Painting: Canvas switcher for painting brushes/tools.

This patch adds color attributes to TexPaintSlot. This allows an easier selection
when painting color attributes.

Previously when selecting a paint tool the user had to start a stroke, before the
UI reflected the correct TexPaintSlot. Now when switching the slot the active
tool is checked and immediate the UI is drawn correctly.

In the future the canvas selector will also be used to select an image or image texture node
to paint on. Basic implementation has already been done inside this patch.

A limitation of this patch is that is isn't possible anymore to rename images directly from
the selection panel. This is currently allowed in master. But as CustomDataLayers
aren't ID fields and not owned by the material supporting this wouldn't be easy.

{F12953989}

In the future we should update the create slot operator to also include color attributes.
Sources could also be extended to use other areas of the object that use image textures
(particles, geom nodes, etc... ).

Reviewed By: brecht

Maniphest Tasks: T96709

Differential Revision: https://developer.blender.org/D14455

1 files changed, 7 insertions, 2 deletions

diff --git a/source/blender/makesdna/DNA_material_types.h b/source/blender/makesdna/DNA_material_types.h
index e83e68a091b..b535d3cdb8a 100644
--- a/source/blender/makesdna/DNA_material_types.h
+++ b/source/blender/makesdna/DNA_material_types.h
@@ -27,11 +27,16 @@ struct bNodeTree;
 /* WATCH IT: change type? also make changes in ipo.h */
 
 typedef struct TexPaintSlot {
-  /** Image to be painted on. */
+  /** Image to be painted on. Mutual exclusive with attribute_name. */
   struct Image *ima;
   /** Custom-data index for uv layer, #MAX_NAME. */
   char *uvname;
-  /** Do we have a valid image and UV map. */
+  /**
+   * Color attribute name when painting using color attributes. Mutual exclusive with ima.
+   * Points to the name of a CustomDataLayer.
+   */
+  char *attribute_name;
+  /** Do we have a valid image and UV map or attribute. */
   int valid;
   /** Copy of node interpolation setting. */
   int interp;