Nodes: Add support to mute node wires

This patch adds the ability to mute individual wires in the node editor.
This is invoked like the cut links operator but with a new shortcut.

Mute = Ctrl + Alt
Cut = Ctrl

Dragging over wires will toggle the mute state for that wire.
The muted wires are drawn in red with a bar across the center.
Red is used in the nodes context to indicate invalid links, muted links and internal links.

When a wire is muted it exposes the original node buttons which are normally hidden when a wire is connected.

Downstream and upstream links connected using reroute nodes are also muted.

Outside scope of patch:
- Add support for pynodes e.g. Animation Nodes
- Requires minor change to check for muted links using the `is_muted` link property or the `is_linked` socket property.

Maniphest Tasks: T52659

Differential Revision: https://developer.blender.org/D2807

19 files changed, 324 insertions, 22 deletions

diff --git a/intern/cycles/blender/blender_shader.cpp b/intern/cycles/blender/blender_shader.cpp
index a1ab5277744..72328333732 100644
--- a/intern/cycles/blender/blender_shader.cpp
+++ b/intern/cycles/blender/blender_shader.cpp
@@ -1234,7 +1234,8 @@ static void add_nodes(Scene *scene,
   for (BL::NodeLink &b_link : b_ntree.links) {
     /* Ignore invalid links to avoid unwanted cycles created in graph.
      * Also ignore links with unavailable sockets. */
-    if (!(b_link.is_valid() && b_link.from_socket().enabled() && b_link.to_socket().enabled())) {
+    if (!(b_link.is_valid() && b_link.from_socket().enabled() && b_link.to_socket().enabled()) ||
+        b_link.is_muted()) {
       continue;
     }
     /* get blender link data */
diff --git a/release/scripts/presets/keyconfig/keymap_data/blender_default.py b/release/scripts/presets/keyconfig/keymap_data/blender_default.py
index 3471a8d0db0..feba4e3bd09 100644
--- a/release/scripts/presets/keyconfig/keymap_data/blender_default.py
+++ b/release/scripts/presets/keyconfig/keymap_data/blender_default.py
@@ -1844,6 +1844,7 @@ def km_node_editor(params):
         ("node.resize", {"type": 'EVT_TWEAK_L', "value": 'ANY'}, None),
         ("node.add_reroute", {"type": 'EVT_TWEAK_L' if params.legacy else 'EVT_TWEAK_R', "value": 'ANY', "shift": True}, None),
         ("node.links_cut", {"type": 'EVT_TWEAK_L' if params.legacy else 'EVT_TWEAK_R', "value": 'ANY', "ctrl": True}, None),
+        ("node.links_mute", {"type": 'EVT_TWEAK_R', "value": 'ANY', "ctrl": True, "alt": True}, None),
         ("node.select_link_viewer", {"type": 'LEFTMOUSE', "value": 'PRESS', "shift": True, "ctrl": True}, None),
         ("node.backimage_move", {"type": 'MIDDLEMOUSE', "value": 'PRESS', "alt": True}, None),
         ("node.backimage_zoom", {"type": 'V', "value": 'PRESS', "repeat": True},
diff --git a/release/scripts/presets/keyconfig/keymap_data/industry_compatible_data.py b/release/scripts/presets/keyconfig/keymap_data/industry_compatible_data.py
index c8fc6abe10a..91f153a0f42 100644
--- a/release/scripts/presets/keyconfig/keymap_data/industry_compatible_data.py
+++ b/release/scripts/presets/keyconfig/keymap_data/industry_compatible_data.py
@@ -1113,6 +1113,7 @@ def km_node_editor(params):
         ("node.resize", {"type": 'EVT_TWEAK_L', "value": 'ANY'}, None),
         ("node.add_reroute", {"type": params.action_tweak, "value": 'ANY', "shift": True}, None),
         ("node.links_cut", {"type": params.action_tweak, "value": 'ANY', "ctrl": True}, None),
+        ("node.links_mute", {"type": params.action_tweak, "value": 'ANY', "ctrl": True, "alt": True}, None),
         ("node.select_link_viewer", {"type": 'LEFTMOUSE', "value": 'PRESS', "shift": True, "ctrl": True}, None),
         ("node.backimage_fit", {"type": 'A', "value": 'PRESS', "alt": True}, None),
         ("node.backimage_sample", {"type": 'LEFTMOUSE', "value": 'PRESS', "alt": True}, None),
diff --git a/release/scripts/startup/bl_ui/space_node.py b/release/scripts/startup/bl_ui/space_node.py
index a9934850acd..7f66cdd3d74 100644
--- a/release/scripts/startup/bl_ui/space_node.py
+++ b/release/scripts/startup/bl_ui/space_node.py
@@ -331,6 +331,7 @@ class NODE_MT_node(Menu):
         layout.operator("node.link_make", text="Make and Replace Links").replace = True
         layout.operator("node.links_cut")
         layout.operator("node.links_detach")
+        layout.operator("node.links_mute")
 
