Geometry Nodes: dim links whose start and end sockets are not visible

This makes node trees with long links that cross other nodes easier to work with.
Dimmed links will be ignored by various modal operators like cut and reroute insertion.

Differential Revision: https://developer.blender.org/D11813

source/blender/editors/space_node/drawnode.cc

@@ -3911,8 +3911,10 @@ static struct {
   GPUVertBuf *inst_vbo;
   uint p0_id, p1_id, p2_id, p3_id;
   uint colid_id, muted_id;
+  uint dim_factor_id;
   GPUVertBufRaw p0_step, p1_step, p2_step, p3_step;
   GPUVertBufRaw colid_step, muted_step;
+  GPUVertBufRaw dim_factor_step;
   uint count;
   bool enabled;
 } g_batch_link;
@@ -3927,6 +3929,8 @@ static void nodelink_batch_reset()
       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);
+  GPU_vertbuf_attr_get_raw_data(
+      g_batch_link.inst_vbo, g_batch_link.dim_factor_id, &g_batch_link.dim_factor_step);
   g_batch_link.count = 0;
 }
 
@@ -4044,6 +4048,8 @@ static void nodelink_batch_init()
       &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.dim_factor_id = GPU_vertformat_attr_add(
+      &format_inst, "dim_factor", GPU_COMP_F32, 1, GPU_FETCH_FLOAT);
   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);
@@ -4119,7 +4125,8 @@ static void nodelink_batch_add_link(const SpaceNode *snode,
                                     int th_col2,
                                     int th_col3,
                                     bool drawarrow,
-                                    bool drawmuted)
+                                    bool drawmuted,
+                                    float dim_factor)
 {
   /* 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));
@@ -4138,6 +4145,7 @@ static void nodelink_batch_add_link(const SpaceNode *snode,
   colid[3] = drawarrow;
   char *muted = (char *)GPU_vertbuf_raw_step(&g_batch_link.muted_step);
   muted[0] = drawmuted;
+  *(float *)GPU_vertbuf_raw_step(&g_batch_link.dim_factor_step) = dim_factor;
 
   if (g_batch_link.count == NODELINK_GROUP_SIZE) {
     nodelink_batch_draw(snode);
@@ -4152,6 +4160,8 @@ void node_draw_link_bezier(const View2D *v2d,
                            int th_col2,
                            int th_col3)
 {
+  const float dim_factor = node_link_dim_factor(v2d, link);
+
   float vec[4][2];
   const bool highlighted = link->flag & NODE_LINK_TEMP_HIGHLIGHT;
   if (node_link_bezier_handles(v2d, snode, link, vec)) {
@@ -4164,8 +4174,17 @@ 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, drawmuted);
+      nodelink_batch_add_link(snode,
+                              vec[0],
+                              vec[1],
+                              vec[2],
+                              vec[3],
+                              th_col1,
+                              th_col2,
+                              th_col3,
+                              drawarrow,
+                              drawmuted,
+                              dim_factor);
     }
     else {
       /* Draw single link. */
@@ -4190,6 +4209,7 @@ void node_draw_link_bezier(const View2D *v2d,
       GPU_batch_uniform_1f(batch, "arrowSize", ARROW_SIZE);
       GPU_batch_uniform_1i(batch, "doArrow", drawarrow);
       GPU_batch_uniform_1i(batch, "doMuted", drawmuted);
+      GPU_batch_uniform_1f(batch, "dim_factor", dim_factor);
       GPU_batch_draw(batch);
     }
   }

source/blender/editors/space_node/node_add.cc

@@ -260,7 +260,7 @@ static int add_reroute_exec(bContext *C, wmOperator *op)
     BLI_listbase_clear(&input_links);
 
     for (link = (bNodeLink *)ntree->links.first; link; link = link->next) {
-      if (nodeLinkIsHidden(link)) {
+      if (node_link_is_hidden_or_dimmed(&region->v2d, link)) {
         continue;
       }
       if (add_reroute_intersect_check(link, mcoords, i, insert_point)) {

source/blender/editors/space_node/node_edit.cc

@@ -21,6 +21,8 @@
  * \ingroup spnode
  */
 
+#include <algorithm>
+
 #include "MEM_guardedalloc.h"
 
 #include "DNA_light_types.h"
@@ -1226,6 +1228,28 @@ int node_find_indicated_socket(
   return 0;
 }
 
+/* ****************** Link Dimming *********************** */
+
+float node_link_dim_factor(const View2D *v2d, const bNodeLink *link)
+{
+  const float min_endpoint_distance = std::min(
+      std::max(BLI_rctf_length_x(&v2d->cur, link->fromsock->locx),
+               BLI_rctf_length_y(&v2d->cur, link->fromsock->locy)),
+      std::max(BLI_rctf_length_x(&v2d->cur, link->tosock->locx),
+               BLI_rctf_length_y(&v2d->cur, link->tosock->locy)));
+
+  if (min_endpoint_distance == 0.0f) {
+    return 1.0f;
+  }
+  const float viewport_width = BLI_rctf_size_x(&v2d->cur);
+  return std::clamp(1.0f - min_endpoint_distance / viewport_width * 10.0f, 0.05f, 1.0f);
+}
+
+bool node_link_is_hidden_or_dimmed(const View2D *v2d, const bNodeLink *link)
+{
+  return nodeLinkIsHidden(link) || node_link_dim_factor(v2d, link) < 0.5f;
+}
+
 /* ****************** Duplicate *********************** */
 
