The lines paint mask IBO extraction was not implemented for GPU subdivision.
For it to work, we also now need to preserve the subdivision loop to
subdivision edge map, which until now was overwritten to store coarse edges
(the map to coarse edges is still preserved).
Also the paint flag stored in the 4th dimension of the loop normal buffer
was not properly set for flat shaded faces, leading to other kind of
artefacts and render issues.
There are two issues revealed in the bug report:
- the GPU subdivision does not support meshes with only loose geometry
- the loose geometry is not subdivided
For the first case, checks are added to ensure we still fill the
buffers with loose geometry even if no polygons are present.
For the second case, this adds
`BKE_subdiv_mesh_interpolate_position_on_edge` which encapsulates the
loose vertex interpolation mechanism previously found in
`subdiv_mesh_vertex_of_loose_edge`.
The subdivided loose geometry is stored in a new specific data structure
`DRWSubdivLooseGeom` so as to not pollute `MeshExtractLooseGeom`. These
structures store the corresponding coarse element data, which will be
used for filling GPU buffers appropriately.
Differential Revision: https://developer.blender.org/D14171
A simple case of missing the tangent VBO. The tangents are computed from
the coarse mesh, and interpolated on the GPU for the final mesh. Code for
initializing the tangents, and the vertex format for the VBO was
factored out of the coarse extraction routine, to be shared with the
subdivision routine.
Reuse the same vertex normals calculation as for the GPU code, by
weighing each vertex normals by the angle of the edges incident to the
vertex on the face.
Additionally, remove limit normals, as the CPU code does not use them
either, and would also cause different shading issues when limit surface
is used.
Fixes T95242: shade smooth artifacts with edge crease and limit surface
Fixes T94919: subdivision, different shading between CPU and GPU
The issue has two causes: on one hand origin indices were not handled
properly, on the other hand the extraction type (Mesh, BMesh, or mapped)
was not detected correctly.
For the second case reuse the MeshRenderData creation from the coarse
code path so that we make the same decisions. Loose geometry extraction
had to be updated to properly handle the BMesh cases.
For the origin indices, in some cases (for edges and faces), the arrays
used by the subdivision code already have the origin indices baked into
them, so mapping them a second time through the origin index layer is
wrong, and could cause out of bounds accesses.
For vertices especially, we would use two arrays: one for mapping
subdivision vertices to coarse vertices, and another one to map coarse
vertices to subdivision loops used for the selection index buffer. The
second one is now removed (which saves a bit of memory) as it is did not
have the proper data setup for use with the origin indices and we can
easily compute it using the first array anyway.
Use a shorter/simpler license convention, stops the header taking so
much space.
Follow the SPDX license specification: https://spdx.org/licenses
- C/C++/objc/objc++
- Python
- Shell Scripts
- CMake, GNUmakefile
While most of the source tree has been included
- `./extern/` was left out.
- `./intern/cycles` & `./intern/atomic` are also excluded because they
use different header conventions.
doc/license/SPDX-license-identifiers.txt has been added to list SPDX all
used identifiers.
See P2788 for the script that automated these edits.
Reviewed By: brecht, mont29, sergey
Ref D14069
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