         layout.separator()
 
diff --git a/source/blender/blenkernel/BKE_node.h b/source/blender/blenkernel/BKE_node.h
index ced76e65ada..04a9855de68 100644
--- a/source/blender/blenkernel/BKE_node.h
+++ b/source/blender/blenkernel/BKE_node.h
@@ -627,6 +627,7 @@ struct bNodeLink *nodeAddLink(struct bNodeTree *ntree,
                               struct bNodeSocket *tosock);
 void nodeRemLink(struct bNodeTree *ntree, struct bNodeLink *link);
 void nodeRemSocketLinks(struct bNodeTree *ntree, struct bNodeSocket *sock);
+void nodeMuteLinkToggle(struct bNodeTree *ntree, struct bNodeLink *link);
 bool nodeLinkIsHidden(const struct bNodeLink *link);
 void nodeInternalRelink(struct bNodeTree *ntree, struct bNode *node);
 
diff --git a/source/blender/blenkernel/intern/node.cc b/source/blender/blenkernel/intern/node.cc
index bbc655d7fc8..ca973bd9d65 100644
--- a/source/blender/blenkernel/intern/node.cc
+++ b/source/blender/blenkernel/intern/node.cc
@@ -107,6 +107,9 @@ static void node_free_node(bNodeTree *ntree, bNode *node);
 static void node_socket_interface_free(bNodeTree *UNUSED(ntree),
                                        bNodeSocket *sock,
                                        const bool do_id_user);
+static void nodeMuteRerouteOutputLinks(struct bNodeTree *ntree,
+                                       struct bNode *node,
+                                       const bool mute);
 
 static void ntree_init_data(ID *id)
 {
@@ -2215,6 +2218,106 @@ void nodeRemLink(bNodeTree *ntree, bNodeLink *link)
   }
 }
 
+/* Check if all output links are muted or not. */
+static bool nodeMuteFromSocketLinks(const bNodeTree *ntree, const bNodeSocket *sock)
+{
+  int tot = 0;
+  int muted = 0;
+  LISTBASE_FOREACH (const bNodeLink *, link, &ntree->links) {
+    if (link->fromsock == sock) {
+      tot++;
+      if (link->flag & NODE_LINK_MUTED) {
+        muted++;
+      }
+    }
+  }
+  return tot == muted;
+}
+
+static void nodeMuteLink(bNodeLink *link)
+{
+  link->flag |= NODE_LINK_MUTED;
+  link->flag |= NODE_LINK_TEST;
+  if (!(link->tosock->flag & SOCK_MULTI_INPUT)) {
+    link->tosock->flag &= ~SOCK_IN_USE;
+  }
+}
+
+static void nodeUnMuteLink(bNodeLink *link)
+{
+  link->flag &= ~NODE_LINK_MUTED;
+  link->flag |= NODE_LINK_TEST;
+  link->tosock->flag |= SOCK_IN_USE;
+}
+
+/* Upstream muting. Always happens when unmuting but checks when muting. O(n^2) algorithm.*/
+static void nodeMuteRerouteInputLinks(bNodeTree *ntree, bNode *node, const bool mute)
+{
+  if (node->type != NODE_REROUTE) {
+    return;
+  }
+  if (!mute || nodeMuteFromSocketLinks(ntree, (bNodeSocket *)node->outputs.first)) {
+    bNodeSocket *sock = (bNodeSocket *)node->inputs.first;
+    LISTBASE_FOREACH (bNodeLink *, link, &ntree->links) {
+      if (!(link->flag & NODE_LINK_VALID) || (link->tosock != sock)) {
+        continue;
+      }
+      if (mute) {
+        nodeMuteLink(link);
+      }
+      else {
+        nodeUnMuteLink(link);
+      }
+      nodeMuteRerouteInputLinks(ntree, link->fromnode, mute);
+    }
+  }
+}
+
+/* Downstream muting propagates when reaching reroute nodes. O(n^2) algorithm.*/
+static void nodeMuteRerouteOutputLinks(bNodeTree *ntree, bNode *node, const bool mute)
+{
+  if (node->type != NODE_REROUTE) {
+    return;
+  }
+  bNodeSocket *sock;
+  sock = (bNodeSocket *)node->outputs.first;
+  LISTBASE_FOREACH (bNodeLink *, link, &ntree->links) {
+    if (!(link->flag & NODE_LINK_VALID) || (link->fromsock != sock)) {
+      continue;
+    }
+    if (mute) {
+      nodeMuteLink(link);
+    }
+    else {
+      nodeUnMuteLink(link);
+    }
+    nodeMuteRerouteOutputLinks(ntree, link->tonode, mute);
+  }
+}
+
+void nodeMuteLinkToggle(bNodeTree *ntree, bNodeLink *link)
+{
+  if (link->tosock) {
+    bool mute = !(link->flag & NODE_LINK_MUTED);
+    if (mute) {
+      nodeMuteLink(link);
+    }
+    else {
+      nodeUnMuteLink(link);
+    }
+    if (link->tonode->type == NODE_REROUTE) {
+      nodeMuteRerouteOutputLinks(ntree, link->tonode, mute);
+    }
+    if (link->fromnode->type == NODE_REROUTE) {
+      nodeMuteRerouteInputLinks(ntree, link->fromnode, mute);
+    }
+  }
+
+  if (ntree) {
+    ntree->update |= NTREE_UPDATE_LINKS;
+  }
+}
+
 void nodeRemSocketLinks(bNodeTree *ntree, bNodeSocket *sock)
 {
   LISTBASE_FOREACH_MUTABLE (bNodeLink *, link, &ntree->links) {
@@ -2257,6 +2360,10 @@ void nodeInternalRelink(bNodeTree *ntree, bNode *node)
             link->flag &= ~NODE_LINK_VALID;
           }
 
