_initialized);
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const int grid_size = data->grid_size;
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/* Get displacement in tangent space. */
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const MDisps *displacement_grid;
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float grid_u, grid_v;
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const int corner_of_quad = displacement_get_grid_and_coord(
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displacement, ptex_face_index, u, v, &displacement_grid, &grid_u, &grid_v);
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/* Read displacement from the current displacement grid and see if any
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* averaging is needed. */
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float tangent_D[3];
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eAverageWith average_with = read_displacement_grid(
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displacement_grid, grid_size, grid_u, grid_v, tangent_D);
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/* Convert it to the object space. */
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float tangent_matrix[3][3];
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BKE_multires_construct_tangent_matrix(tangent_matrix, dPdu, dPdv, corner_of_quad);
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mul_v3_m3v3(r_D, tangent_matrix, tangent_D);
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/* For the boundary points of grid average two (or all) neighbor grids. */
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const int corner = displacement_get_face_corner(data, ptex_face_index, u, v);
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average_displacement(displacement, average_with, ptex_face_index, corner, grid_u, grid_v, r_D);
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}
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static void free_displacement(SubdivDisplacement *displacement)
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{
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MultiresDisplacementData *data = displacement->user_data;
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MEM_freeN(data->ptex_poly_corner);
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MEM_freeN(data);
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}
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/* TODO(sergey): This seems to be generally used information, which almost
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* worth adding to a subdiv itself, with possible cache of the value. */
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static int count_num_ptex_faces(const Mesh *mesh)
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{
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int num_ptex_faces = 0;
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const MPoly *mpoly = mesh->mpoly;
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for (int poly_index = 0; poly_index < mesh->totpoly; poly_index++) {
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const MPoly *poly = &mpoly[poly_index];
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num_ptex_faces += (poly->totloop == 4) ? 1 : poly->totloop;
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}
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return num_ptex_faces;
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}
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static void displacement_data_init_mapping(SubdivDisplacement *displacement, const Mesh *mesh)
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{
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MultiresDisplacementData *data = displacement->user_data;
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const MPoly *mpoly = mesh->mpoly;
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const int num_ptex_faces = count_num_ptex_faces(mesh);
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/* Allocate memory. */
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data->ptex_poly_corner = MEM_malloc_arrayN(
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num_ptex_faces, sizeof(*data->ptex_poly_corner), "ptex poly corner");
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/* Fill in offsets. */
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int ptex_face_index = 0;
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PolyCornerIndex *ptex_poly_corner = data->ptex_poly_corner;
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for (int poly_index = 0; poly_index < mesh->totpoly; poly_index++) {
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const MPoly *poly = &mpoly[poly_index];
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if (poly->totloop == 4) {
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ptex_poly_corner[ptex_face_index].poly_index = poly_index;
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ptex_poly_corner[ptex_face_index].corner = 0;
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ptex_face_index++;
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}
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else {
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for (int corner = 0; corner < poly->totloop; corner++) {
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ptex_poly_corner[ptex_face_index].poly_index = poly_index;
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ptex_poly_corner[ptex_face_index].corner = corner;
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ptex_face_index++;
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}
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}
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}
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}
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static void displacement_init_data(SubdivDisplacement *displacement,
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Subdiv *subdiv,
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Mesh *mesh,
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const MultiresModifierData *mmd)
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{
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MultiresDisplacementData *data = displacement->user_data;
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data->subdiv = subdiv;
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data->grid_size = BKE_subdiv_grid_size_from_level(mmd->totlvl);
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data->mesh = mesh;
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data->mmd = mmd;
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data->mpoly = mesh->mpoly;
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data->mdisps = CustomData_get_layer(&mesh->ldata, CD_MDISPS);
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data->face_ptex_offset = BKE_subdiv_face_ptex_offset_get(subdiv);
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data->is_initialized = false;
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displacement_data_init_mapping(displacement, mesh);
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}
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static void displacement_init_functions(SubdivDisplacement *displacement)
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{
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displacement->initialize = initialize;
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displacement->eval_displacement = eval_displacement;
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displacement->free = free_displacement;
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}
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void BKE_subdiv_displacement_attach_from_multires(Subdiv *subdiv,
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Mesh *mesh,
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const MultiresModifierData *mmd)
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{
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/* Make sure we don't have previously assigned displacement. */
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BKE_subdiv_displacement_detach(subdiv);
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/* It is possible to have mesh without CD_MDISPS layer. Happens when using
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* dynamic topology. */
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if (!CustomData_has_layer(&mesh->ldata, CD_MDISPS)) {
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return;
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}
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/* Allocate all required memory. */
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SubdivDisplacement *displacement = MEM_callocN(sizeof(SubdivDisplacement),
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"multires displacement");
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displacement->user_data = MEM_callocN(sizeof(MultiresDisplacementData),
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"multires displacement data");
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displacement_init_data(displacement, subdiv, mesh, mmd);
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displacement_init_functions(displacement);
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/* Finish. */
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subdiv->displacement_evaluator = displacement;
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}
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