GuiNode: slot location computation, unprotect fields

src/gui/node_editor.h

@@ -11,15 +11,41 @@
 
 class GuiNode {
 public:
-    GuiNode(std::string name, Rect bbox)
-        : name(name), bbox(bbox)
+    GuiNode(std::string name, Rect bbox, uint n_slots_in, uint n_slots_out)
+        : name(name), bbox(bbox), n_slots_in(n_slots_in), n_slots_out(n_slots_out)
             {}
 
-protected:
-    friend class NodeEditor;
+    enum SlotDirection {
+        IN,
+        OUT,
+    };
+
+    ImVec2 slot_location(SlotDirection direction, uint i) const {
+        uint n_slots;
+        switch (direction) {
+        case IN:
+            n_slots = n_slots_in; break;
+        case OUT:
+            n_slots = n_slots_out; break;
+        }
 
-    std::string name;
+        auto x_stride = bbox.size.y/(n_slots+1);
+
+        ImVec2 base;
+        switch(direction) {
+        case IN:
+            base = bbox.pos; break;
+        case OUT:
+            base = bbox.pos + ImVec2(bbox.size.x, 0); break;
+        }
 
+        return base + ImVec2(0, (i + 1) *  x_stride);
+    }
+
+    uint n_slots_in;
+    uint n_slots_out;
+
+    std::string name;
     Rect bbox;
 };