+          if (fromlink->flag & NODE_LINK_MUTED) {
+            link->flag |= NODE_LINK_MUTED;
+          }
+
           ntree->update |= NTREE_UPDATE_LINKS;
         }
         else {
@@ -4014,7 +4121,9 @@ void ntreeTagUsedSockets(bNodeTree *ntree)
 
   LISTBASE_FOREACH (bNodeLink *, link, &ntree->links) {
     link->fromsock->flag |= SOCK_IN_USE;
-    link->tosock->flag |= SOCK_IN_USE;
+    if (!(link->flag & NODE_LINK_MUTED)) {
+      link->tosock->flag |= SOCK_IN_USE;
+    }
   }
 }
 
diff --git a/source/blender/compositor/intern/COM_NodeGraph.cc b/source/blender/compositor/intern/COM_NodeGraph.cc
index f932acfa49e..d8220099f1f 100644
--- a/source/blender/compositor/intern/COM_NodeGraph.cc
+++ b/source/blender/compositor/intern/COM_NodeGraph.cc
@@ -188,7 +188,8 @@ void NodeGraph::add_bNodeLink(const NodeRange &node_range, bNodeLink *b_nodelink
   if (!(b_nodelink->flag & NODE_LINK_VALID)) {
     return;
   }
-  if ((b_nodelink->fromsock->flag & SOCK_UNAVAIL) || (b_nodelink->tosock->flag & SOCK_UNAVAIL)) {
+  if ((b_nodelink->fromsock->flag & SOCK_UNAVAIL) || (b_nodelink->tosock->flag & SOCK_UNAVAIL) ||
+      (b_nodelink->flag & NODE_LINK_MUTED)) {
     return;
   }
 
diff --git a/source/blender/editors/space_node/drawnode.c b/source/blender/editors/space_node/drawnode.c
index 0f2b2b435bc..1354c06305c 100644
--- a/source/blender/editors/space_node/drawnode.c
+++ b/source/blender/editors/space_node/drawnode.c
@@ -3751,17 +3751,21 @@ bool node_link_bezier_points(const View2D *v2d,
 #define LINK_WIDTH (2.5f * UI_DPI_FAC)
 #define ARROW_SIZE (7 * UI_DPI_FAC)
 
+/* Reroute arrow shape and mute bar. These are expanded here and shrunk in the glsl code.
+ * See: gpu_shader_2D_nodelink_vert.glsl */
 static float arrow_verts[3][2] = {{-1.0f, 1.0f}, {0.0f, 0.0f}, {-1.0f, -1.0f}};
 static float arrow_expand_axis[3][2] = {{0.7071f, 0.7071f}, {M_SQRT2, 0.0f}, {0.7071f, -0.7071f}};
+static float mute_verts[3][2] = {{0.7071f, 1.0f}, {0.7071f, 0.0f}, {0.7071f, -1.0f}};
+static float mute_expand_axis[3][2] = {{1.0f, 0.0f}, {1.0f, 0.0f}, {1.0f, -0.0f}};
 
 static struct {
   GPUBatch *batch;        /* for batching line together */
   GPUBatch *batch_single; /* for single line */
   GPUVertBuf *inst_vbo;
   uint p0_id, p1_id, p2_id, p3_id;
-  uint colid_id;
+  uint colid_id, muted_id;
   GPUVertBufRaw p0_step, p1_step, p2_step, p3_step;
-  GPUVertBufRaw colid_step;
+  GPUVertBufRaw colid_step, muted_step;
   uint count;
   bool enabled;
 } g_batch_link = {0};
@@ -3774,6 +3778,8 @@ static void nodelink_batch_reset(void)
   GPU_vertbuf_attr_get_raw_data(g_batch_link.inst_vbo, g_batch_link.p3_id, &g_batch_link.p3_step);
   GPU_vertbuf_attr_get_raw_data(
       g_batch_link.inst_vbo, g_batch_link.colid_id, &g_batch_link.colid_step);
+  GPU_vertbuf_attr_get_raw_data(
+      g_batch_link.inst_vbo, g_batch_link.muted_id, &g_batch_link.muted_step);
   g_batch_link.count = 0;
 }
 
