Undo: unified undo system w/ linear history

- Use a single undo history for all operations.
- UndoType's are registered and poll the context to check if they
  should be used when performing an undo push.
- Mode switching is used to ensure the state is correct before
  undo data is restored.
- Some undo types accumulate changes (image & text editing)
  others store the state multiple times (with de-duplication).
  This is supported by checking UndoStack.mode `ACCUMULATE` / `STORE`.
- Each undo step stores ID datablocks they use with utilities to help
  manage restoring correct ID's.
  Needed since global undo is now mixed with other modes undo.
- Currently performs each undo step when going up/down history
  Previously this wasn't done, making history fail in some cases.
  This can be optimized to skip some combinations of undo steps.

grease-pencil is an exception which has not been updated
since it integrates undo into the draw-session.

See D3113

1 files changed, 4 insertions, 2 deletions

diff --git a/source/blender/editors/sculpt_paint/paint_image_2d.c b/source/blender/editors/sculpt_paint/paint_image_2d.c
index 894277402a7..c1dd31ea055 100644
--- a/source/blender/editors/sculpt_paint/paint_image_2d.c
+++ b/source/blender/editors/sculpt_paint/paint_image_2d.c
@@ -1035,6 +1035,8 @@ static void paint_2d_do_making_brush(ImagePaintState *s,
 	ImBuf tmpbuf;
 	IMB_initImBuf(&tmpbuf, IMAPAINT_TILE_SIZE, IMAPAINT_TILE_SIZE, 32, 0);
 
+	ListBase *undo_tiles = ED_image_undo_get_tiles();
+
 	for (int ty = tiley; ty <= tileh; ty++) {
 		for (int tx = tilex; tx <= tilew; tx++) {
 			/* retrieve original pixels + mask from undo buffer */
@@ -1043,9 +1045,9 @@ static void paint_2d_do_making_brush(ImagePaintState *s,
 			int origy = region->desty - ty * IMAPAINT_TILE_SIZE;
 
 			if (s->canvas->rect_float)
-				tmpbuf.rect_float = image_undo_find_tile(s->image, s->canvas, tx, ty, &mask, false);
+				tmpbuf.rect_float = image_undo_find_tile(undo_tiles, s->image, s->canvas, tx, ty, &mask, false);
 			else
-				tmpbuf.rect = image_undo_find_tile(s->image, s->canvas, tx, ty, &mask, false);
+				tmpbuf.rect = image_undo_find_tile(undo_tiles, s->image, s->canvas, tx, ty, &mask, false);
 
 			IMB_rectblend(s->canvas, &tmpbuf, frombuf, mask,
 			              curveb, texmaskb, mask_max,