UI: Draw real node sockets for node input buttons

For buttons representing node inputs (e.g. in the material properties)
rather than drawing some generic socket icon, the actual sockets are
drawn now. That includes color, shape and the selection outline.

This should make it easier to understand what these buttons relate to.

Screenshots: {F8469252}, {F8469248} (The left alignment will be done in
a follow-up commit.)

Differential Revision: https://developer.blender.org/D7409

Reviewed by: Brecht Van Lommel, Clément Foucault, William Reynish

4 files changed, 188 insertions, 83 deletions

diff --git a/source/blender/editors/space_node/node_buttons.c b/source/blender/editors/space_node/node_buttons.c
index 4cf67dddb57..8fc343a9ed4 100644
--- a/source/blender/editors/space_node/node_buttons.c
+++ b/source/blender/editors/space_node/node_buttons.c
@@ -84,7 +84,7 @@ static void node_sockets_panel(const bContext *C, Panel *panel)
 
     split = uiLayoutSplit(layout, 0.35f, false);
     uiItemL(split, name, ICON_NONE);
-    uiTemplateNodeLink(split, ntree, node, sock);
+    uiTemplateNodeLink(split, (bContext *)C, ntree, node, sock);
   }
 }
 
diff --git a/source/blender/editors/space_node/node_draw.c b/source/blender/editors/space_node/node_draw.c
index bdb7f787be6..bd8950c5085 100644
--- a/source/blender/editors/space_node/node_draw.c
+++ b/source/blender/editors/space_node/node_draw.c
@@ -707,39 +707,19 @@ static void node_draw_mute_line(View2D *v2d, SpaceNode *snode, bNode *node)
 #define MARKER_SHAPE_CIRCLE 0x2
 #define MARKER_SHAPE_INNER_DOT 0x10
 
-static void node_socket_draw(const bContext *C,
-                             bNodeTree *ntree,
-                             PointerRNA node_ptr,
-                             bNodeSocket *sock,
+static void node_socket_draw(const bNodeSocket *sock,
+                             const float color[4],
+                             const float color_outline[4],
+                             float size,
+                             int locx,
+                             int locy,
                              uint pos_id,
                              uint col_id,
                              uint shape_id,
                              uint size_id,
-                             uint outline_col_id,
-                             float size,
-                             bool selected)
+                             uint outline_col_id)
 {
-  PointerRNA ptr;
-  float color[4];
-  float outline_color[4];
-  uint flags = 0;
-
-  RNA_pointer_create((ID *)ntree, &RNA_NodeSocket, sock, &ptr);
-  sock->typeinfo->draw_color((bContext *)C, &ptr, &node_ptr, color);
-
-  bNode *node = node_ptr.data;
-  if (node->flag & NODE_MUTED) {
-    color[3] *= 0.25f;
-  }
-
-  if (selected) {
-    UI_GetThemeColor4fv(TH_TEXT_HI, outline_color);
-    outline_color[3] = 0.9f;
-  }
-  else {
-    copy_v4_fl(outline_color, 0.0f);
-    outline_color[3] = 0.6f;
-  }
+  int flags;
 
