Implement node positions for animations.

src/LayerVisualisation.hpp

@@ -1,12 +1,20 @@
 #pragma once
 
+#include <vector>
+
 namespace fmri
 {
     class LayerVisualisation
     {
     public:
+        LayerVisualisation() = default;
+        LayerVisualisation(size_t numNodes);
         virtual ~LayerVisualisation() = default;
 
         virtual void render() = 0;
+        virtual const std::vector<float>& nodePositions() const;
+
+    protected:
+        std::vector<float> nodePositions_;
     };
 }