@@ -3801,6 +3807,8 @@ static void nodelink_batch_init(void)
   int vcount = LINK_RESOL * 2; /* curve */
   vcount += 2;                 /* restart strip */
   vcount += 3 * 2;             /* arrow */
+  vcount += 2;                 /* restart strip */
+  vcount += 3 * 2;             /* mute */
   vcount *= 2;                 /* shadow */
   vcount += 2;                 /* restart strip */
   GPU_vertbuf_data_alloc(vbo, vcount);
@@ -3844,6 +3852,25 @@ static void nodelink_batch_init(void)
     }
 
     /* restart */
+    set_nodelink_vertex(vbo, uv_id, pos_id, expand_id, v++, uv, pos, exp);
+
+    uv[0] = 127;
+    uv[1] = 0;
+    copy_v2_v2(pos, mute_verts[0]);
+    copy_v2_v2(exp, mute_expand_axis[0]);
+    set_nodelink_vertex(vbo, uv_id, pos_id, expand_id, v++, uv, pos, exp);
+    /* bar */
+    for (int i = 0; i < 3; ++i) {
+      uv[1] = 0;
+      copy_v2_v2(pos, mute_verts[i]);
+      copy_v2_v2(exp, mute_expand_axis[i]);
+      set_nodelink_vertex(vbo, uv_id, pos_id, expand_id, v++, uv, pos, exp);
+
+      uv[1] = 255;
+      set_nodelink_vertex(vbo, uv_id, pos_id, expand_id, v++, uv, pos, exp);
+    }
+
+    /* restart */
     if (k == 0) {
       set_nodelink_vertex(vbo, uv_id, pos_id, expand_id, v++, uv, pos, exp);
     }
@@ -3867,6 +3894,8 @@ static void nodelink_batch_init(void)
       &format_inst, "P3", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
   g_batch_link.colid_id = GPU_vertformat_attr_add(
       &format_inst, "colid_doarrow", GPU_COMP_U8, 4, GPU_FETCH_INT);
+  g_batch_link.muted_id = GPU_vertformat_attr_add(
+      &format_inst, "domuted", GPU_COMP_U8, 2, GPU_FETCH_INT);
   g_batch_link.inst_vbo = GPU_vertbuf_create_with_format_ex(&format_inst, GPU_USAGE_STREAM);
   /* Alloc max count but only draw the range we need. */
   GPU_vertbuf_data_alloc(g_batch_link.inst_vbo, NODELINK_GROUP_SIZE);
@@ -3941,12 +3970,13 @@ static void nodelink_batch_add_link(const SpaceNode *snode,
                                     int th_col1,
                                     int th_col2,
                                     int th_col3,
-                                    bool drawarrow)
+                                    bool drawarrow,
+                                    bool drawmuted)
 {
   /* Only allow these colors. If more is needed, you need to modify the shader accordingly. */
   BLI_assert(ELEM(th_col1, TH_WIRE_INNER, TH_WIRE, TH_ACTIVE, TH_EDGE_SELECT, TH_REDALERT));
   BLI_assert(ELEM(th_col2, TH_WIRE_INNER, TH_WIRE, TH_ACTIVE, TH_EDGE_SELECT, TH_REDALERT));
-  BLI_assert(ELEM(th_col3, TH_WIRE, -1));
+  BLI_assert(ELEM(th_col3, TH_WIRE, TH_REDALERT, -1));
 
   g_batch_link.count++;
   copy_v2_v2(GPU_vertbuf_raw_step(&g_batch_link.p0_step), p0);
@@ -3958,6 +3988,8 @@ static void nodelink_batch_add_link(const SpaceNode *snode,
   colid[1] = nodelink_get_color_id(th_col2);
   colid[2] = nodelink_get_color_id(th_col3);
   colid[3] = drawarrow;
+  char *muted = GPU_vertbuf_raw_step(&g_batch_link.muted_step);
+  muted[0] = drawmuted;
 