   /* sets shape flags */
   switch (sock->display_shape) {
@@ -768,8 +748,120 @@ static void node_socket_draw(const bContext *C,
   immAttr4fv(col_id, color);
   immAttr1u(shape_id, flags);
   immAttr1f(size_id, size);
-  immAttr4fv(outline_col_id, outline_color);
-  immVertex2f(pos_id, sock->locx, sock->locy);
+  immAttr4fv(outline_col_id, color_outline);
+  immVertex2f(pos_id, locx, locy);
+}
+
+static void node_socket_outline_color_get(bool selected, float r_outline_color[4])
+{
+  if (selected) {
+    UI_GetThemeColor4fv(TH_TEXT_HI, r_outline_color);
+    r_outline_color[3] = 0.9f;
+  }
+  else {
+    copy_v4_fl(r_outline_color, 0.0f);
+    r_outline_color[3] = 0.6f;
+  }
+}
+
+/* Usual convention here would be node_socket_get_color(), but that's already used (for setting a
+ * color property socket). */
+void node_socket_color_get(
+    bContext *C, bNodeTree *ntree, PointerRNA *node_ptr, bNodeSocket *sock, float r_color[4])
+{
+  PointerRNA ptr;
+
+  BLI_assert(RNA_struct_is_a(node_ptr->type, &RNA_Node));
+  RNA_pointer_create((ID *)ntree, &RNA_NodeSocket, sock, &ptr);
+
+  sock->typeinfo->draw_color(C, &ptr, node_ptr, r_color);
+
+  bNode *node = node_ptr->data;
+  if (node->flag & NODE_MUTED) {
+    r_color[3] *= 0.25f;
+  }
+}
+
+static void node_socket_draw_nested(const bContext *C,
+                                    bNodeTree *ntree,
+                                    PointerRNA *node_ptr,
+                                    bNodeSocket *sock,
+                                    uint pos_id,
+                                    uint col_id,
+                                    uint shape_id,
+                                    uint size_id,
+                                    uint outline_col_id,
+                                    float size,
+                                    bool selected)
+{
+  float color[4];
+  float outline_color[4];
+
+  node_socket_color_get((bContext *)C, ntree, node_ptr, sock, color);
+  node_socket_outline_color_get(selected, outline_color);
+
+  node_socket_draw(sock,
+                   color,
+                   outline_color,
+                   size,
+                   sock->locx,
+                   sock->locy,
+                   pos_id,
+                   col_id,
+                   shape_id,
+                   size_id,
+                   outline_col_id);
+}
+
+/**
+ * Draw a single node socket at default size.
+ * \note this is only called from external code, internally #node_socket_draw_nested() is used for
+ *       optimized drawing of multiple/all sockets of a node.
+ */
+void ED_node_socket_draw(bNodeSocket *sock, const rcti *rect, const float color[4], float scale)
+{
+  const float size = 2.25f * NODE_SOCKSIZE * scale;
+  rcti draw_rect = *rect;
+  float outline_color[4] = {0};
+
+  node_socket_outline_color_get(sock->flag & SELECT, outline_color);
+
+  BLI_rcti_resize(&draw_rect, size, size);
+
+  GPUVertFormat *format = immVertexFormat();
+  uint pos_id = GPU_vertformat_attr_add(format, "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
+  uint col_id = GPU_vertformat_attr_add(format, "color", GPU_COMP_F32, 4, GPU_FETCH_FLOAT);
+  uint shape_id = GPU_vertformat_attr_add(format, "flags", GPU_COMP_U32, 1, GPU_FETCH_INT);
+  uint size_id = GPU_vertformat_attr_add(format, "size", GPU_COMP_F32, 1, GPU_FETCH_FLOAT);
+  uint outline_col_id = GPU_vertformat_attr_add(
+      format, "outlineColor", GPU_COMP_F32, 4, GPU_FETCH_FLOAT);
+
+  gpuPushAttr(GPU_BLEND_BIT);
+  GPU_blend(true);
+  GPU_program_point_size(true);
+
+  immBindBuiltinProgram(GPU_SHADER_KEYFRAME_DIAMOND);
+  immUniform1f("outline_scale", 0.7f);
+  immUniform2f("ViewportSize", -1.0f, -1.0f);
+
+  /* Single point */
+  immBegin(GPU_PRIM_POINTS, 1);
+  node_socket_draw(sock,
+                   color,
+                   outline_color,
+                   BLI_rcti_size_y(&draw_rect),
+                   BLI_rcti_cent_x(&draw_rect),
+                   BLI_rcti_cent_y(&draw_rect),
+                   pos_id,
+                   col_id,
+                   shape_id,
+                   size_id,
+                   outline_col_id);
+  immEnd();
+
+  immUnbindProgram();
+  GPU_program_point_size(false);
+  gpuPopAttr();
 }
 
 /* **************  Socket callbacks *********** */
@@ -962,17 +1054,17 @@ void node_draw_sockets(View2D *v2d,
       continue;
     }
 
