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blender-archive/source/blender/blenkernel/BKE_mesh_wrapper.h
Kévin Dietrich eed45d2a23 OpenSubDiv: add support for an OpenGL evaluator
This evaluator is used in order to evaluate subdivision at render time, allowing for
faster renders of meshes with a subdivision surface modifier placed at the last
position in the modifier list.

When evaluating the subsurf modifier, we detect whether we can delegate evaluation
to the draw code. If so, the subdivision is first evaluated on the GPU using our own
custom evaluator (only the coarse data needs to be initially sent to the GPU), then,
buffers for the final `MeshBufferCache` are filled on the GPU using a set of
compute shaders. However, some buffers are still filled on the CPU side, if doing so
on the GPU is impractical (e.g. the line adjacency buffer used for x-ray, whose
logic is hardly GPU compatible).

This is done at the mesh buffer extraction level so that the result can be readily used
in the various OpenGL engines, without having to write custom geometry or tesselation
shaders.

We use our own subdivision evaluation shaders, instead of OpenSubDiv's vanilla one, in
order to control the data layout, and interpolation. For example, we store vertex colors
as compressed 16-bit integers, while OpenSubDiv's default evaluator only work for float
types.

In order to still access the modified geometry on the CPU side, for use in modifiers
or transform operators, a dedicated wrapper type is added `MESH_WRAPPER_TYPE_SUBD`.
Subdivision will be lazily evaluated via `BKE_object_get_evaluated_mesh` which will
create such a wrapper if possible. If the final subdivision surface is not needed on
the CPU side, `BKE_object_get_evaluated_mesh_no_subsurf` should be used.

Enabling or disabling GPU subdivision can be done through the user preferences (under
Viewport -> Subdivision).

See patch description for benchmarks.

Reviewed By: campbellbarton, jbakker, fclem, brecht, #eevee_viewport

Differential Revision: https://developer.blender.org/D12406
2021-12-27 16:35:54 +01:00

60 lines
2.2 KiB
C++

/*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#pragma once
/** \file
* \ingroup bke
*/
struct BMEditMesh;
struct CustomData_MeshMasks;
struct Mesh;
struct Object;
#ifdef __cplusplus
extern "C" {
#endif
struct Mesh *BKE_mesh_wrapper_from_editmesh_with_coords(
struct BMEditMesh *em,
const struct CustomData_MeshMasks *cd_mask_extra,
const float (*vert_coords)[3],
const struct Mesh *me_settings);
struct Mesh *BKE_mesh_wrapper_from_editmesh(struct BMEditMesh *em,
const struct CustomData_MeshMasks *cd_mask_extra,
const struct Mesh *me_settings);
void BKE_mesh_wrapper_ensure_mdata(struct Mesh *me);
bool BKE_mesh_wrapper_minmax(const struct Mesh *me, float min[3], float max[3]);
int BKE_mesh_wrapper_vert_len(const struct Mesh *me);
int BKE_mesh_wrapper_edge_len(const struct Mesh *me);
int BKE_mesh_wrapper_loop_len(const struct Mesh *me);
int BKE_mesh_wrapper_poly_len(const struct Mesh *me);
void BKE_mesh_wrapper_vert_coords_copy(const struct Mesh *me,
float (*vert_coords)[3],
int vert_coords_len);
void BKE_mesh_wrapper_vert_coords_copy_with_mat4(const struct Mesh *me,
float (*vert_coords)[3],
int vert_coords_len,
const float mat[4][4]);
struct Mesh *BKE_mesh_wrapper_ensure_subdivision(const struct Object *ob, struct Mesh *me);
#ifdef __cplusplus
}
#endif