GPv3: Drawing attribute API functions #119080

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Falk David · 2024-03-05T11:19:38+01:00

Falk David commented

2024-03-05 11:19:38 +01:00

The Grease Pencil Drawings have many attributes that are built-in (e.g. they are used by the renderer, operators or modifiers). When one wants to use them in code, one has to lookup other places in the code to know what the name and the type of the attribute is. This is not ideal.

To avoid this, we should add new API endpoints to the Drawing with the built-in attributes (e.g. used by the renderer, operators, etc.)

Here is a list of these attributes:

Name	Type	Domain	Default	Note
`".selection"`	`bool`	`Point`/`Curve`	`true`	All curves are treated as selected when this attribute does not exist.
`"position"`	`float3`	`Point`	-
`"radius"`	`float`	`Point`	`0.01f`
`"opacity"`	`float`	`Point`	`0.0f`
`"vertex_color"`	`GeometryColor4f`	`Point`	`ColorGeometry4f(0.0)`	The alpha value is used to mix in the base material color (`0` means only the material color is used).
`"rotation"`	`float`	`Point`	`0.0f`	This is the rotation of a texture on the point.
`"delta_time"`	`float`	`Point`	`0.0f`	Written while drawing. The time difference in the time this point was added and the time the previous one was added. Used by the build modifier to "replay" how the stroke was draw.
`"cyclic"`	`bool`	`Curve`	`false`
`"start_cap"`	`int8_t`	`Curve`	`GP_STROKE_CAP_TYPE_ROUND`	Enum of type `GreasePencilStrokeCapType`.
`"end_cap"`	`int8_t`	`Curve`	`GP_STROKE_CAP_TYPE_ROUND`	Enum of type `GreasePencilStrokeCapType`.
`"hardness"`	`float`	`Curve`	`1.0f`	Used to render a soft gradient from the center line of the stroke to the edge.
`"curve_type"`	`int8_t`	`Curve`	`CURVE_TYPE_POLY`	Enum of type `CurveType`.
`"aspect_ratio"`	`float`	`Curve`	`1.0f`	Value used to scale the x and y of textures on vertices. The aspect ratio is `x / y` where `y` is clamped to a minimum of 1e-7.
`"fill_color"`	`ColorGeometry4f`	`Curve`	`ColorGeometry4f(0.0)`	The alpha value is used to mix in the base material color (`0` means only the material color is used).
`"material_index"`	`int`	`Curve`	`0`
`"init_time"`	`float`	`Curve`	`0.0f`	Written while drawing. The timestamp at which this stroke was created. Used by the build modifier to "replay" how strokes were drawn.

The Grease Pencil Drawings have many attributes that are built-in (e.g. they are used by the renderer, operators or modifiers). When one wants to use them in code, one has to lookup other places in the code to know what the name and the type of the attribute is. This is not ideal. To avoid this, we should add new API endpoints to the `Drawing` with the built-in attributes (e.g. used by the renderer, operators, etc.) Here is a list of these attributes: | Name | Type | Domain | Default | Note | | --------- | --------- | ------------ | ------------ | ------- | | `".selection"` | `bool` | `Point`/`Curve` | `true` | All curves are treated as selected when this attribute does not exist. | | `"position"` | `float3` | `Point` | - | | Assumed to be always present. | | `"radius"` | `float` | `Point` | `0.01f` | | | `"opacity"` | `float` | `Point` | `0.0f` | | | `"vertex_color"` | `GeometryColor4f` | `Point` | `ColorGeometry4f(0.0)` | The alpha value is used to mix in the base material color (`0` means only the material color is used). | | `"rotation"` | `float` | `Point` | `0.0f` | This is the rotation of a texture on the point. | | `"delta_time"` | `float` | `Point` | `0.0f` | Written while drawing. The time difference in the time this point was added and the time the previous one was added. Used by the build modifier to "replay" how the stroke was draw. | | `"cyclic"` | `bool` | `Curve` | `false` | | | `"start_cap"` | `int8_t` | `Curve` | `GP_STROKE_CAP_TYPE_ROUND` | Enum of type `GreasePencilStrokeCapType`. | | `"end_cap"` | `int8_t` | `Curve` | `GP_STROKE_CAP_TYPE_ROUND` | Enum of type `GreasePencilStrokeCapType`. | | `"hardness"` | `float` | `Curve` | `1.0f` | Used to render a soft gradient from the center line of the stroke to the edge. | | `"curve_type"` | `int8_t` | `Curve` | `CURVE_TYPE_POLY` | Enum of type `CurveType`. | | `"aspect_ratio"` | `float` | `Curve` | `1.0f` | Value used to scale the x and y of textures on vertices. The aspect ratio is `x / y` where `y` is clamped to a minimum of 1e-7. | | `"fill_color"` | `ColorGeometry4f` | `Curve` | `ColorGeometry4f(0.0)` | The alpha value is used to mix in the base material color (`0` means only the material color is used). | | `"material_index"` | `int` | `Curve` | `0` | | | `"init_time"` | `float` | `Curve` | `0.0f` | Written while drawing. The timestamp at which this stroke was created. Used by the build modifier to "replay" how strokes were drawn. |

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Falk David added the

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label 2024-03-05 11:19:38 +01:00

Falk David added this to the Grease Pencil project 2024-03-05 11:19:41 +01:00

Falk David referenced this issue

2024-04-05 12:59:24 +02:00

Cleanup: GPv3: Add drawing API for fill color #120296

Falk David referenced this issue from a commit

2024-04-05 15:28:38 +02:00

Cleanup: GPv3: Add drawing API for fill color