Automatic depth increment when placing a source.

Mixer.cpp

@@ -201,6 +201,7 @@ void Mixer::insertSource(Source *s)
     geometry_.scene.fg()->attach(s->group(View::GEOMETRY));
     layer_.scene.fg()->attach(s->group(View::LAYER));
 
+    layer_.setDepth(s);
 }
 
 void Mixer::deleteCurrentSource()

Scene.cpp

@@ -272,6 +272,21 @@ NodeSet::iterator Group::end()
     return children_.end();
 }
 
+
+Node *Group::front()
+{
+    if (!children_.empty())
+        return *children_.rbegin();
+    return nullptr;
+}
+
+Node *Group::back()
+{
+    if (!children_.empty())
+        return *children_.begin();
+    return nullptr;
+}
+
 uint Group::numChildren() const
 {
     return children_.size();

Scene.h

@@ -171,6 +171,8 @@ public:
 
     NodeSet::iterator begin();
     NodeSet::iterator end();
+    Node *front();
+    Node *back();
     uint numChildren() const;
 
 protected:

View.cpp

@@ -400,10 +400,22 @@ void LayerView::setDepth (Source *s, float d)
     if (!s)
         return;
 
+    float depth = d;
+
+    // negative depth given; find the front most depth
+    if ( depth < 0.f ) {
+        Node *front = scene.fg()->front();
+        if (front)
+            depth = front->translation_.z + 0.5f;
+        else
+            depth = 0.5f;
+    }
+
+    // move the layer node of the source
     Group *sourceNode = s->group(mode_);
 
     // diagonal movement only
-    sourceNode->translation_.x = CLAMP( -d, SCENE_DEPTH + 2.f, 0.f);
+    sourceNode->translation_.x = CLAMP( -depth, SCENE_DEPTH + 2.f, 0.f);
     sourceNode->translation_.y = sourceNode->translation_.x / aspect_ratio;
 
     // change depth

View.h

@@ -89,7 +89,7 @@ public:
     void zoom (float factor) override;
     void grab (glm::vec2 from, glm::vec2 to, Source *s, std::pair<Node *, glm::vec2> pick) override;
 
-    void setDepth (Source *, float d);
+    void setDepth (Source *, float d = -1.f);
 
 private:
     float aspect_ratio;