   if (g_batch_link.count == NODELINK_GROUP_SIZE) {
     nodelink_batch_draw(snode);
@@ -3977,7 +4009,7 @@ void node_draw_link_bezier(const View2D *v2d,
   if (node_link_bezier_handles(v2d, snode, link, vec)) {
     int drawarrow = ((link->tonode && (link->tonode->type == NODE_REROUTE)) &&
                      (link->fromnode && (link->fromnode->type == NODE_REROUTE)));
-
+    int drawmuted = (link->flag & NODE_LINK_MUTED);
     if (g_batch_link.batch == NULL) {
       nodelink_batch_init();
     }
@@ -3985,7 +4017,7 @@ void node_draw_link_bezier(const View2D *v2d,
     if (g_batch_link.enabled && !highlighted) {
       /* Add link to batch. */
       nodelink_batch_add_link(
-          snode, vec[0], vec[1], vec[2], vec[3], th_col1, th_col2, th_col3, drawarrow);
+          snode, vec[0], vec[1], vec[2], vec[3], th_col1, th_col2, th_col3, drawarrow, drawmuted);
     }
     else {
       /* Draw single link. */
@@ -4009,6 +4041,7 @@ void node_draw_link_bezier(const View2D *v2d,
       GPU_batch_uniform_1f(batch, "expandSize", snode->runtime->aspect * LINK_WIDTH);
       GPU_batch_uniform_1f(batch, "arrowSize", ARROW_SIZE);
       GPU_batch_uniform_1i(batch, "doArrow", drawarrow);
+      GPU_batch_uniform_1i(batch, "doMuted", drawmuted);
       GPU_batch_draw(batch);
     }
   }
@@ -4041,8 +4074,11 @@ void node_draw_link(View2D *v2d, SpaceNode *snode, bNodeLink *link)
       if (link->flag & NODE_LINKFLAG_HILITE) {
         th_col1 = th_col2 = TH_ACTIVE;
       }
+      else if (link->flag & NODE_LINK_MUTED) {
+        th_col1 = th_col2 = TH_REDALERT;
+      }
       else {
-        /* regular link */
+        /* Regular link, highlight if connected to selected node. */
         if (link->fromnode && link->fromnode->flag & SELECT) {
           th_col1 = TH_EDGE_SELECT;
         }
@@ -4052,7 +4088,8 @@ void node_draw_link(View2D *v2d, SpaceNode *snode, bNodeLink *link)
       }
     }
     else {
-      th_col1 = th_col2 = TH_REDALERT;
+      /* Invalid link. */
+      th_col1 = th_col2 = th_col3 = TH_REDALERT;
       // th_col3 = -1; /* no shadow */
     }
   }
diff --git a/source/blender/editors/space_node/node_intern.h b/source/blender/editors/space_node/node_intern.h
index 1840ec93f6f..21a36ff9683 100644
--- a/source/blender/editors/space_node/node_intern.h
+++ b/source/blender/editors/space_node/node_intern.h
@@ -234,6 +234,7 @@ void NODE_OT_link(struct wmOperatorType *ot);
 void NODE_OT_link_make(struct wmOperatorType *ot);
 void NODE_OT_links_cut(struct wmOperatorType *ot);
 void NODE_OT_links_detach(struct wmOperatorType *ot);
+void NODE_OT_links_mute(struct wmOperatorType *ot);
 
 void NODE_OT_parent_set(struct wmOperatorType *ot);
 void NODE_OT_join(struct wmOperatorType *ot);
diff --git a/source/blender/editors/space_node/node_ops.c b/source/blender/editors/space_node/node_ops.c
index ef28cfe8a8b..e35b444aa11 100644
--- a/source/blender/editors/space_node/node_ops.c
+++ b/source/blender/editors/space_node/node_ops.c
@@ -68,6 +68,7 @@ void node_operatortypes(void)
   WM_operatortype_append(NODE_OT_link_make);
   WM_operatortype_append(NODE_OT_links_cut);
   WM_operatortype_append(NODE_OT_links_detach);
+  WM_operatortype_append(NODE_OT_links_mute);
   WM_operatortype_append(NODE_OT_add_reroute);
 
   WM_operatortype_append(NODE_OT_group_make);
diff --git a/source/blender/editors/space_node/node_relationships.c b/source/blender/editors/space_node/node_relationships.c
index ee07ec7a55c..2cc44d72c72 100644
--- a/source/blender/editors/space_node/node_relationships.c
+++ b/source/blender/editors/space_node/node_relationships.c
@@ -1227,8 +1227,8 @@ void NODE_OT_link_make(wmOperatorType *ot)
       ot->srna, "replace", 0, "Replace", "Replace socket connections with the new links");
 }
 
-/* ********************** Cut Link operator ***************** */
-static bool cut_links_intersect(bNodeLink *link, const float mcoords[][2], int tot)
+/* ********************** Node Link Intersect ***************** */
+static bool node_links_intersect(bNodeLink *link, const float mcoords[][2], int tot)
 {
   float coord_array[NODE_LINK_RESOL + 1][2];
 
@@ -1244,6 +1244,7 @@ static bool cut_links_intersect(bNodeLink *link, const float mcoords[][2], int t
   return 0;
 }
 
+/* ********************** Cut Link operator ***************** */
 static int cut_links_exec(bContext *C, wmOperator *op)
 {
   Main *bmain = CTX_data_main(C);
@@ -1276,7 +1277,7 @@ static int cut_links_exec(bContext *C, wmOperator *op)
         continue;
       }
 
-      if (cut_links_intersect(link, mcoords, i)) {
+      if (node_links_intersect(link, mcoords, i)) {
 
         if (found == false) {
           /* TODO(sergey): Why did we kill jobs twice? */
@@ -1335,6 +1336,110 @@ void NODE_OT_links_cut(wmOperatorType *ot)
   RNA_def_int(ot->srna, "cursor", WM_CURSOR_KNIFE, 0, INT_MAX, "Cursor", "", 0, INT_MAX);
 }
 
