Sculpt: Fix #107123: New normals impl. for PBVH_FACES #107456

Joseph Eagar · 2023-04-29T02:10:05+02:00

Joseph Eagar commented

2023-04-29 02:10:05 +02:00

This patch rewrites PBVH_FACE's normal update code. The old code worked by calculating normals in loop tris and then adding them to vertices, which were later normalized; unfortunately this is incorrect, the first topological ring surrounding vertices needs to be updated too. This is not possible with the existing code which operates on a list of PBVHNodes. We can't add more vertices to the update set without knowing which nodes they belong to.

The new code works a bit differently:

Updates poly normals as well as vertices.
Normals are accumulated at each vertex from surrounding polys via pbvh->pmap, instead of directly propagating normals from loop tris to verts.
pbvh->pmap is now always created, the need_pmap (along with need_mask) arguments to BKE_sculpt_update_object_for_edit will be removed in a separate cleanup commit.
The C++ task API is used for (much greater) code clarity.
There is some use of atomics which I'm not sure is necessary (at least for x86).

This patch rewrites PBVH_FACE's normal update code. The old code worked by calculating normals in loop tris and then adding them to vertices, which were later normalized; unfortunately this is incorrect, the first topological ring surrounding vertices needs to be updated too. This is not possible with the existing code which operates on a list of `PBVHNode`s. We can't add more vertices to the update set without knowing which nodes they belong to. The new code works a bit differently: * Updates poly normals as well as vertices. * Normals are accumulated at each vertex from surrounding polys via `pbvh->pmap`, instead of directly propagating normals from loop tris to verts. * `pbvh->pmap` is now always created, the `need_pmap` (along with `need_mask`) arguments to `BKE_sculpt_update_object_for_edit` will be removed in a separate cleanup commit. * The C++ task API is used for (much greater) code clarity. * There is some use of atomics which I'm not sure is necessary (at least for x86).

Joseph Eagar added 1 commit 2023-04-29 02:11:57 +02:00

3755f4fcda temp-pbvh-normals: commit patch

Joseph Eagar requested review from Hans Goudey 2023-04-29 02:12:34 +02:00

Joseph Eagar referenced this pull request

2023-04-29 02:12:59 +02:00

Sculpt Mode: Smooth Normals don't properly update while sculpting #107123

Joseph Eagar added 1 commit 2023-04-29 02:17:32 +02:00

93d095906e temp-pbvh-normals: Comment out unused parameter

Iliya Katushenock reviewed 2023-04-29 10:25:38 +02:00

source/blender/blenkernel/intern/pbvh.cc Outdated

						
				@ -1446,0 +1417,4 @@

				  float(*vert_positions)[3] = pbvh->vert_positions;

				  Vector<int> verts, tris; /* Note: these two vectors can contain duplicates. */

				  for (int i = 0; i < task_update_verts.size(); i++) {

Iliya Katushenock commented

2023-04-29 10:25:38 +02:00

for (const Span<int> verts : task_update_verts)

