GPv3: Weight gradient tool #118671

Sietse Brouwer · 2024-02-23T16:47:08+01:00

Sietse Brouwer commented

2024-02-23 16:47:08 +01:00

This PR implements the Weight Gradient tool for GPv3. The tool applies
a linear/radial weight gradient to all editable stroke points for the
active vertex group. Useful for creating smooth weight transitions.

The tool works interactively in the viewport. With click-and-drag
a dashed line is drawn in the viewport, representing the orientation
and length of the gradient. The effect of the gradient on the vertex
weights is shown in real time.

The gradient weight is added or substracted to the existing vertex
weight. The direction (Add/Subtract) can be toggled with D.
Alternatively, Ctrl-drag can be used. Holding Ctrl inverts the
direction.

When the 'Auto Normalize' option is enabled and the Grease Pencil
object is deformed by an armature, all deforming weights assigned
to a single vertex (stroke point) automatically add up to 1.0.

The gradient tool will do nothing when the active vertex group is
locked.
When there is no active vertex group, a new one will be created.

This PR implements the Weight Gradient tool for GPv3. The tool applies a linear/radial weight gradient to all editable stroke points for the active vertex group. Useful for creating smooth weight transitions. The tool works interactively in the viewport. With click-and-drag a dashed line is drawn in the viewport, representing the orientation and length of the gradient. The effect of the gradient on the vertex weights is shown in real time. The gradient weight is added or substracted to the existing vertex weight. The direction (Add/Subtract) can be toggled with `D`. Alternatively, `Ctrl`-drag can be used. Holding `Ctrl` inverts the direction. When the 'Auto Normalize' option is enabled and the Grease Pencil object is deformed by an armature, all deforming weights assigned to a single vertex (stroke point) automatically add up to 1.0. The gradient tool will do nothing when the active vertex group is locked. When there is no active vertex group, a new one will be created.

❤️ 2

Sietse Brouwer added 3 commits 2024-02-23 16:47:13 +01:00

80fc3c6e83 GPv3: Weight gradient tool

fe5daaea40 Cleanup after cherry-pick from other branch

2ee52fb10d Cleanup: Better comment and variable name

Sietse Brouwer commented

2024-02-23 16:53:49 +01:00

Note: grease_pencil_weight_paint.cc only needs code review from line 275 and further. The first part is the same as in #118347: GPv3: Weight Paint tools (Draw, Blur, Average, Smear, Sample weight). It's only present in this PR so that it can be build on its own.

Note: `grease_pencil_weight_paint.cc` only needs code review from line 275 and further. The first part is the same as in [#118347: GPv3: Weight Paint tools (Draw, Blur, Average, Smear, Sample weight)](https://projects.blender.org/blender/blender/pulls/118347). It's only present in this PR so that it can be build on its own.

Sietse Brouwer added this to the Grease Pencil project 2024-02-23 16:54:04 +01:00

Sietse Brouwer requested review from Falk David 2024-02-23 16:54:21 +01:00

Sietse Brouwer commented

2024-02-23 19:47:34 +01:00

Little demo with Thickness and Offset modifiers:

Little demo with Thickness and Offset modifiers: <video src="/attachments/fcd58082-d469-471d-a4fb-a6b71c4eb345" title="Weight gradient tool GPv3.mp4" controls></video>

Weight gradient tool GPv3.mp4

2.7 MiB

Iliya Katushenock reviewed 2024-02-24 12:44:34 +01:00

source/blender/editors/grease_pencil/intern/grease_pencil_weight_paint.cc

						
				@ -0,0 +206,4 @@

				  return true;

				}

				void normalize_vertex_weights(const MDeformVert &dvert,

Iliya Katushenock commented

2024-02-24 12:29:52 +01:00

Should this be static in this PR?

SietseB marked this conversation as resolved

source/blender/editors/grease_pencil/intern/grease_pencil_weight_paint.cc Outdated

						
				@ -0,0 +276,4 @@

				/** \name Weight Gradient Operator

				 * \{ */

				enum {

Iliya Katushenock commented

2024-02-24 12:31:11 +01:00

enum class WeightGradientType : int8_t {
  Linear,
  Radial,
};

```Cpp enum class WeightGradientType : int8_t { Linear, Radial, }; ```

SietseB marked this conversation as resolved

source/blender/editors/grease_pencil/intern/grease_pencil_weight_paint.cc Outdated

						
				@ -0,0 +366,4 @@

				            /* Calculate weight change. */

				            float gradient_factor = 0.0f;

				            if (gradient_type == WPAINT_GRADIENT_TYPE_LINEAR) {

Iliya Katushenock commented

2024-02-24 12:33:54 +01:00

Should be switch.

SietseB marked this conversation as resolved

source/blender/editors/grease_pencil/intern/grease_pencil_weight_paint.cc

						
				@ -0,0 +568,4 @@

				      cache.point_positions = Array<float2>(deformation.positions.size());

				      cache.point_original_weights = Array<float>(deformation.positions.size());

				      cache.point_flags = Array<uint8_t>(deformation.positions.size(), 0);

Iliya Katushenock commented

2024-02-24 12:37:33 +01:00

cache.point_flags.reinitialize(deformation.positions.size())

`cache.point_flags.reinitialize(deformation.positions.size())`

Iliya Katushenock commented

2024-02-24 12:38:48 +01:00

Also, can this be index mask?

Sietse Brouwer commented

2024-02-26 14:11:52 +01:00

In general, a lot of stroke points are affected by the gradient tool. I wouldn't recommend using an index mask for that; it would be less performant.

Iliya Katushenock commented

2024-02-26 16:59:39 +01:00

No, index mask usually much faster than a branches in hot loops.
Main reason to do not build index mask is the case of complicated condition for each element, but not sure is there this case is here...

No, index mask usually much faster than a branches in hot loops. Main reason to do not build index mask is the case of complicated condition for each element, but not sure is there this case is here...

Sietse Brouwer commented

2024-02-26 23:51:00 +01:00

I can't see how we can gain much from an index mask. The gradient is an interactive tool, so at the operator's invoke we can't build a mask yet. And at the execute we already have to loop over all the stroke points to see if they are affected by the gradient – we could dynamically build an index mask then, but to what end?

I can't see how we can gain much from an index mask. The gradient is an interactive tool, so at the operator's `invoke` we can't build a mask yet. And at the `execute` we already have to loop over all the stroke points to see if they are affected by the gradient – we could dynamically build an index mask then, but to what end?

Sietse Brouwer added 1 commit 2024-02-26 13:43:20 +01:00

9ed53a7a61 Code review pass

Sietse Brouwer added 1 commit 2024-04-11 23:13:30 +02:00

eebe52481f Merge branch 'main' into gpv3-weight-gradient-tool

This pull request has changes conflicting with the target branch.

source/blender/editors/grease_pencil/intern/grease_pencil_ops.cc
source/blender/editors/grease_pencil/intern/grease_pencil_weight_paint.cc
source/blender/editors/include/ED_grease_pencil.hh

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git fetch -u gpv3-weight-gradient-tool:SietseB-gpv3-weight-gradient-tool

git checkout SietseB-gpv3-weight-gradient-tool

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GPv3: Weight gradient tool #118671

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