+/* ********************** Mute links operator ***************** */
+
+static int mute_links_exec(bContext *C, wmOperator *op)
+{
+  Main *bmain = CTX_data_main(C);
+  SpaceNode *snode = CTX_wm_space_node(C);
+  ARegion *region = CTX_wm_region(C);
+  bool do_tag_update = false;
+
+  int i = 0;
+  float mcoords[256][2];
+  RNA_BEGIN (op->ptr, itemptr, "path") {
+    float loc[2];
+
+    RNA_float_get_array(&itemptr, "loc", loc);
+    UI_view2d_region_to_view(
+        &region->v2d, (int)loc[0], (int)loc[1], &mcoords[i][0], &mcoords[i][1]);
+    i++;
+    if (i >= 256) {
+      break;
+    }
+  }
+  RNA_END;
+
+  if (i > 1) {
+    ED_preview_kill_jobs(CTX_wm_manager(C), bmain);
+
+    /* Count intersected links and clear test flag. */
+    int tot = 0;
+    LISTBASE_FOREACH (bNodeLink *, link, &snode->edittree->links) {
+      if (nodeLinkIsHidden(link)) {
+        continue;
+      }
+      link->flag &= ~NODE_LINK_TEST;
+      if (node_links_intersect(link, mcoords, i)) {
+        tot++;
+      }
+    }
+    if (tot == 0) {
+      return OPERATOR_CANCELLED;
+    }
+
+    /* Mute links. */
+    LISTBASE_FOREACH (bNodeLink *, link, &snode->edittree->links) {
+      if (nodeLinkIsHidden(link) || (link->flag & NODE_LINK_TEST)) {
+        continue;
+      }
+
+      if (node_links_intersect(link, mcoords, i)) {
+        do_tag_update |= (do_tag_update ||
+                          node_connected_to_output(bmain, snode->edittree, link->tonode));
+
+        snode_update(snode, link->tonode);
+        nodeMuteLinkToggle(snode->edittree, link);
+      }
+    }
+
+    /* Clear remaining test flags. */
+    LISTBASE_FOREACH (bNodeLink *, link, &snode->edittree->links) {
+      if (nodeLinkIsHidden(link)) {
+        continue;
+      }
+      link->flag &= ~NODE_LINK_TEST;
+    }
+
+    do_tag_update |= ED_node_is_geometry(snode);
+
+    ntreeUpdateTree(CTX_data_main(C), snode->edittree);
+    snode_notify(C, snode);
+    if (do_tag_update) {
+      snode_dag_update(C, snode);
+    }
+
+    return OPERATOR_FINISHED;
+  }
+
+  return OPERATOR_CANCELLED | OPERATOR_PASS_THROUGH;
+}
+
+void NODE_OT_links_mute(wmOperatorType *ot)
+{
+  ot->name = "Mute Links";
+  ot->idname = "NODE_OT_links_mute";
+  ot->description = "Use the mouse to mute links";
+
+  ot->invoke = WM_gesture_lines_invoke;
+  ot->modal = WM_gesture_lines_modal;
+  ot->exec = mute_links_exec;
+  ot->cancel = WM_gesture_lines_cancel;
+
+  ot->poll = ED_operator_node_editable;
+
+  /* flags */
+  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+
+  /* properties */
+  PropertyRNA *prop;
+  prop = RNA_def_collection_runtime(ot->srna, "path", &RNA_OperatorMousePath, "Path", "");
+  RNA_def_property_flag(prop, PROP_HIDDEN | PROP_SKIP_SAVE);
+
+  /* internal */
+  RNA_def_int(ot->srna, "cursor", WM_CURSOR_MUTE, 0, INT_MAX, "Cursor", "", 0, INT_MAX);
+}
+
 /* ********************** Detach links operator ***************** */
 
 static int detach_links_exec(bContext *C, wmOperator *UNUSED(op))
diff --git a/source/blender/gpu/shaders/gpu_shader_2D_nodelink_vert.glsl b/source/blender/gpu/shaders/gpu_shader_2D_nodelink_vert.glsl
index 4567429f645..9ce2a1be015 100644
--- a/source/blender/gpu/shaders/gpu_shader_2D_nodelink_vert.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_2D_nodelink_vert.glsl
@@ -2,7 +2,7 @@
  * 2D Quadratic Bezier thick line drawing
  */
 
-#define MID_VERTEX 57
+#define MID_VERTEX 65
 
 /* u is position along the curve, defining the tangent space.
  * v is "signed" distance (compressed to [0..1] range) from the pos in expand direction */
@@ -17,6 +17,7 @@ in vec2 P1;
 in vec2 P2;
 in vec2 P3;
 in ivec4 colid_doarrow;
+in ivec2 domuted;
 
 uniform vec4 colors[6];
 
