Fix T80885: Texture paint camera project crashes after undo/redo

Unmatched ED_image_undo_push_{begin/end},
add doc-strings noting why this is needed.

Thanks to @Baardaap for the initial fix.

1 files changed, 4 insertions, 2 deletions

diff --git a/source/blender/editors/sculpt_paint/paint_image_proj.c b/source/blender/editors/sculpt_paint/paint_image_proj.c
index d44654f4fd5..b0ad3ae1302 100644
--- a/source/blender/editors/sculpt_paint/paint_image_proj.c
+++ b/source/blender/editors/sculpt_paint/paint_image_proj.c
@@ -6091,8 +6091,6 @@ static int texture_paint_camera_project_exec(bContext *C, wmOperator *op)
 
   scene->toolsettings->imapaint.flag |= IMAGEPAINT_DRAWING;
 
-  ED_image_undo_push_begin(op->type->name, PAINT_MODE_TEXTURE_3D);
-
   /* allocate and initialize spatial data structures */
   project_paint_begin(C, &ps, false, 0);
 
@@ -6102,6 +6100,8 @@ static int texture_paint_camera_project_exec(bContext *C, wmOperator *op)
     return OPERATOR_CANCELLED;
   }
 
+  ED_image_undo_push_begin(op->type->name, PAINT_MODE_TEXTURE_3D);
+
   const float pos[2] = {0.0, 0.0};
   const float lastpos[2] = {0.0, 0.0};
   int a;
@@ -6117,6 +6117,8 @@ static int texture_paint_camera_project_exec(bContext *C, wmOperator *op)
 
   project_paint_end(&ps);
 
+  ED_image_undo_push_end();
+
   scene->toolsettings->imapaint.flag &= ~IMAGEPAINT_DRAWING;
   BKE_brush_size_set(scene, ps.brush, orig_brush_size);