[Bf-blender-cvs] [5511dac74fc] soc-2021-knife-tools: Knife: Remove entire drag cut on undo

[Cian Jinks]

Commit: 5511dac74fc4795f48edbe0ad1650fc3063416d0
Author: Cian Jinks
Date:   Sat Jul 17 16:25:42 2021 +0100
Branches: soc-2021-knife-tools
https://developer.blender.org/rB5511dac74fc4795f48edbe0ad1650fc3063416d0

Knife: Remove entire drag cut on undo

Previously when a knife cut was created by holding left click and dragging, undo would only undo each segment of the dragged cut individually.
This change makes it so the entire dragged cut is removed when undone.
Some refactors to the undo code were required to implement this.

===================================================================

M	source/blender/editors/mesh/editmesh_knife.c

===================================================================

diff --git a/source/blender/editors/mesh/editmesh_knife.c b/source/blender/editors/mesh/editmesh_knife.c
index 6af5d335049..829960c2551 100644
--- a/source/blender/editors/mesh/editmesh_knife.c
+++ b/source/blender/editors/mesh/editmesh_knife.c
@@ -295,6 +295,7 @@ typedef struct KnifeTool_OpData {
   KnifeMeasureData mdata; /* Data for distance and angle drawing calculations. */
 
   KnifeUndoFrame *undo; /* Current undo frame. */
+  bool is_drag_undo;
 } KnifeTool_OpData;
 
 enum {
@@ -1953,12 +1954,15 @@ static void knife_add_cut(KnifeTool_OpData *kcd)
   GHashIterator giter;
   ListBase *list;
 
-  /* Allocate new undo frame on stack. */
-  kcd->undo = BLI_stack_push_r(kcd->undostack);
-  kcd->undo->pos = kcd->prev;
-  kcd->undo->cuts = 0;
-  kcd->undo->splits = 0;
-  kcd->undo->mdata = kcd->mdata;
+  /* Allocate new undo frame on stack, unless cut is being dragged. */
+  if (!kcd->is_drag_undo) {
+    kcd->undo = BLI_stack_push_r(kcd->undostack);
+    kcd->undo->pos = kcd->prev;
+    kcd->undo->cuts = 0;
+    kcd->undo->splits = 0;
+    kcd->undo->mdata = kcd->mdata;
+    kcd->is_drag_undo = true;
+  }
 
   /* Save values for angle drawing calculations. */
   copy_v3_v3(kcd->mdata.cage, kcd->mdata.corr_prev_cage);
@@ -3336,6 +3340,7 @@ static bool knife_snap_update_from_mval(bContext *C, KnifeTool_OpData *kcd, cons
 
 static void knifetool_undo(KnifeTool_OpData *kcd)
 {
+  Ref *ref;
   KnifeEdge *kfe, *newkfe;
   KnifeEdge *lastkfe = NULL;
   KnifeVert *v1, *v2;
@@ -3345,6 +3350,13 @@ static void knifetool_undo(KnifeTool_OpData *kcd)
   if (!BLI_stack_is_empty(kcd->undostack)) {
     undo = BLI_stack_peek(kcd->undostack);
 
+    /* Undo edge splitting. */
+    for (int i = 0; i < undo->splits; i++) {
+      BLI_stack_pop(kcd->splitstack, &newkfe);
+      BLI_stack_pop(kcd->splitstack, &kfe);
+      knife_join_edge(kcd, newkfe, kfe);
+    }
+
     for (int i = 0; i < undo->cuts; i++) {
 
       BLI_mempool_iternew(kcd->kedges, &iterkfe);
@@ -3363,51 +3375,41 @@ static void knifetool_undo(KnifeTool_OpData *kcd)
         v2 = lastkfe->v2;
 
         /* Only remove first vertex if it is the start segment of the cut. */
-        if (!v1->is_splitting) {
+        if (!v1->is_invalid && !v1->is_splitting) {
           v1->is_invalid = true;
+          /* If the first vertex is touching any other cut edges don't remove it. */
+          for (ref = v1->edges.first; ref; ref = ref->next) {
+            kfe = ref->ref;
+            if (kfe->is_cut && !kfe->is_invalid) {
+              v1->is_invalid = false;
+              break;
+            }
+          }
         }
 
         /* Only remove second vertex if it is the end segment of the cut. */
-        if (!v2->is_splitting) {
+        if (!v2->is_invalid && !v2->is_splitting) {
           v2->is_invalid = true;
+          /* If the second vertex is touching any other cut edges don't remove it. */
+          for (ref = v2->edges.first; ref; ref = ref->next) {
+            kfe = ref->ref;
+            if (kfe->is_cut && !kfe->is_invalid) {
+              v2->is_invalid = false;
+              break;
+            }
+          }
         }
       }
     }
 
     if (lastkfe) {
-      /* If the first vertex is touching any other cut edges don't remove it. */
-      Ref *ref;
-      for (ref = v1->edges.first; ref; ref = ref->next) {
-        kfe = ref->ref;
-        if (kfe->is_cut && !kfe->is_invalid) {
-          v1->is_invalid = false;
-          break;
-        }
-      }
-
-      /* If the second vertex is touching any other cut edges don't remove it. */
-      for (ref = v2->edges.first; ref; ref = ref->next) {
-        kfe = ref->ref;
-        if (kfe->is_cut && !kfe->is_invalid) {
-          v2->is_invalid = false;
-          break;
-        }
-      }
+      /* Restore data for distance and angle measurements. */
+      kcd->mdata = undo->mdata;
 
       if (kcd->mode == MODE_DRAGGING) {
         /* Restore kcd->prev. */
         kcd->prev = undo->pos;
       }
-
-      /* Restore data for distance and angle measurements. */
-      kcd->mdata = undo->mdata;
-    }
-
-    /* Undo edge splitting. */
-    for (int i = 0; i < undo->splits; i++) {
-      BLI_stack_pop(kcd->splitstack, &newkfe);
-      BLI_stack_pop(kcd->splitstack, &kfe);
-      knife_join_edge(kcd, newkfe, kfe);
     }
 
     BLI_stack_discard(kcd->undostack);
@@ -3922,6 +3924,7 @@ static int knifetool_modal(bContext *C, wmOperator *op, const wmEvent *event)
         else {
           kcd->is_drag_hold = false;
           kcd->ignore_edge_snapping = false;
+          kcd->is_drag_undo = false;
 
           /* Needed because the last face 'hit' is ignored when dragging. */
           knifetool_update_mval(C, kcd, kcd->curr.mval);
@@ -3936,6 +3939,7 @@ static int knifetool_modal(bContext *C, wmOperator *op, const wmEvent *event)
           /* Shouldn't be possible with default key-layout, just in case. */
           if (kcd->is_drag_hold) {
             kcd->is_drag_hold = false;
+            kcd->is_drag_undo = false;
             knifetool_update_mval(C, kcd, kcd->curr.mval);
           }