@@ -24,6 +25,7 @@ uniform vec4 colors[6];
 #  define colEnd colors[colid_doarrow[1]]
 #  define colShadow colors[colid_doarrow[2]]
 #  define doArrow (colid_doarrow[3] != 0)
+#  define doMuted (domuted[0] != 0)
 
 #else
 /* Single curve drawcall, use uniform. */
@@ -36,6 +38,7 @@ uniform vec2 bezierPts[4];
 
 uniform vec4 colors[3];
 uniform bool doArrow;
+uniform bool doMuted;
 
 #  define colShadow colors[0]
 #  define colStart colors[1]
@@ -90,13 +93,18 @@ void main(void)
     /* Second pass */
     finalColor = mix(colStart, colEnd, uv.x);
     expand_dist *= 0.5;
+    if (doMuted) {
+      finalColor[3] = 0.65;
+    }
   }
 
   /* Expand into a line */
   gl_Position.xy += exp_axis * expandSize * expand_dist;
 
-  /* if arrow */
-  if (expand.y != 1.0 && !doArrow) {
+  /* If the link is not muted or is not a reroute arrow the points are squashed to the center of
+   * the line. Magic numbers are defined in drawnode.c */
+  if ((expand.x == 1.0 && !doMuted) ||
+      (expand.y != 1.0 && (pos.x < 0.70 || pos.x > 0.71) && !doArrow)) {
     gl_Position.xy *= 0.0;
   }
 }
diff --git a/source/blender/makesdna/DNA_node_types.h b/source/blender/makesdna/DNA_node_types.h
index 06ee22b1452..acbe9da45fd 100644
--- a/source/blender/makesdna/DNA_node_types.h
+++ b/source/blender/makesdna/DNA_node_types.h
@@ -402,6 +402,7 @@ typedef struct bNodeLink {
 #define NODE_LINK_VALID (1 << 1)
 #define NODE_LINK_TEST (1 << 2)           /* free test flag, undefined */
 #define NODE_LINK_TEMP_HIGHLIGHT (1 << 3) /* Link is highlighted for picking. */
+#define NODE_LINK_MUTED (1 << 4)           /* Link is muted. */
 
 /* tree->edit_quality/tree->render_quality */
 #define NTREE_QUALITY_HIGH 0
diff --git a/source/blender/makesrna/intern/rna_nodetree.c b/source/blender/makesrna/intern/rna_nodetree.c
index 04ff181d9b5..fc1f692a8bf 100644
--- a/source/blender/makesrna/intern/rna_nodetree.c
+++ b/source/blender/makesrna/intern/rna_nodetree.c
@@ -10872,6 +10872,11 @@ static void rna_def_node_link(BlenderRNA *brna)
   RNA_def_struct_ui_text(srna, "Valid", "Link is valid");
   RNA_def_property_update(prop, NC_NODE | NA_EDITED, NULL);
 
+  prop = RNA_def_property(srna, "is_muted", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", NODE_LINK_MUTED);
+  RNA_def_struct_ui_text(srna, "Muted", "Link is muted and can be ignored");
+  RNA_def_property_update(prop, NC_NODE | NA_EDITED, NULL);
+
   prop = RNA_def_property(srna, "from_node", PROP_POINTER, PROP_NONE);
   RNA_def_property_pointer_sdna(prop, NULL, "fromnode");
   RNA_def_property_struct_type(prop, "Node");
diff --git a/source/blender/nodes/intern/node_exec.c b/source/blender/nodes/intern/node_exec.c
index 6207a1bf024..dd9d0b6796a 100644
--- a/source/blender/nodes/intern/node_exec.c
+++ b/source/blender/nodes/intern/node_exec.c
@@ -71,7 +71,8 @@ void node_get_stack(bNode *node, bNodeStack *stack, bNodeStack **in, bNodeStack
 static void node_init_input_index(bNodeSocket *sock, int *index)
 {
   /* Only consider existing link if from socket is valid! */
-  if (sock->link && sock->link->fromsock && sock->link->fromsock->stack_index >= 0) {
+  if (sock->link && !(sock->link->flag & NODE_LINK_MUTED) && sock->link->fromsock &&
+      sock->link->fromsock->stack_index >= 0) {
     sock->stack_index = sock->link->fromsock->stack_index;
   }
   else {
@@ -131,7 +132,7 @@ static struct bNodeStack *setup_stack(bNodeStack *stack,
   }
 
   /* don't mess with remote socket stacks, these are initialized by other nodes! */
-  if (sock->link) {
+  if (sock->link && !(sock->link->flag & NODE_LINK_MUTED)) {
     return ns;
   }
 
diff --git a/source/blender/nodes/intern/node_tree_ref.cc b/source/blender/nodes/intern/node_tree_ref.cc
index a66b7b1d2fe..8d979ffac9c 100644
--- a/source/blender/nodes/intern/node_tree_ref.cc
+++ b/source/blender/nodes/intern/node_tree_ref.cc
@@ -77,6 +77,9 @@ NodeTreeRef::NodeTreeRef(bNodeTree *btree) : btree_(btree)
   }
 