 static void node_duplicate_reparent_recursive(bNode *node)

source/blender/editors/space_node/node_intern.h

@@ -265,6 +265,8 @@ int node_find_indicated_socket(struct SpaceNode *snode,
                                struct bNodeSocket **sockp,
                                const float cursor[2],
                                int in_out);
+float node_link_dim_factor(const struct View2D *v2d, const struct bNodeLink *link);
+bool node_link_is_hidden_or_dimmed(const struct View2D *v2d, const struct bNodeLink *link);
 
 void NODE_OT_duplicate(struct wmOperatorType *ot);
 void NODE_OT_delete(struct wmOperatorType *ot);

source/blender/editors/space_node/node_relationships.cc

@@ -36,6 +36,7 @@
 #include "BKE_lib_id.h"
 #include "BKE_main.h"
 #include "BKE_node.h"
+#include "BKE_screen.h"
 
 #include "ED_node.h" /* own include */
 #include "ED_render.h"
@@ -1332,7 +1333,7 @@ static int cut_links_exec(bContext *C, wmOperator *op)
     ED_preview_kill_jobs(CTX_wm_manager(C), bmain);
 
     LISTBASE_FOREACH_MUTABLE (bNodeLink *, link, &snode->edittree->links) {
-      if (nodeLinkIsHidden(link)) {
+      if (node_link_is_hidden_or_dimmed(&region->v2d, link)) {
         continue;
       }
 
@@ -1429,7 +1430,7 @@ static int mute_links_exec(bContext *C, wmOperator *op)
     /* Count intersected links and clear test flag. */
     int tot = 0;
     LISTBASE_FOREACH (bNodeLink *, link, &snode->edittree->links) {
-      if (nodeLinkIsHidden(link)) {
+      if (node_link_is_hidden_or_dimmed(&region->v2d, link)) {
         continue;
       }
       link->flag &= ~NODE_LINK_TEST;
@@ -1443,7 +1444,7 @@ static int mute_links_exec(bContext *C, wmOperator *op)
 
     /* Mute links. */
     LISTBASE_FOREACH (bNodeLink *, link, &snode->edittree->links) {
-      if (nodeLinkIsHidden(link) || (link->flag & NODE_LINK_TEST)) {
+      if (node_link_is_hidden_or_dimmed(&region->v2d, link) || (link->flag & NODE_LINK_TEST)) {
         continue;
       }
 
@@ -1458,7 +1459,7 @@ static int mute_links_exec(bContext *C, wmOperator *op)
 
     /* Clear remaining test flags. */
     LISTBASE_FOREACH (bNodeLink *, link, &snode->edittree->links) {
-      if (nodeLinkIsHidden(link)) {
+      if (node_link_is_hidden_or_dimmed(&region->v2d, link)) {
         continue;
       }
       link->flag &= ~NODE_LINK_TEST;
@@ -1894,9 +1895,11 @@ static bool ed_node_link_conditions(ScrArea *area,
     return false;
   }
 
+  ARegion *region = BKE_area_find_region_type(area, RGN_TYPE_WINDOW);
+
   /* test node for links */
   LISTBASE_FOREACH (bNodeLink *, link, &snode->edittree->links) {
-    if (nodeLinkIsHidden(link)) {
+    if (node_link_is_hidden_or_dimmed(&region->v2d, link)) {
       continue;
     }
 
@@ -1927,13 +1930,15 @@ void ED_node_link_intersect_test(ScrArea *area, int test)
     return;
   }
 
+  ARegion *region = BKE_area_find_region_type(area, RGN_TYPE_WINDOW);
+
   /* find link to select/highlight */
   bNodeLink *selink = nullptr;
   float dist_best = FLT_MAX;
   LISTBASE_FOREACH (bNodeLink *, link, &snode->edittree->links) {
     float coord_array[NODE_LINK_RESOL + 1][2];
 
-    if (nodeLinkIsHidden(link)) {
+    if (node_link_is_hidden_or_dimmed(&region->v2d, link)) {
       continue;
     }
 

source/blender/gpu/shaders/gpu_shader_2D_nodelink_vert.glsl

@@ -18,6 +18,7 @@ in vec2 P2;
 in vec2 P3;
 in ivec4 colid_doarrow;
 in ivec2 domuted;
+in float dim_factor;
 
 uniform vec4 colors[6];
 
@@ -39,6 +40,7 @@ uniform vec2 bezierPts[4];
 uniform vec4 colors[3];
 uniform bool doArrow;
 uniform bool doMuted;
+uniform float dim_factor;
 
 #  define colShadow colors[0]
 #  define colStart colors[1]
@@ -98,6 +100,8 @@ void main(void)
     }
   }
 
+  finalColor[3] *= dim_factor;
+
   /* Expand into a line */
   gl_Position.xy += exp_axis * expandSize * expand_dist;