Same below.

```Cpp for (const Span<int> verts : task_update_verts) ``` Same below.

👍 1

Iliya Katushenock reviewed 2023-04-29 10:25:40 +02:00

source/blender/blenkernel/intern/pbvh.cc

						
				@ -1446,0 +1415,4 @@

				  /* Don't bother de-duplicating. */

				  float(*vert_positions)[3] = pbvh->vert_positions;

				  Vector<int> verts, tris; /* Note: these two vectors can contain duplicates. */

Iliya Katushenock commented

2023-04-29 10:25:40 +02:00

If each vector in task_update_verts contain at least one element.

verts.ensure(task_update_verts.size());

Same for tris

If each vector in `task_update_verts` contain at least one element. ```Cpp verts.ensure(task_update_verts.size()); ``` Same for `tris`

Joseph Eagar commented

2023-04-29 11:27:02 +02:00

That assumption doesn't really hold, and I don't think using the nodes size as a heuristic really works. You'd have to multiply it by some factor (a percentage of the leaf limit most likely) which would have to be tested across a range of conditions.

Iliya Katushenock commented

2023-04-29 11:38:56 +02:00

This heuristic provides some improvement, but yes, without a real calculation, you can't allocate all the memory. But if it's 100 tasks with 3 verts, you'll be allocating 201, not 300 times.
But yes, this is not some real implementation requirement, but just a weak suggestion, you can close it if you don't think it's really useful

This heuristic provides some improvement, but yes, without a real calculation, you can't allocate all the memory. But if it's 100 tasks with 3 verts, you'll be allocating 201, not 300 times. But yes, this is not some real implementation requirement, but just a weak suggestion, you can close it if you don't think it's really useful

Iliya Katushenock reviewed 2023-04-29 10:25:42 +02:00

source/blender/blenkernel/intern/pbvh.cc Outdated

						
				@ -1400,2 +1389,2 @@

				{

				  PBVHUpdateData *data = static_cast<PBVHUpdateData *>(userdata);

				  task_update_verts.resize(nodes.size());

				  task_update_tris.resize(nodes.size());

Iliya Katushenock commented

2023-04-29 10:25:42 +02:00

Vector<Vector<int>> task_update_verts;
Vector<Vector<int>> task_update_tris;

task_update_verts.resize(nodes.size());
task_update_tris.resize(nodes.size());

->

Array<Vector<int>> task_update_verts(nodes.size());
Array<Vector<int>> task_update_tris(nodes.size());

```Cpp Vector<Vector<int>> task_update_verts; Vector<Vector<int>> task_update_tris; task_update_verts.resize(nodes.size()); task_update_tris.resize(nodes.size()); ``` -> ```Cpp Array<Vector<int>> task_update_verts(nodes.size()); Array<Vector<int>> task_update_tris(nodes.size()); ```

Iliya Katushenock reviewed 2023-04-29 10:26:01 +02:00

source/blender/blenkernel/intern/pbvh.cc Outdated

						
				@ -1376,3 +1381,1 @@

				static void pbvh_update_normals_clear_task_cb(void *__restrict userdata,

				                                              const int n,

				                                              const TaskParallelTLS *__restrict /*tls*/)

				static void pbvh_faces_update_normals(PBVH *pbvh, Span<PBVHNode *> nodes)

Iliya Katushenock commented

2023-04-29 10:26:01 +02:00

const Span<PBVHNode *> nodes

`const Span<PBVHNode *> nodes`

Joseph Eagar commented

2023-04-29 11:28:30 +02:00

Shouldn't that be Span<const PBVHNode*>?

Shouldn't that be `Span<const PBVHNode*>`?

Iliya Katushenock commented

2023-04-29 11:42:21 +02:00

The container itself is constant, since you don't change it by value (for example, swap between 2 spans). Its nodes are not contants, so how can you get a Span<const Node> from a Vector<Node>? (and you change nodes in code as i can see, not sure why isn't mutable span now)

The container itself is constant, since you don't change it by value (for example, swap between 2 spans). Its nodes are not contants, so how can you get a `Span<const Node>` from a `Vector<Node>`? (and you change nodes in code as i can see, not sure why isn't mutable span now)

Joseph Eagar added 2 commits 2023-04-29 11:35:31 +02:00

0328886f98 Merge branch 'main' into temp-pbvh-normals

3bc6374267 temp-pbvh-normals: Make requested patch changes

Joseph Eagar added 1 commit 2023-04-29 11:35:52 +02:00

9507494675 Merge branch 'main' into temp-pbvh-normals

Hans Goudey commented

2023-04-30 23:33:27 +02:00

I submitted an alternative fix in #107458, which is more similar to mesh normal calculation and makes more use of the vert -> poly map, and recalculates the entire poly normal at once.

Julien Kaspar added the

Module

Sculpt, Paint & Texture

label 2023-05-01 12:32:57 +02:00

Julien Kaspar commented

2023-05-15 17:21:55 +02:00

@JosephEagar Since #107458 is merged I think this can be closed right?

Hans Goudey closed this pull request

2023-05-15 17:25:43 +02:00

Hans Goudey deleted branch temp-pbvh-normals

2023-05-16 17:19:02 +02:00

Pull request closed

This pull request cannot be reopened because the branch was deleted.

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Sculpt: Fix #107123: New normals impl. for PBVH_FACES #107456

Pull request closed