-    node_socket_draw(C,
-                     ntree,
-                     node_ptr,
-                     sock,
-                     pos_id,
-                     col_id,
-                     shape_id,
-                     size_id,
-                     outline_col_id,
-                     scale,
-                     selected);
+    node_socket_draw_nested(C,
+                            ntree,
+                            &node_ptr,
+                            sock,
+                            pos_id,
+                            col_id,
+                            shape_id,
+                            size_id,
+                            outline_col_id,
+                            scale,
+                            selected);
   }
 
   /* socket outputs */
@@ -987,17 +1079,17 @@ void node_draw_sockets(View2D *v2d,
         continue;
       }
 
-      node_socket_draw(C,
-                       ntree,
-                       node_ptr,
-                       sock,
-                       pos_id,
-                       col_id,
-                       shape_id,
-                       size_id,
-                       outline_col_id,
-                       scale,
-                       selected);
+      node_socket_draw_nested(C,
+                              ntree,
+                              &node_ptr,
+                              sock,
+                              pos_id,
+                              col_id,
+                              shape_id,
+                              size_id,
+                              outline_col_id,
+                              scale,
+                              selected);
     }
   }
 
@@ -1020,17 +1112,17 @@ void node_draw_sockets(View2D *v2d,
           continue;
         }
         if (select_all || (sock->flag & SELECT)) {
-          node_socket_draw(C,
-                           ntree,
-                           node_ptr,
-                           sock,
-                           pos_id,
-                           col_id,
-                           shape_id,
-                           size_id,
-                           outline_col_id,
-                           scale,
-                           selected);
+          node_socket_draw_nested(C,
+                                  ntree,
+                                  &node_ptr,
+                                  sock,
+                                  pos_id,
+                                  col_id,
+                                  shape_id,
+                                  size_id,
+                                  outline_col_id,
+                                  scale,
+                                  selected);
           if (--selected_input_len == 0) {
             break; /* stop as soon as last one is drawn */
           }
@@ -1045,17 +1137,17 @@ void node_draw_sockets(View2D *v2d,
           continue;
         }
         if (select_all || (sock->flag & SELECT)) {
-          node_socket_draw(C,
-                           ntree,
-                           node_ptr,
-                           sock,
-                           pos_id,
-                           col_id,
-                           shape_id,
-                           size_id,
-                           outline_col_id,
-                           scale,
-                           selected);
+          node_socket_draw_nested(C,
+                                  ntree,
+                                  &node_ptr,
+                                  sock,
+                                  pos_id,
+                                  col_id,
+                                  shape_id,
+                                  size_id,
+                                  outline_col_id,
+                                  scale,
+                                  selected);
           if (--selected_output_len == 0) {
             break; /* stop as soon as last one is drawn */
           }
diff --git a/source/blender/editors/space_node/node_intern.h b/source/blender/editors/space_node/node_intern.h
index 42439e88c96..04186c3a727 100644
--- a/source/blender/editors/space_node/node_intern.h
+++ b/source/blender/editors/space_node/node_intern.h
@@ -38,6 +38,7 @@ struct bContext;
 struct bNode;
 struct bNodeLink;
 struct bNodeSocket;
+struct wmGizmoGroupType;
 struct wmKeyConfig;
 struct wmWindow;
 
@@ -77,6 +78,11 @@ void node_draw_sockets(struct View2D *v2d,
 void node_update_default(const struct bContext *C, struct bNodeTree *ntree, struct bNode *node);
 int node_select_area_default(struct bNode *node, int x, int y);
 int node_tweak_area_default(struct bNode *node, int x, int y);
+void node_socket_color_get(struct bContext *C,
+                           struct bNodeTree *ntree,
+                           struct PointerRNA *node_ptr,
+                           struct bNodeSocket *sock,
+                           float r_color[4]);
 void node_update_nodetree(const struct bContext *C, struct bNodeTree *ntree);
 void node_draw_nodetree(const struct bContext *C,
                         struct ARegion *region,
@@ -122,7 +128,7 @@ void NODE_OT_find_node(struct wmOperatorType *ot);
 