   LISTBASE_FOREACH (bNodeLink *, blink, &btree->links) {
+    if (blink->flag & NODE_LINK_MUTED) {
+      continue;
+    }
     OutputSocketRef &from_socket = this->find_output_socket(
         node_mapping, blink->fromnode, blink->fromsock);
     InputSocketRef &to_socket = this->find_input_socket(
diff --git a/source/blender/nodes/shader/node_shader_tree.c b/source/blender/nodes/shader/node_shader_tree.c
index a385cb7039f..3fb4d10979d 100644
--- a/source/blender/nodes/shader/node_shader_tree.c
+++ b/source/blender/nodes/shader/node_shader_tree.c
@@ -388,7 +388,7 @@ static void ntree_shader_groups_expand_inputs(bNodeTree *localtree)
 
     if (is_group || is_group_output) {
       LISTBASE_FOREACH (bNodeSocket *, socket, &node->inputs) {
-        if (socket->link != NULL) {
+        if (socket->link != NULL && !(socket->link->flag & NODE_LINK_MUTED)) {
           bNodeLink *link = socket->link;
           /* Fix the case where the socket is actually converting the data. (see T71374)
            * We only do the case of lossy conversion to float.*/
@@ -557,7 +557,7 @@ static bool ntree_shader_has_displacement(bNodeTree *ntree,
     /* Non-cycles node is used as an output. */
     return false;
   }
-  if (displacement->link != NULL) {
+  if ((displacement->link != NULL) && !(displacement->link->flag & NODE_LINK_MUTED)) {
     *r_node = displacement->link->fromnode;
     *r_socket = displacement->link->fromsock;
     *r_link = displacement->link;
diff --git a/source/blender/windowmanager/intern/wm_cursors.c b/source/blender/windowmanager/intern/wm_cursors.c
index d6e4a93f6a6..cdb7b591907 100644
--- a/source/blender/windowmanager/intern/wm_cursors.c
+++ b/source/blender/windowmanager/intern/wm_cursors.c
@@ -520,13 +520,37 @@ void wm_init_cursor_data(void)
   BlenderCursor[WM_CURSOR_WAIT] = &WaitCursor;
   END_CURSOR_BLOCK;
 
+  /********************** Mute Cursor ***********************/
+  BEGIN_CURSOR_BLOCK;
+  static char mute_bitmap[] = {
+      0x00, 0x00, 0x22, 0x00, 0x14, 0x00, 0x08, 0x03, 0x14, 0x03, 0x22,
+      0x03, 0x00, 0x03, 0x00, 0x03, 0xf8, 0x7c, 0xf8, 0x7c, 0x00, 0x03,
+      0x00, 0x03, 0x00, 0x03, 0x00, 0x03, 0x00, 0x03, 0x00, 0x00,
+  };
+
+  static char mute_mask[] = {
+      0x63, 0x00, 0x77, 0x00, 0x3e, 0x03, 0x1c, 0x03, 0x3e, 0x03, 0x77,
+      0x03, 0x63, 0x03, 0x80, 0x07, 0xfc, 0xfc, 0xfc, 0xfc, 0x80, 0x07,
+      0x00, 0x03, 0x00, 0x03, 0x00, 0x03, 0x00, 0x03, 0x00, 0x03,
+  };
+
+  static BCursor MuteCursor = {
+      mute_bitmap,
+      mute_mask,
+      9,
+      8,
+      true,
+  };
+
+  BlenderCursor[WM_CURSOR_MUTE] = &MuteCursor;
+  END_CURSOR_BLOCK;
+
   /****************** Normal Cross Cursor ************************/
   BEGIN_CURSOR_BLOCK;
   static char cross_bitmap[] = {
       0x00, 0x00, 0x80, 0x01, 0x80, 0x01, 0x80, 0x01, 0x80, 0x01, 0x80,
       0x01, 0x00, 0x00, 0x3e, 0x7c, 0x3e, 0x7c, 0x00, 0x00, 0x80, 0x01,
       0x80, 0x01, 0x80, 0x01, 0x80, 0x01, 0x80, 0x01, 0x00, 0x00,
-
   };
 
   static char cross_mask[] = {
diff --git a/source/blender/windowmanager/wm_cursors.h b/source/blender/windowmanager/wm_cursors.h
index b85616deda5..2842538ebf1 100644
--- a/source/blender/windowmanager/wm_cursors.h
+++ b/source/blender/windowmanager/wm_cursors.h
@@ -72,6 +72,7 @@ typedef enum WMCursorType {
   WM_CURSOR_ZOOM_OUT,
 
   WM_CURSOR_NONE,
+  WM_CURSOR_MUTE,
 
   /* --- ALWAYS LAST ----- */
   WM_CURSOR_NUM,