 /* node_view.c */
 int space_node_view_flag(struct bContext *C,
-                         SpaceNode *snode,
+                         struct SpaceNode *snode,
                          ARegion *region,
                          const int node_flag,
                          const int smooth_viewtx);
@@ -196,7 +202,7 @@ void NODE_OT_detach(struct wmOperatorType *ot);
 
 void NODE_OT_link_viewer(struct wmOperatorType *ot);
 
-void NODE_OT_insert_offset(wmOperatorType *ot);
+void NODE_OT_insert_offset(struct wmOperatorType *ot);
 
 /* node_edit.c */
 void snode_notify(struct bContext *C, struct SpaceNode *snode);
@@ -207,8 +213,8 @@ void snode_update(struct SpaceNode *snode, struct bNode *node);
 bool composite_node_active(struct bContext *C);
 bool composite_node_editable(struct bContext *C);
 
-int node_has_hidden_sockets(bNode *node);
-void node_set_hidden_sockets(SpaceNode *snode, bNode *node, int set);
+int node_has_hidden_sockets(struct bNode *node);
+void node_set_hidden_sockets(struct SpaceNode *snode, bNode *node, int set);
 int node_render_changed_exec(bContext *, struct wmOperator *);
 int node_find_indicated_socket(struct SpaceNode *snode,
                                struct bNode **nodep,
diff --git a/source/blender/editors/space_node/node_templates.c b/source/blender/editors/space_node/node_templates.c
index 7d4095326f8..da0058585cb 100644
--- a/source/blender/editors/space_node/node_templates.c
+++ b/source/blender/editors/space_node/node_templates.c
@@ -45,6 +45,7 @@
 #include "UI_interface.h"
 
 #include "ED_node.h" /* own include */
+#include "node_intern.h"
 
 #include "ED_undo.h"
 
@@ -662,17 +663,23 @@ static void ui_template_node_link_menu(bContext *C, uiLayout *layout, void *but_
   ui_node_menu_column(arg, NODE_CLASS_GROUP, N_("Group"));
 }
 
-void uiTemplateNodeLink(uiLayout *layout, bNodeTree *ntree, bNode *node, bNodeSocket *sock)
+void uiTemplateNodeLink(
+    uiLayout *layout, bContext *C, bNodeTree *ntree, bNode *node, bNodeSocket *sock)
 {
   uiBlock *block = uiLayoutGetBlock(layout);
   NodeLinkArg *arg;
   uiBut *but;
+  float socket_col[4];
 
   arg = MEM_callocN(sizeof(NodeLinkArg), "NodeLinkArg");
   arg->ntree = ntree;
   arg->node = node;
   arg->sock = sock;
 
+  PointerRNA node_ptr;
+  RNA_pointer_create((ID *)ntree, &RNA_Node, node, &node_ptr);
+  node_socket_color_get(C, ntree, &node_ptr, sock, socket_col);
+
   UI_block_layout_set_current(block, layout);
 
   if (sock->link || sock->type == SOCK_SHADER || (sock->flag & SOCK_HIDE_VALUE)) {
@@ -687,8 +694,8 @@ void uiTemplateNodeLink(uiLayout *layout, bNodeTree *ntree, bNode *node, bNodeSo
   }
 
   UI_but_type_set_menu_from_pulldown(but);
+  UI_but_node_link_set(but, sock, socket_col);
 
-  but->flag |= UI_BUT_NODE_LINK;
   but->poin = (char *)but;
   but->func_argN = arg;
 
@@ -798,7 +805,7 @@ static void ui_node_draw_input(
   }
   else if (lnode) {
     /* input linked to a node */
-    uiTemplateNodeLink(split, ntree, node, input);
+    uiTemplateNodeLink(split, C, ntree, node, input);
 
     if (depth == 0 || !(input->flag & SOCK_COLLAPSED)) {
       if (depth == 0) {
@@ -835,7 +842,7 @@ static void ui_node_draw_input(
       row = uiLayoutRow(split, false);
     }
 
-    uiTemplateNodeLink(row, ntree, node, input);
+    uiTemplateNodeLink(row, C, ntree, node, input);
   }
 
   /* clear */